The role of multiaxial loading on the failure of Kevlar® KM2 ballistic fibers during transverse loading is not well understood. Quasi-static experiments reported by Hudspeth M, Li D, Spatola J, et al. (2015) on single KM2 fiber subjected to transverse loading by three indenter geometries over a wide range of loading angles exhibit significant reductions in the average axial tensile failure strain. In this study, a three-dimensional finite element model is developed to predict the degree of multiaxial loading present at the location of fiber failure in these experiments. The model predicts an axial tensile strain concentration within the indenter–fiber contact zone. The fiber is also subjected to multiaxial stress/strain states within the contact zone consisting of axial tension, axial compression, transverse compression and interlaminar shear that can degrade axial tensile failure strain. For a round indenter with a radius much higher than the fiber diameter, the axial tensile strain concentration and multiaxial strain in the fiber are negligible. In the case of a fragment-simulating projectile and a razor indenter, significant axial tensile strain concentrations (2.2–5.9) are predicted and the localized transverse loading results in extensive inelastic deformation within the fiber cross-section. Based on the results, a maximum axial tensile strain failure criterion incorporating the multiaxial loading degradation effects is developed. The failure criterion correlates well with the experimental measurements reported by Hudspeth et al. for all three indenters. Modeling the experiments provides new insights into the tensile failure strain of high-performance ballistic fibers at extremely small gage lengths subject to transverse impact loading.
Polystyrene matrixes containing cellulose nanofibril (CNF) with fiber content of 0.5, 1, 5, and 10 wt% were successfully hydrophobized by silylation and extruded into single filaments using both single and dual heat extrusion processing. The fiber–matrix bonding was examined using a scanning electron microscope. With further characterization, Fourier transform infrared spectroscopy showed a formation of Si-O-C bonds, indicating better fiber–matrix adhesion. Raman spectroscopy showed disruption of hydrogen bonding, which indicates interference of parallel nanocellulose fiber adhesion to neighboring fibrils. Thermogravimetric analysis suggests that the thermal stability of the functionalized CNF is higher than that of the corresponding neat sample, which is resultant of stable Si bond formation. Results from dynamic mechanical analysis showed an increasing ultimate tensile strength (UTS) and elastic modulus, with peak values attributed to the dual heat processing with up 112 MPa and 10.8 GPa for the UTS and modulus, respectively. The increase is assumed to be as a result of the linear arrangement of the CNF in the Polystyrene (PS) matrix during the extrusion process. Micromechanics modeling calculations suggest the increase is moving towards the fiber properties. The results revealed the strong reinforcing ability of CNFs and their compatibility with the thermoplastic matrix if functionalized.
Fabric hand is an indispensable characteristic for the selection of fabric and product development and the buying consideration for manufacturers and consumers. However, there is little comprehensive work on the hand feel property of warp-knitted fabrics due to the mainstream natural fibers (cotton, wool and silk) and other fabric structures (woven, weft-knitted and nonwoven). The increasing potential for the wide variety of applications and development of warp-knitted fabrics is not only because its fabric hand gives better determination for fabric marketing, but also because it provides extensive scope for fabric performance and appearance. This paper reports an experimental study on the integrated fabric hand behavior of a series of warp-knitted fabrics made for various apparel applications, such as sportswear, lingerie and leisure wear. These 105 fabrics were produced by varying different physical parameters, including fabric weight and fabric thickness. The Kawabata Evaluation System for Fabric (KES-F) was employed to obtain the fabric hand properties (primary hand value and total hand value) related with stiffness, smoothness and softness. All low-stress mechanical properties and fabric hand values from the testing results were used to verify the applicability of the KES-F on warp-knitted fabrics and to analyze the relationships of fabric parameters and hand characteristics. The results indicate that the KES-F is an appropriate tool to measure the hand attributes of warp-knitted samples, and moderate correlations between physical properties and mechanical behavior were found.
Sixty-six commonly used suitings were selected as the experimental samples of the current study. The Kawabata Evaluation System was used to measure the mechanical properties of the samples. Each sample fabric was made into a shoulder-back as a part of a men’s suit. In order to study the appropriateness of the samples for making good shaped men’s suits, which is known as fabric formability, sensory evaluation methods have been applied to obtain panelists’ assessments on the shape of the shoulder-backs. During data analysis, principal component analysis was initially adopted to reduce the complexity of the system by extracting a small number of important mechanical properties. Then, a fuzzy neural network was developed to model the underlying relations between the samples’ formability and their mechanical properties. Finally, a number of testing samples were used to verify the effectiveness of the proposed predictive model.
The effects of atmospheric pressure plasma treatment and the tightness factor on the low-stress mechanical properties of weft-knitted wool fabrics were evaluated using the Kawabata Evaluation System for Fabric (KES-F). The statistical analysis showed that the plasma treatment and the tightness factor had significant effects on the fabric low-stress mechanical properties (p-value < 0.05). Plasma-treated fabrics showed significantly higher bending and shear rigidity and hysteresis, compression energy, thickness, compressibility, surface friction and lower compression resilience and geometrical roughness values compared with untreated fabrics. An increase in the fabric tightness factor significantly increased fabric thickness, bending and shear rigidity and hysteresis, and decreased tensile extensibility and geometrical roughness. The relationship between primary handle attributes evaluated by Wool HandleMeter and KES-F mechanical properties was also investigated. The results confirmed a highly linear correlation between these two sets of data, where rough/smooth and hard/soft attributes evaluated by the Wool HandleMeter had the highest correlation with bending rigidity, shear properties and bending hysteresis, as measured by the KES-F.
The effects of reinforcement architecture on the compressive behaviors of carbon fiber polymer matrix composites (CF-PMCs) under thermo-oxidative aging conditions were investigated. Samples of three-dimensional and four-directional braided carbon fiber/epoxy composites (BC) and laminated plain woven carbon fiber/epoxy composites (LC) were subjected to isothermal aging at 80℃, 100℃, 120℃ and 140℃ in air circulating ovens for various durations up to 1200 h. The process resulted in progressive deterioration of the matrix reins and fiber/matrix interfaces, in the form of chain scissions, weight loss and fiber/matrix debonding, which significantly led to the decrease of the compressive strength. In addition, the compressive strength retention rates of BC were higher than those of LC at the same aging conditions due to the differences of their reinforcement architecture. On the one hand, LC lost more weight than BC because the percentage of exposure of fiber ends to air in the LC samples was five times more than that in the BC samples. Moreover, the BC samples could resist the compressive load as an integral structure and did not show delamination damage as in the case of LC samples, although the resin was damaged and the adhesive force between fiber bundles and resin decreased after thermo-oxidative aging. Therefore, adopting the three-dimensional and four-directional braided preform as the reinforcement of CF-PMCs is an effective way to improve their compressive strength under thermo-oxidative aging conditions.
Eight functional single jersey plain knitted fabrics have been developed in order to assess a quantitative analysis of various comfort-related properties in terms of thermal control, air and water vapor permeability, wickability, coefficient of kinetic friction and antimicrobial efficiency, using eight different commercially available functional yarns: Polyester Craque® and viscose Craque® conventional yarns as controls; Finecool® and Coolmax® polyester yarns for moisture management and quick drying; Holofiber® polyester yarns containing an optical responsive material that the producer claims to improve body oxygenation; Airclo® polyester hollow yarns for efficient control of body temperature; and, finally, polyester Trevira® and viscose Seacell® for antimicrobial activity. According to the results, Coolmax® for moisture management, Airclo® for thermal control and Seacell® for antimicrobial activity present the best performances as technical textiles for sportswear for the respective specific functional property.
The damage evolution of C/SiC ceramic-matrix composites with different fiber preforms, that is, unidirectional, cross-ply and 2.5D woven, under cyclic fatigue loading at room and elevated temperatures in air and inert atmosphere has been investigated. The experimental fatigue hysteresis modulus and hysteresis loop area versus cycle numbers have been analyzed. The relationships between the fatigue hysteresis loop area, interface slip and interface shear stress have been established. The evolution of the fatigue hysteresis loop area and interface shear stress as a function of applied cycles has been analyzed for different peak stresses, fiber preforms and test conditions. For different fiber preforms and test conditions, the fatigue hysteresis loop area degrades the fastest for unidirectional C/SiC at 800℃ in air, and the slowest for 2.5D C/SiC at 600℃ in an inert atmosphere, due to the different degradation rates of interface shear stress.
Clothing acts as an important barrier for heat and vapor transfer between the human body and the environment. Parameters that could describe that transfer include, inter alia, thermal insulation (the so-called dry heat exchange) and evaporative resistance (the so-called wet heat exchange). Once the above-mentioned parameters are determined, it is possible to consciously adapt clothing ensembles to the existing thermal environment in the workplace.
In order to validate the mentioned method of thermal insulation and evaporative resistance measurements, proficiency tests (PTs) were organized. The main goal of the PT was to compare thermal insulation and evaporative resistance for one set of clothing using the Newton-type thermal manikin. In total, four laboratories participated in the PT study. The reference value of the thermal insulation (It) and evaporative resistance (Ret) were calculated as the mean of all the results. The assessment criteria included permissible errors for thermal insulation and evaporative resistance measurements, which were 4% and 10%, respectively. Calculations included, inter alia, z-scores and indicators, such as the inter-laboratory coefficient of variation or the reproducibility limit. The results contribute to the worldwide discussion on standardized studies of evaporative resistance of clothing.
This paper presents an experimental investigation on the sound absorption behavior and thermal properties of Struto nonwovens by establishing relationship between these properties. Seven Struto nonwoven fabrics were selected to examine the noise reduction coefficient (NRC) and average values of sound absorption coefficients (
The heat resistance of fabric enhanced by bio-ceramic additives (BCAs) is investigated theoretically and experimentally in order to determine the influence of modification of the infrared (IR) absorption property of the fabric. The enhanced IR sensitivity of textiles improves the thermoregulatory processes when worn in cold environments. The finite element model has been developed by taking into account the coupled phenomena of heat conduction, surface convection and the interaction of the fabric with IR power flux by employing heat transfer differential equations and the Stefan–Boltzmann law. Evaluations of IR absorptivity, reflectivity and transmissivity, the temperature transients during the hot plate chamber test and heat retaining properties of the fabric heated by an IR lamp have been obtained experimentally and simulated by means of the developed finite element model. The values of model parameters have been found, which provided a satisfactory match between the computation and the experiment in all considered cases. Simultaneously, the obtained values were reasonably close to rough theoretical estimations. Efforts have been made to distinguish from each other the influence of diffusive and radiative components of heat transfer, which affect the results of thermal resistance tests. The comparative analysis of contributions of different heat exchange mechanisms allows a better understanding of the peculiarities of standard heat resistance measurement procedures applied to BCA-enhanced fabrics and facilitates the validation of the computational models.
The main content dealt with in this paper was to present an objective method to evaluate the plantar press-comfort performance of warp-knitted spacer fabrics. It aimed to explain the plantar press-comfort performance of spacer fabric by the compression property and structure parameters of spacer fabric. The compression indexes (compression work, recovery work, hysteresis work and maximum compression force) and structure parameters (diameter and thickness) were utilized to classify the plantar press-comfort performance of warp-knitted spacer fabrics by regression analysis and the K-means cluster method. In order to verify the validity, subjective judgments were also made and compared with the objective K-means cluster method. The experimental results showed that a good correlation existed between the subjective judgment method and objective cluster method. This demonstrates that the compression indexes featured, from spherical compression force–displacement curves and structure parameters, can be utilized to characterize the plantar press-comfort performance of warp-knitted spacer fabrics and is effective in obtaining the fabric evaluation score of plantar press-comfort performance.
The paper explores the relationship between subjective assessment of wearing comfort and objectively determined physiological parameters (mean skin temperature, skin relative humidity, amount excreted in sweat absorbed in clothing) in a warm environment. The experiment involved five young girls who wore two different models of women’s summer clothing (women’s dresses and women’s blouse plus shorts) made from five different raw materials, but of nearly identical structural characteristics. The investigation consisted of 450 individual tests. All wearing trial tests were performed under artificially designed ambient conditions within a computer-controlled climatic chamber. It was found that there existed a relationship between subjective assessment of wearing comfort and objectively determined physiological parameters of the test subjects. The statistical analysis results showed that coefficients of multiple linear regression in dependence of the subjective assessment of the degree of skin moisture Wskin on climatic conditions had the value of R2 = 0.87, based on physiological parameters, such as skin temperature Tskin and skin relative humidity RHskin (R2 = 0.90), and on the amount of excreted sweat Esweat and the amount of sweat absorbed within clothing Wsweat (R2 = 0.87).
Sectional warping is the most widely used warp preparation method in weaving, as it enables warping from all kind of yarns with color or type repeat. The quality of warping is directly dependent on the precision of motion control of machine mechanisms. This paper presents a mathematical analysis of motions of a sectional warping machine. Experimental work is also carried out on industrial sectional warping machines. It is shown that the results of mathematical equations derived for motions of a sectional warping machine match well with experimental results and they can be used for computer control of a sectional warping machine.
The impact force loss behavior of flocked energy absorbing materials (FEAM) was experimentally studied in the context of double-side flocked FEAM element layered structures. A ball drop test determined the force loss per cent (FL%) properties of various assembled panels. This study showed that: (a) FEAM layers are most effective when used in multiple layer configurations. (b) When fabricating multi-layer two-side flocked FEAM layer configurations, a film or fabric divider sheet should be placed between adjacent flocked layers to prevent the flocked fibers from intermeshing with each other during compressional deformation. (c) FEAM elements perforated with 6.4 mm (1/4") diameter holes, 12.7 mm (1/2") off staggered centers, exhibit a higher FL% per areal density compared to non-perforated FEAM panels. (d) Promising improvements in FL% properties are found by sandwiching either foam or spacer fabric between two FEAM layers. These three-layer structures are found to have higher FL% values than individual foam or spacer fabric components. A possible synergistic effect might be operating. (e) Low strain rate (5 and 50 mm/min) compressional load deflection rate data on combination FEAM/ vinyl nitrile foam/FEAM layers have shown that the initial ‘hump’ in the foam’s stress–strain curve is eliminated. FEAM layers and their foam and spacer fabric combinations should lead to creating effective impact energy absorbing pads for sport, military and civil servant applications.
This paper is focused on investigating the microstructure of kapok fiber through the observation of residual deformation and fracture morphology of kapok fibers in longitudinal microscopic images. By comparing the morphology of kapok fibers before and after different treatments, unique weak spiral lines inside the cell wall were found. The spiral lines that divide the cell wall into a wound ribbon appear to be the weak locations (e.g., the fracture or bending points) of the fiber. The damage mechanism of kapok fibers in assemblies was summarized. Details of structures inside the ribbon were also examined to reveal that macro-fibrils of 0.2 µm in diameter and >1.0 µm in length were packed neatly along the fiber axial on the surface. A framework of the multi-assembly structure of kapok fiber was summarized.
Smart thermal textiles are becoming increasingly popular and temperature precision is one of the important targets in their industrialization and commercialization. Some thermal products do not rely on temperature sensors but rather the input electric current pulse to achieve thermal control. In this situation, the surrounding environment, especially ventilation, can greatly affect the thermal control process.
Therefore, in this paper, a case study of an apparel system will be provided to study the effect of airflow on the heating process of thermal fabric. The relationship between temperature precision and ventilation is determined when the air flows at any angle to the surface of the thermal fabric. The results show that the thermal conductivity is proportional to the wind speed when the wind speed is high; in contrast, when the wind speed is near to zero, the thermal conductivity of the thermal fabric will not proportionally tend to zero as the result of self-generated heat transfer. This research also shows that the air inflow angle and the wind direction has little effect on the heat dissipation of thermal fabric. This research may generate the data archive and become a valuable reference for future soft thermal studies. It is expected that the developed system will span multidisciplinary gaps and contribute to a new form in a precise and controllable way within the textile industry.
In this paper, a system with six depth cameras was built to scan both feet simultaneously. An improved calibration method based on a T-shaped checkerboard was used to calculate the extrinsic parameters of the cameras. T-shaped virtual checkerboards were introduced to further fine-tune the accuracy of calibration based on the iterative closest point algorithm. Based on the proposed foot scanner, a complete procedure was introduced to measure the foot automatically by locating the anatomical landmarks without manual intervention. Various experiments were presented to validate the performance of the scanner and the measurements. The results verified that the proposed methods were efficient and versatile for three-dimensional foot scanning and measurement.
Traditional computer vision methods cannot match human performance well on fabric smoothness classification, as this is a subjective assessment based on sparse, comprehensive and low-cost visual perception. This paper reports a new assessment method of fabric smoothness appearance, including feature designing and wrinkle classification. A multidimensional feature was designed by generalizing vector quantization of dense scale-invariant feature transform (SIFT) descriptors for sparse coding and max pooling. Sparse coding provides clear understanding about the receptive fields of visual neurons and can build a codebook from the low features. A one-against-rest linear support vector machine (SVM) was utilized to classify the nine grades of smoothness and quantized to level 0.1 by space distance. Results showed that the proposed approach achieved remarkable classification accuracy in comparison with Bag-of-Feature (BOF) and Spatial Pyramid Matching (SPM) algorithms.
Two-dimensional or three-dimensional (3D) textiles have been used as reinforcement in composite materials. Most techniques for weaving 3D textiles have been developed to obtain a compact preform so that the final product, the fiber-reinforced composite, has a high volume fraction of fibers with the least fraction of matrix for high strength. Contrarily, this article describes a novel technique for weaving a loose 3D preform called wire-woven bulk Kagome with polymer wires or threads. Firstly, the principle is explained by using a manual loom. A weaving machine is then designed with detailed mechanisms and its prototype is presented. Finally, the benefit, shortcomings, and future plans are discussed.
Three types of multiwall carbon nanotubes (MCNTs)/glass fiber fabrics (MGf) were prepared by dispersing industrial-grade MCNTs onto commercial E-glass fiber fabrics (GFfs) through an ultrasonic-assisted impregnation deposition method. The multiscale MGf-reinforced composites were fabricated by the vacuum infusion process. The effect of -aminopropyltrimethoxysilane (APS) or APS hydrolysis on the MCNT dispersion and the interfacial bonding between MCNTs and glass fiber were investigated by Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy and their flexural stiffness, respectively. The interfacial adhesion of MGf composites was evaluated by interlaminar shear strength (ILSS) and dynamic mechanical thermal analysis. The results indicated that MCNTs on the MGf surface could form an interpenetrating network and act as anchors to interlock glass fiber with epoxy. The initial storage modulus and glass transition temperature of the MGf composites clearly increased, while the first loss factor of the MGf composites decreased by 30.0–45.0% compared with that of the GFf composite. Whether or not APS was hydrolyzed, it helped the MCNTs disperse on the GFf surface by chemical bonds. The ILSS of the multiscale composite with APS-treated MCNTs was enhanced significantly, while that with hydrolyzed APS-treated MCNTs (MGf-h) had a slight increase. APS hydrolysis increased the flexural rigidity of the MGf-h.
This article presents a number of possible approaches to creating electro-conductive paths and patterns on flat textiles with various structures and raw material compositions. A modifier was selected and the process of creating the electro-conductive paths by screen printing was optimized. The result of this process was evaluated by the measurement of surface resistance and by microscopic analysis using scanning electron microscopy with energy dispersive X-ray spectroscopy. The durability of the obtained effect was evaluated by analyzing electro-conductive paths after multiple washing cycles and after rubbing.
The development of nanotechnology has made it possible to add desirable functions to fabrics. Nanosilver has been used to provide antibacterial and odor control functions for sportswear over decades. However, few studies have explored the thermal comfort and ultraviolet (UV) protection properties of nanosilver-treated sportswear fabrics. In this study, a dynamic thermal model was introduced to predict the thermal comfort of nanosilver-treated fabrics for wearers in different environmental conditions. Nanosilver was applied to cotton and polyester knit fabrics and their antibacterial and UV protection properties were evaluated as well. The results indicated that substantial antibacterial and UV protection properties were achieved from nanosilver-treated fabrics. The dynamic thermal model predicted the thermal comfort of the treated fabrics for various human, clothing, and environmental factors. Although there was between two and four times difference in the thermal and evaporative resistance between the two tested fabrics, the predicted thermal comfort sensations were not significantly different in the same human and environmental conditions. From these results, it can be concluded that nanosilver-treated fabrics may provide desirable functionality, while not detracting from thermal comfort. This is one of the first trials in which a dynamic numerical thermal model was used to predict the thermal comfort of nanosilver-treated fabrics for sportswear, taking human, clothing, and environmental conditions into consideration.
In order to regulate turbulence strength and determine airflow characteristics in a new dual-feed rotor spinning unit, the internal flow field is investigated. A computational fluid dynamics technique is employed to numerically study the three-dimensional model of the internal airflow in the new design. The effects of air velocity variation on turbulence strength, negative pressure, Re, and wall pressure distribution are investigated based on simulation data and previous studies. The results show that the turbulence strength and Re increased with increase in inlet air velocity. Pressure profiles inside the rotor varied significantly with positive pressure observed at the channel exits. Minimal inlet velocity maintains the flow field in the rotor interior below 100 m/s, which gives the ideal turbulence required to minimize yarn quality deterioration. The dual-feed rotor spinning unit showed more orderly streamline patterns with fewer vortices compared to the conventional one. The numerical simulation can provide insights on airflow studies and some guidelines for future prototyping and experiments to further improve the new design.
The main content dealt with in the paper is to present a kind of weft-knitted spacer fabric with high porosity. It is a kind of three-dimensional textile fabric with a sandwich structure that consists of a middle layer of multifilament and two outer layers of plain-knitted fabric. Compared with traditional warp-knitted spacer fabric as cushion mats, weft-knitted spacer fabric is well used as apparel for good softness, thermal/moisture comfort, and air permeability. Therefore, three structures were designed and nine samples were prepared by choosing plain-knitted fabric as the outer layers and selecting soft and thin multifilament as a middle layer. Experimental results show that this kind of weft-knitted spacer fabrics has high porosity, greater than 86%, and also demonstrate that the weft-knitted spacer fabric is suitable for comfortable apparel based on experimental results of air permeability, compression properties, stiffness, and thermal insulation properties.
In textile factories, the sliver can is used to deposit and transport sliver in the process of carding, combing and drawing. Increasing the capacity of the sliver can will reduce the frequency of changing the sliver can; hence, the working efficiency can be improved. A belt drive mechanism with the driven pulley eccentrically installed was developed in this study. This mechanism was used as the driving mechanism of the coiler, which has the effect of increasing the capacity of the sliver can. In this study, several commonly used methods of increasing the capacity of the sliver can were introduced first. Then, the equation of motion of the eccentric belt drive mechanism was established, and the law of motion of the driven eccentric pulley was calculated. Finally, the relationship between the eccentricity (e) of the driven eccentric pulley and the capacity increment () of a sliver can was analyzed by utilizing the evaluation indicators of density of per sliver lap. The result indicates that with the increase in the value of eccentricity (e), the capacity increment () of a sliver can also increases.
This report presents a novel technique to assess the moisture management test on uniformly stretched compression fabrics using a clamping device, which represents behavior close to the actual behavior when worn, the effects of stretching on hydrophobic/hydrophilic and surface patterning on polyethylene terephthalate (PET) and nylon fabrics. The wicking behaviors of stretching, coating and patterning are discussed. We report that (1) coated compression fabrics were found to enhance moisture management based on the bottom spreading speed, top absorption rate and one-way transport capability criteria, (2) stretching plays a significant role in moisture management and (3) the best moisture management performance was exhibited by the hydrophobic inner and hydrophilic outer-coated PET fabric, under stretched conditions.
In the research field of functional materials, electrospinning has become one of the most effective methods to produce nanofiber. The traditional electrospinning method often uses a hollow metal needle to prepare nanofiber with minimal throughput. In this paper, we used needleless electrospinning technology to produce high-throughput nanofiber by using a metal dish as the spinneret. A finite element method has been adopted to investigate electric potential and electric field strength of the spinneret under different applied voltages and collection distance. The effects of different process parameters, including solution concentration, applied voltage and collection distance, on the throughput and diameter of nanofiber have been investigated in the experiment. Narrow distribution nanofiber can be prepared successfully. This novel method of using a metal dish as the spinneret will make a contribution to the development of needleless electrospinning for the production of high-throughput nanofiber.
In order to limit modification to the surface of wool fibers and decrease pollution caused by conventional chemical treatments using chlorine, a water-in-oil-type reversed-phase microemulsion with decamethylcyclopentasiloxane as the external phase was prepared containing very small amounts of an aqueous solution of alkali. The edges of the wool cuticle scales were modified by the alkali in aqueous solution contained in the reversed-phase microemulsion. The external phase decamethylcyclopentasiloxane can be recycled after application. In this paper, the solubility of water in the reversed-phase microemulsion and its stability were first studied and then it was applied in the treatment of wool. The results showed that surfactant sodium alcohol ether sulfate/NaOH aqueous solution was quite stable. Felting shrinkage of treated wool was reduced and the initial dyeing speed was higher than that for untreated wool. The corroded scales of treated wool were observed by scanning electron microscopy and the bromine Allwörden reaction with bromine water was reduced or eliminated after treatment. This adsorbable organohalogen-free modification should be useful in improving the manufacturing properties of wool, such as hydrophilicity, and as a pretreatment for wool printing.
Fiber packing density in the yarn cross-section is one of the major parameters that reflect the yarn internal structure and its final properties. Taking the novel low torque ring spun yarn as the object, this work studied the fiber packing density of low torque ring spun yarns and conventional ring spun yarns under various axial tensions. With the increase of tension, the change of fiber packing state in low torque ring spun yarns and conventional ring spun yarns was compared qualitatively. In this study, fiber distribution in the cross-section of both Tencel yarns and wool yarns was carried out. The results show that, under the same axial tension, the packing density of fibers of low torque ring spun yarn is much higher than that of conventional ring spun yarn. The axial tension has greater influence on the fiber packing density for the conventional ring spun yarn. From the experimental results, in low torque Tencel yarn, the fiber packing density nearly reaches 0.9, which is the maximum value for close-packed yarn. Due to different fiber properties and yarn structure, it is difficult to form a close packing for fibers in low torque ring wool yarns. The current results indicate that low torque ring spun yarn has a more compact structure than conventional ring spun yarn. Compared with conventional ring spun yarns with the same count and twist levels, in low torque ring spun yarns, more fibers contribute to the yarn breaking strength.
Lower abrasion loss and compression, as well as higher compression recovery, are desirable for obtaining maximum carpet durability. Hand-made carpet manufacturers need to satisfy consumers on these diverse durability requirements. Therefore, it is necessary to optimize the carpet durability by considering several objectives simultaneously. In this investigation, carpet durability has been optimized by considering abrasion loss, compression and compression recovery simultaneously. The desirability function approach has been used to combine multiple objectives into a single objective. Knot density, pile height, number of plies in the pile yarn and pile yarn twist have been considered as the four independent variables. The optimum desirability of carpet durability was found to be 0.8. The validation sample also showed good agreement (error < 5%) with the optimized values of carpet durability attributes.
Artificial leather has been developed for decades as a key element in apparel design due to its thermal insulation function. However, with the changes of public preferences, the focus has shifted from functionality to a greater awareness of aesthetics. Therefore, an area for innovative artificial leather with high thermal conductivity as the cover of smart electronic devices is emerging. This leather will enable both special functions and aesthetical appearance to catch the attention of the public. It can also be utilized for spring–summer clothing in following fashion trends. Exploring new markets also means breaking away from the traditional seasonal cycle. However, the only current method for improving thermal conductivity (k) is to reduce its thickness, which sacrifices durability and appearance. Therefore, in this research, a novel solution is established, in which an additive with high k (TCA), aluminum oxide (Al2O3), is added into the resin layer of artificial leather at appropriate ratios to improve its thermal conductivity. Currently, the two most adopted production methods are used to develop a prototype without generating any extra cost. The results indicate that the modified leather has a high k, has an aesthetically pleasing appearance and a soft and cool hand feeling. The k of HTCAL is 48.3% higher than that of normal leather. In addition, in wear trials, a larger temperature difference is found between the skin and the HTCAL, indicating that HTCAL has a good heat transfer. Finally, a prototype for an iPhone case is developed and it is established that the method can be used for mass production to realize benefits.
Conducting linen fabrics were prepared by the in situ oxidative polymerization of pyrrole using ferric chloride as the oxidant and anthraquinone-2,6-disulfonic acid disodium salt as the dopant to enhance conductivity. The effect of the pyrrole concentration on the final performance and properties of the conducting fabrics was evaluated. Scanning electron microscopy and light microscopy showed a polypyrrole layer deposited on the fiber surface associated with penetration into the bulk fiber at the highest concentrations of pyrrole. Saturation of the amorphous domains of the cellulose structure and coating of the fiber surface resulted in good electrical properties, heat development by the Joule effect and reduced moisture adsorption. The mechanical properties and electrical conductivity of the fabrics were affected by the strong acid conditions of the treatment, but significant electrical properties were achieved while preserving up to 70% of the original tensile strength.
Sol–gel is a very effective method to obtain high purity ceramic and hybrid coatings on a variety of substrates. Thanks to their unique structure and extremely reduced thicknesses, sol–gel coatings can remain adherent and transparent even on flexible substrates such as textiles. Hence, their versatile chemistry can be exploited to impart a variety of properties to fabrics. Here, we evaluated the potential of sol–gel coatings for the functionalization of silk fabrics, and in particular for the preparation of coatings able to simultaneously improve abrasion resistance and attain water-repellency. To this end, tetra-ethyl-ortho-silicate based (TEOS) hybrid coatings were prepared using different Si-alkoxides functionalized with either alkyl chains or fluorinated groups. Abrasion resistance, oil and water contact angle, mechanical properties and water vapor permeability were assessed on treated fabrics to identify the more promising formulations.
The polypropylene melt-blown nonwoven membrane (PPM) is widely used in healthcare; however, the highly hydrophobic nature of the PPM readily adsorbs proteins and polysaccharides, which are conducive to bacteria being retained in the network, resulting in biofouling. Therefore, to improve the hydrophilic and antimicrobial properties of PPM, acrylic acid (AA) was first graft-polymerized on PPM (PPM-g-AA) by ultraviolet (UV)-induced photo-grafting polymerization. Chitosan (CS) was then covalently grafted onto PPM-g-AA to obtain the bigrafted PPM (PPM-g-AA-g-CS). Finally, silver (Ag) nanoparticles were immobilized onto PPM-g-AA-g-CS to create the hydrophilic and antibacterial PPM. The surface chemical composition and morphology of the samples were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The hydrophilic and antimicrobial properties of the modified PPM were assessed using static water contact angle measurements, wetting time, and bacteria colony-counting assays. The results show that PPM-g-AA-g-CS with immobilized Ag nanoparticles has excellent antibacterial and hydrophilic properties.
In this study, flax rove was treated in supercritical carbon dioxide. The effect of different treatment temperatures on the surface morphology, chemical and crystal structures, and thermal properties, as well as isolated compounds of flax rove, were investigated by employing scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal analysis, and nuclear magnetic resonance (NMR), respectively. The results showed that more mild grooves and stripes appeared on the surface of the treated flax fibers after supercritical carbon dioxide treatment. FT-IR spectra showed that hydrolysis of macromolecule of flax fibers occurred, producing a CC group. XRD spectra confirmed that the crystallinity of the treated flax samples was gradually increased with the raising of treatment temperature. Simultaneously, thermo gravimetric analyzer (TGA), differential thermal gravity (DTG) and differential scanning calorimetry (DSC) analysis indicated that the thermal properties of flax rove were improved with the increase of treatment temperature. In addition, NMR analysis proved that lignin and the monosaccharide composition of isolated compound were extracted from flax rove. Moreover, a predominance of β–O–4’ arylether linkages, followed by β–5’ phenylcoumaran and β–β’ resinol-type linkages for lignins of isolated compound was shown in NMR. Therefore, the results confirmed that it is technically feasible to using supercritical carbon dioxide to conduct the scouring and bleaching of flax rove.
This study develops polyester modified polypropylene (PP) with disperse dye dyeability. The thermal properties, rheological properties, and spectral properties are used for validation and differential analysis.
The optimum PP dyeable particle process uses polyester as the mixed copolymer. The melt temperature of polyester material is significantly different from PP, which may lead to a failure of the mixing process. Therefore, this study aims to develop low-melting co-polyester. Different proportions of adipic acid are used in the co-polyester molecular chain to reduce the melting point. The melting point has been controlled successfully, the thermal properties of the modified ester pellet are discussed, and the functional group is then verified by Fourier infrared spectroscopy. Afterwards, the low-melting co-polyester and PP are made into a composite through a dual-screw mixing process with PP grafting maleic anhydride compatilizer. The PP is endued with the dyeability of disperse dye through the molecular behavior of the co-polyester chain segment. The optimum process parameters of the made material are designed by using the Taguchi method, gray relational analysis, and fuzzy C means clustering algorithm, aiming at two quality characteristics: dyeing power and melt index (MI). The results show that the MI of the pure PP polymer is 35.78 g/10 min and the color strength is 100 K/S, while the MI of the PP/co-polyester is 37.63 g/10 min and the color strength is 211.20 K/S. The results suggest that the developed polymer exhibits good processing in circulation and color strength.
Vinyl benzoate (VB series) and trans-stilbene (SB series) were added onto polyurethane (PU) via graft polymerization, and the spectroscopic, thermal, tensile, shape memory, and low-temperature flexibility properties of the resulting polymers were compared with those of unmodified PU. The melting temperature (Tm) and glass transition temperature (Tg) of the soft segments are not significantly different for the VB and SB series compared with unmodified PU. The tensile strengths of the VB and SB series sharply increase with increasing vinyl polymer content, whereas the control series does not exhibit an increase in tensile strength. The VB series exhibits excellent shape recovery at 10℃ compared with unmodified PU, and the shape recovery of the SB series remains above 90% at 45℃. The shape retention values of the VB (–45℃) and SB series (–25℃) are not less than 90%. The selected PUs demonstrate better flexibilities at extremely low temperatures compared with unmodified PU. Therefore, the graft polymerization of vinyl benzoate or trans-stilbene onto PU improves the tensile strength, shape recovery at low temperatures, and low-temperature flexibility of the polymer without decreasing the tensile strain or shape retention.
Non-uniformity of the fiber diameter and difficulty in continuous web collection have limited the development and further application of centrifugal spinning (CS). Here, we present a feasible method for fibers' continuous collection and morphology optimization by utilizing vertical electrostatic-assisted centrifugal spinning (E-CS). The effects of spinning parameters, such as applied voltage, nozzle size, and rotational speed on fiber morphology have been evaluated systematically. We find that vertical voltage is strongly correlated with the formation of bead defects, and nozzle size is the most important parameter on fiber size, and the fiber diameter generally decreased with increasing rotation speed. Through the mechanism analysis and jet trajectory observation, we think that the Rayleigh–Taylor instability is the key factor in determining fiber formation in CS. When a vertical electrostatic force is applied to CS, the above instability phenomenon can be effectively controlled resulting more uniform fibers with thinner diameters and fewer beads.
Polypyrrole catalyzed by laccase appears as a black color in solution. Conductive fabric coated with polypyrrole could present a dark green color, but the colorimetric and dyeing properties have not been discussed. In this study, pyrrole was used for the dyeing of wool fabric through in situ polymerization using laccase. The absorbance of reaction solution increases as time goes on and a significant peak appears at 460 nm on the ultraviolet-visible spectrum. Scanning electron microscopy indicated polypyrrole catalyzed by laccase does fix onto the wool fiber comparing to the control sample. The structure and electrochemical activity of dyed wool fabric were characterized by Fourier transform infrared spectroscopy and cyclic voltammetry, respectively. The dyeing depth of the dyed wool fabrics increased gradually with the extension of time and increasing of concentration of laccase and pyrrole. The dyed wool fabric prepared presents good electrochemical activity in terms of in situ polymerization using laccase in solution.
Silk and cotton fabrics were dyed using the extract from blackcurrants, and the properties of the dyed fabrics were investigated. The natural dyes present in the blackcurrants were identified as four types of anthocyanins, i.e. delphinidin-3-glucoside, delphinidin-3-rutinoside, cyanidin-3-glucoside, and cyanidin-3-rutinoside. The colors of the fabrics dyed with and without five types of mordants, including Mg2+, Ca2+, Al3+, Fe3+, and Cu2+, were measured and expressed according to the CIELAB color system, E* value, and K/S value. The affinity of the extracted dye for the silk fabric was higher compared with that for the cotton fabric. The crystallinity of silk was lower than that of cotton. The fabrics dyed with blackcurrants had UV shielding ability, especially at 330–400 nm, and antibacterial properties. Although color fastness to light and washing (color change) was not sufficient, treatment with Mg2+, Fe3+, and Cu2+ mordants could enhance the color fastness.
Textile curtains can be designed to be good sound absorbers. Their acoustical performance, as usually described by the sound absorption coefficient, not only depends on the textile itself but also on the drapery fullness and the backing condition, that is, the spacing between the fabric and a rigid backing wall, or the absence of a backing in the case of a freely hanging curtain. This article reviews existing models to predict the diffuse-field sound absorption coefficient, which to date can only predict the case of flat curtains. A set of existing models is extended to the case of curtains with drapery fullness using a semi-empirical approach. The models consider different backing conditions, including freely hanging curtains. The existing and new models are validated by comparing predicted sound absorption coefficients with data measured in a reverberation room. Hereby, curtains consisting of different fabrics and with different degrees of fullness are considered. Besides situations with rigid backing, also the measurement data of textiles hung freely in space are included in this study. Comparisons reveal a very good agreement between measured and predicted sound absorption coefficients. Compared to currently available commercial sound absorption prediction software that can only handle the situation of flat textiles with rigid backing, the results of the presented models not only show a better agreement with measured data, but also cover a broader range of situations. The presented models are thus well applicable in the design and development of new textiles as well as in the room acoustical planning process.
Popular electrospun technology can only obtain submicron fibers and fiber membranes in random or in slight orientation, in fact, they are not real nanofibers. A fast-rotating drum-collector has been introduced into the electrospinning setup to improve the orientation of electrospun fibers/membranes and, more importantly, to stretch the electrospun fibers. The measured results indicate that: (1) the submicro-fiber orientation and the angle frequency distribution can be characterized quantitatively by Hough transform (HT) and Regionprops function (RF) approaches, and the accuracy of HT is relatively higher than that of RF; (2) through changing the drum speed, an extra stretching force is exerted on the submicro-fibers, so making them thinner; and (3) the higher the drum surface speed, the greater is the orientation of the electrospun fibers, and the finer and stronger the submicro-fibers; their diameter ranges from about 250 nm at zero drum speed to 170 nm at 7 m/min, and may even get into the nanoscale—that is, 1–100 nm.
Seam puckering is often considered an undesirable wrinkling appearance along a seamline, and is a problem that concerns fabric, sewing machine and sewing thread manufacturers. Until now, the standardized evaluation method for seam-puckering grading is still a visual-based, subjective method. This research project was aimed at developing a computer-vision system for automatic seam-puckering evaluation to improve the consistency and efficiency of grading. Fabric seam images were captured by a customized image acquisition system, and the seam images and the optimal image parameters, such as length and width, were determined according to the results of human inspection. The seamline was located with edge detection and Hough transform techniques. After rotating and cropping the image, the projection profile was then obtained and smoothed with the locally scatter-plot smoothing (LOESS) algorithm. Five characteristic features were extracted from the smoothed profile. Finally, an artificial neural network classifier was created to realize the automatic assessment of the seam-puckering grade. The experimental results proved that the proposed system can achieve accurate seam-puckering grades, and has the potential to replace the current manual evaluation.
In this study, the influence of homehold composting conditions on the molecular and supramolecular structure of polylactide (PLA) in the form of spun-bonded nonwovens was investigated. Nonwoven samples were studied using size-exclusion chromatography coupled with multiangle laser light scattering detection, wide-angle X-ray diffraction, differential scanning calorimetry and Fourier transform infrared spectroscopy. In addition, the physical and mechanical properties of the nonwovens before and after composting were determined. The results show the varying degree of influence of the prepared compost mixtures of soil with common horticultural additives, such as chalk, commercially available agents, cow manure and chicken litter, on the molecular and supramolecular structure of PLA and its degradation rate. The obtained experiment explained which popular homehold agent had the strongest affect on the PLA nonwoven dedicated for agriculture use in the first period of season composting (first 6 months).
This paper reports a comparative experimental study of single jersey knitted fabrics made from a novel bio-based and degradable polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) multi-filament yarn, together with polylactide acid , Cupro, polyethylene terephthalate (PET) and polyamide 6 (PA 6) multi-filament yarns. Their structures, mechanical, thermal and surface properties and performances as well as anti-bacterial behavior are measured and compared.
It has been found that the polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) filament yarn has adequate thermal and mechanical properties for normal textile and coloration/finishing processes. The Young's modulus of polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) multi-filament yarn is the lowest among all the candidates investigated except for polyamide 6 (PA 6). The dyed polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) fabric has the highest softness rating among all the fabrics.
Single jersey knitted fabrics from the polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) filament yarn have a bursting strength, extension and recovery that satisfy the industrial requirement. In addition, after fully relaxation, the dyed polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) knitted fabrics exhibit an outstanding pilling resistance, favorable snagging property, as well as good air permeability, Qmax and smoother surface. Finally, this study has led to a discovery of excellent anti-bacterial performance of 100% polylactide acid/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) fabrics against staphylococcus aureus, klebsiella pneumoniae, candida albicans according to AATCC100-2012.
Skin wetness perception (WP) greatly affects thermal and sensorial discomfort in clothing and as such is of great interest to the clothing industry. Following neurophysiological studies of WP, this study looks at textile parameters affecting WP. Twenty-four fabrics varying in thickness, fiber type and absorption capacity were studied. Using 12 participants (males/females), the WP induced was studied in four wetness states: 1. Dry; 2. absolute (ABS), all having the same absolute water content of 2400 µL per sample (=0.24 µL mm–2); 3. 100REL, saturated with water to their individual absorption capacity; 4. 50REL, to 50% of the value in 3. As total absorption capacity was highly correlated (r = 0.99) to fabric thickness, conditions 3 and 4 were equivalent to having the same water content per volume of textile, i.e. 0.8 and 0.4 µL mm–3, respectively. Samples were applied to the upper back statically to minimize the contribution of surface roughness/friction. WP was highly correlated to drop in skin temperature induced by the wet fabric, and increased with application pressure of the fabric. No effect of fiber type was observed. In REL, with equal µL mm–3, WP showed a positive correlation to total fabric water-content-per-area (µL mm–2), and thus also to thickness, given the correlation between the latter two, with saturation above 1.5 µL mm–2. In ABS, on the other hand, with equal µL mm–2, and thus with relative water content (µL mm µL mm–3) inversely proportional to thickness, WP was also inversely proportional to thickness. Thus WP showed opposing responses depending on the wetting type, indicating that the methodology of manipulating water content should be selected in relation to the product end-use.
Currently, the antimicrobial textile market is emerging and has rapidly developed to meet the inherent demands placed on public hygiene. Silver (Ag) is an efficient antimicrobial due to its direct function with the cellular membrane of probe samples. The application of Ag in the textile industry is limited due to its poor stability in repeatedly washing. In this study we synthesized a kind of novel antibacterial fiber containing nano-size silver particles in a reversed emulsion reaction system. The Ag nano-particles are incorporated onto the bamboo fibers solidly through primitive oxidation by sodium periodate. The identification, dependent on Staphylococcus aureus, was implemented to check the influence of the reaction conditions on the antimicrobial property. Meanwhile, reactive oxygen species and the leakage of cytoplasmic contents were focused on investigating the antimicrobial mechanism. The antimicrobial assay suggested that samples from inversed micelle and aqueous system own the comparative antibacterial activity. However, samples from an emulsion system could maintain a better bactericidal property than samples from an aqueous system. Meanwhile, the reactive oxygen species and ultraviolet absorption show the same trend consistent with the antibacterial result. This result might be explained by the morphology and size of Ag particles attached on cellulose surface, which was proved by scanning electron microscopy and energy dispersive spectroscopy. It was revealed that the surface-to-volume ratio of Ag particles played a more crucial role in achieving higher antimicrobial activity than the mass. This approach will provide a practical solution for the synthesis of wash-durable antimicrobial substances.
A new method combining the characteristics of macro-scale texture repeat patterns and micro-scale interwoven yarns of fabric images was proposed for yarn-dyed fabric density detection. The method was formulated in a research framework of multi-scale image processing and analysis. Firstly, a structure–texture decomposition approach was used to extract texture information and woven pattern details from the macro-scale fabric image. Secondly, a texture unit detection model was proposed to extract the texture units and to detect the yarn skewness in these texture units. Thirdly, a simple yet effective image registration method and a lightness gradient projection method were adopted to analyze the micro-scale fabric image and obtain the yarn locations in a texture unit. Finally, the average fabric density was calculated by coupling the near-regular features of texture units and yarn locations. The experiments showed that the proposed method was effective in detecting hundreds of yarns in the fabric samples and the computation time was very reasonable.
The short fiber content (SFC) in raw cotton is an extremely important attribute in the modern cotton classification system, because of its impact on the quality of yarn manufacturing. However, the current SFC measuring methods are costly, time-consuming and tedious for accurate and quick testing. This study aimed to develop a new way to calculate a weight-based short fiber content (SFCw) from a dual-beard specimen via image-processing and bell-shaped fibrogram modeling techniques. A sample from a cotton sliver was clamped and combed in the opposite directions to form two tapered fringes, and then scanned on a desktop scanner to generate a dual-beard image (DBI). The grayscale values in each column of the DBI were accumulated to derive a bell-shaped fibrogram representing the fiber quantity distributions over the distance from the fibrogram center. Based on the fibrogram, a special hierarchical model was proposed to calculate SFCw in two different length limits—12.7 and 16 mm—defined respectively in the USA and China’s specifications. Fifteen samples were tested to compare the SFCw results from the DBIs to those from the Advanced Fiber Information System (AFIS PRO2). Significant correlations were found between the SFCw values from DBIs and AFIS. The regressive equations for SFCw prediction were validated with six additional samples. As shown in the Bland–Altman plots, a good agreement existed between the two sets of SFCw values, demonstrating the DBI’s potential to be an accurate, rapid and portable approach for measuring SFCw, and to transform the SFCw testing from a dedicated machine to an off-the-shelf scanner.
Disperse fluorescent ink was controllably prepared via the cyclic sander grinding process and used for thermal transfer printing on a polyester substrate. Via process optimization, 0.1% pH regulator triethanolamine and 0.15% surfactant NP-12 were added in the disperse fluorescent ink. The lightness L* of the polyester substrate was 101.84 and the saturation C* was 84.21 within thermal transfer printing on the polyester substrate. Compared with flat screen printing, the bending rigidity and bending hysteresis moment of the ink-jet printed polyester substrate presented a slight change. The fluorescent effect of the printed polyester substrate was increased to 165.65, and the fluorescence reflectivity increased 4.1% at the maximum emission wavelength max = 510 nm. The color fastness of the printed polyester substrate was improved. In particular, the wet rubbing fastness was enhanced by one grade after the ink-jet thermal transfer printing.
This study aims to identify different contributions of each layer to ballistic resistance and energy absorption distribution in a soft armor panel under ballistic impact. Different ballistic responses of each fabric layer and energy absorption mechanisms of a multilayer panel were investigated through finite element (FE) analysis using Abaqus. FE models were created to simulate transverse impact of a projectile onto multilayer panels before clay. FE results show that fabric layers in front, middle and back of the panel exhibit different extents of transverse deformation and stress distribution characteristics. Energy absorption in each layer is increased from the front layer to the peak value at the last perforated layer and then gradually decreased in following back layers of the panel. This pattern remains the same regardless of increasing total number of layers in the panel. When increasing the impact velocity, the position of the peak value of energy absorption with the last perforated layer is shifted towards back of the panel. These fundamental understandings contribute to the hybrid design of soft armor panel.
A composite porous scaffold for bone cell culture was fabricated by immobilizing HA (hydroxyapatite) (Ca10 (PO4)6 (OH)2) microparticles on PLA (poly(lactic acid)) nonwoven fibers using the layer-by-layer deposition technique. A nonwoven PLA of thickness 1 mm, with average pore size of 230 µm and a porosity of 94%, was used. The nonwoven was functionalized with aqueous 65% deacetylated chitosan followed by rinsing, and then a second padding with aqueous sodium alginate loaded with varying percentages of HA microparticles (0.01%, 0.1% and 0.2%), resulting in a composite porous nonwoven. Sodium alginate was revealed to be an efficient polymer for obtaining a stable dispersion of the HA microparticles in an aqueous medium.
Atomic force microscopy and scanning electron microscopy images, zeta potential and wettability tests showed successfully the different surface modifications occurring at each step of surface functionalization. The chitosan coating cationized the PLA fiber surface, providing good adhesion of the HA-loaded anionic alginate coating. HA was almost homogeneously distributed at the PLA fiber surfaces with only a small reduction in the scaffold porosity, which reached 75%.
The composite PLA/chitosan/alginate/HA nonwoven structures were tested as scaffold for adhesion and proliferation of rat pre-osteoblast MC3T3-E1 cells. The results showed that higher loading with HA improved the MC3T3 cell adhesion and proliferation after 3 and 6 days of culture.
Thermal manikins simulating human body’s thermal regulatory system are essential tools for understanding the heat exchange between human body and the environment and also for evaluating the thermal comfort of clothing and near environment. However, most existing thermal manikins adopt a male’s body shape and no sweating female thermal manikin has been reported so far. Furthermore, it is unclear how body shape (viz. male vs female) affects the heat loss and perspiration from the body. We report on a novel female sweating thermal manikin "Wenda". Thermal properties of the nude body and clothing ensembles measured on "Wenda" are compared with those measured on the male manikin "Walter". It was found that, although the more curvaceous female body reduces the thermal insulation of the nude manikin, it increases the apparent evaporative resistance at the same time. This may be due to the fact that the more curvaceous female body increases the surface still air layer to add resistance to heat loss by conduction and evaporative water loss by diffusion, and significantly increases the percentage of effective radiative area and the resultant radiative heat loss per unit surface area. It was further shown that clothing thermal insulation and apparent evaporative resistance measured on Wenda are typically 0 ~ 11% higher than those measured on the male sweating fabric manikin-Walter, probably due to the greater clothing microclimate volume on the female manikin resulting from the looser fitting of the garments on the smaller female body and the more curvaceous surface of the female body.
The aim of this research was to prepare and analyze suitable microcapsules for the chosen end use—that is, bow-ties. The produced microcapsules were composed of melamine formaldehyde microcapsules with fragrance oils in the core. Regarding the properties, the surface morphology (studied by Scanning electron microscopy (SEM)), thermal properties (measured by Simultaneous Thermal Analysis [STA]), size and size distribution (by SEM and ImageJ software), and release behavior of the microcapsules were analyzed. The microcapsules were further (in two trials) applied with a screen-printing technique to textile materials which were investigated by microscopy (SEM) and tested for thickness, mass per unit area, and crease recovery angle. Finally, the scented bow-ties were designed and a subjective wear test was performed by the participants. According to the results, the prepared microcapsules were undamaged, with a spherical and smooth surface. An impermeable shell enabled the fragrance to be released simply by rupturing the microcapsules. This property was desired, since a stronger release through the permeable shell could be annoying for the wearer. During wear, the fragrance faded, but by rubbing the surface of the bow-tie and consequently rupturing the microcapsules, the release of the fragrance was initiated again, before or after wear.
Reactive dyes maintain a long reaction with fiber and show a high dye uptake and fixation rate, and effectively decrease the dyeing waste water in siloxane reverse micro-emulsion. However, little research has been carried out into the hydrolysis reaction of reactive dyes in reverse micro-emulsion. In this study, Reactive Blue 19 was selected as a model vinyl sulfone reactive dye to study its hydrolysis in siloxane reverse micro-emulsion. The hydrolysis reaction was analyzed using high performance liquid chromatography. The results show that the hydrolysis rate of vinyl sulfone dyes in siloxane reverse micro-emulsion was slower than that in a traditional bath. Influences due to the ratio of aqueous dye solution to siloxane, non-ionic surfactant, cellulose fiber, and temperature on the hydrolysis reaction of vinyl sulfone reactive dye were also researched. The results show that with more aqueous solution emulsified in the siloxane media, the hydrolysis reaction of vinyl sulfone dye is faster. Reactive dyes were emulsified into a water micro-environment with non-ionic surfactant, which formed reverse micro-emulsion, and decreased the content of free water; this further influenced the hydrolysis of reactive dye.
With a view to minimizing production costs of carbon fiber-reinforced plastics (CFRP), a contoured, variable-axial reinforcing fabric, so-called "CoCo – contoured composites," has been developed for complex, primary structural components. Thereby, scrap in the production of lightweight high-performance components out of CFRP is reduced. Furthermore, components can be designed in an anisotropic way, thus lighter and adapted to the fiber properties. Moreover, production speed will be by far higher than that of conventional variable-axial textiles, like tailored fiber placement and fiber patch preforming. Furthermore, these textiles will show higher drapability than conventional production techniques, like tape-laying or standard textiles. The main focus of this paper is the investigation of draping mechanisms of variable-axial, tailored textiles and their feasibility. To reach high drapability of these semi-finished products, a new draping strategy has been developed. Reinforcing rovings are laid in meander way onto a carrier material holding excess material available for draping. For the textile "CoCo" new draping characteristics have been investigated, showing a kind of stretch forming of the carrier material and a straightening of the reinforcing fibers previously laid in meander. Due to this draping mechanism the material has the ability to form over very complex shapes without showing draping defects, like loops, gaps, or waviness. The calculation of the excess material and the draping mechanism are investigated on a complex form and proven by draping trials.
Nitric acid oxidation of electrospun carbon nanofibers, with varying degrees of oxidation, was carried out to understand the effect of acid treatment on the microstructure and capacitive behavior of the fibers. The increasing treatment time increased considerably the oxygen/carbon (O/C) ratio on the fiber surface, and the increase in the oxygen content was mainly contributed by the formation of carbonyl groups. However, nitric acid oxidation reduced the specific surface area and total pore volume of fibers. The specific capacitance of carbon nanofibers was closely related to the O/C ratio, and the specific capacitance of 365 F/g for carbon nanofibers treated with nitric acid for 5 h was obtained. This was ascribed to the increased fiber polarity that facilitated the diffusion of electrolyte ions into the nanofibers. Furthermore, the functional groups contributed to the pseudocapacitance, which was caused by faradaic reactions of oxygen-containing functional groups. The effect of these groups dominated that of structural change on the electrochemical performance of fibers.
Atmospheric pressure plasma torch (APPT) is a cold plasma technique that can be used to treat materials with a polymeric surface in an environmentally friendly way. The treatment modifies the topography and chemistry of the surfaces. The effect of APPT on woven aramid is studied with the aim of enhancing its impact strength for ballistic applications. The shielding, laminated with several layers of woven and resin, can better resist projectile penetration. Woven aramid has low wettability due to its low polarity. Therefore adhesives penetrate the woven fibers with difficulty. APPT treatment considerably increases the polar component of the surface energy and the wettability is improved. Changes in the micro-topography and chemical composition that generate enhanced adhesion are investigated. The adhesion ability was determined by adhesion pull-off test, T-peel test, and impact test. Two types of adhesives were used: an elastic one (polyurethane-based, with elastoplastic mechanical behavior) and a rigid one (epoxy-based). Composites made with woven aramid treated with APPT exhibit an enhanced resistance to impact in terms of elastic energy recovery due to the greater degree of adhesive penetration between the woven fibers of each layer and better transfer of loads.
Composites of titanium dioxide (TiO2) immobilized on carbon fibers (CFs) were synthesized by a two-step process. Acid-treated CFs were dip-coated in a TiO2 sol and then annealed under superheated steam ambient to form TiO2/CF composites. The effects of titanium sol concentration and annealing temperature on the micromorphology and phase structure of the TiO2/CF were investigated by field emission scanning electron microscopy and X-ray diffraction, respectively. The photocatalytic properties of the as-prepared TiO2/CFs were evaluated by photocatalytic degradation of acid orange II under ultraviolet light irradiation. The TiO2/CF composites prepared by superheated steam annealing exhibited a uniform surface morphology and high loading degree. The photocatalytic degradation of acid orange indicated that the TiO2/CF composites exhibited excellent photocatalytic performance and reached up to 98.7% degradation rate after 2.5 h of irradiation.
In this study, the impact resistance of two-dimensional (2D) fabrics and three-dimensional (3D) preforms is explained. These fabrics and preforms include 2D and 3D woven and knitted flat and circular fabrics. Various types of soft/layered structures as well as rigid composite are outlined with some design examples for ballistic and stab threats. The recent developments in nanotubes/nanofibers and shear-thickening fluids (STF) for ballistic fabrics are reviewed. The ballistic properties of single- and multi-layered fabrics are discussed. Their impact mechanism is explained for both soft vest and rigid armor applications. Analytical modeling and computational techniques for the estimation of ballistic properties are outlined. It is concluded that the ballistic/stab properties of fiber-reinforced soft and rigid composites can be enhanced by using high-strength fibers and tough matrices as well as specialized nanomaterials. Ballistic/stab resistance properties were also improved by the development of special fabric architectures. All these design factors are of primary importance for achieving flexible and lightweight ballistic structures with a high ballistic limit.
In this paper, a series of fatty acid esters, including ethyl laurate (EL), butyl stearate (BS), ethyl palmitate (EP), ethyl stearate (ES) and methyl palmitate (MP), were selected as the solid–liquid phase change materials (PCMs), and then embedded inside the porous network structure of polyacrylonitrile (PAN) nanofibers supporting the skeleton by electrospinning technology, respectively. Morphological structures, chemical structures and thermal energy storage properties of electrospun fatty acid ester/PAN composite nanofibers were characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy and differential scanning calorimetry (DSC), respectively. Observations by FE-SEM images showed that the PAN nanofibers acting as the supporting polymer matrices can perfectly maintain the fiber shape and effectively prevent the leakage of the molten fatty acid esters. Maximum loaded weight percentages of the EL, BS, EP, ES and MP in the composite solutions could reach up to about 70, 45, 55, 65 and 60 wt.%, respectively. DSC results indicated that the prepared EL/PAN, BS/PAN, EP/PAN, ES/PAN and MP/PAN composite nanofibers had appropriate melting peak temperatures (about 1.26℃, 21.20℃, 29.37℃, 29.66℃ and 31.93℃, respectively) based upon climatic requirement, and the corresponding melting enthalpies were about 84.11, 55.10, 95.37, 93.35 and 110.4 kJ/kg, respectively. It can be considered that electrospun EL/PAN, BS/PAN, EP/PAN, ES/PAN and MP/PAN composite nanofibers would be promising form-stable PCMs for the applications related to the storage and retrieval of thermal energy, such as solar energy storage, building energy conservation, indoor temperature controlling and smart textiles and fibers.
The development of an emotion-based (or affect-based) apparel design system has become an important issue nowadays due to the customer’s increased demand for apparel products not only in the aspect of function but also of aesthetics or affect/emotion. This paper presents a study on developing a mapping from affective words to design parameters. The technique employed to develop this mapping is neural networks (NNs). Both linear NNs and higher-order NNs were applied. An example was taken to illustrate and validate the developed mapping. There are two main contributions from the study. The first is that this mapping is the first in the domain of apparel design, and with it, the computer-aided affect-based design for apparel becomes possible. The second one is the provision of some empirical knowledge for the evaluation of so-called higher-order NNs.
In this study, transverse impact of a cylindrical projectile onto a 600 denier Kevlar KM2 yarn (400 individual fibers) is studied using a fiber length-scale three-dimensional finite element model to better understand projectile–fiber and fiber–fiber contact interactions on wave propagation and fiber failure within the yarn. A short time scale response indicates significant transverse compressive deformation in the fiber that increases with impact velocity. Fiber-level modeling predicts a flexural wave that induces curvatures in the fibers significant enough to induce compressive fiber kinking and fibrillation. A spreading wave normal to the direction of projectile impact develops and spreads the fibers at high velocity. The models predict bounce velocities of the individual fibers within the yarn that varies based on spatial location. These mechanisms result in non-uniform loading and progressive failure of fibers within the yarn. In addition, the models show a gradient in the axial tensile stress in the fiber cross-section at the location of failure. Current state-of-the-art experimental capabilities in yarn/fabric impact testing do not have the spatial resolution to track individual single-fiber micron length-scale deformations in real time. These fiber-level mechanisms may explain the experimentally observed lower breaking speed for yarns better the classic Smith solution, which assumes yarns are homogenous (i.e. individual fibers and their interactions are not considered) and loaded uniformly in tension (multi-axial loading and stress gradients are neglected).
Bifacial fabrics were produced on a purpose-built machine, using wool, acrylic and polyester yarns, with the woven structure being plain weave, and the knitted structure being single jersey. In this study, the heat transfer properties of these fabrics were compared with conventional woven and knitted fabrics. The bifacial fabrics had lower air permeability than knitted and woven fabrics, and they were warmer to touch. The thermal resistance of the bifacial fabrics was higher than the knitted and woven fabrics, and the thermal resistance of the two faces of the bifacial fabrics was statistically different.
A twist-film gel spinning process was developed for large-diameter high-performance ultra-high molecular weight polyethylene (UHMWPE) monofilaments. By using polybutene as a spin-solvent, film twisting was demonstrated to be an effective method for solvent removal; approximately 70% of solvent contained in the gel film can be removed simply by film twisting. This mechanical solvent removal process also makes conventional solvent extraction proceed significantly faster. Besides improved solvent extraction efficiency, large-diameter high-strength UHMWPE monofilaments (with diameters of about 80 µm and strength exceeding 3.2 GPa) can be produced with this process, which is difficult to achieve using conventional processes. The capability of making large-diameter high-strength monofilaments may allow new products of UHMWPE to be developed in a number of high-performance applications.
To conduct research into the long-term preservation of fragile wool textile relics unearthed at archeological sites, it is essential to simulate the aging process and evaluate the factors affecting the degradation of wool fabrics. An accelerated aging method is therefore proposed to simulate the degradation process using either CaCl2 or NaCl in conjunction with hydrothermal treatment. The accelerated aging of wool fabrics was investigated by color measurement, scanning electron microscopy, cross-sectional observation, attenuated total reflection Fourier transform infrared spectroscopy, and amino acid analysis. Wool fabrics subjected to NaCl-hydrothermal or CaCl2-hydrothermal treatment exhibit an apparent yellowing with increasing treatment time. Fluctuations of cysteic acid and cystine dioxide content are shown to be the most prominent, and a distinct conversion of α-helices into β-sheets is observed with increasing treatment time. These results indicate that the effect of Ca2+ was greater than Na+ in promoting the degradation of disulfide groups in the hydrothermal degradation process.
Carbon fiber (CF) must be protected from thermal oxidation for high temperature application because of its low thermo-oxidative stability above 450℃ in air. CF is now increasingly being used as a reinforcing material in the construction industry. A thermal and oxidation resistant coating is necessary for CF-reinforced concrete (CFRC) composites in order to satisfy a high level of safety standard in the case of fire. New types of pre-ceramic coatings, such as Tyranno® polymer (Si–Ti based pre-ceramic) and SiO2 sol–gel, have been deposited on CF filament yarn by means of a wet chemical continuous dip coating method. The results of surface analyses, e.g. scanning electron microscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy, showed the changes in topographical properties of CF caused by the coatings. Thermogravimetric analysis proved that the high temperature (up to 800℃) oxidation stability of CF was considerably improved due to the coatings. Tensile test results indicated that the strength of CF yarn at 20℃ was increased by up to 80% with the coatings. Thermo-mechanical properties were also enhanced up to 600℃. CF yarn retains its original strength and elasticity modulus, i.e. the stiffness at 700℃, with a Tyranno® polymer coating.
The aim of this research was to investigate the low-velocity impact properties of syntactic foam reinforced by warp-knitted spacer fabric (SF-WKSF). In order to discuss the effect of warp-knitted spacer fabric (WKSF) and hollow glass microballoon parameters on the impact performance of composites, eight different kinds of SF-WKSF samples were fabricated, including different WKSF surface layer structures, different spacer yarn diameters and inclination-angles, different microballoon types and contents. The low-velocity impact tests were carried out on an INSTRON 9250 HV drop-weight impact tester and the impact resistances of SF-WKSF were analyzed; it is indicated that most SF-WKSF specimens show higher peak impact force and major damage energy compared to neat syntactic foam. The results also demonstrate that the surface layer structure, inclination-angle of the spacer yarn and the volume fraction and type of microballoon have a significant influence on the low-impact performance of SF-WKSF. In addition, a finite element analysis finished with ANSYS/LS-DYNA and LS-PrePost was used to simulate the impact behaviors of SF-WKSF. The results of the finite element analysis are in agreement with the experimental results.
Cotton cellulose is an excellent natural material due to its outstanding characters. Five novel crosslinking reactive disperse dyes containing bi-functional groups, two 3-chloro-2-hydroxypropyl groups, were synthesized and characterized by infrared spectroscopy, proton magnetic resonance spectroscopy and element analysis. The solvent effect on the color of the dyes was assessed by the electronic absorption spectra. The crosslinking printing properties of the five dyes (D1–5) for cotton fabrics were investigated. The electronic absorption property exhibited larger bathochromic shifts in a stronger polar solvent than in the weaker polar solvents. The crosslinking reaction between two 3-chloro-2-hydroxypropylreactive groups and the hydroxyl group of cellulose could take place. The higher color yield and excellent fixation were obtained. The building up property was good for all the dyes on cotton fabric. The printed samples had excellent washing, perspiration and rubbing fastness. The light fastness for cotton fabrics was moderate.
Today many different natural materials are being effectively used in the acoustics and noise control domain. In this study, the acoustical characterization of three different types of natural jute felt material is performed by an experimental method and by using the Dunn and Davern model, along with an inverse characterization method. There are many empirical models available in the literature which describes the acoustical behavior of specific material accurately, as they are specially developed for that material. In this study, the possibility of using only the air flow resistivity based Delany–Bazley model and the Dunn–Davern model for acoustical performance prediction of jute material is tested. However, these two models do not show good matching with the experimental data throughout the frequency range of interest. Particularly in the low frequency region, the level of mismatch between experimental and model data is high. Therefore the inverse prediction of the coefficients
This study prepares and explores the properties of three types of woven fabrics that have electromagnetic shielding effectiveness (EMSE), far infrared (FIR) emissivity, or both (EMSE/FIR). The EMSE woven fabrics use stainless steel (SS) staple blended yarn and the FIR woven fabrics use FIR polyester filaments. The woven fabrics are made with various structures, densities, lamination layers, and warp/weft arrangements in order to yield the optimum EMSE and FIR emissivity. The experimental results show that an increase in SS content slightly increases the EMSE at the frequency range between 300 and 600 MHz, but does not significantly increase the EMSE at a high frequency of between 2000 and 2200 MHz. However, using SS staple blended yarn for both the warp and the weft significantly increases the EMSE by between –8 and –16 dB. The FIR emissivity increases as a result of an increasing amount of FIR polyester filament and reaches the optimum, 0.88.
Filtration performance and fouling behavior of a five-bore hollow fiber membrane was investigated in a membrane bioreactor (MBR) treating printing and dyeing wastewater. A normal single-bore hollow fiber membrane module was used in the same bioreactor for comparison. During an operation over 30 days, the results of chemical oxygen demand (COD) and color removals demonstrated that the five-bore membrane was favorable for this wastewater treatment. The critical flux (Jc) of the five-bore membrane and the single-bore membrane was determined at 21 and 15 L/(m2·h), respectively, using a flux-step method. During a steady running at sub-critical flux of 10 L/(m2·h) without cleaning for 50 days, the average increasing rates of trans-membrane pressure (TMP) for five-bore and single-bore membranes were 0.356 kPa/d and 0.444 kPa/d, respectively, indicating that the five-bore membrane had better fouling resistance. The total resistance values of five-bore membrane and single-bore membrane were 8.68 and 14.1 m–1, respectively. Scanning electron microscope (SEM) and atomic force microscope (AFM) results confirmed the cake layer resistance for five-bore membrane was much lower than single-bore membrane. It was expected that the membrane structure, especially the membrane diameter, influenced the anti-fouling property of five-bore membrane.
The phase structure and dynamic mechanical properties of poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) nanofibers collected in the form of twisted yarn via the two-nozzle conjugated electrospinning method were investigated to study the effects of solution concentration and take-up velocity on the relaxation behavior of nanofibers yarn. The wide-angle X-ray diffraction analyses of P(AN-co-MA) nanofibers show a two-phase structure of nanofibers consisting of crystalline and amorphous phases and polymorphic transition from hexagonal to orthorhombic. Heating P(AN-co-MA) nanofibers at over the glass transition temperature led to an increased degree of both crystallinity and crystallite size with no polymorphic change. Three transitions (tan peaks) were observed in nanofibrous yarn prepared at different spinning dope concentrations and take-up speeds, except for the specimen prepared at a concentration of 14 wt% and collecting speed of 8 cm/min, wherein no α transition was observed due to improved molecular orientation. The temperature dependence of the dynamic Young’s modulus of nanofibrous yarn at different spinning dope concentrations was mainly affected by the diameter of the nanofiber as the morphological property and molecular orientation. Take-up speed was found to affect the and α transitions more than the β transition. Moreover, the maximum storage modulus was obtained at a take-up speed of 8 cm/min at all over recorded temperatures.
Three-dimensional woven fabrics have good structural embeddability, stability and integrity. In this study, three-dimensional double-element fabric antennas (3DFAs) are demonstrated by embedding the microstrip antenna structures into three-dimensional woven fabrics. In order to investigate their electromagnetic performance in practical applications, the 3DFAs are manufactured with different cylindrical radii, ranging from 45 to 75 mm. The professional antenna simulation software and experimental measurements are conducted systematically. Both results match well and support that the 3DFAs with different cylindrical curvature radii share similar rules in return losses and resonant frequencies with the planar 3DFAs. However, the gain values of the 3DFAs show different results when changing the alignment of curvature to the antenna feed direction. The gain value of the 3DFA with the curvature along the feed direction is 5 dB when the curvature radius is 75 mm, while for the 3DFA with the curvature perpendicular to the feed direction, the gain value is just 1.6 dB (R = 75 mm), which then decreases to –2.1 dB (R = 45 mm). Furthermore, when the curvature is along the feed direction, the 3DFAs show a better radiation pattern and directionality.
Research on the simulation and modeling of dynamic puncture penetration is more complex problem due to full consideration of the tightness of the fabric and the sharp profile of the puncture. This study presents numerical simulation of complicated dynamic puncture behaviors on the basis of the roles of extension and stress-wave transmission on the deformation. The unit cell model was used to simulate the yarn crimp and extension during the uniaxial dynamic puncture process. In addition, the puncture deformation and stress distribution of woven fabrics with different elastic modulus and friction distance were simulated followed with dynamic puncture penetration. The result shows that dynamic puncture damage critically depends on the elastic modulus of yarns and the distance between yarns; the inter-yarn distance affects dynamic puncture resistance more significantly. Dynamic puncture stress nonlinearly increases with the elastic modulus, and linearly decreases with yarn distance. The research result indicates that weaving density can be increased to improve dynamic puncture resistance more obviously.
The aim of this study is to design a spinneret that can be used efficiently for the manufacturing of coaxial composite filaments. Poly(ethylene terephthalate) was used as resin matrix with 99.9% pure copper filament as the core. The characterization of the polymer was done to determine polymer thermal and rheological properties. Multi-shaped coaxial composite filaments were obtained after successful laboratory-scale melt extrusion machine modification and spinneret development. The cross-sectional surface and shape were analyzed with a scanning electron microscope. Coaxial filaments having the cross-section including elliptical, triangular, rectangular and circular shapes were developed. The characterization of spinneret design and coaxial composite filaments were also reported. The effect of spinneret design parameters on the cross-sectional shape of the filament were analyzed.
The treatment of cotton fibers using different chemicals, such as alkalis, acids and salt solutions, has captured the attention of researchers because of their important effects in dyeing, cross-linking and mercerizing processes. However, these agents are difficult in terms of process application and the requirement for major effluent treatment prior to discharge. In this paper, we report on the treatment of cotton in aqueous glycine solutions that were moderated, utilizing glycine’s amphoteric nature at different pH values, to enhance the morphological and moisture regain properties of cotton fiber. Treatment in an aqueous glycine solution buffered to pH 11 increased fiber ribbon width by 4.5%, cross-sectional area by 53% and moisture regain by 16%. Changes were dependent on the treatment solution pH value. This paper describes the glycine treatments and their influence on the cotton fiber cross-sectional morphology and regain properties. The results suggest that at suitable pH values aqueous glycine solutions have the ability to enhance cotton fibers in ways very similar to mercerizing.
Natural dye was extracted from Cinnamomum camphora (L.) presl fruit and purified by aqueous two-phase extraction and the macro porous resin adsorption method. The extracted dye was characterized by Fourier transform infrared spectroscopy and liquid chromatography/mass spectrometry. The experimental results showed that the extraction process could be optimized by using a 1:1 mass ratio of water and ethanol as a solvent with the addition of 5 wt% Tween-80 for extracting at 50℃ for 2 h. The extracted dye was applied for the dyeing of wool fabrics, and the optimal dyeing conditions were found to be at 100℃ for 60 min by using 2.5 wt% of antimony potassium tartrate as a mordant. The kinetic study showed that the adsorption of the extracted dyes toward wool fabrics was fitted with the pseudo-second-order model. The dyed wool fabric exhibited excellent color fastness to washing, rubbing and light.
The article presents the results of measurements of pressure exerted by two model knitted products – bands with different structure (WI jersey weft-knitted fabric and WII openwork warp-knitted fabric). The tests were carried out with using the I-Scan system (in vivo and in vitro tests) and the STM 579 device (in vitro test). A comparative analysis of the in vivo and in vitro results for the I-Scan method and in vitro results for the I-Scan and STM 579 method was performed. It was found that the pressure values are lower for openwork warp-knitted fabric than for jersey weft-knitted fabric both in the case of the in vitro and in vivo tests, and the values of pressure for the same band are higher in the case of the in vitro tests.
This paper presents a theoretical bending model to investigate the quasi-three-point bending step of the comprehensive handle evaluation system for fabrics and yarns (CHES-FY). The effect of the friction and extensibility of fabrics on the bending step of the CHES-FY is discussed based on the theoretical bending model in three cases, and bending parameters, including maximum bending force, linear fitting slope and bending work, are featured from the bending force–displacement curves of each case. Comparisons of the theoretical and experimental results were also conducted to validate the model. The results revealed that the friction effect tended to enhance the bending parameters of the bending force–displacement curve of the bending step, and the effect of the friction could be remarkable at low bending rigidity of samples. However, the effect of the extensibility of samples was almost negligible for the bending test of wear fabrics, as the maximal relative error was less than 11.7% for fabrics where the tensile elastic constant was higher than 0.1 N/cm·%. This work can also provide a theoretical guidance for improving the measurement accuracy of the three-point bending test.
Obstructed by the yarn core, the detectable length and the detection rate of a hairy fiber are mainly determined by the geometry of the yarn and the location of the fiber in an optical system. This paper presents a new theoretical method of analyzing detectable angles of yarn hairiness in optical measurements. Firstly, a cylindrical model of the yarn core is constructed by using the yarn diameter, and spiral lines on the cylinder are drawn using the twist angle of the yarn. Secondly, hairy fibers are simulated by short-line segments passing a spiral line and the Z-axis of the model. The yarn model is projected onto a plane under the assumption of a collimated light source, which is the condition similar to that of optical measurements. The yarn model is cut by a plane parallel to the axes of the Cartesian coordinate system (XOY) at the emergence points of hairy fibers. Finally, the relationship between the hairiness length and other factors, such as the test length, yarn diameter and detectable angle (i.e. the angle at which hairy fiber can be detected) is established. It has been demonstrated that the detection angle dictates not only the length of each hairiness but also the rate of detectable hairiness in the scene. Given a detectable angle, the upper and lower limits of detectable hairiness lengths can be predicted. The verification results of the detection rate by three measurement methods indicate that the detection rates of optical measurements have a certain guidance function for correcting the hairiness results of optical measurements.
Hair-wrapping distribution, hair-wrapping direction and yarn moving direction models have been developed to analyze and predict the impact of hair wrappings on yarn properties in theory. Then, Nm 48 ring-spun ramie yarns were respectively treated by various manual hair wrappings, such as the forward diagonal, the forward vertical, the forward random, the backward diagonal, the backward vertical and the backward random. The results showed that the various hair-wrapped yarns had a similar smoothened static surface appearance. Although vertical hair wrappings caused the highest deterioration in yarn unevenness and imperfections, they kept the smallest change of hairiness among all types of hair wrappings during yarn moving. Hair wrapping contributed to large fiber utilization, improving yarn tensile properties, regardless of the worsened yarn unevenness and imperfections. The manual experimental results corresponded well to our modeling suppositions and theoretical analysis.
The most important performance requirement of a traverse mechanism is that the thickness of the silk package formed by the traverse mechanism is uniform or has little variation in the centre. To realize this requirement and overcome the structural shortcomings of traditional traverse mechanisms, a new kind of traverse mechanism is proposed in this paper. The proposed mechanism is characterized by a non-circular gear drive formed by an eccentric gear and a conjugated two-lobed non-circular gear. Its kinematic model is deduced, together with a calculation model for the formed shape of the silk package cross-section. Both of these models contain the influence caused by the shift motion. Based on these two models, a computer-aided analysis program for the traverse mechanism, using MATLAB, is developed and the influences of the mechanical parameters on the formed shape of the silk package are analyzed. Furthermore, the mechanical parameters based on the new traverse mechanism give a better performance when compared with the traditional mechanism.
As basic protective clothing, a chest wader needs to be worn by fishermen during wading work. Its thermal and moisture performance would directly influence fishermen’s comfort and health. In order to increase the thermal-moisture comfort for fishermen, this research aimed to design a new lining chest wader and to carry out both subjective and objective evaluations on its comfort properties. By simulating moisture absorption under a hydraulic pressure environment, we tested the water absorption and conductivity of the selected fabrics and water-absorbent resin materials, and used an appropriate combination of the fabric and the resin to cover different sweating areas of the human body. Ten subjects were recruited to conduct the wearing test on the chest wader to evaluate its thermal-moisture performance. The objective evaluation involved tracking the changes in temperature and relative humidity at four body parts when a participant wore the chest wader, while the subjective evaluation included a questionnaire about the wearing experience on the thermal-moisture comfort and operation convenience. The experimental results showed that the new lining enhanced the comfort significantly. Compared with the common chest wader, the new lining reduced the relative humidity of chest wader on average by 30% approximately, with the largest improvement being at the calf, followed by the thigh and crotch. The thermal-moisture performance of the chest wader was also influenced by the hydraulic pressure of the working environment and the ease allowance to the wearing body.
In this work, a moisture management cotton fabric developed by electrospraying a hydrophobic polymer on the inner surface (close to the skin) of the fabric was investigated. The Janus sheet architecture, that is, one surface ultra-hydrophobic and the other hydrophilic, was obtained in a 100% cotton fabric that is otherwise hydrophilic on both surfaces. The generation of nano-scale surface roughness by electrospraying fluorocarbon resulted in ultra-hydrophobicity (contact angle more than 140 degrees) on the inner surface of the cotton fabric while retaining hydrophilicity (contact angle less than 90 degrees) on the outer surface, thereby imparting the moisture management feature due to one directional water/sweat transport. The overall (liquid) moisture management capability of the cotton fabric could be significantly improved from 2.5 to 4.0, on the scale of 5. The fairly uniform distribution of fluorocarbon as electrosprayed particles on the inner surface of the cotton fabric was revealed by scanning electron microscopy and confirmed by time-of-flight secondary ion mass spectrometry. The developed protocol is eco-friendly and commercially scalable owing to its minimum chemical usage and zero effluent discharge.
Numerous studies have performed analyses of knitted fabric integrating conductive yarn in textile-based electronic circuits, some of which established simulative models such as the resistive network model for knitting stitches. Compared to conductive knitted fabrics, limited studies have been presented regarding the resistive theoretical model of conductive woven fabric. In this paper, a simulation model was derived to compute the resistance of conductive woven fabric in terms of the following fabric parameters: structure, density and conductive yarn arrangement. The results revealed that the model is well fitted (P value < 0.01) and can predict the resistance of woven fabrics, which makes it possible to estimate the fabric parameters and thus to meet the required resistance. Based on this model, thermal conductive woven fabric with maximum energy management and cost control can be efficiently designed.
The aim of the study was to investigate changes of water vapor resistance of coated fabrics with different knitted substrates. For the study different knitted structures were designed and produced, while the conditions for the coating process were kept constant. All structures were exposed to natural weathering in the summer and winter seasons. Thus, the experimental setup enabled the comparison of changes in water vapor resistance of various structures as a result of aging, as well as giving an insight into the differences in resistance after aging in different seasons. After exposure, changes in fabric mass per unit area, thickness and water vapor resistance were observed. The outcomes of the study gave a good insight into the behavior of coated fabrics and may be used when protecting coated materials in order to improve their performance.
A study was conducted on the structure of a single cotton yarn using micro-computer tomography (micro-CT). This article describes two important parameters determining the unevenness of yarn structure, i.e. the migration of staple fibers and packing density of staple fibers in the yarn cross-section. Relationships were found between the variation of staple fiber migration characteristics and the relationship between yarn durability and twist. For the boundary value, the radius and range of migration are the highest, and the variation coefficient of the fiber migration range is the lowest. The number of fibers in the yarn cross-section decreases with twist. Above the boundary twist value, the number of fibers in the yarn cross-section stabilizes at the value corresponding to the number of fibers in the boundary twist.
Biopolymer nanocomposites containing metal nanoparticles have attracted much attention due to their excellent properties and broad applications. In this work, alginate fibers embedded with silver nanoparticles (AgNPs) were prepared. The as-obtained alginate-AgNP fibers exhibited antibacterial activity against both Gram microorganisms of model microbes Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). A growth kinetic study with S. aureus and E. coli displayed the inhibition of bacterial growth at the logarithmic phase. The cytotoxic effect of the fibers in human cervical cancer (HeLa) cells was assessed by cell counting kit-8 (CCK-8) assay and flow cytometry. The as-prepared alginate-AgNP fibers, particularly with high amount and long treatment time, showed high cell-killing efficiency. These findings emphasize that such alginate-AgNP fibers with multifaceted biological activities are a promising material for applications in the textile or biomedical fields.
This article reports the successful manufacturing of hybrid yarns from virgin staple CF (40 or 60 mm) or recycled staple CF (rCF) by mixing with polyamide 6 (PA 6) fibers of defined length. The hybrid yarns are produced using an optimized process route of carding, drawing, and flyer machine. Furthermore, the influence of CF length, CF type (i.e. virgin or rCF), CF volume content, and twist of the yarn are also investigated regarding the tensile properties of unidirectionally laid (UD) thermoplastic composites. The results show that CF length, yarn twist, and CF content of composites play a big role on the tensile properties of thermoplastic composites. From the comparison of tensile strength of UD composites produced from 40 and 60 mm virgin staple CF, it can be seen that the increase of yarn twist decreases the tensile strength. However, the effect of twist on the tensile properties of UD composites manufactured from 40 mm virgin staple CF is insignificant. The tensile strength of UD thermoplastic composites manufactured from the hybrid yarn with 40 and 60 mm virgin staple CF and rCF is found to be 771 ± 100, 838 ± 81, and 801 ± 53.4 MPa, respectively, in the case of 87 T/m containing 50 volume% CF.
In order to realize the ultraviolet (UV) protection property and antimicrobial activity simultaneously, as well as the natural dyeing process, oak bark extract was prepared and applied to dye tussah silk fabric. The effects of dyeing pH value, temperature, time and mordant kinds on dyeing properties of tussah silk fabric were analyzed. The results indicated that the optimum direct dyeing conditions were as follows: pH 5.0, temperature 98℃, time 80 min. As for the mordant dyeing process, the K/S values of the post-mordant dyed samples were higher than those of the pre-mordant dyed samples. The color of the direct, aluminum potassium sulfate, copper sulfate and the ferrous sulfate dyed samples were brown, yellow-brown, dark brown and gray black, respectively. The washing, rubbing and light fastness of the three mordants dyed samples were all good. Moreover, the dyed samples showed an excellent UV protection property and antimicrobial activity. The UV protection factor values of the mordant dyed sample were more than 40; the reduction in bacterial count percent against S. aureus and E. coli reached up to and above 85% and 80%, respectively; and the weight gain rate was more than 6%. Furthermore, the dyed samples had good washing durability of the UV protection function and antimicrobial activity even after 50 consecutive launderings.
This research aims to develop multifunctional polypropylene (PP) fiber with a far-infrared ray emission property and microorganism resistance. The processing parameters, including powder proportion, twin-screw mixing and melt spinning, were planned using the Taguchi method, gray relational analysis and the technique for order preference by similarity to ideal solution. The emission test results showed that the far-infrared ray emission value of composite fiber was 85%, which is 2.3 times that of pure PP. According to the far-infrared ray emission temperature rise test, the composite fiber temperature increases by 8.6℃, which is 43% higher than the 6℃ temperature rise of pure PP. The antibacterial test showed that the composite fiber has an antibacterial effect on staphylococcus aureus and pneumobacillus. Moreover, the composite fiber of PP with nano silicon dioxide and zinc oxide met the far-infrared ray emission property FTTS-FA-010 and qualitative antibacterial JIS L-1902 standards.
With the rapid increase of personalized garment requirements, intelligent garment design has attracted more and more attention. The study reported in this paper concentrates on the modularized design method of garments in order to provide theoretical support for intelligent garment design. The proposed modularized design method consists of composition and transformation of garment parts as well as their configuration and connection. There are two categories of garment parts: essential parts and non-essential parts, each of which is determined by their key design attributes. Rules of transformation for garment parts were analyzed by classification of transformation rules. Binary decision variables were introduced to decide if garment parts should be selected. A mathematical model was developed to analyze constraints of garment parts connection.
Highly aligned polyacrylonitrile (PAN) nanofiber yarns were prepared continuously by a modified electrospinning method. The effects of the different spinning parameters, including applied voltage, solution flow rate, distance between two needles, distance between the neutral metal disc (NMD) and neutral hollow metal rod (NHMR) and rotation speed of the NMD, on yarn formation and physical characteristics of the nanofibers and the yarns were analytically investigated. The distance between two needles, distance between the NMD and NHMR and rotation speed of the NMD were found to be three main parameters affecting nanofiber alignment of the resultant yarns. The results also showed that the applied voltage and rotation speed of the NMD had a very slight effect on diameters of nanofibers. The diameters of both nanofibers and yarns increased to a threshold value and started to reduce thereafter with the distance between two needles increasing. The diameters of both nanofibers and yarns presented the increasing trend at the higher flow rate. Meanwhile, the yarn diameters decreased with increasing the distance between the NMD and NHMR and the rotation speed of the NMD. Moreover, the effect of nanofiber alignment on the mechanical property of the resultant PAN nanofiber yarns was also investigated in this paper. It was found that the increase in the fiber alignment brought about the improvement in the yarn tensile strength. Eventually, the obtained continuous PAN nanofiber yarns were employed to manufacture fabrics by traditional textile techniques, including braiding, weaving and knitting, which showed the potential application in the textile industry.
Patterned fabrics may be regarded as periodic textures, which are defined as the regular tessellation of a primitive unit. A patterned fabric is considered as defective when a primitive unit is different from the others. In this paper, we propose a one-class classifier that uses Reduced Coordinated Cluster Representation (RCCR) as features. In the training step, the size of the primitive unit of defect-free fabrics is automatically estimated using a texture periodicity algorithm. After that, the fabrics are split into samples of one unit and their local structure is learnt with the RCCR features in a one-class classifier. During the test step, defective and non-defective fabrics are also split into samples and are analyzed unit by unit. If the features of a given unit do not satisfy the classification criterion, it is considered to be a defect. Among the advantages of the RCCR is that it represents structural information of textures in a low-dimensional feature space with high discrimination performance. Results from experiments on an extensive database of real fabric images show that our method yields accurate detections, outperforming other state-of-the-art algorithms.
Textiles made of natural fibers, both contemporary and historical, are at constant risk of degradation caused by, among others, microbial enzymatic activity. Fungi, bacteria, or actinomycetes are capable of producing proteolytic and cellulolytic enzymes, enabling microbial growth on textiles and leading to their decay. Ensuring proper storage conditions, including the usage of protective materials, allows long-term preservation of historical textiles in a good condition. These studies involved a broad microbiological analysis in order to verify whether high-density polyethylene (HDPE) materials can protect historical textiles during their storage. The results demonstrate interesting differences in microbial counts between washed textiles stored without HDPE covers and those stored in such covers; the latter presented considerably higher counts of microorganisms. However, when textiles had previously been sterilized, HDPE covers helped maintain appropriate microbiological purity. A considerable portion of historical textile collections, particularly exceptional silk liturgical vestments or burial garments, are kept by church institutions and stored in sacristies, treasuries, or other church rooms. The specificity of these places, both cultural and related to the age of the buildings themselves, makes them exceptional environments for storing textiles. To date, these places have rarely been researched, particularly in microbiological aspects. The analysis recounted below encompasses qualitative and quantitative assessment of fungi and bacteria present in the air of the treasury of the Wawel Royal Cathedral in Krakow, Poland, as well as the analysis of their destructive potential.
Hydrophobic surfaces have great potential in applications in oil–water separation, super water/oil repellents, friction reducing, etc. Hydrophobic performance has been extensively investigated in view of smart textile development. Oxidized multi-walled carbon nanotubes (CNTs) and graphene oxide (GO) were grafted with perfluoro-1-iodohexane, and 10.24 and 17.65 at% fluorine contents of these functional products were obtained, respectively. The surface chemistry of the functionalized CNTs and GO were characterized by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Hydrophobic textiles were achieved by treating the functionalized CNTs and GO using a common dip-dry method. The functionalized CNTs and GO were also applied to polyvinylidene fluoride filter paper by the vacuum filtration method to form hydrophobic films. The morphologies of these surfaces were characterized by field emission scanning electron microscopy. The functional cotton fabrics showed hydrophobicity with water droplet contact angles (CAs) of 149.1°and 154.4°, respectively. The produced films showed hydrophobicity with CAs of 108° and 151°, respectively. The difference of the CA was attributed to the diversity of both the structure and the chemical composition. In future study, multifunctional materials could be created on the basis of the hydrophobic surfaces reported in this paper by combining them with other functional components, which has great potential in applications in the smart textiles.
Color texture classification as a part of fabric analysis is significant for textile manufacturing. In this research, a new artificial intelligence method based on a dual-side co-occurrence matrix and a back propagation neural network has been proposed for color texture classification, which could achieve relatively accurate classification results for yarn-dyed woven fabric compared with the traditional co-occurrence matrix for a single-side image. Firstly, a laboratory dual-side imaging system has been established to digitize the upper-side and lower-side images sequentially. Secondly, the dual-side co-occurrence matrix could be generated based on these dual images; four texture features could be extracted for the evaluation of the fabric texture characteristics. Thirdly, a well-trained back propagation neural network was established with the four defined features as the input vectors and the color texture type of yarn-dyed woven fabric as the output vector. The efficiency of two different classification systems based on a dual-side co-occurrence matrix and a single-side co-occurrence matrix has been compared systematically. Our experimental results show that the artificial intelligence system based on a dual-side co-occurrence matrix and back propagation neural network model could achieve a relatively better classification effect, with the high coefficient ratio (R = 0.9726) when d = 0.
An image database of printed fabrics with repeating dot patterns was created to alleviate issues associated with management of and searches for numerous dot printed fabrics in the printing industry. The function of the database is to archive and allow retrieval of images. First, we discuss image archiving of repeating pattern-based dot printed fabrics. The color image was scanned by resolution of 200 dpi. The wavelet transformation was used to preprocess the image to obtain a scanned image 1/16 of the size of the original to be the stored image. To acquire images with repeating pattern color and repeating pattern template, the binary image of each pattern was obtained using the Sobel edge detection method and a morphological operation. Then pattern elements identical to the target pattern element were screened out. Afterwards, the centroid positions of these identical pattern elements were used to subdivide the repeating pattern color image and repeating pattern template image using a vertical vector method. Finally, the RGB 512-color histogram was used as the color feature of the dot printed fabrics, and the geometric and moment invariant feature values of the repeating pattern template image were used as the pattern feature of the dot printed fabrics. Our experimental results show that images can be acquired that are suitable for use in a dot printed fabric image database. The color and template images of the repeating patterns, which represent the image content of the printed fabrics, were obtained to create an image database of repeating pattern-based dot printed fabrics. This image database contains data on 300 printed fabrics which can be used for subsequent research on database image retrieval.
Biodegradable intravascular stents could become totally degraded after supporting the stenosis diseased vascular without risks of thrombus and restenosis. As the earliest used biodegradable material on stents, poly-l-lactic acid (PLLA) has favorable mechanical and degradable performance. In this paper, poly-lactic acid was used as a stent material for the imitation of the S7 stent (Medtronic AVE, Minnesota, USA). The Z-structure stent was designed and constructed with textile methods by wounding and bonding the strut with a cylindrical mold. Poly-lactic acid Z-structure stents were made into different forms with two different bonding methods for the comparison of stent mechanical properties. In the meantime, polydiaxanon monofilament was used for the preparation of the Z-structure stent and WallStent to compare with poly-lactic acid stents. The stent radial force was tested by the platform compression method. Experimental results showed that the polydiaxanon Z-structure stent had a higher radial force than the poly-lactic acid ones because of better mechanical properties of the strut. Small-diameter stents expressed higher radial force, whereas stents with more crown rows had lower radial forces. Stents bonded with medical glue had higher radial force but lower fastness and inefficient self-expanded performance. The WallStent and Z-structure stent both had favorable elastic resilience performance, whereas the Z-structure stent performed better in compression resistance under large deformation
The spinning triangle is a critical region in ring spinning. To understand the formation principle of the triangle zone, a dynamic mesh model with SIMPLEC algorithm is employed to study airflow around the rotating front roller-pair. The effects of both the top roller offset and the drafting inclination angle are also discussed. The bubble-type vortex breakdown and vortices around two cylinders are observed. The bubble-type vortices will help the edge fibers to converge to the center. A contour line with special value is defined to describe the spinning triangle. A dynamic triangle zone is also observed with time. As the forward offset of the top roller increases, the velocities in the stream-wise (x- and y-) directions decrease and the maximum values of the skin friction deflect gradually towards the apex of the roller. However, the z-velocity for the 3 mm top roller offset is the largest and results in a good converging for fibers and, consequently, increases the yarn tension. With increasing the inclination angle, the velocities increase while both the defined triangle zones and the maximum values of the friction coefficients decrease, thus speeding up the fibers transportation. The simulation results agree well with the theory analysis and experiments of spinning.
In this paper, patterned nanofibrous membranes were fabricated for air filtration. Polyacrylonitrile was employed as the electrospinning material as its fluffy property and bulged bubble template served as collector to prepare the patterned membrane. With this special structure, the pressure drop significantly declined from 151.7 to 24.7 mmH2O, although the filtration efficiency of nanofiber membranes exhibited a slight decline from 99.94% to 96.33% compared to traditional electrospinning nanofibrous membranes. These sharp declines of the pressure drop while retaining the filtration efficiency imply that it could have more extensive applications.
Designing medical devices requires a wide range of verification steps for estimation of the performance and safety. Designing the research program needs a rational selection of appropriate testing methods (in preclinical and clinical studies) for determination of the risk of potential incompatibilities resulting in adverse events. The significance of the appropriate selection of the testing method is increased in advanced medical devices. The presented research considers the verification of the functional properties of recently developed topical haemostatic agents with the use of the chitosan/alginate fibrids, based on the previously elaborated risk analysis made according to the guidelines of the PN-EN-ISO 14971:2012 and PN-EN ISO 22442-1:2008 standards.
The aim of this research was to verify the stability of the performance of the newly developed haemostatic agents during storage. The defined aim of the study arose from the thesis that the appropriate selection of raw materials and a new manner of reprocessing them enabled keeping the usability of the final product for at least two years.
To simulate the structural deformation behavior of Jacquardtronic lace, which is formed on a multibar Jacquard Raschel machine and is widely used in female fashion, the key influencing factors on structural deformation were introduced and a tailored mass-spring model was built in which the lace was considered to be numbers of evenly distributed particles connected by elastane springs. These springs covered structural springs, restriction springs and spiral springs, respectively, created for ground pillars, Jacquard inlays, pattern lapping and elastane yarns. The elastane force on particles was analyzed to study motion state and deformation behavior with the explicit Euler method. The deformation simulated models were implemented by a simulator program via Visual C++ and were tested with a lace sample. Particular attention was paid to analyzing the effect of Jacquard structures and yarn tension on deformation and the detection model was introduced to avoid improper deformation caused by excessive yarn tension. The simulation results showed practicability and efficiency when compared with the real sample.
In this study, conventional long ramie fiber was stretch-broken into short fibers with lengths of 30 mm, 35 mm, 40 mm, 45 mm, and 50 mm. Then, these stretch-broken fibers were processed in a cotton spinning system. The results show that, compared to long ramie fibers processed in a conventional ramie spinning system, the stretch-broken fibers, with reasonable fiber length and high length uniformity, can be processed in a cotton spinning system with high efficiency and generally have better resultant yarn quality. For all of the stretch-broken yarns, the yarn processed from fiber with 40 mm length shows the best comprehensive performance.
A novel three-dimensional (3D) braided material was obtained using group theory. The 3D braided structural unit was found by means of group elements in the point group 4. Based on the symmetry of space group P4, a novel 3D braided material geometry was deduced by transforming the unit. Analyzing the conceivable motion of the yarns, it was found that the geometric structure corresponding to a novel 3D braided material was feasible. The mathematic model for describing the geometry of this novel material was established. The fiber volume fraction of the material was predicted and its value is similar to the traditional four-step 3D braided material. A first prototype of the fabric is produced using manual production.
Combat helmets have been utilized to provide protection against a variety of ballistic threats, by reducing traumatic head injuries and fatalities. Nevertheless, head protection from injury is critical to function and for survivability. Soldiers and civilians incur Traumatic Brain Injury (TBI) most commonly from exposure to homemade bombs or improvised explosive devices. Although the Personal Armor System for Ground Troops (PASGT) helmet is expensive, environmental issues are some technical advantages that encourage using natural/synthetic hybrid laminated composites. The effects of different configuration patterns of kenaf fibers on the Backface Signature and energy absorbed by a military helmet (PASGT) were investigated. The ballistic behaviors of the 19 layers of aramid composite and plain woven kenaf composite were compared to hybrid laminated composites. The ballistic impact tests were performed using a 9 mm full metal jacket bullet and fragment simulating projectiles at various impact velocities, using a powder gun on fabricated square panels and helmets. The results showed the positive effect of hybridization in terms of energy absorbed (i.e. penetration), Backface Signature and damage mechanisms for ballistic impact and NIJ (National Institute of Justice) tests. Hybridization of plain woven kenaf/Kevlar laminated composites will open new avenues to reduce the dependency on the ballistic resistance component (Kevlar) in the helmet shell.
Energy absorptions of a three-dimensional braided composite panel under impact punch shear loading were investigated in testing and numerical calculation. The impact punch shear behaviors were tested on a split Hopkinson pressure bar system. A finite element model was established to numerically characterize the shear behaviors. From both the approaches, we found that the energy absorption is sensitive to strain rate, braided angle and thickness. Based on the numerical calculation and scanning electronic microscopy observation, the energy absorption mechanisms are fiber breakage and pullout, resin debris and panel deformation.
To improve the flame retardancy of polyamide 6 (PA6) fibers, melamine cyanurate (MCA)/PA6 composites were synthesized via in situ polymerization of -caprolactam in the presence of adipic acid-melamine salt and cyanuric acid-hexane diamine salt. The flame retardant MCA/PA6 composite fibers were prepared by melt spinning. The structure and properties of MCA/PA6 composites and MCA/PA6 composite fibers were studied by Fourier transform infrared spectra, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, tensile tests, vertical burning tests (UL94) and limiting oxygen index (LOI) tests. Experimental results indicated that the MCA/PA6 composites loaded with 8 wt% of additives can achieve UL94 V-0 rating with an LOI value of 29.3%. The tenacity at break of PA6 fiber decreased from 4.85 to 3.11 cN·dtex–1 for MCA/PA6-8 composite fiber. However, the MCA/PA6 composite fibers can effectively suppress the propagation of flame in fabric. This means that the in situ polymerization approach paves the way for the preparation of MCA/PA6 composites that have good spinnability and flame retardancy.
This paper presents how the morphology of fibers is affected by CO2 laser treatment. The change in morphology of fibers induced by a laser affects the physical and mechanical properties of the fabric, such as water absorption, dye uptake, resistance to wrinkles and adhesion to other materials, etc. The morphology of laser-treated fibers was analyzed by scanning electron microscopy (SEM). Samples of cotton twill fabric, cotton/polyester blended twill fabric and cotton knitted fabrics with different yarn counts were studied before and after laser treatment. SEM images reveal different sizes of pores and cracks on the surface of cotton fibers. In the case of cotton/polyester blended twill fabric, the two types of fibers responded differently to laser treatment; the change in cotton fibers was slightly different from the SEM images of 100% cotton twill fabric. The number of pores and cracks on the fiber surface of cotton/polyester fabric was lower than that found in 100% cotton twill fabric. Polyester fibers melt and flow while cotton fibers are encased in resolidified polyester. For 100% cotton knitted fabrics, the thickest yarn with the lowest yarn twist exhibited the largest change when compared with fabrics knitted with lower yarn counts. The degree of change of fiber surface modification was enhanced with an increase of laser processing variables.
A modular approach for arranging the component layers used in the construction of structural firefighter turnout garments is explored as a strategy for reducing the thermal burden contributed by these protective garments to firefighter heat stress. An instrumented sweating manikin was used to measure the insulation, evaporative resistance and total heat loss through turnout systems configured to represent different layering strategies. The outer shell, moisture barrier and thermal liner layers of the structural turnout base composite were tested individually to determine each layer's thermal insulation and evaporative resistance. Multiple two- and three-layer combinations were analyzed for their application in specific working conditions. This study demonstrates that the moisture barrier layer contributes the most resistance to evaporative heat loss through the turnout system, while dry heat loss is most restricted by the thermal liner component. Removal of a single inner liner layer was equally beneficial for heat loss, regardless of material properties. It shows the potential benefit of turnout design strategy that utilizes a modular or adaptive layering approach to reduce turnout-related heat strain in conditions consistent with fire protection.
In order to obtain deformation behavior and volumetric characteristic of fancy weft knitted fabric, loop models are built on improved particle systems in this article. The problem of the non-uniform rational B-splines (NURBS) curves, which cannot pass through all control points, is solved by using an interpolation algorithm which can generate new auxiliary points. To simulate the twist of folded yarns, the NURBS curves are regarded as the geometric center, which is rotated with cylinders whose three relative Euler angles are calculated by the spatial coordinates of adjacent points. By analyzing the relationship between the deformation of the loop and the displacement of the particles, the deformation behavior of fancy weft knitted stitches is simulated. Velocity-Verlet, a numerical integration, is introduced to simulate fancy weft knitted stitches, and stable results are obtained. The results show that these models and algorithm accurately display the deformation behavior of fancy weft knitted stitches, as demonstrated by qualitative comparisons to measure the deformations of actual samples, and the simulator can scale up to animations with complex dynamic motion.
An improved heat transfer model, based on the two-flux model, in a multilayer flame-resistant fabric system with an air gap was proposed. The developed model considered the thermal radiation by absorbing, transmitting, emitting and reflecting in porous fabrics. The predicted results of the new model were compared with the previous Beer’s law model and the experimental results, and were found to be in good agreement with the experimental ones. The aim of this study is to investigate the mechanism of radiant heat transfer in the multilayer fabric system and the effects of the optical properties of flame-resistant fabric on heat transfer in the fabric system. The numerical results demonstrated that the self-emission in multilayer fabric system increases not only the rate of thermal energy transferred to human skin during thermal exposure, but also the rate of thermal energy transmitting to the ambience during cooling. The fabric’s optical properties have a complex influence on the transmitted and stored energy in multilayer protective clothing. The finding obtained in this study can provide references for the improvement of the thermal protective performance of flame-resistant fabrics.
This paper reports an investigation of dyeing processes of textiles made from a novel 100% bio-based and fully degradable polylactide/poly (hydroxybutyrate-co-hydroxyvalerate) (PLA/PHBV) fiber. The dye exhaustion, depth of shade and fastness, as well as bursting strength of dyed PLA/PHBV fabrics have been evaluated in terms of types and concentration of dyestuff, dyeing bath temperature, duration, liquor ratio and pH value. Finally, the energy cost of the whole dyeing process of the proposed material is calculated and compared with that of polyethylene terephthalate. The experimental results show that an excellent dyeing effect and bursting strength can be achieved by properly applied dyes (e.g. C.I. Disperse Orange 30, Red 74, and Blue 79) under optimal low-dyeing-temperature conditions (100℃, 10 min, pH 5, LR 30:1). In addition, considering the low energy cost during the whole process, PLA/PHBV fibers can be regarded as a promising and environment-friendly material for the textile industry.
Polarizing films are critical components for a wide range of products and their inspection is helpful to enhance product quality. Inspection and classification of the normal and five types of defects for polarizing films are presented using image processing and neural network approaches. The defects are cloud chromatism, strip chromatism, spot chromatism, scratch and poor pasting. Three features, the area, average intensity and compactness, are selected according to the shapes and brightness of the defects regions. The number of training samples are 20, 30 and 40, and the number of testing samples is 40. The results show the recognition rate is 100% when the number of training samples is greater than or equal to 30, proving that the back-propagation neutral network can achieve a high recognition rate with enough training samples, and it can be successfully applied to the inspection of polarizing film defects.
Structural changes in mercerized cotton by liquid ammonia (LA) treatment were investigated and correlated with changes in dyeability of cotton fabrics with reactive dyes. The pore structures of mercerized cotton and mercerized-liquid ammonia (M-LA) treated cotton were characterized by inverse size exclusion chromatography (ISEC). Results showed that when the mercerized cotton was subjected to LA treatment, cumulative accessible volume of smaller pores (e.g., 25.2 Å) increased, whereas that of the larger pores (e.g., 56.7 Å) decreased. These results might be related to the changes in the amorphous region of cotton fiber. The decrease in crystallinity of cotton fiber would increase accessible volume of smaller pores. The larger pores might be compressed by extrusion during swelling of microfibrils or elementary fibrils in water. The change in dyeability of fabrics with reactive dyes of various molecular weights could be rationalized using the observed changes in pore structure. Results also showed that ISEC was more suitable than the method employing Chrastil's diffusion equation for analyzing the pore structure of cotton fiber.
In this study, the microbial barrier properties of textiles for two bacterial endospores were investigated. The reusable hospital textiles (PET/cotton and Tencel®) most commonly recommended for the manufacture of healthcare professional uniforms were tested for microorganism permeability. The three-layer textile laminate PET/PU/PET, which meets the European standards for surgical drapes EN 13795, was used as the reference material in this study. The microbial barrier properties of PET/cotton, Tencel®, PET/PU/PET, and corresponding seams were tested after 1, 10, 20, 30 and 50 washing-and-sterilization cycles. Washing and sterilization were performed by hospital laundry services under strict and controlled conditions. The testing of dry textile materials was conducted under newly developed methods. The most resistant forms of microorganisms of apathogenic bacterial endospores of the Bacillus genus Geobacillus stearothermophilus and Bacillus atrophaeus were used for investigating the microbial barrier permeability of textiles. This research is the first to investigate the permeability of these microorganisms in dry conditions. Additionally, the microbial barrier properties of the seams of these textiles were investigated. Regression analyses were performed and the effects of the seams on microorganism permeability were determined. It can be concluded that the two most commonly used seam types for the manufacture of healthcare uniforms do not have a significant influence on microbial barrier efficacy; however, the seam type 1.01.05/504.504.301 is more suitable for the manufacture of healthcare professional uniforms.
The comprehensive handle evaluation system for fabrics and yarns can be used to measure the bending property of fabrics and yarns based on three-point bending, in principle. In order to gain a better understanding of the bending mechanism of woven fabrics under three-point bending and to better interpret the influencing factors in the bending process, weaving-structure models of woven fabrics were built using finite element analysis based on ABAQUS software. Simulated bending force–displacement curves were compared with experimental curves based on the bending characteristic parameters extracted from the curves, and stress distribution on the fabric and the pressing pin were visually displayed during the bending process. The results show that the simulated curves have good agreement with the experimental curves. The effects of the property parameters of materials, including the Poisson’s ratio, friction coefficient and modulus of yarns and the structure phase and thread arrangement density of fabrics, as well as apparatus parameters, including diameters, the interval of the supporting pins and the distance of the jaws, on bending test were investigated. It is expected that the three-point bending method will help better characterize the bending property of textile materials.
The air-interlacing nozzle has a yarn channel, an air inlet and a yarn-loading slit. The previously investigated optimum air-interlacing nozzle was analyzed to improve the airflow loss through the slit by reducing the width of the slit and by applying TRIZ tool. TRIZ, the theory of inventive problem solving, was applied to find a solution for the airflow loss through the yarn-loading slit. The airflow inside the air-interlacing nozzle was computed using ANSYS CFX software. The computational results of the air-interlacing nozzle were evaluated by the vorticity, velocity and the airflow loss. The vorticity was increased and the airflow loss was improved slightly when the width of the slit was reduced. The yarn-loading slit is for the yarn loading into the yarn channel before the air-interlacing process. The technical contradiction of the air-interlacing nozzle was that reducing the width of the yarn-loading slit makes it difficult to load the yarn into the yarn channel. Principles 10 and 31 of TRIZ were obtained through the contradiction matrix and were applied to the nozzle. The computational results showed that the vorticity and velocity were increased and the airflow loss through the slit was improved. The air-interlacing nozzle after applying principles of TRIZ showed better results when compared numerically and experimentally with other existing nozzles.
Polyacrylonitrile (PAN) fiber coated with photocatalyst titanium dioxide (P25) was successfully fabricated by a dip coating process using dimethyl sulfoxide (DMSO)/ethanol (EtOH) as co-dispersion solvent. Photocatalytic performance of P25-coated PAN fibers was evaluated by degrading a model dye rhodamine B (RhB) in aqueous solution under ultraviolet (UV) light irradiation. The preparation parameters of P25-coated PAN fibers were optimized by an orthogonal design, and were found to be a P25 concentration of 0.05 g/L, a ratio of 85/15 (v/v) DMSO/EtOH, and a take-up speed of 0.5 m/min. A possible mechanism of co-dispersion solvent dip coating was proposed based on Hansen solubility parameters’ theory. The P25-coated PAN fibers prepared at the optimum conditions had high dye removal efficiency. They also showed an excellent cycling performance for dye removal of up to 99% recovery over several cycles. The coating process has little impact on both the fiber strength and the breaking strength. The breaking strength of P25-coated PAN fibers was maintained even after several cycles. This study provides an easy-to-scale-up method for preparing P25-coated PAN fibers. The obtained P25-coated PAN fibers show great potential as a low-cost, easy handling, and recyclable photocatalyst for dye effluent treatment.
In order to endow cotton fabric with the full wave band (290–410 nm) ultraviolet (UV) protection property, ionic liquid iron coordination complex (ILICC) was applied to modify cotton fabric. ILICC was prepared by in situ reaction on the surface of the cotton fiber directly. The Fourier transform infrared spectra, thermogravimetric and differential scanning calorimetry curves indicated that the strong interaction between ILICC and cellulose macromolecules of cotton fiber occurred through the O-Fe bond. Scanning electron microscopy images and particle size analysis indicated that the surface of the modified cotton fiber was covered by the agminate ILICC particles with diameters of 700–1600 nm. Investigation on the UV protection performances indicated that the UV transmittances (T%) of the modified cotton fabric were less than 1.3% for the full wave band (UVA and UVB) UV. The washing durability results showed that the UV protection factor values were more than 95 when the modified cotton fabric was washed with 30 st washing cycles. The reason for the excellent UV protection performance of the modified cotton fabric was absorption and shielding of ILICC particles to UV light.
The ability of a textile product to change shape under motion-based diagonal forces defines the shear behavior of a fabric and its suitability for a wearable garment design. The principal aim of this study is to introduce a new shear frame and investigate the effects of raw material and setting on in-plane shear behavior of woven fabrics. For this purpose, the mechanical properties of systematic and commercially available non-systematic fabrics were measured. A novel approach to determine the in-plane shear behavior of woven fabrics via two complementary shear frame measurements was presented. The results were also compared with a conventional method known as the bias extension method. It was established that the proposed method provides more accurate and precise results. In order to investigate the correlation between in-plane shear behavior and other mechanical properties, bending rigidity and extension ability of fabrics were measured as well. The analyses regarding the relations between selected fabric parameters showed that there are considerably high correlation coefficients. The effect of raw material and setting was likewise found out to be statistically significant.
Shell formation process is a very vital step in the fabrication of melamine-formaldehyde microencapsulated phase change materials (microPCMs). In this research, the effects of parameters in this process, including system pH value, initial temperature and dropping rate of the prepolymer, were studied systematically to prepare microPCMs with potential application in thermo-regulated textiles. The various properties of obtained microcapsules were investigated by scanning electron microscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Revised encapsulation efficiency (RE) was calculated with a new method based on the results of DSC and TGA, and was used to characterize the encapsulation efficiency of the microPCMs. The experimental results indicated moderate pH, such as 4.6, benefited the formation of regular spherical capsules with high encapsulation efficiency. The products prepared at low pH were almost irregular aggregates, while the microcapsules formed at high pH were easily damaged. It was found that the microcapsules synthesized at a lower initial temperature, such as 40℃, presented poor appearance and low encapsulation efficiency. The suitable initial temperature for shell formation was about 75℃. With the decrease of the dropping rate, the surface morphology of microPCMs showed obvious improvement, while the increment speed of RE was slow. The medium dropping speed could be selected to ensure the encapsulation efficiency as well as the productivity in this experiment. It was also found that RE could reflect the effects of these parameters more accurately in comparison with the conventional apparent encapsulation efficiency (AE).
Sodium hydroxide is commonly used as the main alkali source in the oxidation degumming of ramie in the current studies for natural fiber extraction. However, due to the strong alkalinity of sodium hydroxide, the oxidation reaction speed of hydrogen peroxide is difficult to control and thus results in great damage to the treated fibers. In this paper, magnesium hydroxide was selected as an effective sustained-release alkali source to improve the tensile properties of degummed fibers and reduce the chemical oxygen demand (COD) values of degumming wastewater. This novel reagent can adjust and buffer pH values in the degumming solution. The chemical components and structure properties of degummed fibers were characterized by Fourier transform infrared spectroscopy and X-ray diffraction, respectively, and the as-developed oxidation degumming solution performance was monitored by an oxidation–reduction potentiometer. The results showed that the optimal substitution rate of magnesium hydroxide was 20% during the oxidation process. Compared with the degummed fibers without magnesium hydroxide, the tenacity, work of rupture and degumming yield of treated fibers increased by 39.82%, 46.15% and 5%, respectively. Moreover, the COD values of wastewater decreased by 20% at the same time.
According to the yarn mechanism of self-twist jet vortex spinning, this article analyzes the structure and the fracture mechanism of self-twist jet vortex spinning yarn. Combined with experiments, this article established that the fiber in self-twist jet vortex spun yarn has self-twist, which increases the mutual contact area and the cohesion between the fibers in the yarn. This is helpful to improve the evenness and tensile properties of jet vortex spun yarn. The self-twist jet vortex spinning can keep the high spinning speed of the jet vortex spinning at the same time. The research on self-twist jet vortex spinning lays the foundation for the research and the development of jet vortex spinning.
A three-dimensional particle-level simulation method is developed to simulate fiber dynamics in the ring spinning triangle. The fiber is modeled as a chain of beads connected through massless rods, and its flexibility is defined by the stretching, bending and twisting displacements. As the application of the proposed approach, the effects of the chitosan (CS)/cotton (CT) fiber initial position and length on fiber motion and yarn properties are discussed. The deflections of CS fibers along the roller axis are larger compared with those of CT fibers, which will lead to CS migrating outwards in CS/CT blended yarn. The short CS fibers (22 mm) will move toward the top roller surface and shift quickly out of the roller nip, and thus yarn strength is lower. The tailing end of the longest CS fiber (46 mm) will drift off the roller nip, which makes little or no contribution to the yarn strength. For 38 mm length CS fiber, it moves toward the bottom roller surface and is bound into the roller nip, and thus can produce the highest tenacity CS/CT blended yarns. The simulation results agree with the spinning experimental data reported by other researchers.
Oxidative degumming with hydrogen peroxide provides an efficient pathway and new alternative for natural fiber extraction. In this work, the oxidized cellulose introduced into ramie fibers during the oxidative degumming process was systematically characterized in terms of x-ray photoemission spectroscopy, nuclear magnetic resonance, Fourier transform infrared spectroscopy and scanning electron microscopy. The differences of chemical components, chemical shift, surface structure and surface morphology were analyzed and compared within oxidized cellulose fibers with different oxidation degrees. In addition, the relationship between oxidized cellulose contents and mechanical properties of degummed fibers were further discussed. The results show that the number of oxidized groups increases with increasing oxidation. In addition, the greater presence of oxidized cellulose contributes to a larger loss of tenacity, breaking elongation, flexibility and degree of polymerization in degummed fibers. This study could offer useful information in better understanding the reaction characteristics of oxidative degumming and better control of degummed fiber quality. The contents of oxidized cellulose in ramie fibers could be an effective indicating factor to demonstrate oxidative degumming efficiency and fiber properties.
A kind of paper-based composite was prepared with short carbon fibers (CFs) and para-aramid fibrids through the process of papermaking. The dielectric properties of the paper-based composites at microwave frequency were investigated. Based on the Lichtenecker Rule, the dielectric constants of CFs in composites at different CF concentrations were calculated. The absorbing performances of paper-based composites were calculated from the test results of electromagnetic parameters. It was shown that for the composites loaded with 1 mm CFs, the real part of complex permittivity rises at first then tends to be stable with the increase of the CF content, and the imaginary part rises at first then falls slightly, while for composites loaded with 3 or 6 mm CFs, both the real and imaginary part of complex permittivity grows at first and then falls rapidly with the CF content increasing. When the CF content is below 10 wt%, the composites containing longer CFs have larger permittivity at the same concentration. The Lichtenecker Rule is found to be not suitable for the system studied in this paper, especially when the content of CFs is high. The variations of reflectance and absorbance with the content of CFs generally have analogous trends . It is also found that to achieve better absorbing performance, the length and content of CFs together with the thickness of composites should be considered. In this study, the lowest reflection loss at 10 GHz reaches –27.59 dB when the paper-based composite is loaded with 1 mm CFs at the concentration of 10 wt% and the optimum thickness of 1.84 mm.
This study produced colloidal silver nanoparticle solution, and used the silver nanoparticles in the colloidal silver solution to adsorb dye molecule rhodamine 6 G, measure the surface-enhanced Raman scattering (SERS), and test the ability of colloidal silver nanoparticle solution to detect unimolecules. The Taguchi method was used for optimizing experimental parameters. The SERS and Blinking signals were measured. The two groups of single quality optimum parameter combinations were used as the parental gene of the first-generation population in the genetic algorithm, evolving the next-generation population of high fitness function value. The back-propagation neural system was used as the fitness function indicator of the genetic algorithm, until the gene combination of multi-quality optimization is evolved. Finally, the multi-quality optimal preparation parameter combination was determined as sodium chloride content of 600 μl, mixing time of 90 min, sodium borohydride concentration of
In the needle-punching process, the barbs of a needle catch fibers and orient them along the thickness direction of the fabric. The oriented fibers form a pillar-shaped fiber bundle, which acts as a bonding point of the fabric. The structure of the pillar-shaped fiber bundle thus governs the mechanical properties of needle-punched nonwoven fabric, and both are largely affected by the needle-punching conditions. However, the three-dimensional structure of pillar-shaped fiber bundles and their development under different needle-punching conditions have not been revealed. In the present study, we visualized the three-dimensional structure of a pillar-shaped fiber bundle in needle-punched nonwoven fabric, employing X-ray micro-computed tomography (XCT) on the basis of the difference in the X-ray absorption coefficient between polyethylene terephthalate (PET) and polyethylene fibers. For a material density ratio of less than 1.4 and PET fibers having a diameter of 40 µm, the pillar-shaped bundles of PET fibers were visualized by erasing 20-µm polyethylene fibers in XCT images. Furthermore, we investigated the effects of the penetration depth of the needle on the development of pillar-shaped fiber bundles. The number of fibers constituting a pillar largely increased at a penetration depth of 19.0 mm, and pillars protruded from the bottom surface of the fabric and formed a stitch structure. The XCT applied in this study is thus effective in analyzing the structure of pillar-shaped fiber bundles quantitatively without affecting the structure of the nonwoven fabric.
Using compound microscopy is one of the major options for the identification of cashmere/wool. To interpret human perception via machine vision, microscopic images captured by a charge-coupled device camera were transferred into projection curves. Three different deciphering methods, recurrence quantification analysis, direct geometrical description, and discrete wavelet transform were employed to reveal the embedded numerical features. The extracted parameters were used to screen the supervised classification methods, including a neural network with multilayer perceptrons, kernel ridge regression/classification, and the support vector machine (SVM). The experimental results indicated that the proposed projection curves could be used as a mathematical replica in automatic cashmere/wool identification. The best accuracy came from a SVM-trained decision function with the parameters extracted from recurrence quantification analysis.
Firefighters are required to carry out their responsibilities under a wide range of environmental conditions. For this reason, the physiological and psychological responses of firefighters while wearing their protective clothing should be analyzed to minimize their thermal or cold stress. Four environmental conditions were selected: hot and humid (HH, 34℃, 75% relative humidity (RH)), hot and dry (HD, 34℃, 30% RH), warm and dry (WD, 27℃, 30% RH), and slightly cold (SC, –3℃). Six professional firefighters served as subjects. The exercise was performed on a treadmill at the maximum speed of 8 km/h. The microclimate temperature and RH, skin temperature, heart rate, oxygen uptake, sweat loss, sweat evaporation, moisture accumulation within the outer shell, moisture barrier and thermal liner, and subjective sensations were measured. The microclimate wet-bulb globe temperatures (micro-WBGTs) were calculated. High microclimate measures, skin temperature, and heart rate, as well as low scored subjective sensations, were observed under the HH condition. A 45% difference in RH between HH and HD resulted in clearer differential responses compared with the 7℃ difference in air temperature between HD and WD. Under the SC condition, subjects had a cool to cold feeling. A quite different distribution of moisture accumulation in clothing layers was observed under the SC condition compared with other conditions. This moisture accumulation affected the comfort sensation. A linear relationship was found between the comfort sensation and the micro-WBGT. The micro-WBGT was a good indicator of the physiological status of the wearers. The microclimate, moisture accumulation and its distribution within firefighters’ protective clothing should be extensively studied in the future.
To measure the warp and weft densities of high-tightness fabrics, an efficient inspection method utilizing a novel density–texture formulation is developed. The density–texture relationship of twill and satin weaves is analyzed, and a formulation based on the weft and wale densities is developed and applied to calculate the warp density. In the experiment, the weft and wale densities are detected using a projection method on separately acquired transmittance images, and the warp density is calculated using the density–texture formulation. Experimental results proved that the proposed method is effective for measuring yarn densities of high-tightness fabrics with twill and satin weaves under realistic production conditions and can satisfy the requirement for production practice.
Exuding wound dressing is used to help wound healing. Currently, commercial dressings for heavily exuding wounds still have some drawbacks, such as poor integrity, poor air permeability, low water vapor transmission, and the need for a secondary dressing on the top. To overcome these drawbacks, a new type of wound dressing based on the three-layer spacer fabric structure is proposed in this study. The study includes two parts. The first part focuses on the design, fabrication, and property evaluation of spacer fabrics that can be used for wound dressing. Twelve different types of spacer fabrics were first fabricated. Then, different properties, including wettability, absorbency, permeability, and thermal insulation, were tested and evaluated. A statistical analysis was also conducted to evaluate the effects of structural and yarn parameters on the properties of the spacer fabrics. Based on the testing results, two suitable spacer fabrics were finally selected as the basis for wound dressing material. It is expected that this study could promote the application of spacer fabrics in the medical area.
A novel pathway to improve the substantivity of anthocyanin pigments from Morus rubra fruits onto cotton fabrics is proposed by preparing and applying an anionic agent (sodium, 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate) to fabrics. Successful modification of cotton fabrics with few negative effects was carried out and evidenced by the results of Fourier transform infrared spectroscopy, tensile strength and the whiteness index. The optimum amount of anionic agent was identified to be about 70 mg/g under the following conditions: 20% (owf) anionic agents, 1:20 material-to-liquor ratio, 100 g/L sodium sulfate, 30℃ for 60 min and pH 11.0. A temperature of 40℃ and a time of 60 min were found to be the optimal conditions for cotton fabrics dyeing with anthocyanin pigments. Dyed cotton fabrics had a shade of brilliance and saturation red with acceptable fastnesses for potential commercial applications. The influences of pH and temperature on the stabilities of the extracts were also investigated.
Poisson’s ratio (PR) is defined as the negative ratio between the lateral strain and the longitudinal strain of a material under tensile or compressive loading condition. Auxetic fabrics are those having a negative PR, which means that when their longitudinal strain is positive, their lateral strain is also positive, and vice versa. In this work, tensile and forming properties of auxetic warp-knitted spacer fabrics were investigated and compared with those of the conventional warp-knitted spacer fabrics. Both uniaxial tensile tests and hemispherical compression experiments were conducted, and the relationships of the tensile and forming properties with the auxetic effect were discussed in terms of different fabric structural parameters. The results show that the auxetic warp-knitted spacer fabrics have a prolonged low stress stage in the wale direction, indicating that they are more prone to undergo deformation along the wale direction, and fabric with a longer low stress stage has a better auxetic effect. The results also show that the formability of auxetic warp-knitted spacer fabrics is much better than that of conventional warp-knitted spacer fabrics, due to the much low forming energies required under hemispherical compression, which can be affected by many factors such as auxetic effect, fabric thickness and stiffness, yarn materials and the structure of the spacer layer. When all other parameters are similar, auxetic fabric with a better auxetic effect will have better formability. The study has provided useful information for the design and application of this type of nonconventional spacer fabrics.
Two novel biodegradable intravascular stents (BIS) with different structures are introduced. Braiding-structural BIS and Z-structural BIS were fabricated from polydioxanone (PDO) monofilament by a hand-braiding method with a perforated mold, imitating commercial stents that have been used clinically. The fabrication process of these two BIS is described and stent parameters, mechanical properties, and degradation properties are reported. The findings reveal that Z-structural BIS have higher porosity, smaller longitudinal shortening rate, and higher radial force and recovery rate compared with the braiding-structural stent. During the degradation process, braiding-structural BIS maintained their mechanical properties higher than international standards for 12 weeks, while Z-structural stents maintained them for 16 weeks.
Conventional glass/carbon fiber-reinforced polymer (G/CFRP) composites have been widely used for infrastructure applications in the past decades. Nowadays, there is a trend to use cost-effective and ductile FRP composites such as polyester FRP (PFRP). This paper presents the results of an experimental investigation on the compressive behavior of concrete confined by PFRP jackets with low strength and high ductility. Twenty-seven PFRP confined plain concrete and nine unconfined plain concretes were tested. The considered experimental variables included concrete strength and PFRP thickness. Test results indicated that the PFRP jacket confinement increased the ductility of concrete to a great extent. However, the confinement on the enhancement in concrete ultimate compressive strength is limited. In addition, some existing stress–strain models were used to predict the ultimate stress and compared with the experimental results, and new confinement models were also proposed for PFRP-confined concrete.
In this work, two kinds of 4, 4-difluoro-4-bora-3a, 4a-diaza-s-indacene (BODIPY) composite nanofibers with excellent emitting properties are reported. These contain 5,5-difluoro-1,3,7,9-tetramethyl-10-phenyl-5H-dipyrrolo[1,2-c:2',1'-f][1,3,2]diazaborinin-4-ium-5-uide (DBDP) and 10-(4-(diphenylamino)phenyl)-5,5-difluoro-1,3,7,9-tetramethyl-5H-dipyrrolo[1,2-c:2',1'-f][1,3,2]diazaborinin-4-ium-5-uide (TBDP). DBDP and TBDP, which were obtained using a one-pot process, were respectively incorporated into the poly(methylmethacrylate) (PMMA) matrix with different concentrations and thus formed two series of BODIPY luminescent nanofibers via electrospinning technology. The composite nanofibers were further characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and luminescence. The SEM images show that the composite nanofibers have a smooth and uniform surface with a diameter about 0.4 µm. FT-IR spectra analysis indicates that the BODIPY compounds were successfully doped into the PMMA matrices. The TGA results show that decomposition temperature of BODIPY nanofibers was increased to about 113℃ and 88℃ for TBDP and DBDP, respectively, compared with that of BODIPY compounds. Furthermore, the BODIPY nanofibers also exhibit excellent optical fluorescence properties compared with the BODIPY compounds in dichloromethane (BODIPY/DCM) or in a solid state.
Three different types of yarn have been subjected to transverse impact experiments in efforts to gain an understanding of local yarn failure and to provide input parameters for future transverse yarn impact simulations. Dupont™ Kevlar® KM2, DSM Dyneema® SK76, and AuTx® from JSC Kamenskvolokno were selected as representative materials, as the former two are commonly implemented into bullet resistant panels and the latter is a promising material for future impact resistant fabrics. In order to assess the effect of projectile nose shape on the critical rupture velocity range for each yarn type, three missile geometries have been implemented, namely a 0.30 caliber rounded head, a 0.30 caliber chisel nosed fragment simulation projectile (FSP), and a high-carbon steel razor blade. As opposed to one single velocity wherein yarn behavior transitions from transverse wave development to immediate local failure, a range is defined wherein progressive filament failure is detected with increasing impact velocities. Such ranges are determined for all yarn types using the three projectile geometries yielding critical velocity transition regions of increasing value when impacting via razor blade, FSP, and round projectile heads, accordingly. In addition, post-mortem fracture surfaces recovered from impact experiments have been imaged so as to elucidate the mechanism of failure throughout the range of velocities tested for each projectile type and yarn material and said fracture surfaces correlate well with impact velocity and projectile nose geometry.
Pneumatic yarn splicing is a complex process concerning the winding of multi-filaments in a spiral airflow field. In this study, the joint forming mechanism is revealed by experimental and numerical methods. The whole splicing process in a specific-design splicing device was captured by a high-speed camera. A renormalization-group k-
Understanding seed coat fragment (SCF) spiking results in advanced fiber information systems (AFIS) analysis of seed coat neps (SCN) in ginned cottons is confounded by the opening of entangled fibers in the instrument’s fiber individualizer. This may influence seed coat tissue fragmentation and recovery since a high degree of machine-fiber interaction is required to individualize entities for sensing. In this paper, slivers were pre-opened in the AFIS followed by manual cleaning, spiking, and AFIS analysis. A protocol was developed to spike the pre-opened slivers. The percent recovery of the spiked entity was dependent on the species and cultivar of the cotton used to prepare the slivers. The lowest recovery was with Pima fibers. Also, the recovery improved with the increase in length of the fibers biologically attached to the SCF surface. Delinted seed coat fragments produced the lowest recovery. Seed coat fragments carefully removed from ginned lint and added to the processed slivers gave the highest recovery. Averaged SCN recoveries from two AFIS units ranged from 26 to 100% (theoretical). These results helped to explain why the AFIS analysis of SCN counts in processed cotton is lower than by the microscopic analysis.
This study examined the fiber quality of saw ginned Upland cotton, harvested from one field using a John Deere (JD) 7760 at three moisture levels, <12%, >12% and 14%, and storing the harvested modules for 12 weeks prior to ginning. There was a significant difference between the three moisture levels for fiber color, with seed cotton harvested at >12% and 14% resulting in fiber that was yellower, with lower reflectance and a color grade of 52, as compared to a 51 grade for seed cotton harvested at <12% moisture. The seed cotton harvested at >12% and 14% contained more trash with a leaf grade of 3, compared to a leaf grade of 2 for the seed cotton harvested at <12%. There was no significant difference between the three moisture levels in terms of fiber length and strength, but fiber micronaire was higher for the seed cotton harvested at >12% and 14% moisture content. There was no significant difference between the moisture levels for total nep count, but the seed cotton harvested at >12% had larger neps and more seed coat neps than the seed cotton harvested at <12% and 14%. In the second part of this study the fiber was spun into fine count yarns on a miniature spinning system to assess the impact on textile processing in terms of yarn and fabric quality and processing performance. The study found that the card waste for the lower moisture content harvested fiber was less than the card waste for higher moisture content harvested fiber. In terms of yarn and fabric quality, the statistically significant differences observed in fiber quality did not translate into statistically significant differences in yarn or fabric quality at any moisture content level. Surprisingly, the statistically significant differences in fiber color did not affect the color and appearance of the knitted dyed fabrics.
Air-jet weaving is a weaving technique with high production rate. However, efficiency decreases if instabilities in the motion of the weft yarn leader occur causing weft insertion failure. A 2D geometrical model was developed for the main nozzle of the air-jet loom and a mathematical model employing the fluid–structure interaction (FSI) technique was used to simulate the air-flow and whipping action of the leader in the air flow at the exit of the main nozzle. With numerical results, the resultant force normal to the yarn determined by the yarn shape and the air-flow field has a significant influence on this whipping action. Starting with an initial gravity-induced drooping leader, a large normal force exerted by the air flow subsequently leads to a strong whipping action. To verify the validity of the numerical analysis, an experimental apparatus with a high-speed camera attached was constructed to observe the leader trajectory under different air supply conditions. The experimental results show that during weft insertion the motion is more stable with an initially straight leader than one initially drooping.
In this study, a three-layered composite structure based on spacer fabric was designed for absorbent wound dressings. The fabrication and selection of spacer fabrics were discussed in Part I. In this part, two selected spacer fabrics were further modified by covering a polyurethane or a polystyrene electrospun nanofibrous membrane onto their outer layer surface to form the final spacer fabric-based dressing products. In order to confirm the performance of these new spacer fabric-based dressings, the comparisons were conducted with three types of commercial wound dressings. The comparison indicators included the water contact angle, wettability, absorbency, air permeability and water vapor transmission rate. The results showed that in addition to very good water vapor and air permeability, the developed spacer fabric-based dressings had better absorbing properties than commercial foam dressings. Furthermore, their wettability was also good for application as wound dressings. The study has paved a new way to produce advanced wound dressings using three-dimensional textile structures.
The effects of yarn number and liquid ammonia (L/A) treatment on the liquid moisture management properties (such as wetting time, absorption rate, maximum wetted radius, spreading speed, accumulative one-way transport capability, and overall moisture management capability) of hemp woven fabrics were evaluated by using a moisture management tester on the basis of AATCC test method 195-2011. As a result of the L/A treatment, the crystal structure of hemp fiber was changed from cellulose I into a mixture of cellulose III and cellulose I and its crystallinity was slightly decreased from 66.1% to 57.4%. From scanning electron microscopy analysis, hemp fabric looked swollen and bulked after L/A treatment. The liquid moisture management properties of the L/A-treated hemp woven fabrics showed much better results compared with the untreated ones. Overall moisture management capacity values increased as the yarn number increased and the values of the L/A-treated hemp samples are higher than those of untreated ones. This research could be valuable for the improvement of liquid moisture management properties of hemp woven fabrics.
Electrospinning technology has great advantages in the preparation of nanofiber materials. To improve actual usage of nanofibers for innovative applications, these nanofibers can be assembled into nanofiber yarn. Nanofiber yarn devices can be divided into different types based on the different principles, which are as follows: the auxiliary electrode collecting device, self-bundling spinning device, water bath method collecting device, single needle electrospinning yarn device, double electrode disc twisting electrospinning yarn device, and other nanofiber yarn devices. As for the different preparation methods and devices of nanofiber yarn, the mechanical properties of nanofiber yarn are compared and analyzed.
The purpose of this work is to understand the impact of superheated water hydrolysis treatment on the chemical properties of wool, and compare it with a conventional method of alkaline hydrolysis. The effects of hydrolysis temperature and concentration of alkali on the properties of wool were investigated. Superheated water hydrolysis was carried out at the temperatures of 140℃ and 170℃, with a material to liquor ratio of 1:3 for 1 hour. In conventional alkaline hydrolysis, the experiments were carried out in the same conditions using potassium hydroxide (KOH) and calcium oxide (CaO) with a concentration in the range of 5%–15% on the fiber weight (o.w.f.). The effects of hydrolysis temperature and alkali concentrations on wool properties were checked using optical and scanning electron microscopy. It was observed that the hydrolyzates obtained in both cases contained low molecular weight proteins and amino acids. Both the hydrolysis processes resulted in degradation of the wool fibers. However, superheated steam hydrolysis is an environmentally friendly and less expensive process, as it is performed using water as a solvent. The wool hydrolyzates produced using superheated water hydrolysis could find a potential application in agriculture, such as fertilization, soil improvement and suchlike.
The feasibility of using supercritical CO2 as a cleaning dyeing medium to dye acrylic fibers was investigated on an industrialized unit. The influence of dyeing temperature, dyeing pressure, dyeing time, and dye concentration on the K/S values of acrylic fibers was examined using the fractional factorial design of experiments. A second-order polynomial model was established to analyze the interactions between distinct parameters and to obtain the optimal K/S values. The results showed that an excellent dyeing effect of acrylic fibers was obtained in the industrialized supercritical CO2 unit, but the dyeing effect was easily affected by variations of the dyeing parameters. In the experimental range, a calculated K/S value could be up to 6.14 with the dyeing temperature of 100℃, dyeing pressure of 26 MPa, dyeing time of 60 min, and dye concentration of 3%. The dyed acrylic fibers presented good color fastness to washing, rubbing, and light. Furthermore, a commercially acceptable levelness and reproducibility for acrylic fibers were obtained in the supercritical CO2 dyeing process.
An aqueous solution containing a natural colorant (myrrh extract) was obtained by extraction from myrrh using water as an extracting solvent at 90℃ for 90 min with a fixed material to liquor ratio of 1:10. The dyeing properties, color fastness and deodorizing/antibacterial performance of fabrics (cotton, silk and wool fabrics) dyed with myrrh extract were evaluated. The main component in myrrh extract was found to be polysaccharides composed of D-galactose/D-glucuronic acid/L-arabinose and protein. The yellow-red color of fabrics dyed with myrrh extract was attributed to the copper (I) oxide component. The K/S value of the dyed fabrics increased in the order of cotton < silk < wool. The washing, water and acid/alkaline perspiration fastness of dyed cotton/silk/wool fabrics were good (Grade 4–5), except light fastness (Grade 1–3). The deodorizing performance of dyed fabrics against ammonia and acetic acid was found to be significantly better than the control (undyed) fabrics. The dyed fabrics exhibited an excellent antibacterial performance (99.9% bacteriostatic reduction rate) against both Klebsiella pneumonia and Staphylococcus aureus. These results highlight the strong potential of the natural dyed fabrics as a functional material with both high antibacterial activity and deodorizing function.
The mechanism of dry heat flow through lofty nonwoven structures (i.e. thermal resistance) as occurs in quilts has been established. By contrast, there is a scarcity of published information on the water vapor transport properties. This work explores the thermal and water vapor transport properties of a number of different quilt samples with a focus on identifying fiber type effects. Both commercial product and matched laboratory samples were examined. Steady-state thermal resistance and water vapor resistance measurements confirmed that both properties are primarily determined by sample thickness and are largely independent of fiber type. Experiments were also undertaken to observe transient effects. Test samples were initially equilibrated on a ‘dry’ guarded hotplate (35 ± 0.1℃) in a low relative humidity environment (45%). The relative humidity was then rapidly increased to 85%. Compared to polyester, wool samples exhibited a large reduction in the heat flux required to maintain the hotplate temperature. This transient peak lasted for in excess of 1000 seconds. The magnitude of this transient peak in heat flux was proportional to the quantity of wool in the sample and is believed to be associated with the known exothermic nature of water vapor absorption by wool as relative humidity increases. Based on the published values of the heat of water absorption of wool it is estimated that this additional transient heat source is significant relative to a typical human resting metabolic rate and so the effect may be of practical relevance in the bedding environment.
The end breakage rate (EBR), which is one of the most important quality variables used to determine the yield of a spinning process, depends on various process conditions and fiber/yarn properties. In the current study, historical data consisting of more than 10,000 runs from 55 ring spinning machines recorded under normal operation in YUNSA Worsted and Woolen Company in Turkey were analyzed using exploratory and predictive statistical techniques. Principal Component Analysis (PCA) was used to determine subsets of quantitative variables, which vary collectively, forming clusters for different machine types. Correspondence Analysis (CA) was found to be particularly beneficial to determine the association between machines and nominal variables, which make a significant contribution to product quality in textile industries. The current spinning process requires accurate discrimination between acceptable and faulty yarns, determined via a threshold on the EBR, so logistic regression was utilized for the prediction of faulty yarns. The Receiver Operating Characteristic curves showed that the discriminative capacity of the logistic models was at an acceptable level, almost on a par with that of Artificial Neural Network (ANN) models. For different types of machines, while yarn count, roving count, lot size, twist level and composition were commonly present in logistic models, the magnitude of their partial effects varied significantly. In conclusion, PCA, CA and logistic regression are suggested, along with ANN models, to be used for textile industries in online monitoring, detecting faulty machines, choosing optimum machines for specific operational conditions and determining the range of process variables for which controlled experiments may be required.
Clothing pressure is a very important variable in compression garments that is frequently omitted in other studies, despite the possibility of altering the experimental design and results. Most studies focus on testing the effects of released products rather than on how to design them. The aim of this study is to identify methods to increase stability of an extremity by developing compression pants with a design that assigns differential pressurization. CP1 (clothing pressure knee region: 0.95–1.03 kPa), which reinforces the knee joint, and CP2 (clothing pressure knee region: 1.67–2.12 kPa), which reinforces the knee joint and hamstring, are developed. In addition, CCP (clothing pressure knee region: 0.44–0.58 kPa) was developed as a control garment. Seven subjects wearing CP1, CP2, or CCP, performed single-leg landing from 40 cm height, for motion analysis. As a result, the angular velocity of the hip and knee, as well as the knee joint range of motion was increased significantly when CP1 are worn. Therefore, CP1 is efficient in absorbing the energy of the impact, making it much practical in terms of stability. The peak vertical ground reaction force showed little difference when different design of compression pants were tested. Meanwhile, CP2 significantly increases the knee moment. It is important to add that even a subtle manipulation of the level, location, or the method of pressurization significantly changes the stability of joints and the performance of exercise. This research shows that the functions of compression garments differ according to the level of pressurization and differential pressurization.
The smart control of cotton fabric comfort by cross-linking thermo-responsive random copolymer is investigated. The monomers 2-(2-methoxyethoxy) ethoxyethyl methacrylate (MEO2MA) and ethylene glycol methacrylate (EGMA) with a molar ratio of 17:3 are selected to synthesize the thermo-responsive random copolymer poly(2-(2-methoxyethoxy) ethoxyethyl methacrylate-co-ethylene glycol methacrylate), abbreviated as P(MEO2MA-co-EGMA). By using citric acid as a cross-linking agent, the obtained P(MEO2MA-co-EGMA) is successfully immobilized onto cotton fabrics. Smart control is achieved from the thermo-responsive behavior of the copolymer. Cross-linked P(MEO2MA-co-EGMA) will collapse when the ambient temperature exceeds its transition temperature. Therefore, the formerly compact P(MEO2MA-co-EGMA) layer will switch to a porous structure, and the air/moisture permeability of the textiles is enhanced. As the comfort of the textiles is closely related to the air/moisture permeability, a smart control of the cotton fabric comfort can be realized. In addition, the softness of cotton fabrics with and without thermo-responsive polymers does not show a prominent change, even when the applied solution concentration is as high as 16% (wt%). On the contrary, the stiffness of the cotton fabric coated with poly(N-isopropylacrylamide) (PNIPAM) is significantly higher than the original cotton fabric, indicating that homo PNIPAM is less suitable for textiles used in daily lives. Moreover, the whiteness and mechanical properties are studied and stay unchanged after cross-linking. As a consequence, the introduction of P(MEO2MA-co-EGMA) into textiles can provide textiles with smart control of cotton comfort, and it will not influence the wearabilities of the textiles.
A novel approach to predicting the filtration performance of spunbonded nonwoven using a rough set theory- and support vector machine-based model is presented. The meso-structure of spunbonded nonwoven was characterized using a structural parameter set (Os) containing nine parameters. Four reducts were extracted from Os using rough set theory. Twenty models, each based on either a support vector machine (SVM) or a back-propagation artificial neural network (BP-ANN), were established to predict the filtration performance (under varying filtration velocity and particle size) of spunbonded nonwoven by taking the parameters of each reduct and Os as inputs. The results show that the prediction accuracy of the model that takes thickness, fiber diameter, and pore size as its input parameters is higher than that of any other model, regardless of the model type. Moreover, the predictive power of the SVM-based model was found to exceed that of the BP-ANN-based model.
Many technical applications of woven fabric are subject to increasing high pressure from air transport through the fabric. The through-thickness permeability (TP) of woven materials exhibits a dynamic response to increased air pressure. This paper presents an analytical model for predicting the steady TP of woven fabric. The approach was based on Darcy’s law and the Poiseuille equation, using the flow boundary of an idealized plain-weave unit cell. The unit cell model consists of a gradual converging-diverging (GCD) duct with a rectangular cross-section. Further, the dynamic TP of the GCD duct was established analytically as a function of increasing pressure, which correlates to the separation of air flow from the GCD duct wall. Air flow separation from the duct wall led to a quadratic relationship between the increasing pressure and air flow velocities. This dynamic TP and air flow nonlinearity were simulated numerically in the computational fluid dynamics solver CFX. Five GCD ducts under increasing air pressure were analyzed numerically and analytically. The comparison showed good agreement between the proposed analytical model and the CFD simulation, with a maximum error up to 12%. A sensitivity study showed that an increase in porosity or a decrease in the thickness of weave materials could result in a larger dynamic TP value.
The effect of the coupling approach (chemical by using carbodiimide chemistry and grafting-to versus grafting-from synthesis routes, and enzymatic by using transglutaminase) of -poly-L-lysine (PL) graft yield with wool fibers was studied and evaluated related to their antibacterial activity against gram-negative Escherichia coli and gram-positive Staphylococcus aureus bacteria, after 1–24 h of exposure. While the PL applied was evaluated colorimetrically by wool staining with two acid dyes and quantitatively by evaluation of the basic groups using potentiometric titration, its orientation was determined by Fourier transform infrared spectroscopy and, for the first time, by Electron Paramagnetic Resonance spectroscopy using spin-labeled PL.
The highest (~99% for E. coli versus ~92% for S. aureus) and kinetically the fastest (in 3 h) antibacterial activity with ~83% for E. coli versus ~64% for S. aureus bactericidal effect was determined for the wool functionalized by the chemical grafting-to approach. Such an effect may be related to both quantitatively the highest (~62 gPL/kgwool) grafting yield of PL and conformationally its highly flexible "brush-like" structure. Comparably, the enzymatic coupling (~50 gPL/kgwool) giving ~95% and ~8% reductions of E. coli and S. aureus, respectively, being additionally reduced to ~74% and ~78% by using the grafting-from approach (~34 gPL/kgwool), was identified as the less bactericidally effective (~63% versus ~58%).
It was also shown that a non-ionic surfactant being used in the durability testing of functionalized wool to washing adheres strongly onto the fibers, thus blocking the amino groups of PL, and, as such, decreases the antibacterial efficiency of the wool, being unaffected in the case when the washing was carried out without surfactant.
Simulation of three-dimensional turbulent flow in a rotor spinning machine is carried out, and the flow structure and behavior in the rotor cup are analyzed. The governing equations are the steady three-dimensional Navier–Stokes equations and the Spalart–Allmaras turbulence model. The results show that the rotating speed has great influence on the flow behavior in the rotor cup. It is found that there is a critical speed of the rotor cup beyond which the pressure and velocity on the slip surface is not changed anymore regardless of the magnitude of the rotating speed. When the rotating speed is larger than this critical speed, the flow structure becomes unstable with the increasing of the rotating speed. The mechanism of this phenomenon is that the airflow in the rotor groove passes about 180 degrees from two sides along the rotor wall and a pressure balance is achieved. When the rotating speed is larger than the critical speed, the balance will break down. When the rotor speed is low, the flow characteristic in the air-inlet plane is mainly determined by the high-speed airflow at the outlet of the transfer channel. However, when the rotor speed is higher than the critical speed of n = 80,000 r/min, the flow behavior is mainly determined by the rotating rotor. In the meridian plane perpendicular to the air-inlet plane, the flow behavior is mainly determined by the rotor speed. The rotating speed of the rotor has little effect on the flow characteristics in the transfer channel.
Wearable electronics textiles are a new emerging phenomenon. These are textiles that incorporate electrical properties, for example heating, light emitting, sensing, etc., and are now being rapidly developed due to the creation of new types of fibers and fiber composites. The different ways that can be used to combine conductive fibers with electronics components have been receiving much attention in wearable electronics research. However, to meet the requirements for both aesthetics and function, textiles technology and the garment design method are important for commercial success. In order to apply electronics to fabrics with the use of conductive fibers, complex and elastic fabric structures both need to be modeled. Therefore, the focus of this study is to examine the resistance properties of single pique, a fabric that is conductive and has a knitted structure that uses tuck stitches, a typical structure in knitting. A planar geometric model is established for a single pique structure based on the loop construction of this knitted fabric. Subsequently, resistive network models are developed for different cases of external voltages to calculate the resistance values of single pique fabrics with different numbers of wales and courses. Corresponding experiments are carried out to verify the proposed resistive network modeling. The newly developed resistance model in this study will provide significant benefits to the industrialization of wearable electronics textiles and the apparel industry as they can offer commercial apparel products that are not only aesthetically pleasing and multi-functional, but also have high added value.
The parameters of electrospinning polyvinylalcohol (PVA) of different molecular weights using spiral disk spinnerets were explored. Ethylene-propylene side-by-side (ES) nonwoven was used as the substrate. Electrospun PVA/ES composite membranes were fabricated by laminating a nanofiber web onto the nonwoven substrate via the hot-press method. The adhesion properties between the PVA nanofiber mat and the ES nonwoven were studied. The results showed that the adhesion properties were significantly affected by temperature, pressure, and processing time. The resultant composite membranes, when treated at 145℃ with a pressure of 100 Pa for 10 minutes, exhibited a preferable adhesion energy of 7.95 J/m2 and a maximum peeling strength of 20.17 cN, as well as a maximum air permeability of 73.92 dm3/(m2s). Simultaneously, the effect of electrospinning time on the characteristics of PVA/ES composites was also explored. The filtration efficiency increased with the prolongation of the electrospinning time, whereas the air permeability decreased. All of the samples were grade A in terms of the electrostatic half-life period (which was less than two seconds), and the softness slowly declined with the addition of nanofibrous layers. The breaking stress, the initial modulus, and the elongation were enhanced with the prolongation of electrospinning time.
This paper aims to produce nanoscale crimped fibers using stuffer box crimping and bubble electrospinning. Nanofibers are originally obtained via a ruptured bubble and then crimped with the stuffer box crimping method. During this spinning process, the governing equations for nonlinear transverse vibration of an axially moving viscoelastic beam with finite deformation are established using the Hamiltonian principle. The crimp frequency is affected by many factors, including spinning conditions and mechanical properties of fibers. The obtained governing equations can be further used for numerical or analytical study of the crimping mechanism.
The aim of this study was to evaluate the survival of three challenge bacteria stored at 25℃, 5℃, and 50℃ up to 21 days on 100% cotton textile swatches. The survival of each chosen challenge bacteria was determined by the classical phenotype colony counting method through growth on selective media, and the molecular method of detecting Staphylococcus aureus-, Enterococcus faecium-, and Pseudomonas aeruginosa-specific DNA. E. faecium proved to be the most persistent chosen challenge bacteria at all three chosen storage temperatures. Both E. faecium and S. aureus survived on textile swatches up to 21 days at 25℃ at the highest inoculum. E. faecium and P. aeruginosa persisted at 50℃ only up to 9 and 3 days, respectively. All challenge bacteria survived on textile swatches at 5℃ (E. faecium 12 days, P. aeruginosa and S. aureus less than 6 days). The results of survival at lower initial inoculum were lower and less dependent on temperature. Dehydration phenomena or fluctuation in relative humidity in the refrigerator at 5℃ possibly explains lower survival than at room temperature. Positive results for the detection of E. faecium- and P. aeruginosa-specific DNA were found for some samples with negative results for classical phenotype counting methods, perhaps owing to the fact that the bacterial cells, due to adverse environmental conditions, reached a viable, but noncultivable (VBNC) state, or that the extracellular DNA fragments persisted on the textiles. Survival of the challenge bacteria for more than 3 days regardless of temperature proves that hospital textiles as an inanimate surface should not be neglected as one of the possible vectors for transmission of pathogens causing healthcare associated infections.
This study reports a novel ultraviolet (UV) absorber, N-dihydroxy ethylene cyanoguanidine (NDEC), which was synthesized from dicyandiamide and glyoxal. The NDEC compound was characterized by Fourier-transform infrared spectrum and nuclear magnetic resonance. NDEC was grafted onto cotton fabric through covalent bonding by the pad–dry cure method. The optimal finishing conditions were that the mass concentration of NDEC was 5 g/L, baking time 240 s and temperature 140℃. The UPF value of cotton fabric treated under optimal finishing conditions reached 50+ and was minimally reduced (to 47) after 50 laundry cycles. The breaking strength and thermostability of the original cotton fabric were preserved after treatment. Successful grafting of – CN and –C=N groups onto the treated fabric was confirmed in the Fourier-transform infrared spectrum. Meanwhile, the finished cotton fiber remained smooth, as confirmed by scanning electronic microscopy.
Market demands for cotton varieties with improved fiber properties also call for the development of fast, reliable analytical methods for monitoring fiber development and measuring their properties. Currently, cotton breeders rely on instrumentation that can require significant amounts of sample, which complicates fiber development studies. Herein, we explored the use of high-resolution, Fourier-transform infrared (FT-IR) microscopy to examine cotton fiber secondary cell wall development in single fibers. Notably, there was a marked intensity increase for the C-O bending region near 1015 cm–1 and the C-H stretch at 2900 cm–1. These changes agree with those observed with macroscopic FT-IR tests. Chemical distribution maps and principal component analysis plots visually depict these spectral changes. Our results suggest the FT-IR microscopy can potentially be utilized as a tool to monitor and assess important fiber properties, such as cotton maturity, during fiber development.
This study developed and tested the development of an all-fabric interconnection and one-stop production process for electronic textiles that are combined with electronic technologies on textiles. Primarily, this is a one-stop production method for electronic textiles consisting of multilayer structured fabrics for implementation of electronic functions in which (1) precise circuit patterns are formed, (2) conductive materials or conductive circuits on each fabric layer are electrically connected, and (3) individual fabric layers are fixed to the base layer through embroidery, while fabric layers are layered one by one using a commercial computer numeric control embroidery machine. Since the multilayer fabric structured electronic textiles constructed have different layers of conductive materials connected electrically, quickly durably, and reliably through embroidery, (1) the electrically connected parts are not likely to be broken by external forces, (2) all parts to be connected to external devices are formed on one piece of fabric so that the work to connect the textiles to an external device is simple, and (3) workability and productivity are improved so that manufacturing costs can be reduced and the textiles can be mass produced. Therefore, this one-stop method using commercial machinery has great potential as a highly useful technology that can be implemented on an industrial scale.
Image analysis of a fiber cross-section can provide direct measurements for cotton maturity. Effective segmentation of fiber contours in a cross-sectional image is paramount for accurate fiber geometrical measurements. In a wide-field microscopic image, the adhesion, breakage, and ambiguity (low contrast or noise) of fiber contours make the segmentation rather challenging. This paper presents a new approach for contour segmentation that takes advantage of the shape features of the triple concentric contours, called the coupled-contour model (CCM), of a cross-section, and a CCM-based algorithm developed to locate, split, merge, and refine fiber contours based on the established rules concerning contour features. For a wide-field microscopic image (12 megapixels), this CCM-based algorithm could detect >500 fiber cross-sections with a recall rate of 93.53% and a precision rate of 98.13%, and reduced the errors in maturity measurements by 50%.
Chopping is an efficient way to produce short carbon fiber (CF). Generally, there are two types of fixing constraints available in the chopping process: rigid-fixing and flexible-fixing. Simplified experiments were performed using glass and rubber as the fixing constraints in cutting a single polyacrylonitrile-based CF to reveal the influence of the fixing constraints in CF chopping. The cutting forces and the bending angles with different fixing constraints were analyzed. Furthermore, the failure surface of the CF was observed. Due to an additional bending effect in the flexible-fixing cutting, the failure surface of the CF was rough, and the cutting-off force was approximately 5% of the force in rigid-fixing cutting. Therefore, flexible-fixing cutting is a suitable way to decrease the cutting-off force in CF chopping. Moreover, it was concluded that the fiber fracture in rigid-fixing cutting is caused by compression, whereas in flexible-fixing cutting, it results from bending. We hope our work is beneficial to the design of the chopping procedure for short CF.
Applying mesh to reconstruct the pelvic floor is a new surgery method developed in recent years. The composite mesh property is expected to reach perfection by taking advantage of absorbable material and non-absorbable material. This work adopts the dipping method and the electrospinning method to produce polylactic acid/polycaprolactone (weight ratio = 7/3) membrane-coated composite meshes (D-PP1, D-PP2, E-PP1, E-PP2). The effect of coating methods on the mesh structure, such as thickness and weight, is first measured. The electrospinning membrane is tested for only around 3% of the mesh weight, while the dipping membrane is tested for more than 30%. The composite meshes then experience mechanical testing, including tensile strength, bursting strength and flexibility. The coating process is demonstrated to increase elongation at the break in tensile testing: E-PP1 (76.7%) > D-PP1(60%) > PP-1(41.2%); D-PP2 (143.3%) > E-PP2(112.3%) > PP-2(56.7%). It also strengthens the bursting strength: D-PP1 (179.8 N) > E-PP1(157.3 N) > PP-1(149.8 N); D-PP2 (183 N) > E-PP2(174.8 N) > PP-2(154.3 N). However, the dipping method shows weaken composite mesh flexibility, with larger initial modulus for D-PP1 and D-PP2 meshes. Hydrophilicity is represented by the water contact angle and absorption rate. Even though the result of the hydrophobic surface on the composite mesh is reported to easily cause shrinkage, the polypropylene mesh base in this study is considered to prevent this phenomenon. E-PP1 mesh degrades in 20 weeks; D-PP2 mesh degrades in 34 weeks with an induction period of 20 weeks. The optical density value tested, measuring biocompatibility, proves the non-toxicity of both E-PP1 and D-PP2 meshes.
During firefighting, thermoregulation is challenged due to a combination of harsh environmental conditions, high metabolic rates and personal protective clothing (PPC). Consequently, investigations of thermoregulation in firefighters should not only consider climate and exercise intensity, but technical properties of textiles too. Therefore, laboratory textile performance simulations may provide additional insights into textile-dependent thermoregulatory responses to exercise. In order to investigate the thermo-physiological relevance of textile properties and to test how different garments affect thermoregulation at different exercise intensities, we analyzed the results of a standard laboratory test and human subject trials by relating functional properties of textiles to thermo-physiological responses.
Ten professional, healthy, male firefighters (age: 43 ± 6 y, weight: 84.3 ± 10.3kg, height: 1.79 ± 0.05m) performed low and moderate intensity exercise wearing garments previously evaluated with a sweating torso system to characterize thermal and evaporative properties.
Functional properties of PPC and the control garment differed markedly. Consequently, skin temperature was higher using PPC at both exercise intensities (low: 36.27 ± 0.32 versus 36.75 ± 0.15℃, P < 0.05; moderate: 36.53 ± 0.34 versus 37.18 ± 0.23℃, P < 0.001), while core body temperature was only higher for PPC at moderate (37.54 ± 0.24 versus 37.83 ± 0.27℃, P < 0.05), but not low-intensity exercise (37.26 ± 0.21 versus 37.21 ± 0.19, P = 0.685).
Differences in thermal and evaporative properties between textiles are reflected in thermo-physiological responses during human subject trials. However, an appropriate exercise intensity has to be chosen in order to challenge textile performance during exercise tests.
Pneumatic yarn splicing is a technical process for joining two yarn ends together. The process involves injecting compressed air into a splicing chamber. The inlet pressure and chamber slope determine the main parameters affecting this process. In this paper, large eddy simulation of the flow field in four selected splicing chambers is carried out. The chambers are used for splicing ends-together yarns. The results of these simulations are analyzed to investigate first the effects of the inlet pressure. Secondly, the effects of the geometry of the chambers on the flow field inside the splicing chambers are determined. These effects are studied and analyzed to interpret the experimental results, which have been obtained using the same splicing chambers. This provides further insight into the parameters that are important in order to obtain good splicing characteristics. It is demonstrated that the volume of the splicing chamber and the location of the air inlet channel play crucial roles in the splicing of the end-together yarns. The root mean square values of the velocity magnitude inside a splicing chamber have predictive values for the retained splice strength. The results provide solid evidence on the effectiveness of the computational fluid dynamics technology to study pneumatic splicing and optimize the geometry of an ends-together splicing chamber.
This review covers imaging techniques of wicking in textiles ranging from visible light to synchrotron x-ray. First, the wicking phenomenon and its relevance are exposed. Then, the main wicking experimental setups, namely the strip test and the spot test, are described. Next, the imaging techniques are described together with the relevant studies applied to wicking. Finally, the analysis of wicking measurements is presented. The conclusion presents imaging techniques applied to wicking in a historical perspective and highlights areas where further development is desirable.
Micronaire is a key cotton fiber quality assessment property, and changes in fiber micronaire can impact fiber processing and dyeing consistency. Micronaire is a function of two fiber components—maturity and fineness. Historically, micronaire is measured in a laboratory under tightly controlled environmental conditions. There is increased interest by the cotton and textile industry to measure key fiber properties both in the laboratory and in-field (non-controlled conditions), using small portable near infrared (NIR) spectroscopy instruments. A program was implemented to determine the feasibility of using portable NIR instruments to monitor fiber micronaire, maturity, and fineness. Prior to outside the laboratory measurements (field, warehouse, etc.), laboratory feasibility was performed to assess the NIR instruments’ capabilities. Comparative evaluations for fiber micronaire, maturity, and fineness were performed on three portable NIR instruments. Instrumental, sampling, and operational procedures and protocols for each instrument were established. Although representing different measurement technologies, very good spectral agreement was observed between the portable NIR instruments and a bench-top NIR unit used as a comparison. Rapid (less than 3 minutes per sample), easy to use, and accurate measurements of fiber micronaire and maturity were achieved, with regressions (R values) greater than 0.85, low residuals, and a low number of outliers observed for each NIR instrument. Improvements are required for the accurate measurement of fiber fineness by portable NIR instruments. Thus, for well-defined cotton fiber samples, the universal nature of the NIR measurement of cotton fiber micronaire and maturity by portable NIR instruments was validated.
The air-jet loom is widely used in the textile industry and the main nozzle is one of its key components. In this paper, the influence of some parameters, including the input air pressure and the structure of nozzle core and its internal diameter, on the internal flow field of the main nozzle is analyzed. Then the optimized structure of the main nozzle is proposed from the perspective of fluid dynamics. In the present simulations, the realizable
The tactile perception of temperature of fabric measured by the thermocouple placed between fabric and a fingertip was analyzed. The experimental data were compared to the mathematical model of heat transfer between body and fabric. A high correlation between mathematical model, which presents a theoretical approach to heat transfer, and the experimental part was found. It proves that the very basic laboratory setup for measurement of heat transfer can be a reliable source of information concerning this phenomenon. It was proven that two time constants, and L, and two temperature values, T0 and T0, are the essential parameters to obtain a reliable agreement between the mathematical model and the experimental results.
In this study, we aimed to develop an enzyme-immobilized support using polyester woven fabrics and to optimize the development process. We obtained information about the storage stability and reusability of the enzyme and showed the applicability of the polyester woven fabric as an enzyme-immobilized support. In particular, the samples hydrolyzed by hydrogen chloride were treated with N,N’-dicyclohexylcarbodiimide and N-hydroxysuccinimide to activate the surfaces. We evaluated the relative activity of the enzyme immobilization processes, the introduction of spacers, crosslinking and enzyme immobilization and optimized these parameters. The introduction process was controlled to a bovine serum albumin concentration of 1.5% (w/v) and treatment time of 3 h. The crosslinking process was optimized to pH 10.0, a glutaraldehyde concentration of 3% (v/v) and a crosslinking time of 90 min. The immobilization conditions were maintained at pH 8.5, a temperature of 25℃, a time of 45 min and a trypsin concentration of 6% (o.w.f.).
The mechanics of nonwoven fabrics is largely dependent on fiber properties, and other physical factors such as structural arrangement and degree of entanglement of the fibers. In this study, modeled and experimental stress–strain behaviors of uniaxially loaded hydroentangled nonwoven fabrics have been analyzed and compared. The theoretical values from the model were deduced from the measured properties of micro-samples, namely, fiber volume faction, orientation distribution and mechanical properties. Testing of the micro-samples was performed on a Deben Microtest Module fitted in the FEI Quanta 200 Scanning Electron Microscope. The experimental stress–strain results show that the structure is in the linear region when the modeled results approach the highest specific stress. Also, the theoretical models highly overestimate the specific stress of the hydroentangled nonwoven fabrics. The results show that the application of the model was limited in predicting tensile stress. Furthermore, a trapezoid method was used to quantify the actual deformation energy from the stress–strain graphs up to the ultimate tensile strength. The theoretical deformation energy was estimated and compared to the experimental values. The model was subsequently modified to improve its predictive capability.
Textile structural antenna is one of the most important components for wearable electronics. To obtain structural integrity and stability, three-dimensional orthogonal weaving technology is adopted to weave three-dimensional fabric antennas (3DFAs). The electromagnetic performance of the 3DFAs with the radii of curvature of 75, 60, 45 and 25 mm are simulated with a High Frequency Structural Simulator and tested experimentally. The simulated and tested results agree reasonably well. The results show that the return losses are less than –10 dB, while the resonant frequencies and radiation patterns are significantly influenced by the curvature and the feeding direction. The 3DFAs with the curvature perpendicular to the feeding direction show more stable resonant frequencies and radiation patterns than those of the 3DFAs with the curvature parallel to their feeding direction.
This paper includes results of the blast tests which were performed with the aim of comparing the energy absorption and protection efficiency of protective boots with different sole configurations. Tests were performed on a mechanical leg model vestured with protective boots. Load and three axis acceleration values were measured during the blast tests to determine the protection efficiency of boot samples. Herewith, it was understood that merely a monolithic composite layer used in a sole does not provide protection, whereas compressible metallic honeycomb material-based sandwich composites demonstrate better energy absorption. With the innovative sandwich composite material developed in this study, energy absorption was increased by 209% in comparison to monolithic composites.
This study presented a mechanism to automatically identify consecutiveness of textile patterns so as to help classify the ever-growing number of patterns. The pattern consecutiveness was first decomposed into two factors, including repeat angle and unit span. Then the pattern image was sliced into pieces on various angles with various spans, and the similarity degree of slices on each angle with each span was calculated to constitute the similarity space in which the peak values suggested the potential repeat angles and unit spans. The conjugacy of repeat angles was inspected in the similarity space, and the conjugate angles were advanced to distinguish the four-consecutives from the two-consecutives. Given the relativity of conjugate angles, the conjugate coefficient was brought forward to quantify the conjugate level of two perpendicular angles so as to find the optimal conjugate angles for the four-consecutives. The peak significance was proposed to discriminate sharp peaks against weak ones, and the similarity spaces of mono patterns were investigated to figure out the range of peak significance for the mono pattern, and thus the mono pattern could be identified with an absence of sharp peaks. A scheme for consecutiveness identification based on similarity space was finally carried out and implemented with computer programming, and it proved highly accurate and capable of tolerating certain flawed pattern images.
This paper describes the concept of creating and testing of a textile heat flow sensor in order to determine the amount of heat exchanged between the human body and its environment. The main advantage of this sensor is the permeability to moisture, which allows taking into account the evaporation phenomenon, contrary to the traditional heat flow sensors. Another property related to this new sensor is its flexibility conferred by the textile substrate, which allows it to be applied on deformable surfaces.
The development of lightweight flexible materials for electromagnetic interference shielding has received increased attention in recent years, particularly for clothing or technical applications and especially in areas of aircraft, aerospace, automobiles and flexible electronics, such as portable electronics and wearable devices. There are many references in the literature concerning the development and investigation of electromagnetic shielding lightweight flexible materials, especially those that are textile based with different electrically conductive additives. However, little attention has been paid to the problems related to the performance of developed electromagnetic shielding materials for clothing in use, above all wet processing (washing and drying). The main aim of this paper is a description of the influence of washing/drying cycles on the fundamental properties of metal fiber-containing fabrics. Changes in electromagnetic shielding ability and electric conductivity after washing/drying cycles were studied and also other characteristics, such as pilling, changes in mass per unit area and thickness of conductive fabrics, were evaluated. For the purpose of this study, fabrics with different structures (knitted, woven) containing extremely thin stainless steel staple fibers incorporated to the yarn structure as the conductive filler were chosen. For quantification of the influence of the washing/drying cycles on the above-mentioned characteristics, regression methods and simple t-tests were used. Both knitted and woven fabrics withstood satisfactory repeated application of wet processing with respect to the main requirement – electromagnetic shielding ability; in addition, woven fabrics exceeded in higher electrical conductivity, higher shielding effectiveness and lower inclination to pilling and therefore can be used for the production of protective cloth.
The effect of adhesive interlining on the creep behavior of a woven fabric in the bias direction was investigated. Three-element viscoelastic models were used to approximate the creep behavior of a face fabric and adhesive interlining. The creep model of a laminated fabric comprised a six-element model in which two three-element models are connected in parallel with the three-element model. Creep tests were carried out using face fabrics, adhesive interlinings, and their laminated fabrics without and with bonding adhesive interlining by hanging samples in the 45° bias direction under their own weight for 7 days. Creep strains of face fabrics bonded with adhesive interlining were found to be weaker than those of the face fabrics. The creep behavior for the face and interlining fabrics could be approximated using the three-element viscoelastic model with appropriate parameters. The experimental creep behavior of a laminated fabric without bonding was similar to the theoretical behavior. However, the experimental creep of laminated fabrics with bonding interlining was less than the calculated creep, owing to the increase in stiffness due to the adhesive. By revising the six-element model with the strains just after hanging and for 2 days, it was possible to predict the creep strain over 7 days.
The performance of the traditional color prediction model in the color prediction of colored fiber blends is usually not very satisfactory under a variety of conditions, due to the limitation of the trail data and the assumptions used for derivation. In contrast to the traditional model, artificial neural networks (ANN) have an excellent nonlinear mapping ability; however, they also have poor generalization ability if the training data are not sufficient. In this paper a hybrid model, called the Stearns–Noechel (S-N)–ANN model, is proposed, which combines the S-N model with the ANN model. This uses the S-N model first to build the approximate relationship between the recipe and spectrophotometric response of the color blends, followed by optimization with the ANN to achieve higher prediction accuracy and better practicability. Compared with the ANN model, the S-N–ANN model needs less training time with the same training data, yet achieves higher validation and correlation coefficients, indicating that the training of the S-N–ANN model is much easier. The average color difference of the predicted spectrum obtained with the S-N–ANN model was 0.86 CMC(2:1) unit, which was much lower than that obtained with either the ANN model (~2.21) or the traditional S-N model (~1.66), indicating that the S-N–ANN model is a more accurate method for the color prediction of colored fiber blends.
Chitosan has been widely studied for use in many areas, such as for its applications in the biomedical, engineering and pharmaceutical fields, as well as in industry, because of its unique properties, including biodegradability, antimicrobial activity, polycationic nature and biocompatibility. Thanks to the rapid development of materials science, chitosan applications are now possible in textiles. However, there are still many limitations of chitosan fibers in terms of their high electrostaticity, poor mechanical properties and high cost, which are obstacles that inhibit potential applications of chitosan fiber in the industry. Generally, in order to achieve the best performance with chitosan and enhance its commercial value, chitosan fibers are usually blended with long cotton fibers in the textile industry. Therefore, based on preliminary experiments and feedback from the industry, this study was carried out to further investigate the relationship between fiber length, fiber interaction and yarn performance. The results of this study would therefore help to reduce the production cost of yarns with the blending parameters used and also expand the utilization and applications beyond medical applications to fashion-based functional wear. The sliver-blending method offers better tensile properties of yarn samples, while the fiber-blending method offers higher uniformity of fiber distribution. This study would help to reduce the production cost of yarns by blending and also to expand the utilization and application not limited to fashion-based functional wear.
Enrichment of chemically resistant hydrophobic polymers with polar biomolecules is relevant to the production of fiber-based drug delivery devices and adsorptive filtration media, as well as fibers for selective molecular recognition of antibodies, enzymes and nucleic acids. Polysulfone (PSU) is an amorphous polymer possessing high-strength, rigidity and excellent thermal stability. The preparation of PSU spinning solutions requires lengthy dissolution times at elevated temperature that tends to degrade commixed polar biomolecules. Using the highly polar metabolite creatinine, as a model system, a variety of co-solvents was evaluated for electrospinning commixed solutions of PSU and creatinine at room temperature. The selection of solvent systems was informed by Hansen solubility parameters. A binary system of N, N-dimethylacetamide (DMAc):methanol (4:1) was not found to be a suitable solvent because of the need for elevated temperature (80℃) to facilitate dissolution, and a binary solvent system of N, N-dimethylformamide (DMF):dimethyl sulfoxide (DMSO) (3:2) resulted in nozzle blockage during spinning. A binary system of DMAc:DMSO (13:7) enabled preparation of PSU with creatinine at ambient temperature, and sub-micron fibers substantially free of beads were produced continuously via electrospinning, yielding fiber diameters in the range 470–870 nm. The presence of creatinine was confirmed by high performance liquid chromatography (HPLC), and fiber morphology was examined by scanning electron microscopy (SEM).
Angle-interlock woven fabric offers an option for making female body armor as it can form integrally the required dome shapes because of its extraordinary moldability and satisfactory ballistic performance. A mathematical model is created to determine the pattern geometry for the front panel of female body armor, and the front panel can be quickly created using this mathematical model. However, the body armor is multi-layer, which indicates that the relationship between the thickness of the fabric and the pattern block projection for different layers of fabric needs to be investigated, in order to create the whole panel, to improve this novel approach for making seamless female body armor with satisfactory ballistic performance.
In this paper, the thermal comfort properties of flat knitted acrylic fabrics differing in terms of knit structure, tightness, thickness and porosity were investigated within the perspective of its usage in winter wear products. Measured and calculated using the data from Permetest and Alambeta devices, the thermal comfort properties were handled in three aspects, namely thermoregulation characteristics, breathability and thermo-physiological characteristics, and their relationship with fabric structural parameters were investigated statistically. The results indicated that rib 2 x 2 structures provide the optimum condition in terms of thermoregulation, breathability and thermo-physiological comfort, whose thickness and porosity values should be adjusted accordingly, since the thickness improves thermal insulation and porosity improves breathability.
This paper focused on investigating impact factors and relationships of the aerodynamic frictional drag on the surface of flexible fabrics. Firstly, based on fluid dynamics, a preliminary model for aerodynamic frictional drag was defined as
The derivation and performance of yarn quality prediction models in a program called Cottonspec is reported. Cottonspec incorporates a large database of fiber and yarn data from commercial spinning mills, a series of regression-based models predicting yarn quality from measured cotton fiber quality parameters and yarn specifications and a user interface. The inclusion of independent variables into prediction equations was dependent on the criteria that their inclusion was statistically significant and that variables had a theoretically direct influence on yarn structure. Yarn data was corrected to allow for twist, yarn count and yarn irregularity before correlation with fiber properties. Differences in yarn testing results between mills could be corrected by a Mill Correction Factor. Adherence to these criteria and the ability to draw on the very large database meant prediction ability of the models was excellent, as demonstrated in a series of cross-validations.
A novel formaldehyde-free flame retardant containing phosphorus and dichlorotriazine components (CTAP) for cotton fabrics was synthesized. As an active group, the dichlorotriazine could react with cotton fabric via covalent reaction. The addition of 20.7 wt% CTAP into the cotton fabric obtained a high limiting oxygen index value of 31.5%, which was 13.5% higher than the pure cotton fabric. The results of heat release rate, total heat release and effective heat combustion indicated that CTAP effectively imparted flame retardancy to cotton fabric by the cone calorimetry test. With respect to the untreated cotton fabrics, the treated cotton fabrics degraded at lower decomposition temperature and form a consistent and compact char layer, which could be observed by thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. Compared to the untreated cotton fabrics, CTAP performed an effective role in flame retardancy for treated cotton fabrics. Meanwhile, it stimulated the formation of char and promoted the thermal stability of treated cotton fabrics during combustion.
Camphor oil/poly (methyl methacrylate) (PMMA) composites were prepared by the miniemulsion polymerization method, and characterized by Fourier transform infrared spectroscopy, transmission electron microscopy and thermo-gravimetric analysis. The results indicated that based on the weight of camphor oil/PMMA composites, the amount of 18% camphor oils was encapsulated by the PMMA; the dispersion of the prepared composites showed excellent stability to temperature in the range of 20–60℃. Application properties of camphor oil/PMMA composites, such as sustained release, antibacterial and mosquito repellent performance, were further investigated. The results indicated that the PMMA covering can effectively reduce the release rate of camphor oil. The antibacterial rates for E. coli and S. aureus were 67.21% and 41.59%, respectively, and the "landing time" for the first mosquito was about 144.9 min when the cotton fabrics were coated eight times. The coated cotton fabrics can retain the antibacterial and mosquito repellent performance for a long time, even after multiple washings.
Based on traditional frequency selective surfaces (FSSs), the research ideas of novel frequency selective fabrics (FSFs) are proposed. In this paper, the specific square-loop patch FSF was chosen as an example to illustrate the design procedures, including ANSYS (HFSS) simulation and numerical calculation methods, and then a computer-based experiment was conducted to develop prototypes. Although the simulation, calculation, and experiment results have minor differences, especially the resonance frequency, they show good consistency overall, which demonstrates that traditional design methods could also apply to 2D FSFs. The experiment transmission curve shows obvious band-stop response, peaking at -37.12 dB at the resonance frequency 11.65 GHz, and the narrow bandwidth of -10 dB is predicted from 10.85 GHz to 12.55 GHz. To further verify the validity of design procedures, two complementary cross-shaped FSFs were fabricated through a computer embroidery process, and the experimental transmission curves are complementary as expected, peaking at -26.05 dB and 0 dB at the same resonance frequency 9.65 GHz, and the narrow bandwidths of -10 dB and -0.5 dB are 1.07 GHz and 0.41 GHz, respectively. Although many problems need to be solved in further research, this convenient fabrication method and theoretical basis could make relevant work feasible in later study.
In the first part of this study, the drying behavior of wool-acrylic yarn bobbins was investigated by a theoretical model and genetic algorithm method. Each candidate solution for Do, D1 and D2 was presented on a single chromosome. The values of Do, D1 and D2 yielding the best fit between the experimental and predicted moisture contents were obtained using the genetic algorithm. In the second part of this study, the suitability of various empirical and semiempirical models in the modeling of the drying process was investigated by the genetic algorithm. The population number was taken as 30 and the tournament selection method was used. The calculations were performed until the 20th generation for the theoretical model and 100th generation for the empirical and semiempirical models. The results show that the genetic algorithm can be successfully used in the modeling of the drying process of yarn bobbins. The results also show that the Verma et al. and Diffusion Approach models yield the best fit with experimental data.
The use of narrow tubular braided structures for biological tissue support has made it possible to produce highly flexible and robust soft tissue reinforcement structures. These attributes make the braids ideal in supporting ruptured and broken tissues during healing and regeneration. There have been continued efforts to improve the design in order to reinforce tissues while still maintaining their flexibility; this has been undertaken by exploring the deformation behavior of these structures. Mechanical modeling, which provides an in-depth understanding of the deformation mechanism of structures, plays an important role in designing structural changes in tubular braids. This paper reports the results of numerical and experimental investigations into the radial contraction and deformation mode of two types of tubular braided fabrics—single and double braided—subjected to uniaxial tensile loading under quasi-static conditions. Realistic geometrical structures were developed for mechanical modeling of tubular braids in terms of tensile loads, elongation, radial contraction and braid angle. The results indicated that there was a good match between experimental and simulated tensile behavior of the braided structures. It was established that the amount of braided yarns within the structure had the likelihood of influencing the radial contraction and braid angle in the braided structure under uniaxial tensile deformation. The results portrayed that braided structures would undergo large deformations at low loads. It was also established that there would be more structural stability as the yarns increased, evidenced by more loads in the double-braided structure as compared to the single-braided tubular structure.
The possibility of direct preforming in the near net shape of final component structure with load- and shape-conforming fiber orientations is highly essential in composite production, not only to reduce costs but also to attain better mechanical properties and form stability. Based on the concept of varying the reinforcement yarn lengths during the feed-in (warp yarn delivery) and segmented doffing, synchronous working numerically controlled warp yarn delivery and doffing machine modules have been newly developed for multiaxial warp knitting machines to create a resource efficient textile process chain by a single-step, large-scale oriented production of load- and form-conforming warp knitted three-dimensional shell preforms with free-form geometrical surfaces. Such customized preforms in the near component net shape offer higher material utilization and increased lightweight potential.
The pilot study summarized in this paper aimed to raise awareness of a gap that exists in the forensic textile science literature about damage caused to clothing by trained sharp-weapon users. A male trained in the Filipino martial arts discipline of Eskrima performed attack techniques on a physical model of a male torso covered with a 97% cotton/3% elastane knitted T-shirt, that is, a garment commonly worn by males. Fabric severance appearance created by three different, but commonly available, knives was evaluated. High-speed video was used to capture each attack. After each attack the resulting damage to the garment was assessed. This pilot study highlighted differences in severances associated with weapon selection, that is, not all knives resulted in similar patterns of textile damage. In addition, a mixture of stab and slash severances were observed. The findings demonstrated the possible misinterpretation of textile damage under these circumstances compared to damage patterns reported in the existing forensic textile science literature for more commonly occurring knife attacks (i.e. stabbings).
This paper presents a comprehensive experimental study, conducted on a series of woven and non-woven fabric samples from different materials (cotton, polyester, and polyamide) and 14 three-layer systems of textile materials, used for production of outerwear clothing for protection from cold. Heat and mass transfer properties, related to the thermophysiological comfort of the outerwear clothing, namely conductive thermal resistance, water vapor resistance, relative water vapor permeability, air permeability, accumulative one-way transport of liquids, and overall moisture management capacity, were determined for the system of layers and the compound single layers. The transfer properties of the single layers were presented as a function of their thickness, mass per unit area, and areal porosity. The transfer properties of the system of layers were presented as a function of the thickness, mass per unit area, and bulk density of the systems. Regression analysis was applied to derive regression equations. The results obtained allowed assessment of the existence and trend of the influence, as well as evaluation of the strength of the dependences.
This study investigated the differences in thermal properties of primary seam types used in athletic apparel construction. Traditional seam types, such as overlock and flatlock, as well as adhesive films, were studied. Laboratory experiments in a controlled environment showed that adhesives created a considerably thinner seam than the other methods, while flatlock seaming showed the greatest increase in the garment weight because of dense stitching. A series of thermal manikin tests and statistical analysis showed a significantly higher thermal insulation rating in a bodysuit constructed with flatlock seams, which was found to have lower air permeability than the overlock and adhesive physical property testing samples. There was no significant difference in water vapor transport properties among the three test seams. The findings of this study provide the impacts of seams on thermal properties of active bodywear, which may have practical applications in the sports apparel industry’s decision-making in activewear design and production.
High-performance yarns such as aramid fibers are nowadays used to reinforce composite materials due to their advantageous physico-chemical properties and their low weight. They are also resistant to heat and fire. Para-aramid filament yarns (p-AFs) wound on a cylindrical dyeing package have been silvered successfully by means of a newly developed wet-chemical filament yarn metallization process on a laboratory scale. The surface morphology of untreated and silvered p-AF was determined by means of scanning electron microscopy. The chemical structure of the surfaces (contents of carbon, oxygen, nitrogen and silver) was determined by means of energy-dispersive X-ray spectroscopy (EDX). The eliminated and newly formed groups of p-AF before and after silvering were detected by infrared spectroscopy (Fourier transform—attenuated total reflectance). After metallization, the silver layer thickness, the mass-related silver content and washing and rubbing fastness were assessed. Furthermore, textile-physical examinations concerning Young's modulus, elongation at break and electrical conductivity were performed. Subsequently, the electrically conductive p-AFs were integrated in thermoset composite materials reinforced by glass fibers and para-aramid.
This paper introduces a co-design-based method for generating two-dimensional (2D) block patterns for physically disabled people with scoliosis, using three-dimensional (3D) virtual technology. A parameterization process is first performed on a scanned 3D body for creating a digitalized model of the human body, permitting simulation of the consumer's morphological shape with atypical physical deformations. Feature points of the human body for designing a garment block are discussed and classified with wearing ease for obtaining a desired fit effect based on the parameterized model. A basic garment block wire-frame aligned with body features is then established based on the defined feature points of the human body. Based on the deformed wireframe, a 3D expandable garment block is modeled. Customized 2D and 3D virtual garment prototyping tools are applied to create customized garment products based on the general concept of co-design by running the sequence Design–Display–Evaluation–Adjustment using the garment design process and design knowledge, which have already been applied to normal body shapes successfully. Through this process, the classical 2D garment design knowledge, especially 2D pattern design rules, will be modified according to the virtual garment evaluation procedure. The proposed method is validated and compared with the conventional block patternmaking methods in the virtual environment. The experimental results show that the proposed method is easier to implement and can generate garment patterns with satisfactory fit. Furthermore, the method can be used to create fit-ensured mass-customized apparel products (the top body type) for disabled people with scoliosis.
Nowadays, artificial leather is an important commodity in daily life, especially in the fields of apparels, stationery and furniture. However, due to the maturity of producing technology and market segmentation, the industry trends to be saturated. Leather product manufacturers face intense competition and increasing production costs to survive on feeble profits. Thus, everyone is seeking a solution to break this predicament. Thanks to technical advancement and diversified intelligent electronics, a promising market opportunity has emerged that looks for innovative functional leather. This leather can exhibit high thermal conductivity and act as an essential component of electronic outside packages to prevent over-heating.
This study aims to develop a high thermal conductive artificial leather (HTCAL). It incorporates smart electronic textile material (conductive yarn) into traditional artificial leather production through modifying the material and structure of its base layer. The result showed that the thermal conductivity of HTCAL was improved by 19.6% and, when wearing directly, a significant temperature gap between skin and the inner side of the leather occurred, which could offer a comfort cool feeling when worn in summer. This approach is a breakthrough to seize a new opportunity and offer an advancing direction. Further, this HTCAL can free the industry from periodical demand restriction, that is, seasonal limitation, and broaden product research and development into more fields. Thus, this approach can not only improve manufacturers' competitiveness and break them out of the current predicament, but also it creates new business opportunities.
This paper presents an experimental study on the vibration isolation performance of weft-knitted spacer fabrics under forced harmonic excitation. The weft-knitted spacer fabrics with two different thicknesses were first designed by varying the linking distance of the spacer monofilament and fabricated using an electronic flat knitting machine. Then, their vibration isolation performance was tested under forced vibration condition via sinusoidal sweeps from low to high frequencies. The typical acceleration transmissibility curve and effects of fabric thickness, load mass and excitation level were discussed in detail. The results obtained show that the thicker spacer fabric has a lower resonance frequency than the thinner fabric due to lower stiffness, and thus can isolate the vibration at a lower frequency level. The results also show that changing the load mass and excitation level changes the loading conditions of the fabric structure, and thus also changes fabric stiffness and vibration isolation performance due to nonlinear behavior of spacer fabrics. It is expected that this study could provide some useful information to promote the application of weft-knitted spacer fabrics for vibration isolation.
In this study, a novel smart electrically heated sleeping bag was developed by incorporating a proportional–integral–derivative heating control system into a traditional sleeping bag. The smart sleeping bag was aimed to maintain human feet temperature within the thermoneutral range (i.e. 25.0–34.0℃) by automatically adjusting the heat power to the feet region based on real-time human toe temperatures. Subsequently, the performance of the newly developed smart sleeping bag in improving human thermal comfort was investigated by human trials. Eight female subjects underwent two 8-hour sleep trials, that is, the smart sleeping bag with power turned on (SleepingbagHT) and the smart sleeping bag with power turned off (SleepingbagCON). All trials were performed at an air temperature of 6.1 ± 0.5℃ (i.e. the EN 13537 defined comfort temperature for females), relative humidity of 80 ± 5% and air velocity of 0.4 ± 0.1 m/s. It was found that SleepingbagHT could maintain both the foot and toe temperatures within the thermal neutral range as well as keep the local-, and whole-body thermal and comfort sensations in thermal neutral state throughout the 8-hour cold exposure. In contrast, linearly decreasing foot and toe temperatures and aggravated local-, and whole-body thermal and comfort sensations were detected in SleepingbagCON within a 4.5-hour cold exposure. It could thus be concluded that the smart electrical heating sleeping bag was able to provide wearers an 8-hour comfortable sleep in the studied cold environment.
In this study, the mechanical load on a bullet-shaped indenter when impacted by a single-ply Kevlar fabric was experimentally investigated using a reverse ballistics method at both quasi-static and dynamic rates. Different indenter geometries, namely the 9-mm Luger, .223 Remington, and .308 Winchester bullet geometries, were used. The penetration load of the stationary indenter was measured using a force transducer located behind the indenter, and the penetration load was then plotted against the impact velocity of the fabric sample. Different mechanisms of penetration were observed at different impact velocities. Penetration mechanisms were also found to be highly dependent on projectile nose geometry. A modified method to obtain an approximate ballistic limit based on the impact loads was used to compare the efficacy of different geometry types.
This study investigates the effect of the drawing process of ethylene vinyl alcohol (EVOH) fibers on their physical properties. Three different ethylene contents, namely EV-32, EV-38 and EV-44, were used where the ethylene content has the order of EV-44 > EV-38 > EV-32. The result indicates that at the same drawing temperature and draw ratio, the online drawing stress of the fiber with high ethylene content is higher than that with low ethylene content. Moreover, the drawn EVOH fiber, at the drawing temperature of 80℃ and the draw ratio of 2.0, exhibits an optimal mechanical property. As the draw ratio increases, the online drawing stress, birefringence and initial modulus increase. Notably, unlike typical polymeric fibers, the glass transition temperature (Tg) of the drawn EVOH fibers decreases with the draw ratio due to more water being absorbed by thinner fibers within the same number of samples. The draw ratio was found to have little effect on the melting temperature (Tm). At the same draw ratio, the online drawing stress, birefringence, stress and initial modulus of the fiber EV-44, which has the highest ethylene content, is higher than those of EV-32 and EV-38. The creep strain of the drawn fibers EV-32 and EV-38 linearly increase with the drawing time when the applied stress maintains constant at 150 MPa, while an insignificant increase is observed for EV-44, suggesting that EV-44 is difficult to deform and has higher size stability. In the stress relaxation test, the elongation increases with the initial stress. At the same elongation percentage, the initial stress of the drawn fibers has the following trend: EV-44 > EV-38 > EV-32 and the stress relaxation time () has the following trend: EV-44 > EV-38 > EV-32, indicating again that EV-44 is relatively difficult to deform during drawing. Finally, EV-44 fiber performed the best in the hot water resistance test.
This study investigated the effects of fabric movement on detergency in a front-loading washer. To this end, various fabric movements of 3.25-kg loads were induced by controlling wash spin speeds at 34, 46, 50, and 54 r/min and detergency was measured, after which the correlation between the fabric movement and detergency at each wash speed was analyzed. The observed fabric movement characteristics were represented by 10 Fabric Movement Indexes (FMIs), with numerical values defined to describe fabric movements in a front-loading washer. It was revealed that detergency was highest at the wash spin speed of 46 r/min. It was also found that each speed resulted in distinguishing characteristics of fabric movements and two FMIs, "Distance from the center of the drum to the tracer fabric" and "Number of appearances of the tracer fabric", had the greatest influence on detergency. These results show that not only falling movement, which provides high mechanical force to fabric, but also fabric interactions, such as abrasion and mixing, also affected detergency just as significantly.
The present study aims to develop an immobilization support from woven poly (lactic acid) (PLA) and establish the optimum immobilization conditions for trypsin. Woven PLA was modified by ammonia-based plasma treatment in order to incorporate amine groups on its surface. X-ray photoelectron spectroscopy analysis showed that the N1s composition of PLA increased significantly, from 0.66% to 5.92%, after ammonia-based plasma processing. Trypsin from porcine pancreas was immobilized onto modified woven PLA by covalent binding after activating PLA with glutaraldehyde (GA). The results indicated that the optimal GA treatment conditions were as follows: pH of 10.0, 2% GA (v/v), and 180 min crosslinking time. In addition, the optimum immobilization conditions were as follows: pH of 8.5, 10% (owf) of trypsin concentration, 30 min, and 25℃. Under the optimum conditions, the amount of immobilized enzyme on woven PLA was 0.28 mg/mg and specific activity was 3.763 U/mg. In addition, the pH and thermal stabilities of the immobilized trypsin were improved. The immobilized trypsin retained approximately 55% of its initial activity after 20 days of storage and exhibited the potential for repetitive use through approximately 15 cycles. GA crosslinking and trypsin immobilization were found to improve the roughness of the PLA surface and increase its hydrophobicity. The data indicate that modified woven PLA, used as an immobilization support, shows suitable properties for use as a biocatalytic material in enzymatic applications.
The complexity of the free surface electrospinning process makes empirical determination of the effects of parameters very difficult. The parameters of the free surface-roller electrospinning process have not been fully defined. In this paper, new electrospinning parameters were suggested and studied. The relationship between rotating roller speed as a dependent parameter and independent parameter was investigated. The effects of rotating roller speed on electrospun nanofiber diameters and the quality of a nano web are determined experimentally. The velocity of the spinning roller and the content of salts in the solutions were selected as independent process parameters. The results show that the velocity of the rotating roller, which is related to the flow rate/feed rate of a solution on the surface of the rotating roller, affects the spinning performance as well as the quality of the fibers. Moreover, the spinnability and spinning behavior of polyurethane and polyethylene oxide solutions mainly depend on the salt content, viscosity and rotating roller speed. The high speed of the rotating roller caused a thick fiber diameter for the polyurethane solutions and polyethylene oxide, while the slow motion of the rotating roller caused low spinning performance. The diameters and diameter distribution of the electrospun nanofibers and quality of the nano web were most significantly affected by the speed of the rotating roller.
Compression textiles as adjuvant physical interventions are increasingly applied for prophylaxis and treatment of chronic venous insufficiency (CVI), providing benefits of calibrated compression and controlled stretch. Pressure dosage delivered and mechanical properties (stiffness, elasticity and hysteresis) are determined by material nature, stitches structures, fabrication technology and delivery modes. Laplace’s Law and Pascal’s Law contribute to elaborate the static and dynamic working mechanisms behind the interaction between compression interventions and a biological body. However, there is still a lack of sufficient awareness on compression materials, and there is controversy regarding the best solution for clinical application of compression. This study integrates the views from physiology, pathophysiology, biomechanics, material science and textile engineering, to review and clarify physical–mechanical characteristics of compression materials, working mechanisms of textile-based compression interventions and their medical benefits in chronic venous insufficiency treatment. The aim is to enhance understanding of compression textiles applied in compression therapy, and to facilitate cooperation among multiple parties working in related supply chains, thus promoting textile-based compression interventions in chronic venous insufficiency treatment and growth of technical textiles applied in healthcare, medical and rehabilitation fields.
Currently, conductive yarn can be knitted into fabrics to endow the traditional textile product with special attributes, such as shielding electromagnetic waves, detecting and transferring electrical signals, replacing fingers in the operation of touch-screen panels, etc. Research on the electrical properties of conductive knitted fabrics can contribute to the development of such functional textiles. A few studies have been conducted, and it has been found that the variation of the knitted structure can impact the properties of a conductive knitted fabric. Among the properties of conductive fabrics, the resistance value is an important index to decide the performance of electrical functions. Several researchers have conducted practical experiments and theoretical analyses to predict the resistance of plain weft knitted structure. However, in addition to the plain weft knitted structure, the float structure is another important basic knitted structure.
Therefore, a geometric model incorporated with a simplified resistive network is proposed for the calculation of the electrical resistance of conductive knitted fabrics with float stitches and will be studied in this paper. The aim of the model is to determine the resistive effects of conductive float stitches on knitted structures with different numbers of knitted courses and wales. The geometric model can provide a detailed mathematical description of a single knitted loop in the Cartesian coordinate system. With the simplified resistive network, the resistance of conductive float stitches in knitted fabrics can be modeled and computed. The experimental results revealed that the proposed model could approximate the equivalent electrical resistance of the conductive float stitches in knitted fabrics to an acceptable degree.
Pneumatic splice chambers are the industry method for splicing yarns. Most investigations in the literature occurred with ends-opposed splice chambers. For several applications, ends-together splicing is industrially interesting to consider. In this paper, we determine the importance of some process and splice chamber design parameters for ends-together splice chambers. We find that splicing pressure can be maximized, splicing duration needs to exceed a minimum duration and optimum splice length depends on yarn type and chamber design. Important splice chamber design parameters are chamber size and both yarn inlet and air inlet size relative to chamber size. This study also demonstrates the usefulness of three-dimensional printing to evaluate new splice chamber designs.
This study investigated the influence of pretreatment conditions of helium/oxygen (He/O2) atmospheric pressure plasma, including treatment duration, oxygen flow, and distance between the nozzle and the sample (DBNS), on sizing properties of cotton roving. Results indicate that plasma treatment can effectively improve the surface roughness, static friction coefficient, and the wettability of raw cotton fibers, as well as the absorption ability of cotton rovings for starch size. Consequently, sizing adhesion strength (SAS) and breaking elongation (BE) of the roving sized by starch are greatly influenced by the treatment. They first rise and then slightly drop with the increase of treatment duration or oxygen flow, but decrease with the elongation of the DBNS. Compared with a roving without plasma pretreatment, pretreated rovings can possess 59% and 36% improvement of SAS and BE, respectively, by a chosen plasma treatment condition, i.e. 15 s of treatment duration, 1.5 mm of DBNS, 30/0.3 L/min of He/O2, and 40 W of the power.
Wet fabric bothers everyone as it sticks to the skin, hinders body movement and brings discomfort and awkwardness on many occasions. Much has to be done to evaluate this adhesion of a wet fabric to human skin for minimizing the discomfort resulting from this phenomenon. In this study, an improved measurement is developed to test and distinguish the adhesion forces of different materials under controlled conditions. A new and improved theoretical model is proposed to estimate the adhesion force based on the gravity of the liquid bridge that formed beneath the fabric. The theoretical values are reasonably consistent with the experimental results. A potential solution is also proposed for reducing the volume of the liquid bridge in designing a less adhesive fabric by constructing hydrophobic protrusions to the fabric surface.
Rotor spinning is an open-end spinning method that uses air as the medium to transform the fibers into yarn. Nowadays, the properties of its final product—yarn—such as yarn strength and yarn twist, are not satisfied due to the fiber morphology, which greatly depends on the distribution of the massive fibers in the rotor spinning unit (RSU). In this paper, theoretical analysis is given to describe the trajectory of fiber on the slide wall. A numerical study is performed with the massive fibers being simplified into granules to study their distribution characteristics in the RSU. According to our numerical results, the forming process of the fibrous ring is discussed and the effects of two variables, the rotor speed and the angle of the slide wall, on the distribution of fiber granules were also studied. The simulation results indicate that the fiber granules are not evenly distributed during their transport in the fiber transport channel (FTC) and they tend to accumulate on the upper and lower edge of the FTC. The distribution of fiber granules in the groove (fibrous rings) is closely related to the rotor speed. The higher the rotor speed, the longer and thinner the fibrous ring. The distribution of fiber granules on the slide wall is related to the angle of the slide wall such that a smaller angle leads to a scattered distribution on the slide wall, while a larger angle tends to bring a concentrated one. The simulation results show good agreements with our experimental results.
Many biological plants have bifacial leaves with an adaxial surface and an abaxial surface. These two surfaces can often have different morphologies and properties, and they serve different functions in plant growth. This has inspired us to develop novel bifacial fabrics, with a knitted structure on one face and a woven structure on the other. Bifacial fabrics were produced on a purpose-built machine, using wool, acrylic and polyester yarns, with the woven structure being plain weave, and the knitted structure being single jersey. In this study, the moisture properties of these fabrics were compared with conventional woven and knitted fabrics. The water contact angles of the bifacial fabrics were similar to knitted and woven fabrics, but the absorption time on the woven fabric was much higher than the other fabrics. Liquid moisture transfer properties on both faces of the bifacial fabrics were different, with water spreading and absorption on the woven face being quicker than on the knitted face. These unique properties of bifacial fabrics show that these fabrics could be used as moisture management fabrics, without the need for any additional treatments.
A superhydrophobic fabric surface was fabricated by forming a dual roughness structure in combination with lowered surface energy. The contribution of the innate micro-scale roughness resulting from the waviness of filaments and yarns in a woven fabric on hydrophobicity was investigated in comparison with a smooth film surface. Though the micro-scale roughness coming from the multi-filaments of fabric was conducive in enhancing the hydrophobicity of the surface, the micro-scale roughness itself was not enough to create superhydrophobicity. Thus a nano-scale roughness was introduced by an anisotropic etching employing oxygen plasma etching followed by plasma enhanced chemical vapor deposition. As for the nano-scale roughness, however, it was possible to achieve the superhydrophobicity only with nano-scale roughness, but with a very large aspect ratio of nano-pillar structure. In the presence of dual-scale roughness consisting of both micro- and nano-scale structures, the superhydrophobic characteristic was effectively achieved even at a small aspect ratio of nano-pillar. By adjusting the number of filaments in a yarn and by controlling the plasma process time, it was possible to control the dual-scale roughness of a woven fabric and its wettability. An excessive thinning and lengthening of nano-pillars may negatively affect the hydrophobicity by the collapse and aggregation of pillar tips, and an appropriate processing condition is critical to design a durable superhydrophobic surface.
Fourteen types of composite laminates—plain carbon/epoxy composite laminate, plain glass/epoxy composite laminate, and 12 carbon fiber–glass fiber/epoxy intra-layer hybrid composite laminates—were made with different relative proportions of the two fiber types and different dispersions. Tensile and compressive mechanical properties were tested and the results were simulated using the ABAQUS/Explicit commercial software package. The relative proportion of carbon fiber content largely affected the tensile and compressive mechanical properties and the so-called hybridization effect, and should be treated as one of the most crucial parameters. Though the degree of dispersion does not significantly affect mechanical performance, it certainly affects the failure modes of the composites. Scanning electron microscopy revealed that under both tensile and compressive loading, the low-elongation carbon fiber failed first, there was a stress drop in the stress–strain diagram, and then the materials continued extending; meaning that the rest of the load was carried by the remaining glass fibers. With a high dispersion of fiber types, composites tend to fail in a more controlled way, i.e. the curves have a plateau region at the end, and catastrophic failure is thereby avoided.
In this work, based on the geometrical model given in Part I, a mechanical model is created for dry relaxed slack plain knitted technical fabrics including the three-dimensional friction effects. The equilibrium of forces and moments applied on a loop are written by using the elasticity theory of thin rods. Through this model, it is shown that a dry relaxed plain knitted fabric can be in a stable state induced by friction. The application of the model was carried out on E-glass technical fabric, which was also used in Part I as its dimensional properties were obtained through the created geometrical model. In the current part, Part II, the mechanical properties of this fabric are obtained and discussed as an exemplary application.
A mathematical model based on the principles of conductive heat transfer is presented to predict the thermal resistance of cut pile carpet. The cut pile carpet assembly is considered as a network of thermal resistances of the tuft yarns, trapped air, and the primary backing fabric. A straightforward calculation of the thermal resistance was not possible as the data for thermal conductivity of the tuft yarns along their axes was not known. Therefore, the calculation of thermal conductivity in the direction of the yarn axis was based on the construction of surface pile and on the measured thermal resistance of carpet for a set of samples. Theoretical thermal resistances of another set of cut pile carpets were calculated by applying the developed thermal model. The results show that the simple network model is robust and gives reasonable values by using the carpet construction parameters. The model can be used for engineering of cut pile carpets to provide a desired level of thermal insulation.
Bleached cotton fabric was chemically modified (cationized)with natural amino acids extract obtained by acid hydrolysis (6N HCL) from soya bean seed waste, adding MgCl2 as an acid donor in the pad-dry-calendaring process to investigate the changes in textile properties and its dyeability with reactive dye in both a conventional alkaline dye bath and salt-free acidic dye bath. This modified cotton incorporates new functional groups producing
Purple-fleshed sweet potato (PSP) has a reddish purple color with high amounts of anthocyanins and phenolic acids, both of which have various health-promoting effects. The acylated anthocyanins present in PSP are more heat-resistant than the nonacylated types found in other plants. Therefore, PSP extract was considered as a natural pigment and functional agent for textile dyeing and/or finishing processes. Here, wool and cotton fabrics are pretreated by a tannic acid aqueous solution to increase their dyeability and then dyed by PSP extract. The dyed fabrics are then investigated by various analysis techniques. The results revealed that wool and cotton fabrics can be dyed bluish red through the pretreatment and dyeing process. The wool and cotton fabrics also showed antibacterial and antioxidant characteristics.
Silk fabric was dyed with extract of roasted yerba mate (Ilex paraguariensis). Dyeing experiments were carried out at varying dyestuff concentration, temperature and pH. The influence of mordants, such as potassium alum and tannin, was investigated. The best results in dyeing were produced with 20 g L–1 of dyestuff concentration, pH 3 and temperature of 90℃. Mordants showed negligible influence. The kinetic study showed that the pseudo-second-order equation better represented experimental data, which is related to the chemisorption process as the rate-controlling step. The equilibrium data were easily adjusted by the Langmuir–Freundlich model, indicating the significant contribution of the chemisorption process in a monolayer followed by a multilayer physisorption. The thermodynamic study indicated that dye adsorption was spontaneous and endothermic.
Cotton extraneous matter (EM) and special conditions are the only cotton quality attributes still determined manually by US Department of Agriculture Agricultural Marketing Service (USDA-AMS) classers. To develop a machine EM classing system, a better understanding of what triggers a classer EM call is needed. The goal of this work was to develop new information about cotton EM, such as bark and grass, and leaf particles, using machine measurements, to aid in the development of instrumentation for cotton quality measurements. AMS classers were tasked in identifying and denoting bark/grass in large-area color images of cotton samples. Image segmentation analysis was applied to detect non-cotton items, such as leaf particles, and the classer denoted bark/grass objects were segmented manually. Further image analysis was used to measure shape and color parameters of these bark/grass objects and leaf particles in the sample images. These measurements of the bark/grass objects and leaf particles were compared and logistical regression analyses conducted to evaluate classification. For every shape and color parameter, there were significant differences between the bark/grass objects and the detected leaf particles in the images. The differences were greater for the shape parameters than for the color parameters. A classification model with shape, color, and log-transformed shape parameters consistently classified the bark/grass objects and leaf particles most accurately with 99.5% and 97.6% correct classification rate, respectively. However, classification models that were 99% correct classifying manually segmented bark/grass were only about 77% correct when applied to the machine detected bark/grass particles.
To solve electromagnetic interference of electronic devices and health issues by the expansion of the electronic industry and the extensive use of electronic equipment, flexible and stretchable conductive elastic textiles are beneficial. This study prepared conductive Ni/polyaniline (PANi)/polytrimethylene-terephthalate (PTT) composite fabric by in situ chemical polymerization and electroless nickel plating. Their direct current electrical resistance and the shielding efficiency energy were tested. Furthermore, the effect of electroless plating conditions was investigated on surface resistivity and electromagnetic shielding effectiveness (EMSE) of the composite fabric, and the correlation between electrical resistivity and EMSE was explored. The results show that the shielding efficiency energy of Ni/PANi/PTT composite fabric optimized can reach more than 40 dB and at a given frequency it has an inverse parabolic relation with the electroless plating conditions. In addition, when the electroless plating conditions is the determinant, the SE has little change in the electromagnetic wave frequency, especially in the frequency range of 600 MHz or more. It is concluded that the EMSE of the Ni/PANi/PTT conductive fabrics could be tailored by modifying the chemical reagent contents in the electroless plating solution.
In the current literature, there is a lack of knowledge concerning which parameters are effective on relaxed slack plain-knitted conventional fabrics, although slack fabrics (i.e. fabrics with no occurrence of jamming) are commonly used for technical applications. Thus, the present series of works are conducted as further investigation on relaxed slack plain-knitted fabrics.
In the present part, Part I, a geometrical model is created based on Kurbak's 1998 model. The created model is then applied to conventional dry, wet and wash relaxed wool plain-knitted slack fabrics. The model is also applied to E-glass dry relaxed technical plain-knitted slack fabric. The applied models are then drawn to scale by using 3DS-Max computer graphical software. At first glance, the loop shapes obtained through the three-dimensional modeling of E-glass fabrics are observed to be similar to the E-glass fabric loops that were recorded in the photographs of the knitted samples.
An investigation on the physical conditions for obtaining such a special loop shape is going to be the subject of the following part, Part II.
Specific levels of the carbohydrates melezitose and trehalulose deposited on the surface of cotton fibers are indicators of whitefly or aphid contamination. These deposits could cause stickiness problems during cotton ginning and textile processing. Cotton stickiness is highly complex, but surface carbohydrates may play the largest role in manifesting an issue. We utilized ion chromatography (IC) to identify and quantify nine sugars of interest present in the water extracts of 25 cotton samples to create sugar profiles for each sample: inositol, trehalose, glucose, fructose, trehalulose, sucrose, melezitose, raffinose and maltose. We compared the sugar profiles to the respective Minicard ratings of either NONE, LIGHT, MODERATE or HEAVY to draw correlations between the IC data and the rating. Trehalulose and melezitose in water extracts highly and positively correlate to Minicard ratings, confirming past researchers’ attribution of cotton stickiness to insect sugars. Trehalose and maltose also highly correlated, possibly due to their marker content in honeydew. Glucose and fructose moderately correlated to the ratings. IC studies of the collected Minicard sticky spot material found trehalulose and melezitose were the most prevalent sugars in HEAVY rated samples. Glucose and fructose were present in larger amounts in the MODERATE versus HEAVY rated samples. This result may indicate that the Benedict Test, which attributes these reducing sugars to stickiness, may not be sufficient for conjecturing a stickiness issue. When comparing the averages of the nine sugars present in water extracts versus those sugars contained in Minicard sticky spots, the overall distributions were very similar.
We proposed a new method for measuring apparent Poisson’s ratio for yarn and developed a new tensile tester equipped with a digital micrometer that can measure the omni-directional diameter of the yarn annularly while the yarn is elongated. Values of apparent Poisson’s ratio were obtained from the longitudinal and transverse strains continuously. The mean diameter measured omni-directionally was used to calculate the transverse strain for each longitudinal strain. We tested five spun yarns, one monofilament yarn and two filament yarns and obtained values of apparent Poisson’s ratio against longitudinal strain for all samples. Apparent Poisson’s ratio was not constant for spun and filament yarns, while it was constant for monofilament yarn. When the longitudinal strain was low, apparent Poisson’s ratios of ring spun yarns and filament yarns were large, owing to the fiber packing density. As the longitudinal strain increased, apparent Poisson’s ratio gradually decreased. Furthermore, we approximated the relationship between apparent Poisson’s ratio and the longitudinal strain using a power function. The apparent Poisson values can be used in the simulation of fabrics.
This study investigated moisture management properties of a single-faced superhydrophobic fabric. A single-faced superhydrophobic lyocell fabric, where one face of the surface is superhydrophobic and the opposite face is hydrophilic, was produced by a two-step plasma process on one side of the fabric: (1) the addition of nano-scale roughness by 5 minutes of O2 plasma etching; (2) subsequent 30 seconds of plasma enhanced chemical vapor deposition with hexamethyldisiloxane to lower the surface energy of lyocell fibers. As a result, the superhydrophobic lyocell fabric exhibited water repellency with a static water contact angle greater than 161° on the treated surface, allowing water absorption from the untreated face. The nanometer depth of the superhydrophobic layer in the hydrophilic textile affected water absorption capacity, drying rate, vertical wicking rate, and moisture management properties. The air permeability and water vapor transmission rate of the superhydrophobic treated lyocell fabric were hardly changed. The superhydrophobic properties were maintained after a gentle wash cycle, although the level of superhydrophobicity was reduced, especially when it was washed with detergent. This superhydrophobic and moisture managing textile would be relevant for an application that requires a water repellent property on one face and water absorbing property on the opposite face, such as medical operation gowns, wound dressings, and hygienic products.
In aramid fiber-reinforced composites manufacturing, para-aramid fiber requires surface modification to improve its interfacial adhesion with matrix materials. In this study, aramid fiber was modified with dilute sulfuric acid, which was gradually concentrated under microwave irradiation. Results showed that the aramid fiber could be efficiently modified. Sulfonic acid groups were introduced on the surface of the aramid fiber, as confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The breaking strength and thermal stability of the modified aramid fiber were not adversely affected. When the concentration of sulfuric acid was 30.0 g/L, the breaking strength of the aramid fiber remained at 90.7% of the original value, and the number of sulfonic acid groups of 1 g modified aramid fibers was 1.38 x 10–5 mol/g. Thermogravimetric and X-ray diffraction analyses showed that the main structure of the aramid fibers was not affected. The aramid fiber surface was not severely etched, as evidenced by scanning electron microscopy images. Therefore, this modifying method involving a gradual change in sulfuric acid concentration may be widely applied in many fields.
The concentrations of a considerable number of trace elements (Ag, Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ti, Tl, V and Zn) were determined in various skin-contact clothes (T-shirts, blouses, socks, baby pajamas and bodies) from the Catalan (Spain) market. In addition, migration experiments with artificial acidic sweat were conducted in order to establish the migration rates of these elements. High levels of Zn (186–5749 mg/kg) were found in zinc pyrithione labeled T-shirts, while high concentrations of Sb and Cr were found in polyester and black polyamide fabrics, respectively. An environmental scanning electron microscope (ESEM) confirmed the presence of Ag and Ti particles and aggregates in several clothing items. The use of the ESEM complemented the results of the elemental analysis and migration experiments. Dermal exposure to trace elements was subsequently calculated, and the human health risks were assessed. Antimony showed the highest mean hazard quotient (HQ = 0.4) for male and female adults wearing polyester clothes; for one of the examined items (polyester T-shirt) the HQ was even above the safety limit (HQ > 1). Exposure to Sb from polyester textile could mean potential health risks in subpopulation groups who frequently wear these clothes, and for long time periods. The migration experiments with artificial sweat showed to be essential for establishing the exposure to trace elements through cloth with direct contact with skin.
In this paper, a computer-based carving experiment was conducted to make frequency selective fabrics (FSFs) with cross-shaped units. Different samples with varying frequency selective fabric types, structure parameters, conductive layers, base fabrics and unit shapes were prepared and the transmission characteristics were tested using the Shielding Room Method. The reflection characteristics under different electromagnetic (EM) wave incidence angles were also tested to study the angle stability. Experimental results showed that in the given frequency range of 4–14 GHz, two types of frequency selective fabrics had good complementary transmission characteristics, with ideal bandwidths and resonance peaks, and the aperture frequency selective fabrics showed certain stability to small electromagnetic wave incidence angles. Structure parameters played a very important role in determining frequency response characteristics and base fabrics with different effective dielectric constant could also exert a great influence. However, the change of electrical conductivity within a certain extent would not affect the transmission characteristics and related work should be continued to explore the effect rule. Through rational control of the unit shape to increase or decrease the conductive material mass, broad-spectrum shielding or passing-through properties could be obtained. In the paper, the experimental results were discussed and analyzed in detail aiming at different parameters, and internal causes were further investigated, which could provide reference values for the relevant design and product development process.
Because of the friction between the hollow spindle surface and the fiber end increasing, the fiber end rolls on the hollow spindle surface under the high-speed rotating airflow during the twisting process. The fiber gets self-twist, which will be wound into the yarn body. The self-twist of the fiber will increase the friction and the cohesion between the fibers in the yarn, which will improve the strength of the yarn. This article analyzes traditional jet vortex spinning and self-twist jet vortex spinning comparatively from the three aspects of the hollow spindle structure, the airflow distribution inside the nozzle, and the yarn performance. It is beneficial for exploring the yarn mechanism, the yarn performance, and the development of self-twist jet vortex spinning.
A new method of automatically identifying ramie and cotton fibers using analysis of shape, color, texture, and surface stripes is here introduced. The shape, color, texture, and stripe features of the fibers were extracted by transformation from red, green, blue images to hue saturation intensity images and then to grayscale and binary images, by segmentation of the fiber from background, by edge detection of the outline of fibers, and by stripes on the surface of the fiber. Eighteen characteristic parameters suitable for identification were selected according to their probability distribution curves. A three-layer multilayer perceptron artificial-neural-network-based prediction system is here presented as a means of distinguishing cotton fibers from ramie fibers. The system training was carried out using a back propagation algorithm. The proposed system was tested on more than 2000 cotton and more than 2000 ramie fibers. The experimental results showed that the overall tolerance for false identification of cotton or ramie fiber was under 5%.
The article concerns the widespread issue of thermal comfort; investigations into textiles and thermal insulation problems are presented. Materials that were tested include double-layer knitted fabrics with potential application in multi-layer garments addressed to a specific group of users. The investigated materials were constructed with the following raw materials: cotton, polypropylene, polyester, polyamide, bamboo, and viscose. The textiles with a comparable geometric structure and different composition were tested for their thermal insulation. In the experimental section the temperature gradients in specific constant ambient conditions using a thermal imaging camera were obtained. In the simulation section three-dimensional models of actual textiles were designed and the temperature gradients on the basis of performed simulations were calculated. Both measurements and simulations yielded comparable results and showed that the comparatively thick knitted fabrics’ thermal insulation strongly depends on the raw materials from which they were made and less on the parameters of the yarn.
Hybrid organic–inorganic coatings prepared by the sol–gel method can impart desirable properties to textiles, but may adversely affect properties such as bending rigidity. This study investigated the causes of increased bending rigidity. Woven wool fabric was pad coated with formulations of methyltriethoxysilane (MTES) and Hercosett polyamide resin, examined by scanning electron microscopy, and the bending rigidities were determined. MTES coatings of up to 3.0% solids on mass of wool did not impart unacceptable bending rigidity. The coatings were not uniform on the fiber surfaces, and the increases in fabric bending rigidity could be partially attributed to inter-fiber bonding. In addition, the coatings "pinned" the edges of the cuticle scales, making individual fibers harder to bend. These effects are only weakly dependent on the Young's moduli of the coating materials.
Three novel vinyl sulfone reactive dyes of various metallic salts (Na, K, Li) have been synthesized by coupling 1-amino-phenyl-4-beta hydroxyethyl sulfone sulfate ester with 1-amino-8-hydroxynaphthalene-3,6-disulfonic acid (H-acid). The reactive dyes were then purified using ultrafiltration (UF). The ultrafiltrated dyes of the various metallic salts were characterized by their spectrophotometrical data using Ultra Violet-visible (UV-vis), Fourier transform infra-red and optical emission spectroscopy, X-ray diffraction, and elemental analysis. The purity of the dyes was checked by Thin Layer Chromatography (TLC). The solubility characteristics of the various salts of the ultrafiltrated reactive dyes were assessed and compared with the non-ultrafiltrated reactive dyes of the same salts. The dyes were characterized and applied to cotton, wool, and nylon 66 by exhaustion (dyeing).
Novel water-based reactive ink-jet inks were prepared with the ultrafiltrated reactive dyes of the various metallic salts. Their suitability for digital printing applications was examined by using a digital printer on suitably pretreated cotton samples. Color and fastness properties measurements were performed for both the dyed and digitally printed samples.
K/S values of the dyed samples were higher than those of the digitally printed ones, whereas K/S values of the samples dyed with the ultrafiltrated dyes were much higher than those of the non-ultrafiltrated dyes. The other coloristic co-ordinates L*, a*, b*, C*, and ho were in line with strength changes of the dyes before and after UF. The dyed and digitally printed samples had excellent wash and good light fastness properties. UF slightly improved the fastness properties of the dyed samples.
With the use of new materials for technical textile applications, evaluation of electrical properties in accordance with the intended application is required. In this study, experimental investigations are carried out to check the electrical behavior of hybrid and non-hybrid woven structures of basalt/polypropylene, basalt/polyester, and basalt/jute fibers. Three types of weaves were used for both hybrid and non-hybrid structures. These textile fabrics were evaluated by methods of measuring surface resistance and the volume resistance. Results are discussed in terms of fiber composition and woven structure. The aim is to compare different structures on the basis of electrical properties. The purpose of this study is to identify parameters that have the strongest influence on electrical properties of fabrics.
The compressive deformation and load of a spacer filament in a warp-knitted spacer fabric was analyzed theoretically in this work. It was found that the compression process of the spacer filament can be divided into four stages, including a Stiff Stage, an Elastic Stage, a Restful Stage, and an Ineffective Stage. Based on the theoretical analysis of the compressive displacement and the radius of the spacer filament at different stages, as well as the bending moment of the spacer filament during compression, the relationship between the critical compressive load at different stages and the structural parameters of the spacer filament in a warp-knitted spacer fabric was found. Furthermore, plane plate compression experiments for spacer filaments were designed and tested to verify the correctness of the theoretical analysis.
The goal of this study was to develop an approach that could automatically generate the customized patterns for women’s suits based on the body measurements taken from two-dimensional (2D) frontal and side images of a subject. The 26 important pattern dimensions relevant to certain body dimensions were first chosen, and the mapping relationships between the body and pattern dimensions were then established for pattern alterations. For the body dimensions (e.g. girths) that could not be directly measured in the 2D images, prediction models were created based on the available width and depth measurements. The body measurements from the 2D images (auto-measurements) of 295 subjects were compared with the corresponding manual measurements, which showed a good correlation between the auto and manual measurements. The try-on test of five suits made with the altered patterns demonstrated the good fitting effects of the customized suits at important characteristic landmarks of five participating subjects through a visual evaluation. The subjective test also showed a satisfactory result of clothing fit under five different postures. Since this pattern-making method is originated from the relationship between the features of a human body and the elements of a pattern prototype, the generated patterns are individualized by unique body shapes to attain a good fit. This method can also accelerate the pattern-making process, reducing human efforts, costs, and production time.
The presence of foreign matter in ginned cotton lowers the quality and ultimately the monetary value of cotton. Previous studies have shown benefits of using ultraviolet excited fluorescence to detect certain cotton contamination that is difficult to detect using other methods. The overall goal of this study was to explore the feasibility of using hyperspectral fluorescence imaging as a complementary tool for foreign matter differentiation. The mean spectra of lint and seven types of foreign matter were extracted from the hyperspectral fluorescence images using a region-of-interest-based approach. The principal component analysis was applied to select the optimal features from a total of 113 wavelengths covering the spectral range of 425–700 nm. The linear discriminant analysis with the selected wavelengths achieved an average classification rate of 90% for all samples. Therefore, this imaging method could be used as a complementary sensing modality to current instruments that are employed for cotton quality assessment in the textile industry.
To date, the trend in the development of knitting promotes higher requirements for warp tension control, and the fluctuation of knitting warp finally comes down to the imbalance between yarn demand and feed while forming every loop. According to warp knitting machine characteristics, four typical points are chosen to calculate the value of yarn demand, and in this way a model is built to obtain and plot the overall change trend in yarn demand in one knitting cycle. Combined with the theoretical tension curve calculated based on the yarn demand and the measured one, it is verified as coincident. The model is useful for analyzing the factors causing warp dynamic tension variation, and lays the groundwork for accurate active tension compensation.
In this study, a model was developed and numerical simulations based on the developed model were performed to investigate the convective air drying behavior of porous materials and to discuss the reliability of assumptions often used in convective drying models. Simulation results were obtained for a wool yarn drying process with various values of the drying air temperature and inlet velocity. The results show that a symmetric pair of vortices is formed in the wake region of the material as a result of boundary separation. The length of the vortex formation increases with the inlet velocity, depending on the increase in the Reynolds number. The results also show that temperature is the major factor affecting the drying rate, while the velocity has a secondary effect. The results also show that the temperature in the material and on the surface of the material varies significantly depending on the evaporation rate, developing boundary layer, and boundary layer separation. Therefore, a constant temperature assumption in the material and on the material surface is not reasonable. Furthermore, the results show that the temperature gets significantly lower values, especially in the early stages of drying, due to the energy consumed for evaporation. Therefore, it is not reasonable to neglect evaporation, as this would result in an over-prediction of the drying rate.
The objective of this study was to evaluate washing performance by beating and rubbing movements that simulate traditional washing methods. By comparing washing performance between these washing methods and a front-loading washer, we examined the potential of the new washing technique and proposed an efficient washing system. In this study, the new rubbing movement, that mimics a washboard, shows low fabric damage with high washing efficiency. The rubbing movement provides high mechanical force, which allowed easy transfer between soil and the detergent solution on the fabric surface. Thus, efficient washing can be accomplished by rubbing movements which minimize fabric damage and achieve high washing efficiency. A beating movement that copies a laundry bat gave the lowest damage and washing performance, so may be used for delicate textiles. In addition, location changes through flexing enhanced washing efficiency and showed better performance than strong force in a fixed location.
A method is presented for modeling the tensile behavior of multifilament twisted yarns. A filament assembly model and a computer-aided design/computer-aided engineering (CAD/CAE) approach are proposed for the tensile analysis. The geometry of the twisted yarn and the nonlinear filament properties were considered. The finite element method (FEM) and large deformation effects were applied for computation of the stress–extension curves. Ideal yarn structures of five layers with different twist angles were simulated to predict the tensile behavior of each filament and each layer. The stress acting on the filaments after yarn extension could be directly analyzed by the FEM. The stress distribution in the filaments showed that the highest stress regions were located at the filament in the center of the yarn and decreased slightly to the yarn surface. The stress–extensions of the filaments were converted to yarn tensile behavior that is shown in terms of the maximum and average stress–extension curves. The results of this prediction model were compared with the stress–strain curves of high-tenacity rayon yarn and the energy method. The maximum stress–extension curves showed very good agreement with experimental results and are more accurate than those obtained by previous methods.
Polysulfonamide/poly(3,4-ethylenedioxythiophene) (PSA/PEDOT) conductive composite yarns were prepared by the vapor phase polymerization technique. Ferric chloride (FeCl3) was used as the oxidant initiator with five different concentration settings (20, 40, 60, 80, and 100 g/L). The effects of oxidant concentration on the chemical composition, mechanical properties, and electrical conductivity of PSA/PEDOT composite yarns were analyzed. The surface resistance and mass-specific resistance of conductive yarns were measured to investigate its conductive behavior in terms of oxidant concentration, reaction time, impregnating time, and heating temperature. The effects of the applied voltage and the yarn’s combination structures (knotted, bundled, series, and parallel) on the electrothermal properties were determined using a direct current regulated power. It was concluded that the molecular structure and chemical composition of PSA is not changed significantly with the deposition of PEDOT. The optimized deposition settings for the preparation of the PSA/PEDOT conductive composite yarns were found to be 10 min (reaction time), 60 min (impregnating time), 80℃ (heating temperature), and 80 g/L (FeCl3 concentration). Correspondingly, the mass-specific resistance of PSA/PEDOT composite yarns could be up to 0.94 g cm–2. The maximum heating temperature of PSA/PEDOT conductive composite yarns during the electrical heating procedure could be increased rapidly with an increase of applied voltage and then tended to be stable. The electrothermal properties of PSA/PEDOT conductive composite yarns with different combination structures (knotted, bundled, series, and parallel) have been investigated systematically. This study presents a new way to develop conductive polymer based yarns, which can be used as fibrous sensors, connection devices in smart clothing, and for electromagnetic shielding applications.
Glass-fiber felts have emerged as a popular material for noise reduction. This paper investigates the effect of various morphologies (micro-layer, macro-layer and air-layer) of glass-fiber felts on sound insulation. The sound transmission loss is measured by a Brüel & Kjár (B&K) impedance tube. The results show that the sound insulation of glass-fiber felts can be improved by increasing the number of macro-layers. The comparison between the macro- and micro-layer of glass-fiber felts on sound insulation is systematically carried out. Notably, the sound transmission loss of glass-fiber felts with similar areal density and thickness favors macro-layer structures over micro-layer structures. A simple model is established to explain this phenomenon. In addition, the sound transmission loss exhibits period fluctuations due to the presence of the air-layer between glass-fiber felts, which can be theoretically explained by the resonance effect. It is found that sound transmission loss can be improved by increasing the number of air-layers.
The bending moduli of solid and hollow glass fibers were determined by means of fiber deflection tests. The test method was modified by measuring both the vertical and horizontal displacements of the end of the deflected fiber, without increasing the number of tested fibers, in order to reduce the high scatter of conventional test results obtained by measuring only the vertical displacement. Upper and lower boundary curves of the fiber end displacements were determined to filter out inaccurate measurements, for example, when the neutral line of the fiber is not a plane but a spatial curve. The mean and coefficient of variation of the fiber bending modulus were estimated from the recorded coordinates of the fiber ends, applying two newly-developed statistical evaluation methods based on the individual coordinates or on their average. After comparing several evaluation methods, it was demonstrated that the individual coordinate-based method provided the least relative error of the average.
Stretch woven fabrics are widely used owing to their comfortable properties such as formability, fitting to the human body and shape retention after wearing. These distinguishing properties are determined by stretch and recovery tests. The aim of this study is to determine the optimum elastane draw ratio, load and relaxation type for best stretch and recovery properties of woven stretch fabrics. An optimization model is developed to determine the optimum draw ratio of the elastane core in the yarn, load applied to the fabric and relaxation type for the best response variables of stretch and permanent stretch. The effects of the elastane draw ratio, load applied to the fabric and relaxation type on stretch and permanent stretch properties are found to be statistically significant according to analysis of variance results. Regression models are obtained to estimate the stretch and recovery properties for different elastane draw ratios and load levels. Additionally, the effect of the elastane draw ratio of the yarn on the fatigue properties of woven bi-stretch fabrics is investigated for dry relaxed and laundered states.
The main topic investigated in the present paper is the analysis of the effect of bending rigidity, Poisson’s ratio and surface friction of fabrics on the stretching step of the comprehensive handle evaluation system for fabrics and yarns (CHES-FY) by using a theoretical tensile model. Simulated pulling-out force–displacement curves of the stretching step for several cases were investigated and compared with the experimental curves. The results showed that bending rigidity and surface friction of fabrics were the important factors that affected the test results of the stretching step. The slope of the simulated pulling-out force–displacement curve becomes larger by including the bending rigidity and surface friction of fabrics. However, the effect of Poisson’s ratio was small and was able to be neglected in the formulation of the model. In addition, the relationship between the bending indices, i.e. and k, and the diameter of the testing pins was discussed. It has been confirmed that the effect of the bending rigidity of fabrics on the pulling-out force–displacement curve strongly depended on the diameter of the testing pins. The model also detected that the surface friction effect became more remarkable for fabrics with a high tensile modulus.
In this study, –NH2 groups were introduced to a poly(ethylene terephthalate) (PET) fabric to make the fabric hydrophilic and, then, soybean protein was bonded on the surface of the modified PET fabric to obtain a soybean protein/PET composite fabric. The –NH2 groups allowed the soybean protein to be firmly bonded on the surface of the modified PET fabric. Scanning electron microscopy images showed that the surface of each modified PET fiber had a small number of grooves and that there was a thin film on each soybean protein/PET fiber. Attenuated total reflectance Fourier transform infrared spectra demonstrated that the nitrated and reduced PET fibers were introduced –NH2 groups and that there were –CO–NH– groups on the surface of soybean protein/PET fibers. X-ray photoelectron spectroscopy analyses showed that there was a nitrogen element on the modified PET fibers. The X-ray diffraction patterns suggested that the crystal structures of the modified fibers did not change significantly during the modification processes. The thermogravimetry results showed that the thermal stability of soybean protein/PET fiber kept well. The wearability tests indicated that the breaking strength and elasticity of the original fabric were well retained by the modified fabrics. The soybean protein/PET fabric had good levels of hydrophilicity and softness when the binding rate was below 3.0%.
Superhydrophobic and transparent surfaces on cotton fabrics have been developed using silica nanomaterials. Initially, trichlorododecylsilane was treated on the silica nanoparticles to lower the surface energy of the fabric. By simply spraying alcohol suspensions containing hydrophobized silica nanoparticles, extremely water repellent coatings were formed on the textile fabrics. The effect of three types of alcohol solvent on the hydrophobicity of the coated cotton fabrics was examined by measuring the surface wettability. The treated cotton textiles in methanol exhibited contact angles higher than 160°, contact angle hysteresis lower than 10°, and good water repellency. It proved to be essential to form hierarchical morphology in achieving superhydrophobicity.
Highly electrical conductive fibers have received significant attention because of their potential to be utilized for wearable technology. Conductive fibers have already been developed by many research groups using metal and carbon nanotubes (CNT); however, productivity is limited. Conductive fibers composed of conductive additives embedded in a polymer matrix were fabricated by a melt-spinning process. This enables the scaling-up of production and gives high mechanical strength compared to fibers prepared by other processes. Silver (Ag) was selected for the conductive material, and embedded in polypropylene (PP) fiber. However, the melt-spinning process has an inherently lower filler content threshold; therefore, it was difficult to fabricate with sufficient silver for the required electrical properties. CNT forests were introduced to make up for this shortcoming, and they could serve as a conductive bridge between unconnected Ag. The CNT percolation effect confirmed that non-conductive Ag/PP increases electrical conductivity after CNTs were added. It was determined that 80 nm Ag (46 wt%) and single wall CNT (4 wt%) embedded PP composite fiber (Ag80/SW_46/4) was the optimum fiber; with a thickness of less than 100 µm its electrical conductivity was 4.1–7.2 x 10–2 S/cm. Conductive fabric was fabricated using our composite fiber, and it had higher electrical conductivity than that of a single fiber because multi-filaments induced lower electrical resistance. Although the electrical value attained does not approach a satisfactory goal, it is thought that this fiber has a potential to be applicable for wearable technology.
The inter-segmental ventilation rate at clothing inter-connection of arms and trunk affects the estimation of local ventilation rates of these clothed segments. The accurate estimation of the inter-segmental ventilation rate is based on the integration of a connected clothed cylinders model with a bio-heat model to predict a realistic segmental skin temperature. This integration is validated with experiments on a thermal manikin using the tracer gas method. The results show that accounting for the inter-segmental ventilation rate improves the estimation of the segmental ventilation of the arm and the trunk for different garment apertures at external wind velocities less than 4 m/s. For a wind velocity of 1 m/s, the inter-connection increased the trunk ventilation by up to 12% and heat loss by up to 5.46%.
A statistical correlation is established for the inter-segmental ventilation rate in terms of the influencing parameters: air permeability, wind velocity, mean air gap size between skin and clothing, and the upper clothing aperture design. Furthermore, a local ventilation rate correction factor equation is developed as a function of the inter-segmental ventilation rate to correct for local ventilation rates when derived from values of isolated/unconnected clothed segments.
This paper reports a geometrical modeling technique for tubular braided structures based on the generalized rose curve as the mathematical model. By analysis of the braiding process, the modeling method for the tubular braided structures is derived based on the intersection of braiding surface and helical surface. As application of this method, braided structures of diamond braid, regular braid and Hercules braid with strands and tapes are simulated using SolidWorks®, and the modeling effect is validated by two different real braided ropes with different braiding elements. This modeling method is not confined by the profiles of mandrels, and could be employed to simulate the braided structures for overbraiding bodies with varying cross-sections. As an application, braided models overbraiding a rotary hyperboloid and a bottle-like structure with strand and tape elements, respectively, are constructed.
An increase in the application areas of textiles has resulted in the need for improved and additional properties and functions, which should be provided by polymers with different functionalities or the addition of particles to the fibers. In the framework of this study, microsized talc particle-filled polypropylene (PP) fibers and yarns were produced and the mechanical, physical and thermal properties of the fibers and yarns were analyzed with respect to production parameters. The main motivation of the selection of talc as the filler material is to improve the thermal shock resistance and decrease the shrinkage of PP fibers and yarns. As a result of experimentation, it was observed that an increase of talc ratio decreases the tensile strength of fibers and yarns. However, this reduction does not seem to be an obstacle to produce fabrics. Furthermore, the addition of microsized talc particles in PP yarns dramatically improved thermal shock resistance and helped to decrease the shrinkage of these yarns.
This research identifies laboratory test methods designed to advance assessment of the effects of structural firefighter gloves on a firefighter’s ability to perform tasks with their hands. Two new hand dexterity test methods are discussed: a modified tool test for measuring glove effects on gross or whole hand motor control, and a novel cylinder lift method for evaluating glove effects on fine or fingertip hand dexterity. Data generated by testing a representative group of structural firefighter and other responder gloves are used to show that these new test methods provide less variable data and a more useful and informative assessment of the effects of glove construction on hand dexterity than that provided by standard small pin pegboard tests. Based on these comparisons, a combination of the newly developed tool and cylinder lift test methods are recommended for evaluating the effects of structural firefighter gloves on hand dexterity in standards used as the basis of certifying the performance of structural firefighter clothing.
This paper presents optimization of the hot air welding process parameters for the formation of textile transmission lines and the electro-conductive properties of these manufactured transmission lines. A dedicated manufacturing set-up has been developed to allow a reliable and flexible textile signal transmission line at adequate conductivity. In order to manufacture textile transmission lines, different welding parameters with different conductive yarns and welding tapes were considered. Layered fabric structures consisting of textile transmission lines and fabrication tolerances were determined, as well as electro-conductive properties for welded samples. It was found that the choice of welding parameters, depending on the materials used for the formation of textile transmission lines, is extremely important for obtaining good electro-conductive properties. In addition, welding tapes and thermoplastic materials play an important role during the set-up of welding process parameters. Results statistically confirmed that welding tapes with conductive yarns can significantly cause a variety of changes in the signal qualities of welded textile transmission lines. The obtained results based on conductivity and signal-to-noise ratios are really promising for the manufacturing of e-textile transmission lines via hot air welding technology.
Considering the increasing resistance of numerous bacteria to antibiotics, a novel wound dressing material was developed with naturally acquired olive leaf extract, which shows not only good antimicrobial activity, but also very good antioxidant activity. Besides that, the leaves are treated as waste in agriculture, giving an impact on waste management. An environmentally friendly procedure, electrospinning, was used for the first time to prepare polysaccharide nanofibrous mats with incorporated olive leaf extract, with the unique property of releasing the active phenolic components in a prolonged manner over 24 hours. The developed electrospun mats were characterized using scanning electron microscopy, high-performance liquid chromatography and ultraviolet-visible spectroscopy for determination of free radical scavenging activity by 2,2-diphenyl-1-picrylhydrazyl, antimicrobial testing and release kinetics. Antimicrobial tests have shown that electrospun mats with olive leaf extract achieve reduction towards the tested microorganisms: Staphylococcus aureus (G+), Escherichia coli (G-), Enterococcus faecalis (G+) and Pseudomonas aeruginosa (G-), while the high antioxidant activity of olive leaf extract was preserved during the electrospinning procedure. Release of olive leaf extract from electrospun mats was mathematically modeled, and the release kinetics evaluation indicates the appropriateness of the Korsmeyer–Peppas model for fitting the obtained results of release ability due to erosion of polysaccharide nanofiber mats.
Sueded fabric quality control depends on the processing parameter settings. The quality characteristics considered in this study are surface softness and color difference. The Taguchi method was combined with gray relational analysis (GRA) to optimize the multi-quality sueding processing parameter combinations. First, an orthogonal array is designed by using the design of experiments of the Taguchi method for the major processing parameters of the sueding machine. The signal/noise ratio and analysis of variance are calculated from the measured fabric surface softness and color difference data, significant factors influencing the quality characteristics obtained, and GRA used to remedy the deficiency in the Taguchi method, which is only applicable to single-quality characteristics. The optimum processing parameters of multiple-quality characteristics are obtained from the response table and response diagram of GRA. The quality of suede fabric can be controlled effectively by using the optimum processing parameters to set the processing parameters, and the 95% confidence interval validates the reliability and reproducibility of the experiment.
The effect of yarn torsional rigidity was verified on the Cooper model for fabric bending rigidity in any direction. We made five cotton fabrics with different weft densities and prepared three commercial fabrics as experimental samples. The torsional rigidity of yarn from the bobbin and that of yarn directly extracted from fabric were measured with a yarn torsional tester. The bending rigidity of yarn from the bobbin was measured using the same pure bending tester as used in fabric bending testing. The bending rigidity of thin fabric was calculated using torsional rigidities of yarns extracted from the fabric and showed better agreement with the experimental values than that calculated using the torsional rigidity of yarn from the bobbin. Indeed, measurements showed that the torsional rigidity of yarn from the bobbin was appreciably higher than the torsional rigidity of yarn from the fabric. This is due to the crimp in the yarn. The fabric bending rigidity can be predicted using the Cooper model with torsional rigidities of yarns extracted from the fabric.
Fabric prints may contain intricate and nesting color patterns. To evaluate colors on such a fabric, regions of different colors must be measured individually. Therefore, precise separation of colored patterns is paramount in analyzing fabric colors for digital printing, and in assessing the colorfastness of a printed fabric after a laundering or abrasion process. This paper presents a self-organizing-map (SOM) based clustering algorithm used to automatically classify colors on printed fabrics and to accurately partition the regions of different colors for color measurement. The main color categories of an image are firstly identified and flagged using the SOM’s density map and U-matrix. Then, the region of each color category is located by divining the U-matrix map with an adaptive threshold, which is determined by recursively decreasing it from a high threshold until all the flagged neurons are assigned to different regions in the divided map. Finally, the regions with high color similarity are merged to avoid possible over-segmentation. Unlike many other clustering algorithms, this algorithm does not need to pre-define the number of clusters (e.g. main colors) and can automatically select a distance threshold to partition the U-matrix map. The experimental results show that the intricate color patterns can be precisely separated into individual regions representing different colors.
Spacer fabrics are very attractive nowadays for use as technical fabrics. Our interest in this study is to give geometrical models for weft-knitted spacer fabrics which can be used in related engineering software. Models of two commonly used weft-knitted spacer fabrics are created here based on Kurbak’s 1998 plain knit model and are drawn to scale using the 3DS-MAX computer graphical program. It is observed that similar shapes to the real fabrics are obtained by the models.
Unmodified nylon is dyeable to a single color only, and is almost exclusively dyed with acid dyes that are absorbed with amine groups of nylon molecules. Two types of polycaprolactam (PA6) copolyamide were successfully prepared with 5-sulfoisophthalic acid monosodium salt and poly(ethylene glycol) (PEG) units named cationic dyeable polyamide (CD-PA6) and easy cationic dyeable polyamide (ECD-PA6). The chemical and crystalline structures of CD-PA6 and ECD-PA6 were characterized by Fourier transform infrared spectroscopy and wide angle x-ray diffraction, and their thermal properties were tested by differential scanning calorimetry and thermogravimetric analysis, respectively. In addition, the rheological behavior and mechanical properties of copolyamide are presented in this paper. The influence of chemical modification in polyamide 6 fibers on the dyeing properties was investigated using cationic dye (methylene blue). The incorporation of PEG not only destroyed the regularity of the molecular chain arrangement and created more amorphous regions of ECD-PA6 samples, but also led to nylon 6 changing from the α-form to the -form. In addition, the crystallinities and degradation temperatures of samples which corresponded to different mass losses of CD-PA 6 and ECD-PA6 declined as the sulfonic group content increased, since large –SO3Na side groups in the copolymers prevented the chain molecules from tightly coagulating and obstructed the formation of larger crystals. Based on the analysis of the dyeing, a distinct improvement in tinctorial affinity and wash fastness for modified fibers compared with unmodified fibers was revealed.
Foaming parameters are the foundations of foam-sizing technology. The impacts of foaming parameters, including temperature, agitator speed, quality fraction of the foaming agent, size recipe and concentration, on foam properties are remarkable. Aiming at optimizing the foaming parameters, foam height, foaming ratio, foam half-life and foam viscosity were chosen for testing and analysis. The experimental results indicated that the comprehensive indexes of the foam achieved the optimal properties at 50℃ with the agitation speed of 1200 r/min and the foaming agent of 2.5%, the oxidized starch and polyacrylic acid ratio of 50:50 and the size concentration of 9%. Compared with the yarn properties with the traditional process, foam-sizing can achieve the same results.
Changing the process of jet vortex spun yarn will result in the change of its structure, and further changing its properties. In this article a comparative study is carried out about three aspects, namely the internal structure of the nozzle, the internal flow field distribution of the nozzle, and the yarn properties of MVS861 and MVS870. The correlation between the yarn formation process and yarn properties will be discussed theoretically, which will be validated by designed experiments. There is significant meaning for researching the correlation between yarn formation process and yarn structure because, on the one hand, it can optimize the process of yarn formation and improve the structure of key components used to form yarn, and on the other hand, it can guide theoretically the design of the yarn structure.
This paper presents a wireless power transmission method that uses magnetic resonant coupling with resonant coils made of conductive yarn that can be integrated into clothing. The conductive yarn consisted of silver-plated copper and polyester filaments. The transmission characteristics of the yarn and copper resonant coils were compared using simulation and measurement tools. It was determined that the signal loss of the conductive yarn resonant coils was higher than that of the copper coils. However, the increase in the signal loss variation was less than 1 dB when the transmission distance was less than 6.5 cm. The conductive yarn resonant coils were placed in the shoes and trouser cuffs of a human subject, and the transmission efficiency was measured after the received alternating current power was converted to direct current power using an alternating current–direct current converter. The measurement results showed a maximum transmission efficiency of 50%; the average transmission efficiency was 45%, despite the change in the coil shape and alignment conditions due to body movement. In addition, the results demonstrated an excellent transmission efficiency of over 40% when the subject was moving at a speed of 6 km/h. It was also shown that the textile coils can be an integrative solution, overcoming clothing comfort and continuous power supply for a new generation of wearable devices.
N-halamines are highly efficient antibacterial agents. They can inhibit or inactivate bacteria by transformation of the N-Cl bond to an N-H bond, and be regenerated by chlorination. In this study, regenerable biocidal poly(VAc-co-MAM) was synthesized by emulsion polymerization with vinyl acetate (VAc) and methacrylamide (MAM). Polymerization was optimally carried out at 100℃ for 7 hours using a 10:1 molar ratio of VAc to MAM in the presence of 1% initiator in mass to the total of VAc and MAM. The synthesized polymer emulsion was used for antibacterial treatment of polypropylene (PP) nonwoven fabric. The treated fabric was found to have an active chlorine value of 0.21%, which exhibited excellent antibacterial activity. The active group N-Cl in PP fabric treated with poly(VAc-co-MAM) was unstable under ultraviolet irradiation, but could be recovered through chlorination. Poly(VAc-co-MAM) can be used as an antibacterial agent for many other fibers, not limited to PP, since it has a hydrocarbon chain that provides a good compatibility with other synthesized fibers through the Coulomb force and hydrophobic bond.
The durable press-finished cotton fabrics were prepared with dimethylol dihydroxy ethylene urea (DMDHEU) and methylated DMDHEU, and tested for formaldehyde release in distilled water or synthetic sweat at pH 5 or 8 to simulate the extraction of formaldehyde by sweat under similar wearing conditions. The release mechanism of formaldehyde was studied and compared using three diffusion kinetic models. The effect of release conditions and finishing process on the formaldehyde release was also investigated. The results indicated that the release process of formaldehyde from the finished fabric includes a burst release phase and a slow release phase, which is explained by five different sources. The formaldehyde release mechanism followed the Fickian mode, and could be described by Higuchi, Double phases and Korsmeyer–Peppas kinetic equations, respectively. Higher formaldehyde release was found at pH 8 than that at pH 5. Formaldehyde showed a lower release rate in synthetic sweat solution than that in water under the same conditions. Increasing water volume or temperature enhanced the formaldehyde release, suggesting that a high sweat rate and skin temperature may accelerate the formaldehyde release. When finishing the fabrics, a higher concentration of finishing agent and the addition of softener accelerated the formaldehyde release. However, increasing catalyst concentration and curing temperature could reduce the formaldehyde release. It is concluded that formaldehyde release can be effectively reduced by optimizing the durable press finishing process of cotton fabrics, thus possibly decreasing risk of allergic contact dermatitis from formaldehyde in textiles.
In order to form a well-ordered structure of SiO2 photonic crystals on polyester fabrics with fewer defects, a series of influential factors such as particle size and monodispersity of colloidal microspheres, evaporation temperature, relative humidity, mass fraction of colloidal microspheres and solvent in vertical deposition assembly were deeply studied, and the complexities of the self-assembly process of colloidal microspheres on polyester fabric substrates were revealed. In different self-assembly conditions, the quality of SiO2 photonic crystals on polyester fabric substrate was investigated by field emission scanning electron microscopy for the morphology of the crystal structures and by spectrometer measurements for their stop band intensities. Under the conditions of suitable sizes and monodispersity (PDI ≤ 0.08) of colloidal microspheres, the high-quality SiO2 photonic crystals with face centered cubic (fcc) array on polyester fabrics were produced at a low evaporation rate by adopting relative humidity of about 60% with a medium mass fraction of 1.0–1.5% SiO2 microspheres at 25℃ with ethanol as the solvent.
This paper discusses that three-dimensional (3D) warp knitted spacer structures offer significant attributes that create sustainable production advantages in dry exhaust systems for the automotive paint industry. The advantages that are offered include improved airflow and the potential to combine to a composite solution with a high paint holding capacity; this concept of filtration also offers the possibility of a durable filter capable of industrial cleaning and reuse numerous times. The paper describes the innovation of these 3D warp knitted spacer filters from theoretical and traditional filtration aspects, followed by an empirical characterization that justifies commercial trials within the industry.
Eight visible photoinitiators composed of a series of erythrosine B derivatives with different structures, combined with ethyl-4-dimethylaminobenzoate and diphenyliodonium hexafluorophosphate, were evaluated for their photoinitiating characteristic and the tensile properties of photo-curing films initiated by them, to acquire the relationship between structure and performance. The visible photoinitiator was the key component for the pigmented visible photo-curing ink of textile digital printing. So, based on the experimental results, the preferred photoinitiator was incorporated into three pigmented photo-curing inks (red, yellow and blue) to perform textile digital jet printing. After photo-curing under visible light irradiation, the printed fabric samples showed excellent dry–wet rubbing fastness, and possessed a consistent hue with the samples initiated by the photoinitiator containing camphorquinone.
In this paper, non-thermal plasma induced by dielectric barrier discharge (DBD) air discharging was used to treat the moving polyethylene terephthalate (PET) yarn samples and the motionless samples, respectively. The air drag force of the resultant samples was tested, and their surface characteristics were analyzed by X-ray photoelectron spectroscopy (XPS) for chemical composition and by scanning electron microscopy (SEM) for microscopic morphology. The results of the drag force of the samples indicated that, compared with the pristine yarn, the drag force of the samples treated via the two types of plasma treatment clearly varied under different processing conditions. The maximal drag force was 28.26cN for the moving sample treated at 34 V control voltage for 30 s in the discharge zone (zone A) and 27.81cN for the motionless sample treated at 36 V control voltage for 60 s in the long-lived plasma species treating zone (zone B), which increased by 18.9% and 17.0% over that of untreated sample (23.77cN), respectively. The fluctuation of the drag force probably depends on the change of the chemical composition and microstructure of the polyethylene terephthalate yarn surface, which implies that the feasibility of weaving efficiency improvement for an air-jet loom could be realized via controlling and optimizing the dielectric barrier discharge operating conditions.
The present investigation is connected to the field of medical textiles, which includes the development and application of composite fibers. The aim of the paper is the processing and investigation of polyamide 6 (PA6)–amber composite fibers. The use of amber filler for the preparation of a new type of polymer composite fiber is described in detail for the first time. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and granulometry testing were used to test the structure and the size of the prepared amber particles. The obtained amber particles were characterized by an average size of up to 3 µm and a regular shape. Fourier transform infrared (FTIR) spectroscopy investigations showed that amber in the dispersed state does not change its chemical structure and contains one of the active compounds—succinic acid. The effect of the amber filler inclusion on the melt-spinning routes of fully drawn yarns (FDY) and pre-oriented yarns (POY) was determined. Amber composite fibers general use is medical fabric (compression socks and tights); it is biocompatible with skin cells.
In this paper, the design, manufacturing and characterization of two-dimensional warp-knitted textiles with auxetic performance is reported. Four warp-knitted structures based on a rotational hexagonal structure are produced, and these structures can lead to a negative Poisson’s ratio mathematically. The testing results have confirmed that the knitting structure of the front bar, as well as let-off values of the front bar’s chain parts, has a great effect, and auxetic properties of the warp-knitted textiles have a complicated relationship with the rotation angle. These novel structures can expand the applied area of auxetic structures.
A silk fibroin tubular scaffold (SFTS) has been designed and fabricated using silk fabric and regenerated silk fibroin, and used in the construction of artificial blood vessels. As a replacement for blood vessels, scaffolds should have a suitable interface for the adherence and proliferation of vascular cells, and the pore structure of the internal surface is one of most important factors. In this article, we investigate the effect of SFTSs with different pore structures on cells growth. Pore structures were controlled by adjusting the concentration of both the silk fibroin and the polyethylene glycol diglycidyl ether cross-linker as well as the freezing temperature. Intuitive cell fluorescence imaging and MTT assays on fibroblasts and human umbilical vein endothelial cells (HUVEC) were used to probe interactions with internal surfaces of differing pore diameter and density. The results showed that SFTSs fabricated under different conditions exhibited no cytotoxicity. Furthermore, fibroblasts were highly migratory, occupied the interface and could bridge the macropores well when the pore diameter was 50 ~ 75 µm. SFTSs with micropores of about 30 ~ 50 µm in diameter were deemed suitable for the growth and proliferation of HUVECs.
We have investigated new applications of the Maillard reaction in textile industries as an alternative to conventional dyeing methods. Our previous paper indicated that only textile fibers having amino groups, such as wool, silk, and nylon fibers, were colored by chemical reactions with reducing sugars, such as
In this study, the cooling effect of a portable hybrid personal cooling system (PCS) was investigated on a sweating manikin operated in the constant temperature (CT) mode and the thermoregulatory model control (TMC) mode. Both dry (i.e., no sweating) and wet manikin tests (i.e., sweating) were performed in the CT mode in a warm condition (30℃, 47% relative humidity (RH), air velocity va = 0.4 m/s). For the TMC mode, two case studies were simulated: light work condition (30℃, 47% RH, air velocity va = 0.15 m/s, duration: 60 min, metabolic rate: 1.5 METs) and construction work condition (30℃, 47% RH, va = 1.0 m/s, 40 min exercise [5.5 METs] and 20 min rest [1.2 METs]). Four test scenarios were selected: fans off with no phase change materials (PCMs) (i.e., Fan-off, the Control), fans on with no PCMs (i.e., Fan-on), fans off with fully solidified PCMs (i.e., PCM+Fan-off) and fans on with fully solidified PCMs (i.e., PCM+Fan-on). Under the dry condition, the cooling rate in PCM+Fan-off during the initial stage (e.g., 55 and 50 W for the first 15 min and 20 min, respectively) was higher than that in Fan-on (i.e., 45 ± 1 W); under the wet condition, the cooling rate in PCM+Fan-off (e.g., 45 W for 10 min) was much lower than that in Fan-on (i.e., 282 ± 1 W). The hybrid PCS (i.e., PCM+Fan-on) provided a continuous strong cooling effect. Simulation results indicated that ventilation fans or PCMs alone could provide sufficient cooling while doing light work. For the intensive work condition, the PCS in all three scenarios (i.e., PCM+Fan-off, Fan-on and PCM+Fan-on) exhibited beneficial cooling, and the hybrid PCS showed an optimized performance in alleviating heat strain during both exercise and recovery periods. It was thus concluded that the PCS could effectively remove body heat in warm conditions for moderate intensive activities.
Quaternary ammonium compounds, commonly referred to as quats, are cationic surfactants widely used as the active biocidal ingredient for disposable disinfecting wipes. The cationic nature of quats results in a strong ionic interaction and adsorption onto wipes materials that have an anionic surface charge, such as cellulosic materials, including cotton. The degree of adsorption of quats onto cotton nonwovens is affected by pretreatment of the substrate, more specifically whether it is a greige or a scoured and bleached fabric. This study examined the effect of varying the chemical and physical properties of solutions on the adsorption of the quat alkyl-dimethyl-benzyl-ammonium chloride (ADBAC) onto greige and scoured and bleached cotton nonwoven fabrics produced by hydroentanglement. At a constant surfactant concentration, the liquor ratio, pH, temperature, and concentrations of various electrolytes in the solution were varied and the amount of ADBAC depleted from solution was determined over time. The results suggested that a more alkaline solution increased the amount of ADBAC adsorbed onto both cotton nonwoven fabrics, while a more acidic solution reduced ADBAC adsorption. Likewise, increasing the temperature and concentration of salts in the solution reduced the adsorption of ADBAC onto the cotton fabrics. The presence of nonionic surfactants or low molecular weight quats also reduced ADBAC adsorption onto cotton fabrics in a concentration-dependent manner. The results of this study will provide guidance for optimized chemical formulations compatible with disposable disinfecting cotton-based wipes, cloths, and other cotton-containing implements intended for use in cleaning and disinfecting applications.
Cellulose nano fibrils (CNFs) were isolated from banana rachis bran using enzyme hydrolysis with subsequent ultra-sonic treatment. The CNFs and bran were characterized by particle size distribution (only the CNFs), X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy; the morphology of the banana rachis fiber and CNFs was observed using scanning electron microscopy and transmission electron microscopy, respectively. The furnished nano fibrils had an average diameter of 14.02 ± 2.10 nm and length of 619.6 ± 90.7 nm. The aspect ratio of the CNFs is in the range of long fibrils, that is 44.18. XRD studies revealed that CNFs (48.83%) were more crystalline than the banana bran (27.76%). TGA and derivative thermogravimetry thermograms showed that CNFs were more thermally stable than the bran.
In this paper, variables in an environmentally friendly rechargeable antimicrobial finishing process were studied. Cotton fabric was treated with nitrogen plasma after padding with 5,5-dimethylhydantoin (DMH) when fabric was treated through the pad-dry-cure method, that is, pad-plasma-dry-cure. After that, fabric was chlorinated with sodium hypochlorite to impart antimicrobial property and function. An orthogonal array testing strategy was used in the finishing process for finding the optimum treatment condition. Ultraviolet spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy were employed to evaluate the properties of treated cotton fabric, including concentration of chlorine on cotton fabric, morphological properties of the surface of cotton fabric and function groups on the cotton fabric. The results showed that cotton fabric finished with DMH with the help of plasma treatment followed by chlorination inhibits microorganisms effectively, the antimicrobial property against Staphylococcus (S.) aureus was rechargeable and durability of antimicrobial property was improved by plasma treatment.
A waterborne polyurethane (WPU) with a double bond in the main chain was modified with a poly(dimethylsiloxane) (PDMS) macromer having a terminal methacrylate group (PDMS methacrylate macromer) by using a radical mechanism, and the changes in various physical properties were examined. Although the crystallinity of the soft segment domain increased, the cohesion of the hard segments was weakened as a result of the modification with the PDMS methacrylate macromer. The adhesion between the WPU and nylon decreased due to the hydrophobic/low polarity of the PDMS component, and this improved the flexibility and the tear strength of the nylon-6,6 textile coated with WPU. The air permeability of the coated textile also increased as a result of the modification.
Yarn pull-out is one of the major modes of fabric failure during an event of impact. In this article, the effects of weave and fabric sett on yarn pull-out force have been investigated for untreated and shear thickening fluid (STF) treated p-aramid fabrics. Further, the effect of different fluid treatments on yarn pull-out behavior has been analyzed using p-aramid and ultra-high molecular weight polyethylene (UHMWPE) fabrics. For all levels of fabric sett, plain woven fabrics exhibited higher yarn pull-out force compared to twill, matt and satin weaves. STF impregnation increased the yarn pull-out force considerably for p-aramid and UHMWPE fabrics and this was found for all the weaves in the case of the former. However, increase in fabric sett beyond a threshold level caused yarn breakage before yarn pull-out in case of STF-treated plain woven p-aramid fabrics. Yarn pull-out force was found to have good association with the energy absorption by the high-performance fabrics during low-velocity impact (6 m s–1). The normalized yarn pull-out force was higher for two consecutive yarns than for two yarns with a single gap.
Additive deposition of inks with metallic inclusions provides compelling means to embed electronics into clothing in a seamless way. We present a simple single-step brush-painting method for depositing copper and silver inks directly on ordinary cotton fabric and discuss the optimization of the photonical sintering of both materials. For the first time, we demonstrate the deposition and sintering of copper oxide ink on fabric achieving high electrical conductivity suitable for radio-frequency electronics. The results from wireless testing confirmed that the radio-frequency identification tags based on the copper and silver ink antennas were readable from 6 and 10 m, respectively.
In this study, theoretical analysis was conducted for hair trapping by a short grooved surface contacting in different distances during conventional and siro-spinning, respectively. Then, blended cotton/ramie conventional and siro yarns were produced without and with the short grooved surface at different position distances. Hairs longer than 3 mm decreased as the surface position distance increased for both conventional and siro spun yarns, reducing short hairs by binding them onto the yarn stem. Conventional yarn hairiness H values decreased gradually as the surface position distance increased; however, siro spun yarn hairiness H values were similar without a gradual decrease as the surface position distance increased. The hair wrapping caused reduction of thin places, and occasional increase of thick places and neps for both conventional and siro yarns spun with the surface, respectively. Unevenness CVm results showed no serious deterioration after applying the surface during conventional and siro-spinning, and even some improved. The experimental results corresponded well to our theoretical analysis.
This study aims at investigating air permeability in the transversal direction of pairs of woven textiles. Three samples of woven macrostructures with different characteristics are selected for the numerical investigation of 16 two-layer ensembles. Computational fluid dynamics (Reynolds-averaged Navier–Stokes equations) is used for modeling the air permeability, applying the theory of jet-systems: the flow through each of the layers in the ensemble is modeled as an "in-corridor" ordered jet-system. The influence of the order of arrangement of the layers in the ensemble is analyzed, indicating higher air permeability of the ensemble when a tighter structure is placed as a first layer. The effect of the distance between the two woven macrostructures is also analyzed, showing a strong influence on the flow development as well as on the extrema of flow velocities, especially in the drop of the flow velocity in the air gap between the two layers. The analysis made and the results obtained show that the method can be applied for further investigation of ensembles of textile layers.
In the work, the Contourlet transform is modified for a more complex situation in order to obtain a subtler decomposition of the warp-knitted fabric image. The new Contourlet transform is named the non-subsampled wavelet-packet-based Contourlet transform (NWPCT) and it consists of wavelet-packet transform and a non-subsampled directional filter bank. Firstly, the fabric image is processed by means of wavelet-packet transform with segmented threshold de-noising to acquire the subtle frequency coefficients. Secondly, the more elaborate directional coefficients will be obtained by decomposing the wavelet-packet coefficients with non-subsampled directional filter bank. Then the directional coefficients with higher energy are chosen to reconstruct the wavelet-packet coefficients. Finally, the iterative threshold method and object operation based on morphology are applied to segment the defect profile. The final experimental result demonstrates that NWPCT has excellent properties to segment out the defects (broken wrap, oil and width barrier). The defect profile is distinct enough for the further work concerning warp-knitted fabric defect recognition.
For a poly(ethylene terephthalate) (PET)/cotton blended fabric, a reactive-type flame retardant 2, 3-dibromo-succinic anhydride (DBSA) was used to endow durable flame retardancy via the pad-dry-cure method. DBSA was synthesized via the addition reaction of maleic anhydride and bromine in ethyl acetate solution and extracted by solventing-out crystallization. DBSA was used to finish a cotton fabric firstly with sodium hypophosphite as the catalyst. Thermal behaviors and amount of DBSA that esterified with the cotton was determined. Pyrovatex CP new was applied as a comparison. It was speculated from the thermogravimetric analysis result that esterification of cellulose with DBSA worked similar to phosphate-ester at the initial stage of thermal decomposition. DBSA was also applied to PET and PET/cotton blended fabrics. Flame retardancy, thermal behaviors and durability of the finished fabrics were investigated. Evidence of the condensed phase effect of DBSA was also observed on PET and PET/cotton.
According to the self-twist jet vortex spinning process, the free fiber end lays flat and rolls rotationally on the surface of the stationary hollow spindle under the high-speed rotating airflow and the tangential friction torque, which results in the self-twist of the fiber. The self-twist will be wound into the yarn body and increases the friction and the cohesion between the fibers in the yarn, which will improve the strength of the yarn. Based on mechanical analysis and numerical simulation, this article obtains the motion trajectory of the free fiber end and designed six different hollow spindle groove micro-feature structures. Combined with experiments, this article analyzes comparatively the influence of different hollow spindle groove micro-feature structures on the free fiber end and the yarn performance, which lays the foundation for the research and the development of jet vortex spinning.
Multiaxis 3D weaving technology allows insertion of in-plane fibres reinforcements, designated as bias yarns, oriented in directions other than 0° and 90° in the woven preform, unlike in the case of conventional weaving technology. By different existing weaving advanced techniques, two opposite bias yarn layers are formed, with no possibility to separate them by in-plane yarn layer oriented in 0° to reduce inter-layer angle. That could be the cause of weak interlaminar shear resistance in the final composite structure. In this present paper, a novel development is proposed to solve the issues related to the guide block technique, which is used to position the bias yarns in the weaving zone on the weaving loom. Thus, in order to enable insertion of in-plane yarns layer oriented in 0° between the two opposite successive bias yarn layers (±°). Furthermore, the proposed technique is upgraded to control the width of produced preform on the loom. The proposed approach has reduced degradations of the in-plane warp and bias yarns during a weaving process caused by the friction with reed blades. Geometrical characterization of manufactured preform, using the developed multiaxis 3D weaving loom prototype, has been carried out to observe the yarn geometry inside the impregnated preform. Similarly, the geometrical properties of the impregnated preform are compared with those of multiaxis 3D woven preforms produced by the tube carrier weaving technique and the tube rapier weaving technique.
In this study, multi-component antistatic fibers with segmented pie structures were prepared by conjugate spinning of carbon black (CB)/polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) polymers. The antistatic property of the CB/PBT/PET fibers can be attributed to two factors: thorough mixing of the CB powder in the polymer matrix, and the close contacts formed between the segmented pie fibers. The fibers were woven and knitted into fabrics whose washing durability and antistatic properties were also tested. The surface resistivity of the woven and knitted fabrics did not change significantly (1.1 x 106 /cm2 to 1.2 x 106 /cm2) even after washing the fabrics 100 times. Thus, these fabrics can be used in a variety of applications that require antistatic materials.
Structural coloration is a kind of biomimetic coloring technology. (Silica/polyethyleneimine)n (SiO2/PEI)n films with structural color on the surface of silk fabrics were fabricated by the electrostatic self-assembly method. The structural color of silk fabrics with (SiO2/PEI)n films was captured by a digital camera, and the reflectance spectra were measured by the DigiEye system and a multi-angle spectrophotometer. The morphological structure of (SiO2/PEI)n films on silk fabrics was observed by a field emission scanning electron microscope. The coloring mechanism of the silk fabrics is in agreement with single thin film interference theory, and the variability of the structural color on the silk fabrics is similar to those on polyester fabrics varying with the assembly cycles, particle sizes and viewing angles. However, the color brilliance, brightness and iridescence effect of the silk fabrics are inferior to those of polyester fabrics with the same films, due mainly to the differences in fiber surface structure and microstructure between silk fibers and polyester fibers.
A poly(N,N-dimethylaminoethyl methacrylate) nonwoven was produced by the blowing out technique. The basic structural and mechanical properties of the obtained material were measured and described. It was found that the formed nonwoven has a smooth and delicate structure with quite weak mechanical properties. Its antibacterial properties against Staphylococcus aureus and Escherichia coli bacteria were shown. Some medical applications were suggested.
It is generally accepted that harvesting and storing of seed cotton above a moisture content of 12% prior to ginning will compromise fiber quality. This advice stems from research conducted on harvesting seed cotton with the conventional basket and separate module building system, which produces large rectangular modules. It is hypothesized that the 12% moisture content limit will also hold true for harvesting seed cotton in a high-production system using alternative harvesters. The latest generation of harvesters, such as the John Deere (JD) 7760 spindle harvester with on-board module building capacity producing smaller round modules, have greater horsepower, traction and fan capacity, which enables them to harvest cotton when field conditions would have made harvesting difficult with conventional systems. This study examined the fiber quality of saw ginned Upland cotton, harvested from one field using a JD 7760 at two moisture levels, <12% and >12%, and storing the harvested modules for 12 weeks prior to ginning. There was a significant difference between the two moisture levels for fiber color, with seed cotton harvested at >12% resulting in fiber that was yellower, with lower reflectance and a color grade of 52, compared to a 51 grade for seed cotton harvested at <12% treatment. The seed cotton harvested at >12% had more trash with a leaf grade of 3, compared to a leaf grade of 2 for the seed cotton harvested at the <12% level. There was no significant difference between the two moisture levels in terms of fiber length and strength, but fiber micronaire was higher for the higher moisture content. There was no significant difference between the moisture levels for total nep count, but the seed cotton harvested at >12% had larger neps and more seed coat neps.
Tourmaline nano powder was used for the first time in the production of poly(ethylene terephthalate) nanofibers. The polymer chips of poly(ethylene terephthalate) and poly(ethylene terephthalate) containing 3 wt% tourmaline powder were obtained. The electrospun nanofibrous mats were produced from both of the polymer solutions prepared by using the polymer chips. The nanofibrous mats were characterized by using scanning electron microscopy, energy dispersion spectroscopy and Fourier transform infrared spectroscopy. In order to investigate the effect of tourmaline additive in the poly(ethylene terephthalate) nanofibrous mat, water contact angle, electrical conductivity and negative ion releasing measurements were performed on the mats. The incorporation of tourmaline in the nanofibers improved the wettability, electricity transmission and anion emitting property of the poly(ethylene terephthalate) mat.
A new approach for intra-/inter-laminar reinforcement using needle-punching and thermal bonding was proposed for improvement of puncture resistance of multilayer compound fabrics that were composed of different kinds of nonwovens and woven fabrics. Effects of woven fabric orientation and thermal bonding on static and dynamic puncture properties were explored. Multilayer compound fabrics with different compositions of nonwoven and sequence of woven fabrics were comparatively discussed to confirm fabric and nonwoven influencing on static and dynamic puncture resistances. Puncture resistance mechanism of plied orientation and thermal bonding was analyzed for multilayer compound fabrics. The research result shows that woven fabric orientation affected static and dynamic puncture resistances more significantly when multilayer compound fabrics were comprised of high-modulus nonwovens and woven fabrics. Plied orientation correlated with the yarn density of woven fabric that was contained in compound fabrics. Contact length between woven fabric and nonwoven, as well as specific fiber toughness from nonwoven, was respectively responsible for static and dynamic puncture resistances of multilayer compound fabrics.
Yarn unwinding from a package is a key problem in many textile processes, such as weft insertion and warping. Stability of the unwinding has a direct influence on the efficiency of the entire textile process and the quality of the final product. The quality of the yarn is numerically expressed mainly in terms of mechanical quantities. In the unwinding process, viscoelastic properties are the most important. They depend on how the yarn is stressed. The quality of the yarn that is being unwound should not be reduced, unless this reduction does not significantly lower the quality of the fabric. We strive to achieve as large warping and weaving speeds as possible; therefore, our aim is to improve the theory of cross-wound package unwinding and to find the necessary modifications of the yarn unwinding process. The goal of our contribution is to state the equations of motion that describe the unwinding yarn.
In this paper the current generation of 350 dtex airbag coated and uncoated fabrics are examined experimentally under a multitude of simple and complex deformations. The geometric dimensions of the fabric architecture and the load–elongation behavior of the yarn constituents are studied. Furthermore, deformational shear behavior of airbag fabrics, which have not previously been investigated, are examined here. The stress–strain behavior of the yarn as well as the fabrics with and without coating are found to be highly nonlinear. Under uniaxial loading, nonlinearities of the fabric occur at lower strains due to crimp of the fabric, whereas under biaxial loading, the nonlinearity occurs at low and intermediate strain levels resulting from a combination of the inherent nonlinear material response of the yarn and geometric changes in the fabric structure. The data generated not only provide the basis for structural analysis of the airbag, but can also be used to develop more sophisticated definitions of the constitutive behavior of the fabric.
In order to advance consistent lightweight construction principles in automotive and mechanical engineering, support frame construction made from high-performance materials is becoming more commonplace. These consist of complexly structured nodular connection elements. The required connection elements have not yet been produced satisfactorily. The developed node element structures in this paper are produced on a shuttle weaving loom by flattening and weaving them as multi-surface woven fabrics. The development of the woven concept for the realization of node element structures is based on the fragmentation of the individual sub-elements. The goal of this research is development of a flexible technology for weaving fabrics and intended for the integral realization of woven nodular semi-finished products with complex geometries and connections, which are to be used to connect Fiber-reinforced Plastic components in support frame structures.
Polyurethane (PU) is a unique polymeric material with excellent chemical and physical properties and is widely used in textile materials. There has been a need for superhydrophobic PU for wider applications, such as coating materials. In this research, SiO2 nanoparticle (SNP) incorporated PU webs with superhydrophobic and breathable properties were prepared by one-step sol-gel electrospinning and post-treated with a non-fluorinated water repellent chemical, n-dodecyltrimethoxysilane (DTMS). SNPs were observed to be distributed evenly all over the fiber surfaces when 1–6 wt% SNP and tetraethoxysilane (TEOS)/acetic acid solution were added. TEOS was hydrolyzed to form larger nanoparticles while developing cross-linking with aromatic groups of the PU matrix. Interestingly, the addition of 20 nm SNPs was thought to act as nucleating seeds for enhanced hydrolysis of TEOS within the PU matrix. The hierarchical surface roughness consists of different sized SNPs and polymer beads, which resulted in superhydrophobicity with water contact angles as high as 157° and shedding angles as low as 5°. Laminating PU/SNP/DTMS webs onto polyester fabrics maintained the air permeability and water vapor transmission rate, which proves the potential of the developed PU/SNP/DTMS webs for practical applications as textile laminate materials with simple processing.
As a biological fibrous structure, silkworm cocoon provides multiple protective functionalities to safeguard the silk moth pupa’s metabolic activity. The mechanism of this protection could be adopted in clothing manufacture to provide more comfortable apparel. In this study, the thermal insulation properties of both domestic Bombyx mori (B. mori) and wild Antheraea pernyi (A. pernyi) cocoons were investigated under both warm and cold environmental conditions. Computational fluid dynamics models have been developed to simulate the heat transfer process through both types of cocoon wall structures. The simulation results show that the wild A. pernyi cocoon reduces the intensity of convection and heat flux between the environment and the cocoon interior and has higher wind resistance than its domestic counterpart. Compared with A. pernyi cocoon, the B. mori cocoon facilitates easy air transfer and decreases the temperature lag when the surrounding conditions are changed. The new knowledge has significant implications for developing biomimetic thermal functional materials.
Cotton blends are very important and widely used in our lives. In this research, the heat release properties and the flammability of the nylon/cotton, the polyester/cotton and the Nomex/cotton blends are investigated. By comparing with the heat release rate (HRR) and other thermal parameters calculated from their individual components, it is found that both the nylon and the polyester have interaction when they are blended with cotton during the decomposition process. For the nylon/cotton fabrics, the blend has lower total heat release (THR) and much higher percent char yield than the arithmetic sum of those of cotton and nylon as single fibers. The char yield of the nylon/cotton blends decreases when the blend contained less cellulose. But for the polyester/cotton fabrics, the blend has higher THR than the arithmetic sum of cotton and polyester as single fibers with a bit increase in the percent char yield, and its char yield increases as the cotton ratio in the blend decreases. It is illustrated that the interaction that occurs between nylon and cotton is different from that between polyester and cotton. In the case of Nomex/cotton blends, the actual HRR curve matches well with the simulated curve, and the THR and percent char yield are almost the same as the calculated data. There is nearly no interaction between Nomex and cotton components during the degradation of the blend. Overall, the results show that the decomposition process of blended fabrics is not simply the addition of the decomposition process of the component single fibers, but is in fact more complicated.
Analytical method for determining free chromium in chromium-complex acid dye where Cr is chelated to dye molecules is developed by their solid phase separation using C-18 column. Total Cr was measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) on digested dye samples without the solid phase separation. Aqueous clear solutions extracted from C-18 columns, on the top of which each dye sample dissolved in methanol was loaded, were subjected to ICP-OES measurements for free Cr and to ion chromatographic measurements for Cr(VI), respectively. The deep-dyed nylon fabrics were subjected to the test of extractable Cr with artificial sweat solution. For eight commercial monosulfonated strongly polar Cr-complex acid dyes, total Cr and free Cr in dye products were estimated to be 15,271 mg/kg to 45,677 mg/kg and 193 mg/kg to 4048 mg/kg, respectively, while free Cr(VI) were measured to be 2.35 mg/kg to 16.2 mg/kg. Extractable Cr in their dyed nylon fabrics were measured in the range of 0.28 to 3.95 mg/kg. A proportional relationship between free Cr in dyes and extractable Cr in dyed nylons was observed. The analytical scheme using the solid phase separation using C-18 column is suggested for future quality control of Cr-complex acid dye products so that consequent dyed textiles do not fail in satisfying the globally- recognized human ecological criteria.
The time course of degradation for biodegradable and fully biobased plastic agricultural mulches prepared from polylactic acid (PLA) and PLA–polyhydroxyalkanoate (PHA) blends using meltblown (MB) nonwovens processing technology in compost-enriched soil during a 45 week burial duration was investigated under controlled conditions in a greenhouse to better understand the underlying mechanism for degradation. Mulches underwent an initial 4 week period during which the tensile strength decreased by ≥ 60%. For MB-PLA, between weeks 4 and 12, the crystallinity increased and the molecular weight slightly increased. After 12 weeks, the molecular weight decreased linearly. At 28 weeks, the crystallinity increased significantly, corresponding to an observed increase of macroscopic fragmentation. For MB-PLA+PHA, the mass fraction of PHA decreased significantly (by 11.6%) during the first 4 weeks; subsequently; the PHA fraction decreased linearly. Between 17 and 22 weeks, a large increase of crystallinity for the PLA component and a decrease of molecular weight occurred. After 22 weeks, the molecular weight and crystallinity of PLA increased nearly linearly. These results suggest that during the first 4–12 weeks, microorganisms begin to utilize the more readily available components of the mulches as carbon sources: amorphous PLA regions and PHA for MB-PLA and PLA+PHA, respectively, and that microbial activity is greater and occurs more strongly for PHA. After the initial induction period, depolymerization occurs slowly and steadily for both MB plastic mulches.
Predicting the behavior of geotextiles made of polyesters and polypropylene fibers is described by differential equations derived from mechanical models. Thereby, we describe the behavior of geotextiles up to the elastic limit. The elastic limit represents the permissible load which the geotextile material may be subjected to during exploitation, and without distorting its structure. The elastic limit is defined by analyzing the stress–strain curve of analyzed geotextiles. Nonwoven geotextile materials of polyester and polypropylene fibers with surface mass of 150, 200, 250, 300 and 500 g/m2 were used as experimental material.
The availability of a considerable amount of waste carbon fiber (CF) and the increased pressure to recycle/reuse materials at the end of their life cycle have put the utilization of recycled CF (rCF) under the spotlight. This article reports the successful manufacturing of hybrid yarns consisting of staple CF cut from virgin CF filament yarn and polyamide 6 fibers of defined lengths (40 and 60 mm). Carding and drawing are performed to prepare slivers with improved fiber orientation and mixing for the manufacturing of hybrid yarns. The slivers are then spun into hybrid yarns on a flyer machine. The investigations reveal the influence of fiber length and mixing ratio on the quality of the card web, slivers and on the strength of the hybrid yarns. The findings based on the results of this research work will help realize value-added products from rCF on an industrial scale in the near future.
The Tekscan® pressure pad was adopted to study the pressure-relief property of spacer fabric used as a mattress, where pressure peak, average pressure and contacting area were recorded directly. In order to better analyze the pressure-relief property of spacer fabric, average gradient integral and six derivative indices were featured from a pressure map. Testing results showed that spacer fabric effectively improved the pressure concentration effect by improving contacting area and decreasing pressure peak. Comparisons of the pressure-relief property of spacer fabric demonstrated that different grade weight of the seated volunteer influenced the contacting area, average pressure and average gradient integral. Correlations between objective pressure indices and subjective pressure comfort level indicated that both pressure peak and pressure comfort level had significant relations with the three basic pressure indices and six derivative indices, and they showed higher correlations under light weight, medium weight and heavy weight. It was also found that pressure peak was a good index to effectively evaluate the pressure-relief property of spacer fabrics, and both relieving average pressure per weight and relieving average gradient integral per weight are two effective pressure indices to evaluate the pressure-relief level. It is helpful in designing the structure of spacer fabrics to improve pressure comfort.
In this paper, the effects of water on the ballistic performance of the para-aramid fabrics were investigated through three typical projectiles (1.1 g FSP, 9 mm FMJ and 7.62 mm TYPE51). Three different aramid fabrics made up of Taparan 629 fiber or Kevlar 129 fiber were shot by these projectiles in both dry and wet conditions according to ballistic limited velocity V50 testing method (MIL-STD-662 F). Pull-out testing, water absorption, static contact angle, and failure mode of the fabrics were performed to study the possible ballistic mechanisms. The results reveal that the V50 values of three aramid fabrics all decrease after immersion in water, even the fabric has been treated with water-repellent finishing. The V50 values of aramid fabrics in wet state is affected by water absorption of fabric, yarns friction and bullet types. And, the slippage of yarns is a dominant mechanisms affected on ballistic performance of aramid fabric in wet condition. The lower water absorption and higher friction between the yarns can improve the ballistic performance of aramid fabrics.
In this paper, three kinds of knitted heating fabrics (KHFs) were designed and fabricated by using silver plating compound yarns (SPCYs) and polyester staple fiber spun yarns (PSFSYs), and thermo-electric properties of KHFs and SPCYs were investigated by performing a series of experiments. Experimental results showed, with increasing ageing time and ageing temperature, the breaking strength of PSFSYs and SPCYs had nearly not changed, but resistances of SPCYs increased markedly. After performing 264 hours ageing at 120℃ environment temperature, resistances of SPCYs exceeded the measuring range of the multi-meter. By taking and analyzing infrared temperature images of KHFs and SPCYs, strong linear correlation can be observed between surface maximum equilibrium temperature (SMET) of KHFs and SPCYs and power consumption density. Furthermore, strong linear positive correlation is between power consumption density of KHFs and inner equilibrium temperature of mimetic clothing. KHFs will have wide application prospect in active warming field because of a lot of advantages, such as an even surface temperature field in the heating process, structure simplicity, flexibility, etc.
The aim of this work was to investigate the color change of cotton fabrics with stainless steel yarns incorporated. In order to establish the impact of conductive yarns’ composition properties in the fabric, concentrations and two different dyeing profiles based on direct and reactive dyes chemistry were applied. The success of this novel e-textile design was evaluated colorimetrically with two different dye concentrations as well through various linear electrical resistances to obtain solid statistical conclusions. The dyed samples were colorimetrically evaluated and the electrical resistances of conductive yarns inside the fabric structure were compared and discussed statistically before and after dyeing. The results provided evidence that dyeing has great influence on electrical resistances of conductive yarns used as transmission lines for electro-textile applications. The greatest changes in electrical resistances were observed with samples including thin conductive yarns and untwisted conductive yarn after dyeing processes. Additionally, it can be concluded that the presence of stainless steel conductive threads significantly retards the dyeing processes depending on the dyestuff concentration and weave type, resulting in major color differences, especially when plain weave type is used or the dyestuff concentration is less than 1% for twill and sateen weaves.
Non-crimp fabrics (NCF) have become established in the fields of the automotive, aircraft, and wind power industries, which has led to an increasing demand of fiber plastic composites. In order to utilize the known excellent load-bearing properties of NCF and also to reduce the related disadvantages such as fiber undulation caused by stitching yarn, inclusions of resin and filament breakage by the stitch-bonding process have to be addressed. Hence, an alternative manufacturing technology is presented. This technology is defined by the punctiform application of a polyester hot melt adhesive to enable different geometries of NCF and ensure the position of the high-performance fiber in the load direction. The new manufacturing process, on the one hand, demands new testing methods to investigate the adhesion between the used adhesive and high-performance fibers, while, on the other, the surface of the adherend (carbon fiber) needs to be improved. Oxyfluorination is used here for the surface modification. Different tests such as peel test, shear test and transverse tensile test were developed and evaluated with different adhesives and high-performance yarns based on glass and carbon. The influence of the used copolyester hot melt on the curing kinetics of an epoxy matrix was investigated by differential scanning calorimetry using quasi-isothermal and non-isothermal measurements. In addition, the interface between the thermoplastic epoxy resin and the copolyester hot melt was analyzed by scanning electron microscopy.
Rapid hydrophilic modification of poly(ethylene terephthalate) (PET) fabric was carried out by deep eutectic solvent, ethylene glycol-choline chloride (EGC), under microwave irradiation. EGC is an inexpensive eco-friendly solvent, which is easy to handle along with low toxicity. Results showed that alkali concentration and microwave irradiation time were critical factors in determining surface characteristics of PET. The EGC-treated PET fabric showed highly hydrophobic surface with long wicking time (>2000 s) and high contact angle (135°) at 60 s of microwave irradiation time. However, by merely adding 0.5% sodium hydroxide, the EGC-treated PET fabric surface was drastically changed to highly hydrophilic surface with instant wicking time. The structure of modified PET was studied by various instrumental analyses such as Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Tensile strength and methylene blue staining tests were also carried out to determine characteristics of the modified PET fabrics.
The current study is aimed to analyze the consistency and reliability of untrained consumers' perception of fabric hand. A group of untrained assessors are recruited to evaluate the fabric hand of a number of suit fabrics through free sorting and rating experiments. Two statistical methods have been used to measure the consistency between the sorting and rating data of the assessors in replicated sessions. According to the types of data obtained from different evaluation procedures, different multidimensional scaling techniques are applied to investigate the tactile dimensions, and further on the assessors' preference regarding the total hand of the samples for the end-use of men's suit. It is found that simple sorting and rating procedures are efficient methods for acquiring consistent sensory results from untrained assessors on a relatively large number of textile products, and that multidimensional scaling is an effective technique for interpreting the obtained non-descriptive sensory data.
This paper proposes an automated analysis system for Tatami embroidery fabric images that automates color analysis, pattern shape analysis and texture analysis. Firstly, the RGB (red, green and blue) image of embroidery fabric is obtained by a color scanner. In color analysis, the wavelet transforms and median filter are used for RGB image preprocessing, and then the Fuzzy C-Means (FCM) clustering method is used for the binary region splitting method, the color features of statistical values of colors and number of colors can be obtained. In the pattern shape analysis, the individual pattern components are segmented by the separated colors, and the shape features of pattern components are obtained by moment invariants. Finally, in the texture analysis of Tatami embroidery fabrics, the gray image of the weave block is segmented from the pattern component region, after the entropy filter, the parallel division lines are segmented by a threshold value, and then the angle and spacing between Tatami embroidery parallel division lines are obtained by Hough transform to represent texture features. The experimental results show that this method can implement Tatami embroidery fabric color, shape and texture analyses automatically.
Three-dimensional (3D) profiled woven fabrics with varying cross-sections along the component parts are needed in a number of industrial applications. One of the main advantages of the ribbon loom weaving technique is the ability to produce highly diverse structures with open or closed edges. The realization of 3D profiled woven fabrics that satisfy the requirements is directly connected to the ability to process high-performance fibers in the weft direction. The processing of high-performance yarns in the weft direction with low fiber damage will open new application areas for shuttle weaving machines. By employing modified mechanical loom elements, the variety of producible structures can be increased significantly.
The porosity and high surface-area-to-volume ratio of nanofiber membranes offer potential for diverse applications, including high-efficiency filters and barrier fabrics for use in protective textiles. The objective of this research is to examine the morphology and pore size distribution of nanofiber membranes prepared using two spinning methods, that is, electrospinning and forcespinning. The results indicate that fiber diameter is impacted by spinning solution viscosity in an analogous way for both spinning methods. Higher concentrations resulted in larger fiber diameters in both electrospun and forcespun membranes. Fiber diameter and membrane areal density were found to significantly impact membrane pore size distribution. A theoretical model was used to describe pore size variation and was found to agree with the empirical patterns in the case of electrospun membranes.
This paper provides a critical overview about the state of the art in the area of three-dimensional modeling of braided structures. It gives a generalized geometrical approach for modeling braided structures with arbitrary floating length and filaments in the yarn. The approach is tested with large set of structures of different types. Subsequently, one of the simulated geometries is compared with the real geometry of braided tube.
Female participants present a unique challenge as the design of the bra used to support the breasts occludes the correct positioning of many recommended trunk marker sets. This study aimed to compare the effect of two existing and one new trunk marker set on the calculation of trunk and breast kinematics. Twelve females had markers placed on their trunk and right nipple; these markers were tracked using infrared cameras during five running gait cycles and used to define three trunk calculation methods: Trunk 1: suprasternal notch, right and left ribs; Trunk 2: supersternal notch, processus xiphoideus, 7th cervical and 8th thoracic spinous process; Trunk 3: Trunk 2 plus a marker 33% from the suprasternal notch to the processus xiphoideus, and another 50% between the 7th cervical and 8th thoracic spinous process. Trunk segment capture success, segment origin instability, segmental residual, trunk kinematics, and breast range of motion (relative to the trunk segment), were calculated for each trunk segment. Segment capture success varied from 88% (Trunk 1) to 100% (Trunk 2 and 3). Segment origin instability ranged from 0.2 cm (Trunk 2 and 3) to 1.5 cm (Trunk 1). Maximum trunk extension differed by 7° and breast range of motion varied by 41% (anterioposterior), 54% (mediolateral), and 21% (superioinferior) between trunk calculation methods. The selection of marker set used to construct the trunk segment is critical before recommending improvements to bra design to improve breast support. The Trunk 3 marker set is recommended for subsequent breast research.
In this work, we tried to enhance anti-bacterial activity of fabric fibers by controlling the shape of filaments, such as tetragonal and cross-pillar, which led to an increase of the surface portion of filaments. With this purpose, silver and platinum nanoparticles were immobilized on the surface of TiO2 nanoparticles within tetragonal and cross-pillar-shaped polyester (PET) filaments. The process consists of preparing 4 wt.% of TiO2 compounding PET chips, melt-spinning of them and photo catalytic deposition of nanoparticles in sequence. To obtain tetragonal and cross-pillar-shaped morphologies of filaments, two different nozzles were used in the melt-spinning process. For the photo-deposition of metal nanoparticles, adsorption of the metal ions on the surface of the filaments was performed by immersing them in AgNO3 and H2PtCl6 aqueous solutions, respectively, with simultaneous addition of methanol as a sacrificial agent. Photo-deposition was then carried out under ultraviolet light with an irradiation time of 300 s. The structural and antimicrobial properties of the tetragonal and cross-pillar-shaped PET/TiO2 filaments with noble metal loaded were systematically characterized. Ag and Pt metal photo-deposited filaments showed excellent antimicrobial effect against the two types of bacteria, Staphylococcus aureus and Klebsiella pneumonia, under the dark condition.
This paper describes the modelling of the structure and mechanical parameters of rope components made of natural fibers. Modern X-ray micro-tomography (Micro-CT) was employed to measure the parameters of the internal structure of the multi-component yarns making up rope and utilized as a basic model of twisted rope. The results allowed calculation of the tensions generated in the component yarns and detection of the unevenness of the filling of the component yarns by fibers, which was clearly visible in cross-section. The unevenness of twist measured as a function of distance from the center of the yarn was also detected. The unevenness of fiber distribution in the twisted element decreased its intensity, starting from the surface of the yarn and going deeper into the structure. Migration of the fibers in the frame of the circumference of the component yarns was associated with the mutual slide of single fibers.
The tangentially injected swirling tube flow has broad applications in various engineering fields. In the textile industry, the vortex spinning technology, which produces short-staple yarns by means of a tangentially injected swirling airflow, is of great prospect in view of its spinning speed and yarn structure. In this paper, the vortex spinning nozzle is abstracted into a model of concentric tubes of different lengths with tangential injectors. A computational fluid dynamics model is presented to study the effects of some structural parameters on the swirling flow generated in this tube system. The particle image velocimetry (PIV) technique is adopted to measure the flow field. Due to the difficulty in duplicating the Mach number, Reynolds numbers are matched between the tube model and prototype in the PIV experiment. Despite the discrepancy between the velocity values provided by the numerical simulation and experiment due to the compressibility effects not being reproduced in the PIV measurement, a comparative analysis concludes that qualitatively matched results on the flow pattern and effects of the structural parameters are obtained by the numerical simulation and PIV measurement.
The clothing pattern is an important feature of She nationality clothing, whose characteristics provide in-depth inference for digital computers to classify She nationality clothing automatically. In this paper, we propose a novel method to jointly reveal the texture characteristics and spatial distribution of the clothing pattern in She nationality clothing. Our approach employed visual features based on Scale Invariant Feature Transform and Gaussian blur to obtain robust and representative key points. We involved the Bag of Visual Words model and K-means clustering to construct a fundamental code word for texture representation. Also, spatial distribution was analyzed by frequencies of key points in spatial bins of the clothing’s design area. We then proposed a unified classification model applying the nearest neighbor method by utilizing both texture and spatial features. To demonstrate the efficiency of our method, we conducted 13 images of four types of typical She nationality clothing for training and testing. Our method achieved an average accuracy of 92.3% in cross-validation. The result revealed good consistency between the key points of texture and spatial features, and the different types of She nationality clothing characteristics. We further showed that our proposed algorithm could be used as inference for general clothing automatic classification and design.
In card webs, many fibers are not straight and generally have hooks or bends. In this study, a one-dimensional fiber figure model is discussed. Using correlation coefficients, a simple classification method for fiber figures is proposed. This method enables us to classify fiber figures into five categories: straight, leading- and trailing-hooked, and leading- and trailing-bent figures. This method is then applied to experimental data. The results indicate that the absolute values of the correlation coefficients of the vector quantities between the measured fiber figures and one of our models are greater than 0.8 in many cases. Thus, our proposed method is viable for the classification of fiber figures in card webs.
A diameter of single yarn is well known as one of the main geometrical descriptive characteristics of yarn formation. Many experimental methods also measure and define this parameter while assuming cylindrical shape of a single yarn. Very rare information exists in the case of two-ply yarn geometrical parameters. This paper, in its first part, introduces the geometrical parameters of two-ply yarn from a mathematical ideas point of view. The second part presents the longitudinal view method of their measurement. The longitudinal view method is functional also for single yarn diameter evaluation. Contribution proves the method on a set of five single polypropylene yarns variable in fineness and on a set of five polypropylene two-ply yarns different in ply twists, while two-ply yarn fineness stays constant. The third part of this paper presents a cross-sectional method of linear textiles, here of two-ply yarn and single yarn. Images of two-ply yarn and additionally single yarn cross-sections are used to measure transversal proportions of two-ply yarn and single yarn equivalent diameter. Results are discussed in terms of the set of five two-ply polypropylene yarns and some outputs are compared to those from the longitudinal view method.
Luminous fiber embroidered fabric with a long afterglow effect is prepared by luminous fiber through a computer-aided embroidery machine. As the main raw material, rare earth luminescent material and polymer are used to produce the luminous fiber by the melt spinning process. In this research, the light-emitting portion of the fabric, which uses the principle of superposition of light, is designed by multi-layer construction in computer-aided design software. The afterglow performance of the designed fabric has been characterized. As a result, the size of stitch spacing is inversely proportional to the afterglow intensity of the fabric, and the fabric with a tatami needle has the maximum afterglow intensity in this experiment. Compared to the fabric with non-superimposed stitches in layers, the luminous fabric with superimposed stitches has higher brightness, longer duration of emitting light, and better stable luminescent properties.
Image retrieval has been an active research topic in recent decades. In this paper, a novel and effective algorithm is proposed for printed fabric image retrieval by combining color moments methods and gist feature description methods. Color information distribution could be declared by color moments very well and gist feature description has an advantage in representation of spatial information. Therefore, color features and spatial information features are respectively extracted by color moments and the gist feature description method, which constitutes a feature database. After that, the similarity between query image features and the feature database is computed by Euclidean distance. To demonstrate the efficacy of the framework, experiments are conducted on the FABRIC database. Experimental results indicate that the proposed algorithm is more effective and accurate than other hybrid schemes for printed fabric images, in terms of precision and recall.
Polyester fabrics were coated by polyaniline synthesized via in-situ chemical polymerization and doped with HCl and H3PO4. The coated fabrics were examined by scanning electron microscopy, infrared spectrum and thermogravimetric analysis. The performance of flame retardancy and conductivity of polyester fabrics were studied by Limiting Oxygen Index (LOI) and cyclic voltammetry measurements. Experimental results indicated that the modified polyester fabrics had both excellent flame retardancy and conductivity. The sample molar ratio of ammonium persulfate (APS) to aniline of 1.2:1 resulted in the highest conductivity of 17.8 s/cm and the highest LOI of 42 vol% was acquired at the molar ratio of aniline to APS of 1:2.
This paper presents a mathematical model to predict the distribution of yarn tension and the balloon shape as a function of spindle speed in the ring spinning process. The dynamic yarn path from the delivery rollers to the winding point on the cop has been described with a non-linear differential equation system. These equations have been integrated with a Runge–Kutta method using MATLAB software. Since the numerical solution of the equations strongly depends on initial values, an algorithm of sensitivity analysis has been developed to predict the right choice of initial values in order to find a stable solution. For model validation purposes, the yarn tension has been measured between delivery rollers and yarn guide. Furthermore, a high-speed camera has been used to capture the balloon shape at different spindle angular velocities in order to compare the theoretically determined balloon shape with the one that actually occurs on the machine.
This study investigates melt spinnability of ethylene vinyl alcohol (EVOH) copolymers with various ethylene contents, which exhibits excellent biocompatibility but cannot easily undergo single-component fiber spinning. The chemical, thermal and rheological properties of EVOH were examined herein. Three EVOH copolymers, EV-32, 38 and 44, with different ratios of ethylene to vinyl alcohol (EV ratio), were used to evaluate the influence of the ratio on melt spinnability. The EV ratios of EV-32, EV-38 and EV-44 examined by nuclear magnetic resonance were 0.64, 0.82 and 1.0, respectively. The experimental results reveal that the melting temperature (Tm) and crystallinity (Xc) of EVOH decreased in the order EV-32 (178.9℃, 46.6 wt%) > EV-38 (171.9℃, 41.8 wt%) > EV-44 (166.0℃, 40.0 wt%). The thermal stability, however, increases in the order EV-32 < EV-38 < EV-44. The viscosity decreases in the order EV-32 > EV-38 > EV-44. EV-44 has much higher flow activation energy than EV-32 and EV-38, indicating that it has a temperature sensitivity higher than EV-32 and EV-38. The pellets of EV-32, EV-38 and EV-44 were melt spun. Three as-spun fibers, EV-32, EV-38 and EV-44 have cross-sectional diameters of 151.3, 150.9 and 154.1 µm and tensile stresses (strain (%) at breaking point) of 123.1 (205.2%), 121.4 (202.0%) and 131.1 MPa (180.2%), respectively. Most importantly, EV-44 can easily be spun at a relatively low temperature, 245℃, while the other two, EV-38 and EV-32, can hardly be made on condition that the spinning temperatures are higher than 255℃ and 265℃, respectively. Notably, once the spinning temperature of EVOH polymers was higher than 258℃, the degradation of vinyl alcohol segments would cause fuming and broken filaments to eventually terminate the entire spinning process. Ultimately, a brand new fiber, EVOH, with an EV ratio of 1.0, was successfully melt spun and mechanically characterized in this study.
Borneol, one of the commonly used Chinese medicines, can be used to treat many diseases. The main ingredient of natural borneol is d-borneol extracted from the volatile oil of dipterocarp trees. Numerous studies have proved the effectiveness of borneol. It has been widely used in relieving symptoms of anxiety, fatigue and insomnia; inducing anaesthesia and analgesia to alleviate abdominal pain, wounds and burns; relieving rheumatic pain, hemorrhoids, skin diseases and ulcerations of the mouth, ears, eyes or nose; treating sore throats and skin infections; and is mainly used to treat cardiovascular and cerebrovascular diseases. Although borneol has a significant therapeutic effect, its easy sublimation and low water absorbability make it difficult to control the efficiency of delivery and decrease its function in connecting to various applications in the needs of modern society. Electrospun nanofiber has been commonly used as a delivery vehicle for various medicines for biomedical applications. Poly(L-lactic acid) and cellulose acetate butyrate (CAB) nano-fibrous nonwoven membranes were electrospun and used as drug carriers for borneol. To load borneol into a PLLA/CAB composite membrane, borneol/acetone solution was sprayed on PLLA/CAB fibers. While part of the CAB was dissolved by acetone, borneol was combined with CAB by hydrogen bonds between hydroxyl and carbanyl groups. PLLA still kept a porous morphology of the whole drug-loaded membrane since it does dissolve in acetone. This structure provided a high quality and stable drug delivery system. With adjustable drug release properties, PLLA/CAB nano-fibrous composite nonwoven membranes can be alternative candidates for developing novel external medical textiles.
This paper describes studies on the surface modification of so-called ballistic materials (materials commonly used to protect the human body against firearms, i.e. fragments or bullets). Two materials, an ultra-high molecular weight polyethylene (UHMWPE) composite and aramid fabric, were investigated. The surfaces of these fibrous materials were modified using plasma-assisted chemical vapor deposition (PACVD) to examine the effects of the modification on the material properties, which are important for designing ballistic protections. Accordingly, both the mechanical strength and water resistance of the modified materials were tested. The results clearly show the impact of the modification on both parameters.
Electrospinning is a common method used to produce nanofiber from almost all types of polymers. By changing effective parameters of this process, especially polymer solution concentration, it is possible to produce nanoweb that consists of nanofibers with different averages of diameter. Here, the effect of nanofibers’ diameter on textural properties (water absorption time and pore size) of polyamide-6 nanoweb has been studied. In this way, three nanowebs with nanofibers’ average diameter of 111, 151, and 318 nm were electrospun from three different concentrations of 15, 20, and 25 wt%, respectively. Contact angle measurement and mercury porosimetry were used to investigate the nanowebs’ water absorption properties and porosity (pore size). The results from the water absorption test demonstrated that the absorption time of a 2 µL water droplet was remarkably shorter for electrospun nanoweb with larger nanofiber diameter. Nanowebs electrospun from 15 and 20 wt% concentrations had roughly the same absorption regime, while for 25 wt% the absorption regime was totally different. Mercury porosimetry of electrospun nanowebs revealed that the pore size in the nanoweb structure decreased by decreasing average diameter of nanofibers. The results of this study showed that contact angle measurement and mercury porosimetry tests could be used as complementary methods to scanning electron microscopy and atomic force microscopy and presented as promising methods to study the textural and physical properties of electrospun nanowebs.
This research work describes a new technique for producing staple fiber core-filament wrapped composite yarn, with the help of an innovative multifilament spreading method, using a slightly modified ring frame. The purpose is to develop an efficient and economic process for spreading the multifilament uniformly, to realize and improve the wrapping of the multifilament around staple core. Scanning electron microscopy was used to study the role of micro grooves’ dimensions in the formation of the multifilament layer and related effects on cover spun yarn properties. A modified ring frame was used to make 48 tex (12 Ne) composite yarn, which was compared to a similar composite yarn made on a conventional ring frame, for the tensile and hairiness properties. It was concluded that this mechanical spreading method can be used to increase the spinnability for short staple fibers and to overcome the problems associated with other spreading techniques and also can help to improve the breaking extension and hairiness properties of the composite yarn without the decrease of yarn tenacity.
Recent research on ballistic vests has focused on comfort performance by enhancing thermal comfort and moisture management. Kevlar/wool fabric has been developed as a potential material for ballistic vests. This study investigates the thermal comfort properties of woven Kevlar/wool and woven Kevlar ballistic fabrics. In this context, the thermal resistance, water-vapor resistance, moisture management performance, air permeability and optical porosity of 100% Kevlar and Kevlar/wool ballistic fabrics were compared. The effects of fabric physical properties on laboratory-measured thermal comfort were analyzed. This study also presents the fabric bursting strength and tear strength for comparison. Experimental results showed a clear difference in thermal comfort properties of the two fabrics. It was found that Kevlar/wool possesses better moisture management properties and improved mechanical properties than Kevlar fabric.
A broad band dielectric spectrum measurement system and a newly presented measuring method were adopted to measure the dielectric spectrum of cotton fiber assemblies with different moisture regains in the measurement frequencies from 0.1 Hz to 20 MHz. The experimental results showed that the permittivity of cotton fiber assembly increases with the increase in the moisture regain, and decreases with the increase in measurement frequency. For the cotton fiber assembly with the moisture regain less than 3%, its real part of permittivity is linear with respect to moisture regain from 0.1 Hz to 20 MHz. However, for the cotton fiber assembly with moisture regain greater than 3%, its real part of permittivity is linear with respect to moisture regain only in the frequency much higher than 100 kHz. Moreover, the change rate of the real part permittivity per unit mass, which is independent of the weight but closely related to the moisture regain of the cotton fiber assembly, was presented to estimate the moisture regain of cotton fiber assembly with moisture regain greater than 3%.
This paper presents an approach for the kinematic design of a rapier drive mechanism containing a spatial mechanism and analyses rapier motion curve. Kinematic design and analysis equations are derived and then the link lengths of the spatial mechanism are calculated in order to satisfy the critical rapier positions inside and outside the shed. In this way, the portions of one loom revolution, during which the rapiers are inside and outside the shed, are determined. The rapier motion curve is obtained by using kinematic analysis equations. It is shown that the position of the oscillating link in the spatial mechanism and the loom main shaft angle at which the rapier enters the shed have the most significant effect on the rapier motion curve. The gear ratio has also some effect on the rapier motion curve. Different rapier motion curves are obtained by changing these parameters and the suitability of these curves for rapier motion is discussed.
Previous research had shown that processing greige cotton on a commercial-grade hydroentanglement (HE) system at a water pressure greater than 120 bar resulted in a low-weight hydrophilic nonwoven fabric. With that ability to make hydrophobic greige cotton easily wettable and hence absorbent without the conventional scouring phase, an investigation was conducted to determine whether a fabric made by hydroentangling greige cotton fibers at a high water pressure could be successfully bleached without the traditional scouring. The investigation involved production of greige cotton nonwoven fabrics at a low hydroentangling water pressure of 60 bar and at a high hydroentangling water pressure of 135 bar and their subsequent evaluations before and after scour only, one-stage bleach only, and two-stage scour and bleach. In the results, both the 60 bar and 135 bar fabrics bleached successfully in the two-stage bleaching process and yielded acceptable absorbency and whiteness values. However, when bleached in the single-stage bleaching process with no separate scour, the 135 bar fabric still produced the whiteness index almost equal to that obtained in the two-stage bleaching process and even equal to that of a fabric made with commercially scoured and bleached cotton fibers, but the 60 bar fabric yielded about 15% lower whiteness index value while its wettability-induced improved water absorbency still was comparable to that obtained via the two-stage bleaching. This shows that a hydroentangled greige cotton fabric produced at a high enough water pressure (hydro energy) could be bleached satisfactorily without the traditional scouring chemicals and that a fabric produced even at a lower water pressure and bleached without scouring could still be satisfactory for subsequent aqueous treatments for certain end-use applications where the whiteness may not be as critical as the absorbency.
N-doped TiO2 powders were synthesized via a sol-gel processing, and N-doped TiO2/activated carbon fiber (ACF) composites have been fabricated using the impregnating method. The prepared powders and composites were characterized using X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet visible absorption spectroscopy, N2 adsorption-desorption, and scanning electron microscopy. The results show that N-doped TiO2 powders prepared are anatase phase, and the mean size of the particles is about 15 nm when calcined at 500°C. Nitrogen atoms were incorporated into the surface of TiO2 mainly as interstitial nitrogen and molecularly chemisorbed -N2 molecules. N-doped TiO2 powders exhibit an evident red shift in the band edge and an obvious increase in visible region absorption, and the powders are homogeneously dispersed on the surface of ACF. The photocatalytic degradation of methylene blue shows that N-doped TiO2/ACF composites exhibit enhanced visible light photocatalytic activity. This could be attributed to the synergistic effect between strong adsorption of the ACF and visible light photocatalytic activity by N-doped TiO2.
In order to diversify the structure of spun yarn as textile material and to develop novel composite spun yarn with good functionality, we investigated how to construct single yarn with a twin staple-core and sheath structure and/or adopt the production method of triplet spun yarn using an experimental ring spinning frame. Fundamentally, the unique spinning conditions were not only the arrangement and the distances of three rovings and the twist level of yarn, but also the types of staple fibers.
The following results were obtained: (1) by adopting the production method of triplet spun yarn with three rovings under the spinning condition with two differing roving distances, the yarn combining side-by-side and sheath-core structures could be constructed by two points of yarn formation and one twisting process without the device for controlling of spinning tension; (2) in the spinning method of twin staple-core spun yarn, it was necessary to control the difference between spinning tensions of the sheath layer and the twin staple-core layer with side-by-side structure under the spinning condition with the lower twist level of yarn and the greater difference between two roving distances; (3) for combining the twin staple-core and the sheath layers, it was important not only to control the greater length of drafted fiber strands for the sheath layer, but also to choose the cut length of the sheath and the core fibers.
Previous researchers established a set of reference cottons with known fiber maturity and linear density (fineness) values based on the analysis of a large number of individual transverse fiber cross-sections viewed under the optical microscope. Part 1 identified that the limited optical resolution of the captured images may be the source of a significant systematic error in the assigned values of cell wall area and hence fiber maturity and linear density values. In this paper the optical microscopy technique was implemented. Individual cross-sections were measured using this approach and also higher resolution and higher magnification images were obtained using scanning electron microscopy. It was found that the data obtained from optical microscopy were similar to the SEM data, with the perimeter being 2% smaller, the cell wall area being 6% larger and the maturity ratio values being 8% higher. It was concluded that the combined approach of utilizing SEM in conjunction with optical imaging is a useful approach for verifying and perhaps correcting the data obtained from optical imaging. Further the SEM images highlighted that the current experimental protocol does not adequately address the challenge of ensuring that the fibers are mounted normal to the plane of cutting the transverse cross-section. Modeling demonstrated that while maturity ratio values are relatively insensitive to this misalignment, measured cell wall area values and hence fiber linear density values will be overestimated. This may be the major source of error associated with the technique and warrants further attention in future studies.
This work explores the transverse forced flow of precursor gases during hyperbaric pressure laser chemical vapor deposition (HP-LCVD). Axial and mass growth rates of carbon fibers are measured experimentally, and a numerical model is developed that provides fiber growth rates in both the mass-transport-limited (MTL) and kinetically limited (KL) regimes. It is found that the fiber’s transport-limited rate increases as the square root of the flow velocity, while simultaneously, the temperature drops with the inverse square root of the flow velocity. Growth is enhanced by forced flow so long as the reaction zone remains within the MTL regime; upon reaching a critical temperature and flow rate, however, fibers enter the KL regime, and the growth rate declines with rising flow rate. Molecular properties of the precursors employed and gas concentrations ultimately determine the range of the MTL and the locations of the critical temperature and flow rate. The growth rates of fibers can indeed be enhanced by transverse forced convection—to at least three times the zero-flow steady-state rate, provided an MTL regime exists. Complex three-dimensional structures may be grown from these fibers in a freeform manner, and the more rapidly such microstructures can be fabricated, the more practical HP-LCVD becomes for industrial use, including the fabrication of novel textiles.
Polyester fibers (PET) are greatly used in textiles but depend on fossil fuel resources. Poly-(lactic acid) (PLA) is an aliphatic polyester that can be derived from 100% renewable resources. The load–extension plot of a polylactide fiber seems to be especially compatible with that of wool. Consequently polyester/wool 55/45 and polylactide/wool 55/45 yarns were spun using the Sirospun process and plain and twill woven fabrics were industrially produced. Washed and heat set fabrics were subjected to a conventional process of dyeing and decatizing. Fabrics were gradually worn by abrasion using a Martindale wear and abrasion tester.
Using the bursting strength test, the viscoelastic behavior of the fabrics when multidirectional extended was simulated and modeled using a modified non-linear Maxwell model. The three steps of fiber decrimping and orientation, fiber stretching and maximum yield and breaking were analyzed. PET/wool fabrics show a more linear behavior than PLA/wool ones and the influence of weave, finishing and wearing on the viscoelastic behavior of PLA/wool fabrics were highly relevant when compared with that on PET/wool ones. It seems that when blended with PET, wool develops its felting effect during finishing and wearing, while when blended with PLA, the felting effect of wool is hardly developed due to the lower resistance of PLA to hydrolysis and its lower thermal stability. PLA fiber properties need to be improved probably through the development of new L-D lactide (PLDLA) copolymers of different ratios between components and molecular weights to reach the optimal desirable properties for the fiber.
The yarn diameter is an effective property in determining fabric structure and processing settings. There are different systems of measuring the yarn diameter; among them is the image analysis of the yarn’s microscopic images. This method is considered to be more precise than other methods, but it is "static" in nature as it measures the property at scattered intervals and does not reflect the continuous variation of the yarn diameter. The goal of the current work is to measure the yarn diameter and its variation over a long length of yarn at fixed intervals to consider the "dynamic" change in the property. To achieve this goal, a high-speed camera (HSC) with a proper magnification was used to capture the images of the yarn and a new robust algorithm was developed to analyze the massive amount of yarn pictures in a reasonable time. The collected data for the yarn diameter were analyzed and compared to the results of the commercial Uster Evenness Tester IV. The results of the HSC were very comparable to the results of Uster and they were able to detect the short-term, the long-term, and the periodic variation of the yarn diameter.
A fundamental understanding of the relationship between cotton fiber strength (or tenacity)/elongation and structure is important to help cotton breeders modify varieties for enhanced end-use qualities. In this study, the Stelometer instrument was used to measure the bundle fiber tenacity and elongation properties of different cotton fibers. This instrument is the traditional fiber strength reference method and could be still preferred as a screening tool owing to its significant low cost and portability. Fiber crystallinity (CI IR) and maturity (M IR) were characterized by the previously proposed attenuated total reflection (ATR)-based Fourier transform infrared protocol that has microsampling capability and is suitable for the tiny Stelometer breakage specimens (2 ~ 5 mg), which cannot be readily analyzed by a conventional X-ray diffraction pattern. Relative to the distinctive increase in fiber tenacity with either CI IR or M IR for Pima fibers (Gossypium barbadense), there was an unclear trend between the two for Upland fibers (G. hirsutum). Although fiber elongation increases with elevated CI IR and M IR for Pima fibers, it generally decreases as CI IR and M IR increase for Upland fibers. Furthermore, small sets of Upland fibers with known varieties and growth areas were examined, and their responses to both CI IR and M IR are discussed briefly.
This study aimed to enhance the capability of multiple weave color reproduction for Jacquard textiles. Today, the subtractive color mixing of CMYK color system is being widely used for rendering weave patterns and assorting filling yarn colors. However, as Jacquard color creation involves optical color mixing, the direct application of pigment mixing is limited to corresponding to an artwork that involves red, green, blue and saturated solid black. Since Jacquard colors are realized by opaque and non-blended material of yarns, it requires a different approach of light and pigment mixing to simulate colors of an original image in woven forms. Therefore, in this study, the optimization of weave color reproduction was approached to properly embrace the proposed color gamut of the CMYK model in digital Jacquard textiles. Based on the ink densities of the CMYK color scope, segmentation was applied in reflection of optical thread color mixing to attain optimal weave patterns. A pair of primary color layers was merged by defining a set of rules to classify individual primary and secondary color patterns to designate colored threads in associated regions, and weave structures were designed and aligned to generate varied levels of color shades in weaving form. The correlation between shaded weave structures and the primary color-based weave patterns were matched to present a faithful color reproduction in weaving.
This paper describes an intensity-based notched polymer optical fiber (POF) fabric strain sensor and its application in human respiration monitoring. A mechanical analysis illustrates geometrical profiles of constrained fiber loops on the fabric substrate. V-shaped notches are made by laser ablation on the sides of the POFs. The effects of loop parameters and processing conditions on the sensing performance are investigated. The experimental results show that the fabric sensor is more sensitive to strain with notches on the outer side of the loops, a small radius of the loops and a low scanning speed of laser. This fabric sensor exhibits a large measurable strain range of up to 21%. The achieved strain sensitivity is 3.77. The temperature and relative humidity have little effect on strain sensitivity between 0°C and 60°C. A belt has been fabricated by integrating the fabric sensor for monitoring human respiration. The evaluation trials show a strong correlation between the belt system and a clinic monitor.
The geometric structure of woven fabric affects the appearance and physical properties and can be used to predict the weavability of the fabric. An accurate description of the structure is beneficial to predict the characteristics and the appearance of the woven fabric. The purpose of the study is to build an accurate, realistic, and stable three-dimensional (3D) geometric structure model based on the mechanics for plain woven fabrics. Parameters such as the initial Young's modulus of the yarn materials, thicknesses, warp density, pre-loaded tension on the yarns, and the amount of letting-off and taking-up are considered in the model. The yarns are simplified as a series of spring-sliders that are stretched in the fabric and moved along the direction of the resultant forces step by step according to the changing forces. The yarns stop moving when all the forces reach equilibrium. The tests demonstrate that the algorithm conforms to the weaving principles. The 3D images of the geometric structure of the woven fabric at different steps are displayed by B-spline surface modeling technology. A Keyence VH600 micro-measurement system is used to measure the 3D coordinates of the real fabric accurately without destroying the fabric structure. The similarity of the real geometric structure and the calculated geometric model is evaluated by calculating the discrete Fréchet distances. The result validates that the similarity of the calculated geometric structure and the measured value is more than 90% for both the warp and weft direction.
This study evaluated the effect of the raising condition on the mechanical, comfort, and hand properties of artificial suede made of <underline>nylon/polyester</underline> microfibers, and identified those best suited for the consumer's needs. The suede became thicker and heavier; in addition, the wale density increased by repeated raisings as the base knits contracted and naps increased after a repeated raising process. Water vapor transmission decreased, but thermal resistance and water repellency increased. The increased number of raisings caused the suede to stiffen and not readily deform by compression; however, the suede had a soft and smooth surface. The thickness, weight, wale density, thermal resistance, and perception of luxuriousness increased between one and four cycles and remained unchanged at six cycles. The hand preference, preference for jackets, and luxuriousness of the suede improved with the number of raisings, with the best performance obtained at four raising cycles.
Though ZnO nanoparticles (NPs) are an excellent UV absorber, their photocatalytic activity greatly limits the application areas of these particles. Under sunlight exposure, ZnO NPs used as a UV absorber can accelerate the wool yellowing process by generating free radicals. To reduce this photocatalysis effect, a physical barrier has been fabricated by coating the ZnO NPs with a silica layer (ZnO@SiO2), hence providing good UV-shielding with low photocatalytic activity. The structure and optical properties of ZnO and ZnO@SiO2 NPs were characterized by transmission electron microscope (TEM) and UV–Vis spectrum. The photocatalytic activity of ZnO and ZnO@SiO2 NPs was evaluated by photo-degradation of Rhodamine B. The ZnO and ZnO@SiO2 NPs were applied to knitted wool fabrics using the dip coating method. The treated wool fabrics were characterized by a scanning electron microscope (SEM) and the photoyellowing level of treated fabrics after exposure under simulated sunlight was evaluated by a Datacolor Spectraflash spectrophotometer. The ZnO@SiO2 NPs demonstrated excellent protection of wool against photoyellowing.
The existing machine vision systems cannot efficiently detect white contaminants in cotton under the illumination of visible lights, because their color is the same or very close. To solve the problem, this article proposes an imaging method based on line lasers. Under the illumination of a line laser, the white contaminants and cotton showed the differences in the optical characteristic of their surface. Then, according to the features of the intensity of their reflected lights or the distribution of the fluff around their surfaces in the images, an example algorithm for identification of white contaminants from cotton was suggested. The experimental results indicated that, using our method, the mean successful detection rate of the typical white contaminants in cotton was over 87%.
The electrical resistance of knitted fabrics embedded with conducting yarns at different temperatures was studied in this paper. Two types of resistance, linear resistance and contact resistance have been considered and discussed by experimental studies and theoretical modeling. Two silver-coated conductive yarns, yarn A and B, with linear resistance of 68.6 /cm and 1 /cm respectively, were embedded into normal knitted woolen fabrics. The temperature effect on the resistance of these two conductive knitted fabrics as a function of applied voltages was extensively explored. The results have shown that the resistance of either conductive knitted fabric decreases significantly (maximum 30%) when its temperature is rising. It can be explained by two main factors: the electrical resistance of the silver-coated conductive yarns decreases as temperature rises; the physical contact of the overlapped conductive yarns extends due to heating on woolen fabrics, which causes a decrease in contact resistance. This research has shown that the temperature effect on the conductivity of the knitted fabrics embedded with conductive yarns should be carefully considered in future industrial applications.
In this study silver nanoparticles were deposited by electroless coating onto glass-stitched fabrics via the Tollens’ reaction for technical textile applications. The effect of fabric compactness and the amount of silver nitrate solution on conductivity and electromagnetic interference shielding effectiveness (EMI SE) were studied. The results showed that a compact fabric surface promoted the EMI SE and that a critical threshold of surface conductivity of 0.3 S.cm–1 was required to obtain an EMI SE above 50 dB in the frequency range 300 MHz–1.5 GHz. Using SEM analysis we found that conductivity values were compatible with the coating thickness of samples. FT–IR analysis revealed that the presence of Ag particles caused the aliphatic C–H stretching frequencies (2858 and 2927 cm–1) to become shifted to higher values (2901 cm–1, and 2988 and 2972 cm–1, respectively).
Textile high-performance filament yarn subjected to extremely high thermal loads can be found in various technical application fields. Besides the mechanical loads, textile fiber materials have to also satisfy high safety requirements in these applications with respect to thermal loads. Some of the main fields of application in the field of mechanical engineering are turbines, drive devices, rocket components and fire protection coatings. Textile grid-like structures are also being increasingly used in civil engineering as reinforcements (textile concretes). The design and development of textile structures for these applications demands studying and acquiring the material behavior under high thermal loads. Neither sufficient data nor standardized testing methods have been extensively achieved for evaluating the tensile characteristics of filament yarns under thermal influences. Hence, studying the thermal behavior of these yarns, which are used as input material for the reinforcing structures, is essential. The impact of the standard atmospheric condition on the oxidation behavior of the yarns, as in the case of carbon filament yarns and their influence on the physicochemical and tensile mechanical properties, have to be studied as well. This paper aims to address this issue and provides an insight into the current research about the development and realization of a novel test stand and the subsequent study of tensile mechanical behavior for textile high-performance fiber material under extreme thermal loads together with their physicochemical behavior.
Examples are presented of three new methods for preparing electromagnetic (EM) textiles for a variety of applications. These are metalized textiles containing pores and meshes, textiles with planar periodic structures, and space-structured textiles. Firstly, an aluminum foil model with pores was prepared, then metalized textiles with pores, and finally silver-coated nylon net fabrics, and the relationship between shielding effectiveness (SE) and pore structure was studied. The size of the pores and the distance between them obviously influence the SE, and in particular the pores on the metalized fabrics decrease the SE. Secondly, the factors affecting the frequency selective surface (FSS) of the metal were analyzed and a FSS textile was prepared as a band-pass filter. The FSS fabric with non-conductive periodic units on the conductive fabric surface showed good resonance peaks. Finally, three types of space-structured EM textiles, including a plush fabric, a warp-knitted spacer fabric, and a velvet fabric were constructed using different conductive yarn blends. The EM reflection coefficient curves showed that these structures also obviously affected the EM properties. The three types of new EM fabrics were soft and light compared with traditional metallic EM devices. There is still, however, a long way to go to establish the exact relationship between the structure and EM properties of these new EM textiles.
In this study, the mechanical response of a single yarn pull-out from single layers of Kevlar® and Twaron® fabric under out-of-plane loading at both quasi-static and dynamic rates was experimentally investigated. In order to perform the dynamic experiments, a pendulum impact setup was designed and constructed to pull out a single yarn dynamically. The pull-out load was measured directly by a load cell and the movement of the fabric was measured to portray the load–displacement history. The effects of transverse pressure, different weave direction, and loading rates were also investigated.
The tensile damage behaviors of co-woven-knitted (CWK) composite materials under high strain rates were investigated with a simplified microstructure model. In the microstructure model, the knitted structure is homogenized with the resin in the CWK composite. Then the CWK composite was simplified as a woven structure reinforced homogenized knitted composite. In the woven composite, the mechanical properties of the resin were calculated from a homogenized, knitted-structure, reinforced composite. With this homogenization of the knitted component, the CWK composite is transformed as a woven composite. The tensile behaviors of the CWK composite under high strain rates were predicted with the finite element method (FEM) at the woven composite level. The stress–time curves and the damage fractures of the CWK composite along the warp direction (0°), the diagonal direction (45°) and the weft direction (90°) under various strain rates were obtained and compared with those from the experiments. The influences of the strain rate on the tensile behaviors of the CWK composites were analyzed both from the experiments and the FEM results. It was shown that FEM results and experimental results were in good agreement in terms of strength and failure morphology prediction. It was concluded that the simplified model and the methodology developed are suitable for the design of other kinds of hybrid-structure composite under both quasi-static and impact loading by homogenizing some parts of the reinforcing materials.
Polyamide 5,6 (PA 5,6) fibers were prepared using the melt-spinning method. The effects of draw ratio and temperature on the structure and properties of PA 5,6 fibers were investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction, sonic velocity and tensile test measurements. DSC results revealed that the melting temperature showed no considerable variation, while the heat of fusion increased with increments with draw ratio and temperature. It was found that the crystallinity and crystal size of PA 5,6 fibers were directly proportional to the draw ratio and temperature and the orientation factor increases as expected upon drawing. The tenacity and Young's modulus were found to be increased, while the elongation at break decreased with the draw ratio and temperature. The improvement in mechanical properties may be attributed to the increase of orientation along the fiber axis and the crystallinity.
We report the detection of cellulose polymorphs, using spectroscopic and diffraction techniques, in cotton fabrics treated with commercial textile mill processes designed for better dyeing and mechanical properties. Vibrational sum frequency generation (SFG) spectroscopy analysis of cotton is known to be selective and sensitive to the crystalline cellulose portion in the sample. The SFG analysis results were compared with the results from conventional analytical techniques such as X-ray diffraction (XRD) and infrared (IR) spectroscopy. The XRD detection of a small fraction of cellulose II present in the partially-mercerized fabric was difficult, while SFG and IR analysis indicated the partial conversion of cellulose I to II without significant reduction of the cellulose crystallinity. Processing the cotton fabric with the liquid-ammonia treatment mill caused partial conversion of cellulose I to III and significant reduction of the overall crystallinity of cellulose. All XRD, SFG, and IR techniques were able to monitor this conversion. When the cotton fabric was treated with the partial mercerization process first and then the liquid-ammonia process, both cellulose II and cellulose III were produced and identified with SFG. But XRD and IR failed to detect the presence of cellulose II in the mercerized and ammonia-treated fabric. The polymorphic changes found in the SFG, XRD, and IR analyses provided insights into the physical property changes of cotton fabric after commercial mercerization and liquid-ammonia treatment processes.
Kapok fiber is a kind of cellulosic fiber harvested from the kapok fruit and has many unique properties and potential applications owing to its high degree of hollowness. It is important to understand the mechanical properties of the kapok fiber under transverse compression because its hollow structure can be squashed easily. In this research, kapok fibers were carded slightly to form a kapok fibrous assembly (KFA) in which the fibers were straightened and parallel. A KFA was considered as an approximately isotropic matrix material in the transverse direction. The fiber arrangement in a KFA was geometrically modeled with a pipe-piling structure. The viscoelastoplastic model and its constitutive equations were established to characterize the mechanical response of the KFA under transverse compression. Three compressional stages (A – the viscoelastic stage, from the initial point 0 to the yielding point 1; B – the viscoelastoplastic stage, from the yielding point 1 to the point 2; and C – the senior viscoelastic stage, from the yielding point 2 to the point at the maximum compressional load) were observed from the stress–strain curve, and four parameters were determined to describe the elastic, viscoelastic, and viscoplastic behaviors under each compression cycle performed on the Instron compression tester. The results indicate that the variable elasticity of the KFAs exists throughout the total compression, viscoelasticity appeared only in stage C, and the viscoplastic property was evident in stage B. The KFAs did not exhibit viscoelastic behavior in stages A and B because the viscoelastic element of the Kelvin model failed to work in these two stages. The influence of conditioning humidity on the parameters was also investigated.
Biomaterials are commonly used in vitro or in vivo. Synthetic vascular prostheses, artificial bones, and artificial joints are used in vitro. Bone scaffolds demand components with good biocompatibility, mechanical strengths, and pore size. This allows the bone tissue to attach to and grow inside the bone scaffolds. Polyethylene terephthalate (PET) filaments and chitosan have good biocompatibility and are non-toxic. This study prepares biocompatible, porous, 1- and 2-layer three-dimensional PET/chitosan tubular knits by a freeze-drying method. PET plied yarns with three combinations of various denier (D) and coefficients of twist-150D/2, 225D/4, and 300D/3-are knitted into tubular knits with proper mechanical properties and porous structure. The resulting tubular knits are then alkali treated with 3 M sodium hydroxide (NaOH) reagent for 90 min, immersed in 1 wt% chitosan solution, and then freeze-dried, forming the porous PET/chitosan tubular knits. The functional group analysis and degradation of the alkali-treated chitosan films are first evaluated, and then the tensile strength, surface observation, pore size, and biocompatibility of the resulting PET/chitosan tubular knits are evaluated. The experimental result shows that 1- and 2-layer PET/chitosan tubular knits have desirable mechanical strength, stability, and biocompatibility antibacterial properties.
In this study, jet current and jet life in roller electrospinning of polyurethane (PU) were measured. The relationships between jet current and jet life and number of Taylor cones/m2 (NTC/m2), spinning performance (SP), and fiber properties (diameter, non-fibrous area) were analyzed. In addition, the effects of PU and tetraethylammonium bromide (TEAB) concentrations on jet current and jet life were determined. It was observed that jet current increases with PU and TEAB concentration, while jet life decreases. According to the results, NTC/m2 and spinning performance increase with jet current and decrease with jet life. Moreover, it was observed that jet current movement gives an idea about jet life, and it was also determined that there is a relationship between jet life and fiber morphology.
In the present study, a novel, wearable textile based microfluidic device was developed that provides a non-invasive, rapid, semi-quantitative detection of the lactate level in simulated sweat solution. The potential application was envisioned to be a biosensor that can monitor an athlete’s physical status during exercise. A photolithography technique was used for the fabrication of hydrophilic micro channels and reservoirs surrounded by hydrophobic barriers made from SU-8 negative photoresist. The reservoirs were functionalized by co-immobilization of lactate oxidase (LOX) and horseradish peroxidase (POX) enzymes. LOX uses L-(+)-Lactic acid as substrate and produces H2O2 which is a POX substrate. Then, POX oxidases H2O2 in the presence of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) and results in color formation. The studies showed that excess amount of analyte presence resulted in analyte inhibition. It was also shown that analyte pH and temperature were effective on the color formation. For effective results, analyte pH and temperature should be ≥5°C and 25–30°C, respectively. Lower pH and higher temperature values resulted in a decrease in the enzyme activity. The textile based biosensor system could make a semi-quantitative visual detection to differentiate between the normal (<5 mM) and high (≥5 mM) lactate level: while a high lactate level led to a denser purple color formation, normal levels led to a light purple formation and a green color started to be observed.
This study has identified the quantitative relationship between the level of hydrophobicity and the surface roughness, represented f 1, of superhydrophobic nylon fabrics treated with ZnO nanorods and n-dodecyltrimethoxysilane. With this objective, ZnO nanorods were uniformly grown to give varied particle dimensions on nylon fabrics by a hydrothermal process at a range of solution concentrations. ZnO nanorods, having a unique rod-like hexagonal section structure, were assessed in terms of their dimensions and density to estimate the solid area fraction, f 1 , in the Cassie–Baxter model. While the static contact angle did not discriminate between the hydrophobicity of superhydrophobic surfaces, the sliding angle and shedding angle were able to achieve this. The estimated value of f 1 was quantitatively associated with hydrophobicity. The assumption that there was no penetration of into the gaps between nanorods (zero h') appeared to be valid for superhydrophobic surfaces, and this was confirmed by the strong correlation between the increased sliding and shedding angles and the increase in f 1.
The main research objective of this study was to investigate the effect of the impregnation of Twaron® fabric with various shear thickening fluids (STFs) on the stab resistance at quasi-static conditions—being the main parameter characterizing the future application of the impregnated textiles in the scope of the new functionality of the elaborated protection of the multi-layer system. It was found that the STF/Twaron® fabric composites required significantly higher loading than the untreated fabric to achieve spike penetration. In the composite fabric tests, the spike did not fully puncture the material.
The association between the incidents counted by the measurement wire of the Wool ComfortMeter (WCM) and the previously published neurophysiological basis for fabric-evoked prickle have been investigated for lightweight knitted woolen fabrics. The fiber lengths and diameters capable of triggering the fabric-evoked prickle sensation were calculated using Euler’s buckling formula, and it is suggested that fibers as fine as 10 µm are capable of triggering the prickle response if they have a short enough free length protruding from the surface. Good agreement was found between the sensory assessed human prickle sensation and the wearer prickle response predicted using the WCM outputs, especially when the latter were transformed using Stevens’s Psychophysical Power Law.
Cotton fabric was supported by three types of cerium-calcium hydroxyapatite (CeCaHap) solid solution particles and the properties were compared. The three types of CeCaHap were prepared using different wet methods. The crystallinity and morphology of the particles were altered depending on the preparation conditions. Because all the CeCaHap particles exhibited a strong ultraviolet (UV) absorption under 400 nm on the ultraviolet-visible spectra, they were supported on cotton fabric by immersing the fabric into the dispersion containing the particles. The treated fabric showed UV shielding properties and fine particles especially showed stronger UV screening properties than large and long particles. With increasing the concentration of the particles in the dispersion, the amount of particles that was supported on the fabric increased and UV screening properties of the fabric were enhanced. The UV shielding ability of the fabric was sufficiently maintained after washing using water or a sodium dodecyl sulfate solution.
Many previous studies on cotton maturity used a sole parameter to rank the maturity of a cotton sample containing a large number of fibers. In light of the complexity of maturity distributions, the sole-parameter approach does not appear to be reliable and rational for cotton maturity evaluation. More distributional parameters should be examined and included in the new classification methods. This paper (1) introduces important changes in the image-analysis algorithms for cotton cross-section measurements to enhance the consistency of fiber detections in order to reduce the bias on immature fibers, (2) investigates the characteristics and patterns of cotton maturity distributions, and (3) presents the experimental results on the cross-section images selected from seven cotton varieties that have a wide range of maturities. It is found that the skewness of a maturity distribution is an essential parameter for classifying the distribution pattern and that the dead fiber content and the mature fiber content are the important distributional parameters for assessing cotton maturity.
Auxetic materials are a kind of non-conventional materials having negative Poisson’s ratio. They laterally expand when stretched or laterally shrink when compressed. Compared to conventional materials, auxetic materials have a number of enhanced properties that could be very interesting for some special applications. This paper reviews the latest achievements in auxetic materials, including their properties, structures and applications. A special discussion on their potential applications in textiles is also made. It is expected that this review could provide some useful information for the future development of auxetic textile materials.
A novel method combining the characteristics of corner information and second-order statistics of fabric images is proposed for analyzing the repeat size and identifying the weave type of fabrics. The analysis method is formulated in a research framework of near regular texture analysis. Firstly, the original fabric image is split into two components: the geometric component and the textural component, in which low-level cues of corners are detected by the Harris detector. Secondly, clustering techniques are used to cluster interest points by image patch appearance. Thirdly, a Markov Random Field (MRF) model is adopted for inferring the location of texture elements, and their shape is then used for classifying the weave patterns. The experimental results show that the main disadvantages and difficulties of using structural and frequency methods in texture classifications have been overcome by the proposed method.
Maturity and fineness are important physical properties of cotton fibers affecting qualities of fibers and yarns. A number of methods are used for measuring fiber maturity and fineness from developed fibers that are desiccated and harvested from open bolls. With the recent advent of molecular breeding and genomics, there is a growing need for measuring the physical properties of developing fibers that are living cells containing genetic materials. Unlike the developed fibers, the developing fibers are immature fibers composed of high levels of physiological sugars causing stickiness. Therefore, there is a challenge in measuring fiber properties from the developing fibers. To identify methods enabling the measurement fiber maturity and fineness from developing fibers, we compared various methods including the use of the USTER Advanced Fiber Information System (AFIS), high-volume instrument, Cottonscope, fiber cross-section image analysis microscopy, cellulose assay, and gravimetric fineness methods. Our results showed that maturity ratios (MR) measured from high maturity fibers correlated among all methods, whereas AFIS MR measured from low maturity fibers did not correlate with other methods. The fineness values measured by AFIS and Cottonscope were affected by the levels of physiological sugars in developing fibers. As a result, we conclude that pre-elimination of physiological sugars causing the stickiness was crucial to measure accurate fineness values from developing fibers. The results demonstrated strengths and weaknesses of various methods of measuring fiber maturity and fineness from immature and developing fibers. The information will help cotton scientists measuring and interpreting fiber properties from developing fibers.
Defect detection has been a focal point in fabric inspection research and remains challenging. In this paper, a novel method for fabric defect detection is presented. In the proposed algorithm, only defect-free fabric images are used to build the over-complete basis set via sparse coding. Compared to traditional defect detection methods via sparse coding, our method uses a Gabor filter to reduce the complexity of the fabric signal, and takes the fabric patch’s projections in the small scale over-complete basis set as the original features, not the sparse representation. We compare the averages of the patch and its neighborhoods’ features with the standard features, which are the averages of all defect-free fabric images’ features. At last, according to this compared distance, the patch is classified as defective or non-defective. The experimental results on our own database and the TILDA database reveal that our features are more robust and the proposed algorithm can detect defects on twill, plain, gingham and striped fabric effectively.
This study evaluated the application of medicinal plants to fabric finishes and the functionality of the fabrics finished with ethanolic extracts of the lotus plant, such as lotus leaf, lotus pot and lotus seed. Treated cotton was dyed a light orange and yellow-green color using lotus pot and lotus leaf, respectively, and the color difference ( E ) of fabrics before/after treatment with extract solution of lotus leaf was a maximum of 36.4. When the processing concentration of extract solution and treatment temperature of cotton fabric were increased, the color and color ingredient uptake increased, but the optimal processing time was found to be 30 minutes. Regarding the dyeing properties, the fabrics treated with the lotus leaf extract showed the best color in terms of color intensity, whereas the antibacterial activity was highest in the case of fabric treated with lotus pot extract. Antibacterial activity was significant in the order of lotus pot > lotus leaf > lotus seed. The fabric treated with the lotus leaf extract exhibited significant antibacterial activity only when it was treated at high concentrations (>8%), whereas the fabric treated with the lotus pot extract showed significant antibacterial activity even when treated at low concentrations (4%) or low temperatures (40°C). Accordingly, ethanolic lotus pot extract is recommended as an environment-friendly antibacterial finishing.
An important role of garments is to provide adequate comfort. A study was undertaken of the sensory scores for perceived comfort of wool base layer long sleeve knitted T shirts. This paper, the first in a series, describes and evaluates the wearer trial protocol in which untrained female wearers scored tactile, thermal, and moisture-based sensations during a controlled series of activities in a range of controlled climatic environments. Wearer scores were sufficiently consistent, that significant differences in aggregate scores between garments were detected that reflected changes in the fiber type (wool, cashmere, and cotton) and fiber specifications. Prickle and discomfort scores responded to different factors. The importance of choosing appropriate test conditions when assessing garments for particular end uses was highlighted as both the environment and activity affected wearer's perception of garment performance. A novel test feature was the use of a ‘link’ garment common to separate trials. This, combined with the observed absence of an effect due to garment washing, enabled the testing to be expanded so that 38 garments were successfully compared over 30 months in nine trials. Finally while the first trial used 43 wearers to obtain good estimates of absolute comfort levels, it was demonstrated that a reduction to 25 wearers was adequate for later trials with minimal loss in sensitivity.
This study melted and mixed poly lactic acid and nano mica into a new nano composite material for injection molding. The injection parameters for the mixture included the melting time, screw speed, heating plate temperature, nano mica content, melting temperature, nozzle temperature, holding pressure, and injection speed. The quality considerations of the new nano composite material were ultraviolet (UV) absorption rate, far-infrared absorption rate, Rockwell hardness, and flame resistance. This study applied main effect analysis and variance analysis theory of the Taguchi method to analyze the single quality characteristic of the experimental results. The optimal factors and level combination was identified through multi-quality integration using the Analytic Hierarchy Process. After consistent examination and calculation of the total weighting of various parameter levels, as well as the ranking of the parameter levels, the optimal injection parameters were obtained. According to the confirmation experiment results, the Signal-to-Noise ratio of the four qualities for the new nano composite fell within the 95% confidence interval, indicating the experiment was reproducible and reliable. The results indicated that the best qualities for the new nano composite are UV absorption rate at 98.22%, far-infrared absorption rate at 90.53%, Rockwell hardness at 108.07, and the limiting oxygen index for fire resistance rating at 30.
In this study, nanostructured polypyrrole (PPy)-coated cotton textiles were produced by in situ chemical oxidative polymerization and dielectric/electrical properties of PPy-coated cotton fabrics were presented in the low- and high-frequency regions. The conductive cotton fabrics showed a relatively high dielectric constant in the low- and radio-frequency region. The dielectric constant and dielectric loss for all fabrics presented relatively high values at low frequency and were found to decrease with the frequency. The influence of the PPy content and the type of dopant and oxidant on the morphological, dielectric/electrical and thermal properties of the cotton fabrics was investigated. It was found that the type of dopants and oxidants had a noticeable effect on the electrical/dielectric and morphological properties. The frequency dependence of AC conductivity, dielectric constant, dielectric loss and electric modulus were analyzed in the frequency range from 0.1 kHz to 10 MHz. The nanofiber network morphology of coated fabrics produced by dodecylbenzenesulfonic acid sodium salt improved the electrical/dielectric and thermal properties of cotton composites.
Polypropylene (PP) is widely used in hernia repair for its compatibility with most mesh constructions. Polyvinylidene fluoride (PVDF) is a non-absorbable fluoropolymer with improved biostability, lower bending stiffness and less tissue reaction. Creep behavior and elasticity are significant properties of hernia mesh that influence the surgical handling of mesh and the postoperative recurrence. This work compares PVDF monofilament and hernia mesh with PP in creep deformation and elastic recovery percentage. The experimental results indicate that PVDF monofilament and mesh exhibit larger elastic recovery percentage, higher initial elongation and less creep deformation than PP mesh. The creep deformation of PVDF mesh in wale and course directions are 3.19 mm and 5.38 mm, which for PP mesh in wale and course directions are 7.73 mm and 8.30 mm. PVDF mesh has better performance in shape stability and elasticity. Additionally, creep models are used to analyze the experimental data and predict the long-term creep deformation. This method greatly reduces the time of creep experiment. In contrast to the four-element model and the Eyring's model, the modified generalized Maxwell model is more suitable to describe the creep curves of hernia meshes. Better agreements between theoretical and measured creep curves are observed. The predicted results demonstrate that PVDF mesh has better long-term shape stability than PP mesh.
Composite-forming processes involve mechanical interactions at the ply, tow, and filament level. The deformations that occur during forming processes are governed by friction between the contacting tows on the mesoscopic level and consequently between filaments on the microscopic level. A thorough understanding of the frictional properties at the level of individual filaments is essential to understand and to predict the macroscopic deformations of a textile reinforcement during forming. This work presents a contact mechanics modeling approach to provide a theoretical background of the frictional behavior of dry fibrous tows in contact with each other. The predicted frictional behavior is in qualitative and quantitative agreement with experimentally observed frictional forces of carbon fiber tows in sliding contact. The relative orientation of the contacting tows is of great importance for the developed frictional forces in the contact.
A formaldehyde-free flame retardant (EFFR) for bamboo viscose fabric was synthesized by raw materials of silanol, phosphorus pentoxide, and diethanolamine. The flame retardant had the dual function of imparting fire resistance and softness to bamboo viscose fabric; moreover, it had no halogen and free formaldehyde, and wouldn’t release formaldehyde during processing and end-use. The experimental results about choice of cross-linker stated that the cross-linker played a significant role in decreasing the flammability of bamboo viscose fabrics and improving durability of flame retardance. Cross-linkers of hexamethylol melamine (HMM) or dimethylol dihydroxy ethylene urea (DMDHEU) or water-soluble isocyanate-terminated (WIT) not only cross-linked with flame retardant and bamboo viscose cellulose to enhance durability of inflaming retarding, but also had nitrogen to improve nitrogen–phosphorus synergism. However, HMM and DMDHEU can release free formaldehyde. WIT is a kind of cross-linker which has no formaldehyde. The experimental results showed that the Limiting Oxygen Index (LOI) value of Vis-EFFR–WIT treated fabric was basically above 30%, and the handle of the finished fabric was ameliorated greatly because of its organosilyl constituent part, even after 30 laundry cycles, the fabric still had some flame retardancy and soft feeling.
A large number of fatal accidents of fire-fighters during operations can be attributed to circulatory collapses due to cardiovascular diseases or heat stress. A recent project thus aimed at developing a highly functional, reliable and suitable system which can be used under different conditions such as common indoor operations. Measurement of vital signs, like ECG, breathing, and skin temperature, had to be combined with limited weight, acceptable skin comfort, affordable price, and speed and ease of dress and connection to the electronics in the fire-fighter’s jacket. The article gives an overview of technical and clothing technology aspects of the developed sensory shirt.
Electrospinning was used for the coating of the polyurethane/silica hybrid solutions on the cotton fabric surface. An ultraviolet curing process was performed on the collector by an ultraviolet lamp positioned inside the electrospinning cabin. In order to investigate the effect of fluorinated, silane-functionalized urethane (inorganic part) content on the water-repellency; five different fluorinated concentrations (10%, 20%, 30%, 40%, and 50% by weight) were used. The disappearance of isocyanate peaks during the silane-functionalized urethane synthesis was observed by Fourier transform infrared spectroscopy. Surface morphology and elemental analysis of the coated cotton fabric surfaces was investigated by scanning electron microscopy and energy dispersive spectroscopy analysis respectively. Water-repellency was evaluated by contact angle measurements. A sample that contained 50% inorganic part showed a contact angle of 154.5°. Samples were thermally characterized by differential scanning calorimetry. Glass transition temperature of the synthesized hybrid polymer increased with increasing inorganic part ratio. Additionally, abrasion resistance and crease recovery angle tests were performed to evaluate the effect of fluorinated part percentage on the mechanical and comfort properties of fabrics.
Registration of acoustic emission (AE) events during tensile loading of fiber-reinforced composites allows the damage caused by these events to be defined and monitored, including damage initiation and progression thresholds. It also provides frequency-based recognition of different types of damage and comparison of its intensity in materials with different reinforcement architectures. The paper reports results of AE registration for 3D non-crimp orthogonal woven (3DNCOW) carbon/epoxy composites. The observed repeatability and spatial distribution of AE events confirm that damage initiation and development are uniform over the tensile sample. The damage characterization by AE is compared with the morphology of damage observed on the specimen cross-sections at characteristic stages of the damage development. The main parameter distinguishing damage mode obtained from the AE registration is the AE energy. It has however been found that the peak frequency of the AE events does not correlate directly with the sequence of the observed damage modes. AE events of high peak frequency, assumed to be related to fiber fracture, suggest that it starts at a later stage than predicted by the Weibull statistics of fiber strength.
Auxetic spacer fabrics are a novel kind of three-dimensional (3D) fabric structure with a negative Poisson’s ratio. They have found a number of applications in functional garments, protective pads and sportive shoes due to their unusual properties. In this paper, a study on deformation behaviors of 3D spacer fabrics that could be fabricated on a large scale is reported. Through experimental observations of deformation of a basic hexagonal unit at different tensile strains, two different geometrical models are proposed for the fabric structure when extended in the course direction and wale direction, respectively. Based on the geometrical models, two semi-empirical equations between the Poisson’s ratio and tensile strain are established for both tensile directions. The study shows that the established semi-empirical equations fit well with experimental results. Therefore, they could be used in the design and prediction of 3D auxetic spacer fabrics with different values of geometrical parameters.
Earlier studies on prickle have been largely fabric based and designed to elucidate mechanisms and also the relative importance of different parameters. The current work has importantly extended the study of prickle from fabric to garment giving for the first time extensive knowledge of wearer responses to garments for a particular market segment. Also the range of fabrics and garments has been extended significantly from the heavier 14-gauge knit structures that formed the basis for the majority of the earlier seminal studies to finer, lightweight 24-gauge structures. The observed prickle responses from the garment studies remain consistent with the existing mechanistic understanding of prickle and confirmed that the forearm fabric test can be used as a useful predictor of relative prickle levels. An analysis of the garment prickle data relative to an overall assessment of a like/dislike assessment of the garments identified that wearers are willing to experience a low level of prickle, that is, beneath a critical level without effecting an overall like/dislike decision. Analysis of the like–dislike data was able to generate, for the first time, quantitative information on the likely percentage of ‘satisfied wearers’ as a function of fiber quality.
The applicability of chitosan, trimethyl chitosan chloride and nano-chitosan for removal of Cu(II) ions from water used in textile wet processing was studied. The liquor before and after treatment was analyzed iodometrically to find the presence of Cu(II) ions, and Fourier transform infrared spectroscopy was employed for the characterization of the chitosan–Cu(II) complex. The study included the effect of molecular weight of chitosan, particle size of chitosan and the degree of quaternization of trimethyl chitosan chloride, pH of the medium, etc., on the sorption of Cu(II) ions. The influence of the molecular weight of chitosan was found to be an important criterion on the rate of sorption of Cu(II) ions. Reduction in the particle size of chitosan enhanced both the rate and amount of scavenging of metal ions.
The effect of the modifier structure and content, as well as the dye structure, on the absorption on montmorillonite nanoparticles has been studied. The discovered dependencies have been used for obtaining nanopigments with high content of the coloring component based on cationic, direct, acid, active or disperse dyes. The effect of the coloring component on photopolymerization of the oligomer/monomer binder is estimated and the optimum compositions of ultraviolet (UV) paints with nanopigments are determined. It has been shown that developed UV paints possess higher light sensitivity compared with conventional organic pigments, and allow a dyed material with increased resistance to rubbing and tensile strength to be obtaining.
Low-torque ring yarn spinning is a modified-ring spinning technology with the false-twisting devices attached on the conventional ring spinning machine. The introduction of the false-twisting operation gives low-torque yarn a new fiber and yarn configuration, and thus causes different characteristics of low-torque yarn fabric from that of conventional ring and rotor yarn fabrics. In this paper, a comparative study has been carried out to evaluate the performance of jeans and trousers produced by low-torque yarns to conventional ring and rotor yarns. The results from the objective measurements of fabric performance indicate that the tensile and tear strength of low-torque ring yarn fabrics in the weft direction is similar to or only slightly lower than that of fabrics using conventional ring yarns with a normal twist level as the weft yarns, but they are much higher than that of the fabrics using rotor yarns. Compared to the fabrics produced from conventional ring and rotor yarns, the low-torque ring yarn fabrics exhibit higher compression energy (WC) and lower mean deviation of friction (MMD) and achieve higher values in fabric Numeri and Fukurami. The subjective evaluation of jeans and trousers through wear trials further confirms that low-torque yarn jeans have significant advantages of a better appearance in jean smoothness, less ‘small snake’ patterns, a more prominent slub effect and better overall quality than the conventional ring and rotor yarn jeans. The low-torque yarn trousers also show better luster, smoothness appearance and overall quality than the conventional ring and rotor yarn trousers.
Proper setting of process conditions in the melt spinning setup is one way to yield uniform quality of spinline tension. The optimum setting to give uniform spinline tension is determined using experiment plans in the Taguchi method and significant process parameters are also identified. When the setting shifts from the optimum, the spinline tension becomes non-uniform and downgrades product quality. This study aims to diagnose single or double fault conditions of those significant process parameters based on the spinline tension signal. The critical procedures of fault diagnosis are feature extraction and classification. The tension signal is decomposed into a wavelet packet tree of four resolution levels. Four entropies from the best-basis wavelet packet tree and the lowest entropy at level four are selected as features. The back-propagation neural network acts as a classifier. The experimental results demonstrate that the features and classifier actually work well to identify the single and double fault conditions with high accuracy in melt spinning.
The low-velocity impact properties of the developed two-dimensional multistitched/micro/nano E-glass/polyester woven composites were studied. It was observed that material type (silicate or carbon or metal), material particle size (nano or micro), amount of materials (weight, %), stitching density (step/cm) and stitching type (hand or machine) influenced the damaged areas of composites. The unstitched/nano and unstitched/micro E-glass/polyester woven composites had small damaged areas in the front face but they had large damaged areas in the back face. The multistitched structure had also a small damaged area in the front face; however, it had a very small damaged area in the back face. The results indicated that the multistitching suppressed the impact energy relatively at a small area. Therefore, the two-dimensional multistitched and multistitched/nano E-glass/polyester woven composite structures showed a better damage resistance performance compared to those of the unstitched or unstitched/nano composites.
The flame engulfment test according to ISO 13506 assesses the protective performance of ready-made heat and flame protective clothing when exposed to a flash fire condition using an instrumented manikin. It uses a thermal model of the human skin to predict the risk of skin burns. This evaluation method is based on a pass/fail criterion, as either a burn is predicted or not. Therefore, it provides only limited information about the transfer of heat through the protective clothing. In this study, we investigated the use of the total transferred energy as an improved characterization method of the performance of the garments. We defined an energy transmission factor as the quotient between the transferred energy on the clothed manikin divided by the transferred energy registered by the nude manikin during calibration. We analyzed the performance of seven garments and show that the energy transmission factors can be assessed with very high repeatability. When comparing the results of the right and left arms and legs, we found very high correlation coefficients of 0.96 and 0.98, respectively, showing that the thermal insulation of the garments tested was very symmetrical. This new assessment method will be proposed for the revision of ISO 13506.
In the field of e-commerce or virtual prototyping of textile fabrics and garments, tactile stimulators could be very pertinent and useful tools for the industry. The challenge is to stimulate the human hand using a tactile device in order to simulate the textile fabric touch. The principle of the tactile device is described. The kinds of fabrics investigated are pile fabrics, such as velvet. In this study, the illusion of pile is given when touching the smooth plate of the tactile device by modulating the coefficient of friction between the plate and the finger during an active movement. The control signal is qualitatively designed from some tribological features identified in this study as velvet fabric characteristics. The influence of each tribological feature on the tactile rendering is studied via psychophysical studies comparing real and simulated fabrics. The best rendering needs a simulation with three specific features: a coefficient of friction, which depends on the finger movement direction; a transition phase for the change of movement direction; and small amplitude variations of the coefficient of friction with about one millimeter wavelength.
Kapok fiber is light, buoyant, and excellent in thermal insulation because of its high degree of hollowness. However, it is difficult to preserve the lumen structure of kapok fiber under repetitive compression in the course of manufacturing and utilization, and then the fiber may lose its unique features quickly. Thus, it is critical to know the resilience of kapok under repeated compression and how it can be affected by environmental factors. In this paper, we studied the compressional resilience of fibrous assemblies made of slightly carded kapok fibers by using an Instron compression tester. The nonlinear compressional behavior of the assemblies was observed in the repeated transverse compressing cycles with a constant compressional strain, and three characteristic stages of the entire compressing cycles—linear elastic, metamorphosis, and densification—were identified. The plastic and the visco-elasto-plastic compressional deformations were characterized from the compressional stress–strain curve. It was found that the conditioning humidity and the number of compressing cycles could affect the compressional resilience of the kapok fibrous assembly, and that the dry-treated kapok fibrous assemblies possessed better resilience and higher strains than the wet-treated ones.
Within the field of composite manufacturing simulations, it is well known that the bending behavior of fabrics and prepregs has a significant influence on the drapeability and final geometry of a composite part. Due to sliding between reinforcements within a fabric, the bending properties cannot be determined from in-plane properties and a separate test is required. The Peirce cantilever test represents a popular way of determining the flexural rigidity for these materials, and is the preferred method in the ASTM D1388 standard. This work illustrates the severe inaccuracies (up to 72% error) in the current ASTM D1388 standard as well as the original formulation by Peirce, caused by ignoring higher-order effects. A modified approach accounting for higher-order effects and yielding significantly improved accuracy is presented. The method is validated using finite element simulations and experimental testing. Since no independent tests other than the ASTM D1388 standard are available to determine the bending stiffness of fabric materials, experimental validation is performed on an isotropic, homogeneous Upilex-50S foil for which the flexural rigidity and tensile stiffness are related. The flexural rigidity and elastic modulus are determined through both the cantilever test (ASTM D1388) and tensile testing. The results show that the proposed method measures an elastic modulus close to that determined through tensile testing (within 1%), while both the Peirce formulation (+18%) and ASTM standard (+72%) over-estimate the elastic modulus. The proposed methodology allows for a more accurate determination of flexural rigidity, and enables the more accurate simulation of composite forming processes.
The cut resistance of organic and inorganic high-performance single fibers has been studied. Several fiber types were examined, including Kevlar, Twaron, Vectran, Technora, Zylon, Dyneema, carbon fiber, and S-glass. Experiments were conducted using a custom-designed fixture that forces an industrial cutting blade laterally into a single fiber at varying blade and fiber angles. The effects of cutting angle and fiber type were explored, and the detailed progression of failure was inferred from post-failure imaging. All organic fibers demonstrated similar levels of cut resistance, with both organic and inorganic fibers showing less cut resistance as cutting angle is increased. Failure in the organic fibers was dominated by the anisotropic structure of the fibers. In contrast, isotropic, inorganic glass fibers demonstrated less cutting angle dependence and failed according to simple, localized brittle fracture. The inorganic fibers demonstrated higher average cut resistance than organic fibers, most likely due to their relative hardness and expected higher transverse mechanical properties.
Human hair keratin/cellulose blend films were prepared in 1-butyl-3-methylimidazoles chloride ([BMIM]Cl) ionic liquid (IL), by the combination of human hair keratin and cotton fibers in different mass proportion, and these films were formed subsequently from the coagulated solutions. The hair/cellulose blend films were prepared by taking different weight ratios of hair and cellulose in ILs, dissolving them individually and mixing them with each other. For example, 90/10 hair /cellulose blends were prepared by mixing hair solution (9 g of 8wt% hair/[BMIM]Cl) and cellulose solution (1 g of 8wt% cellulose/[BMIM]Cl) together to get a mixture solution, and stirring them at 80°C for 1 h in order to ensure complete intermixing. Then hair/cellulose blend films were obtained. The tests indicated that there was a good compatibility between human hair and cellulose in the regenerated human hair/cellulose blends as determined by Fourier transform infrared spectroscopy and transmission of light. The crystallization behavior and scanning electron microscope photograph showed that human hair and cellulose are miscible. The films were analyzed by thermogravimetric and differential scanning calorimetry; the results showed that the blend films exhibited an increasing trend of the mechanical property and thermal stability with increase in cellulose content in the blends. This could be used for the development of keratin-based materials with improved mechanical properties.
A jigger dyeing machine is used to dye fabric across the width, which enables the fabric to be passed back and forth in a perfect dyeing bath. A three-drive jigger dyeing machine contains an injection nozzle system. The flowfield inside the injection nozzle system was computed using ANSYS CFX software and was evaluated by mass flow rate, velocity, and pressure. The injection nozzle system was observed by installing two different division plates and by changing the diameter and distance of the outlet holes to improve dyeing efficiency. The division plates have slits and holes help to distribute the dye liquid evenly over all the holes. The standard deviations of the mass flow rate of the division plates with slits and holes were 0.000551 and 0.000368, respectively. The effects of distance and diameter of the outlet holes were analyzed and evaluated by mass flow rate and standard deviation. The developed injection nozzle system of the jigger machine has more uniform mass flow rate. A diameter of 5 mm for the outlet holes and a distance of 50 mm between them were selected to manufacture a prototype. The prototype of the injection nozzle system of the three-drive jigger machine was manufactured and tested. The test results were compared with the computational results from the developed three-drive jigger dyeing machine, the original three-drive jigger dyeing machine, and a classic jigger dyeing machine.
The expansion of the electronic industry and the extensive use of electronic equipment in communications, computations, automations, biomedicine, space, and other purposes have led to problems such as electromagnetic interference of electronic devices and health issues. For the reasons given above, the demand for the protection of human beings and sensitive electronic and electrotechnic appliances against the undesirable influence of electromagnetic signals and troublesome charges has been increasing. This paper presents the present state of fabrication and characterization of multifunctional high-performance metal/m-aramid hybrid fabrics with increased resistivity to electromagnetic smog while preserving basic properties of textile structures designated for clothing or technical purposes. In this paper, hybrid electromagnetic shielding fabrics made of high-performance fibers are introduced. An effect of metal content is studied and a form of relation between resistivity and total shielding effectiveness is proposed. Furthermore, chosen mechanical properties of developed fabric are evaluated.
The wetting behavior of a hydrophobic rough surface is investigated on a surface fabricated by applying low surface tension materials such as silicone or fluoropolymer to polyester woven fabric consisting of multifilament yarns. The roughness factor of various woven fabrics can be calculated by Wenzel’s and Cassie–Baxter’s equations. For the fabrics treated with silicone or fluoropolymer, the Cassie–Baxter model was applied, showing a level of agreement for the fabric specimens non-textured filament fibers between the predicted contact angles and the measured values. More precisely, the fabrics treated with silicone or fluoropolymer represent the transitional state between the Wenzel type and the Cassie–Baxter type; that is, the fractional contact area between the water and air f2 is greater than zero, and the sum of the fractional contact areas for solid–water f1 and air–water f2 is greater than 1. A surface with lower energy and higher roughness gave f1 + f2 close to 1 with smaller f1 and larger f2 , which resulted in a high contact angle.
A 24 factorial design of experiments complemented with a central point was performed to examine the influence of operating factors on color strength and color fastness of polyethylene terephthalate (PET) fibers dyed with the Disperse Orange 30 dye in supercritical CO2. The effects of temperature, pressure, dyeing time and mass ratio between the dye and PET introduced in the dyeing chamber (α ratio) were considered. An additional set of kinetic results of color strength was obtained at the optimum condition in terms of pressure at the already presented temperatures and α ratios. A significant statistical effect of all the investigated factors on the color was observed, but except for the temperature, the influence of the same variables on wash fastness was negligible (p < 0.05). The color results expressed in terms of K/S from 2.4 to 21.8 revealed that the use of supercritical CO2 as a solvent for the dye is a rapid and reliable alternative procedure for dyeing of PET fibers with the Disperse Orange 30 dye. The results of wash fastness currently obtained (i.e. 4.69 ± 0.18) support the use of ScCO2.
Recent research results have indicated positive influences of inter-yarn friction on ballistic performance of woven fabrics and panels made from such fibers. The current investigation explores the effect of coating by means of atmospheric pressure plasma-enhanced vapor deposition with organic chemical (CH3)2Cl2Si on the inter-yarn friction. The scanning electron microscopy observations indicated that as the treatment time increases, more particles have been deposited on the surface of the fibers. The Fourier transform infrared spectra supported the existence of Si-O-Si vibration, which can be attributed to the chemical deposition. Energy-dispersive X-ray analysis further supported the deposition of the chemical compound. Experiments were carried out to evaluate the coefficients of static and kinetic frictions between the yarns and the results showed that the inter-yarn coefficient of static friction was increased from 0.1617 to 0.2969 and that of the kinetic friction increased from 0.1554 to 0.2436, as the treatment time increased to 4 minutes. In addition, there is evidence that the mechanical properties of the treated yarns were not negatively affected by the treatment.
The effects of conductive polymers on conductivities and morphologies of electrospun fabrics are analyzed. The factors that affect the conductivities and morphologies are discussed. Some applications of these conductive nanofibers are reported. The introduction of conductive polymers into nanofiber mats has the potential to provide sufficient conductivity for many applications. An improved conductivity can be achieved by maximizing the content of conjugated polymers. The selection of conductive and carrier polymers, solvents, doping agents, oxidizing agents and ratios of them are also important to obtain sufficient properties. Carbon fiber, carbon black and carbon nanotubes are not covered in this review.
UK Armed Forces wear items of clothing that incorporate fragment protective fabrics (Tier 1 Pelvic Protection) and other items of clothing are under development (e.g. Improved Under Body Armor Combat Shirt). The long-term robustness of such garments is of interest. In this paper four candidate fabrics (knitted silk, ultra-high molecular weight polyethylene felt, para-aramid felt and a woven para-aramid) were investigated. The effect of laundering on 0.24 g chisel-nosed fragment simulating projectile ballistic protective performance was measured on packs containing the candidate fabrics that were representative of clothing layers. Changes in the physical properties (mass, thickness, dimensional change) of candidate fabrics were measured. The ballistic protective performance of two candidate fabrics was unaffected by laundering; for the other two fabrics improved performance was measured. The masses of the specimen packs was unaffected by laundering; however, the thickness of all fabrics increased, relative to dimensional change.
One of the major purposes of fiber is to protect the body from hazardous environments and keep the body temperature at its normal level. To enhance thermal insulation, specially processed fibers have been produced to form air pockets, or various types of heat storage materials are mixed with polymer fiber filament yarns. In addition to thermal insulation, heat-generating fibers have recently been developed. In terms of heat-generating mechanism, there are two methods: the chemical method in which heat is generated through reaction with sweat, and physical method, which converts kinetic energy into thermal energy through the continuous expansion and contraction of fibers. Unlike these heat-generating methods, a brand-new fiber that generates heat using microorganisms was developed. Heat-generating polyester yarn was successfully produced by combining heat-generating microorganisms and ceramic powder together. New fabrics made with this yarn showed superior thermal properties compared to other specially developed fabrics for good thermal insulation. In addition to this, since ceramic powder is embedded in yarns, the heat-generating function of fiber was found to operate normally despite tens of washing. This process may open up a new possibility for the development of functional textiles.
This paper proposes a theoretical model for maximum hairiness, defined as the number of fiber ends with a certain length in the surface layer of a unit length of ring-spun yarn. These fiber ends have the potential to become protruding hairs, that is, form hairiness of the spun yarn. With consideration of yarn twist, but excluding loops and wild fibers, this model predicts the maximum yarn hairiness or maximum numbers of potential fiber ends with various lengths, which is derived by employing kernel estimation of fiber length distribution. A hairiness contribution factor is introduced as the ratio between the number of fiber ends in the surface layer that potentially contribute to yarn hairiness and the total number of fiber ends in the yarn cross-section. Previous and the present models associated with hairiness or fiber ends are discussed and compared with the measured number of hairs to verify the proposed theoretical model for maximum hairiness of ring-spun yarn.
Shrinkage instability is currently the main difficulty that occurs during the production of cashmere sweaters manufactured with high-count worsted yarns. By evaluating the details at various processing stages, four factors that affect the shrinkage of high-count yarn cashmere sweaters are determined, including the quality indexes of cashmere fiber, the decolorizing process, the yarn counts, and the dyeing process. The shrinkage regularities are shown in these aspects: the longer the cashmere fiber, the lower the yarn/clothing shrinkage; the greater the fiber strength, the lower the yarn/clothing shrinkage; the more the yarn count, the larger the yarn/clothing shrinkage. The shrinkage of natural white cashmere is lower than that of natural color (gray or brown) cashmere. The shrinkage of decolorized cashmere becomes larger than that of natural color cashmere, but the shrinkage of dyed cashmere (especially with weak acid dyes) is even greater than that of the decolorized fiber. These results should lead to the development of some practical processes and appropriate measures to control the high and unstable shrinkage of the cashmere sweater.
There is often a need to dismantle staple fiber yarns into their component fibers, without significantly changing the fiber physical properties, or damaging the fibers in the process, so that the fibers can be tested for their physical properties. In the past, this could only be done by the very time-consuming and tedious manual method. In view of this, an instrument, termed the yarn dismantler, which could automatically dismantle short staple ring-spun yarns, was developed and patented. This paper reports research undertaken on Upland cotton ring-spun yarns to further develop, evaluate and optimize the original demonstration model into a final prototype ready for commercialization. Results are presented which show that, according to Advanced Fibre Information System (AFIS) single fiber length tests, the fibers from automatically dismantled ring-spun cotton yarns are very similar in their properties to those dismantled by hand (manually). It was also found that, at a speed of 2 m/min, the yarn dismantler functioned very well, enabling the length of cotton yarn required for subsequent AFIS testing to be dismantled within an acceptable time of less than 10 minutes, with excellent reproducibility of results and without changing the fiber length properties. According to the test results obtained here, neither steaming the dismantled fiber strand nor the spinning draft appeared to affect the dismantled fiber length significantly, or in a consistent manner.
This paper proposes a particle-based modeling method for predicting the constitutive behavior of textiles when subjected to various compressive loading conditions. The method, which is demonstrated for stacked layers of plain woven textiles, utilizes discrete mechanics as an alternative to traditional continuum mechanics. Fibers are modeled as a series of conjoined points, and their configurations are determined mechanistically using a modified Metropolis algorithm and inter-particle strain energy terms. The implementation presented in this paper enables intricate geometric modeling of textiles at microscopic, mesoscopic and macroscopic scales. It also enables extensive mechanical modeling of the textiles, from first principles, as they are loaded upon manufacturing of typical technical textile structures. While this paper focuses on the compaction behavior of weaves, the modeling method is readily adaptable to the analysis of shear, bending, buckling, punching, relaxation and other loading scenarios applied on a wide array of different textile types. These scenarios will be demonstrated in forthcoming publications.
Comparative data from in silico and in situ testing shows excellent agreement. Results demonstrate an improvement in simulation accuracy over prior comparable modeling techniques. The method presented here successfully predicts the actual behavior of yarns, single-layer and double-layer textile stacks in compaction.
The crystal structures of bacterial cellulose (BC) obtained by cultivation of an Enterobacter species CJF 002 stock under the presence of direct, acid, and basic dyestuffs were examined. Optical microscopic observation showed that direct and basic dyestuffs stained BC samples but acid dyestuff did not. This suggests that direct and basic dyestuffs are contained within the resulting BC samples. Analysis of wide angle x-ray diffraction (WAXD) data indicates that direct dyestuffs inhibited crystallization of BC at dyestuff concentration in culture media (Cdye ) of more than 0.05 wt% with lower angle shift of the diffraction peak for the (200) plane of BC, but almost no influence on BC crystallization in the case of basic dyestuff was observed. In addition, we investigated the crystallinity of regenerated cellulose (RC) from a cuprammonium solution and the reaction of RC with the dyestuffs. The dyestuffs had almost no impact on the crystallinity of RC even in cases where the samples showed staining. It was found that the apparent crystallite size of (110) and (020) in the RC samples with dyestuffs were slightly lower than that in the RC blank sample, while the apparent crystallite size of (1) in the RC samples with dyestuffs retain the values at the same level as the RC blank sample. These results suggest that the cellulose molecular sheets held together by van der Waals interactions were the basic structure formed from RC and they probably retain their structure in the cuprammonium solution at relatively high concentrations of cellulose.
Scouring is the first stage of wool processing and is essential for determining the quality of fiber. Traditional aqueous scouring is a method that emulsifies and removes contaminants (such as wool grease, suint, and dirt) from the fiber surface; however, it promotes wool felting and is energy and water intensive. This study has shown that modification of the traditional wool scouring line by introducing an ultrasonic device could be a viable alternative for the wool scouring industry. A standard six-bath wool scouring line was retrofitted with two ultrasonic panels working at 80 kHz in bath 2. Scouring was carried out in three modes: conventional mode without the transport rake, ultrasonic mode without the transport rake, and conventional mode with the transport rake. Fiber samples after scouring were measured for color index, residual grease content, and residual ash content. Ultrasonic scouring was found to improve removal of grease and ash from the wool fiber. Modifications were proposed for the design of an industrial scouring line including the addition of fiber transport and dunking rollers and number of baths for the installation.
The development of a unique multi-nozzle electrospinning set-up and the study of the effect of an electric field on different types of spinneret are of major concern for broadening the industrial application of electrospinning. In the present paper we describe a novel robot-assisted angled multi-nozzle electrospinning set-up for the mass production of nanofibers and compare the computer simulation and the experimental results for the measurement of the electric field and fiber morphology. Three nozzle configurations, with a 90°, 100°, or 180° angle between the nozzles, and two operating conditions of the nozzle holder (fixed and movable), were studied to observe the electric field strength and its effect on fiber diameter. The results of the electrospinning experiments and electric field simulation demonstrated that the interference of the electric field was greatest with the 90° configuration and the nozzle holder held in a fixed position, whereas when the nozzle holder was movable it was greatest at 180°. The study was carried out using either two or eight nozzles, and the results showed that the electric field remained the same for a given configuration of the nozzle holder and the configuration angle, regardless of the number of nozzles. The study also showed that by controlling the movable nozzle holder and its angle the fiber diameter could be regulated without changing other material or processing parameters.
This study compared reactive dyestuffs and vat dyestuffs in the dyeing of cotton. We investigated the possibility of reuse of the effluent generated, the ecological costs, and the colorfastness to water, rubbing, daylight, and perspiration. The experiments with vat dyestuffs showed slight advantage in terms of ecological costs, generating less molecules of carbon dioxide than the experiments conducted with reactive dyestuffs, lower consumption of energy, and greater possibility for reuse of treated effluent. In addition, vat dyestuffs exhibited decolorization efficiency above 99% and rates of total organic carbon removal over 90% in all cases, in addition to higher values in colorfastness properties.
In this study, chitosan with a specific molecular weight was added into a commercialized waterborne polyurethane to form a polyurethane/chitosan bio-composite emulsion, and this was used to treat wool fabric to obtain an anti-felting effect. The mechanical property of the treated fabric was also measured. The results showed that the addition of chitosan to polyurethane enabled the total dosage of polymer to be reduced by 45% while still retaining the anti-felting properties. The treatment endowed wool fabric with a comparatively soft handle. The influence of the molecular weight of chitosan for this application was investigated. The mechanical properties of films of the polyurethane and the polyurethane/chitosan bio-composite were measured as well as the thermal properties. The tensile strength of the films increased with the addition of chitosan to the polyurethane, but the elongation decreased. The composite films were found to be more thermally stable and degradable than the polyurethane alone.
Wrinkling is one of the most important factors that determine the visual aesthetic of our clothes. To investigate wrinkling characteristics in actual wear and explore the relationship between the wrinkling caused by wearing and testing results of the wrinkle recovery angle (WRA) method, we made a device that can produce wrinkles very similar to those on clothes. Twenty-four fabrics were wrinkled by the device, and the images of wrinkled fabrics were analyzed. Wrinkle density (WD) was defined for wrinkling characterization. In addition, fractal dimension (FD) and gray level co-occurrence matrix (GLCM) variables were also used to describe wrinkling. These features were subsequently correlation analyzed with wrinkle recovery angles in 11 directions. The results show that both FD and WD can be used to characterize the wrinkling behavior and wrinkles generated by the device have obvious fractal characteristics. The larger the wrinkle recovery angle, the lower the fractal dimension. GLCM variables (energy, entropy, contrast, and correlation) had not shown obvious correlation with WRA. Furthermore, the wrinkling behavior in the 45° direction plays an important role in actual wear. It is advised that the WRA in the 45° direction be tested.
In order to explore the accurate image segmentation of fabric defects, we will introduce the visual attention mechanism of the wavelet domain to the dynamic detection of fabric defects. First of all, feature maps are formed by extracting simple features from a collection image. Secondly, feature maps by multi-layer wavelet decomposition are decomposed into a lot of feature sub-maps of the wavelet domain. On this basis, the center-surround operator among feature sub-maps of the wavelet domain is adopted to build the feature difference sub-maps, which are fused into feature saliency maps through fuse strategy. Finally, the defect interest areas are segmented based on the maximum between-cluster variance method in saliency maps, and the fabric defects through the region growing method are detected in the defect interest areas. Comparing with the wavelet transform algorithm, experimental results show that the proposed method is able to segment the defect information completely, and it has a strong ability to resist noise interference, which can improve the accuracy of defect detection.
The color of textile products is mainly controlled during the material production process, e.g. dyeing or printing, using color management protocols. Little attention has been given to researching the color appearance of the textile material applied to final products, where textile material is applied to a shape. The results are reported of research into the color appearance of textile materials of varying material characteristics, color, and geometrical shape to which they are applied. The main focus was on determining color differences between real textile material color and the perceived one. Materials were characterized by their composition, fabric structure, fiber type, thread count, surface characteristics, and glossiness. Samples of red, blue, orange, violet, and green color were chosen as the most frequently used colors in real application. Textile materials were applied on three differently shaped objects (flat surface, cube, and cylinder). The object color was determined by objective instrumental measurements as well as subjective judgment. A specially constructed light chamber was used to ensure constant experimental conditions. Data were subjected to statistical analysis in order to determine differences of each CIE Lch color coordinate. Results indicate significant effects of objects shape on color appearance.
There are technological limitations in the processing of smooth, slippery and rather flat multifilament viscose rayon yarn. The present work describes a shorter route for viscose rayon modification through mechanical crimp texturizing. Texturizing was performed with different pre-twists and optimized texturizing twist. This work describes a shorter and cost effective route for viscose rayon modification through mechanical crimp texturizing. The prepared texturized viscose rayon yarn has achieved the desirable structural characteristics of spun yarn as depicted in SEM micrographs. The textured yarn has retained an almost identical fineness with the parent yarn. Unlike air jet texturizing, mechanical crimp texturizing has benefits in terms of retro-processing of costlier viscose rayon yarn. Although it was textured, it has not shown any significant drop in tenacity and, apart from that, shows enhanced the elongation property compared to the parent yarn.
Aqueous extract of gallnut is well known to have remarkable antioxidant and antibacterial activities. Gallnut is expected to be a safe antibacterial agent for textile application because it is a non-toxic natural substance. Thus, we applied gallnut extract to cotton fabrics using an infrared dyeing machine and a pad-dry-cure process, in order to develop multi-functional clothing material with no harmful side effect. Through this study, we found the optimum condition (via a pad-dry-cure process at 120°C/15 min) for the gallnut extract treatment of cotton fabrics. The surface appearance, mechanical properties, antibacterial ability, and antioxidant performance of the treated cotton fabrics were thoroughly investigated. Consequently, it was found that antibacterial and antioxidant cotton fabrics were obtained via the gallnut extract treatment.
Textile structures made of biocompatible, osteoconductive and resorbable chitosan-filaments provide excellent preconditions as scaffolds for Bone Tissue Engineering applications. The novel Net Shape Nonwoven (NSN) technique that enables short fibers to be processed into three-dimensional net-shaped nonwoven structures with adjustable pore size distributions is described. NSN scaffolds made of pure chitosan fibers were fabricated. NSN hybrid scaffolds for improved initial cell adhesion were realized by combining the NSN technique with electrospinning and dip-coating with collagen, respectively. Scanning electron microscopy and liquid displacement porosimetry revealed an interconnecting open porous scaffold structure. The novel chitosan-hybrid scaffolds provide proper conditions for adhesion, proliferation and differentiation of the seeded human bone marrow stromal cells, proving that they are suitable for usage in hard-tissue regeneration.
All thin materials, such as textiles, papers, polymers, or metals, are handled on rollers during manufacture and subsequent use. This requires several unwinding and winding processes. The goal of this study was to investigate the friction behavior of fabrics relative to sliding velocity and to introduce friction coefficient evolution in a fabric transport model. For the experimental part, a specific fabric/roll friction bench is presented. The friction coefficient was calculated from the capstan equation. The evolution of the friction coefficient was quantified relative to the sliding velocity for different textile fabrics and also for a polymer and a paper web. The influence of some measurement process parameters was studied: web tension, roll diameter, and wrap angle. The friction coefficient initially increased with sliding velocity and then became constant. This phenomenon can be explained by the deformation of the fabric due to friction, thereby inducing an increase in web tension with the sliding velocity. The relationship between tension and rolling friction behavior of the fabric was investigated. The variability of the friction coefficient was introduced to web/roll simulator, and improvements to the simulator are shown.
The seven azole compounds, econazole nitrate, sulconazole nitrate, miconazole nitrate, thiabendazole, epoxiconazole, propiconazole, and tebuconazole, were applied to wool fabrics at 3.0% on mass of wool and the protection from wool-digesting Tineola bisselliella (common clothes moth) larvae was assessed in bioassays. Econazole nitrate gave the greatest protection according to Wools of New Zealand Test Method 25, easily passing the bioassay. Other good results with sulconazole and epoxiconazole led to further bioassays being performed with Australian carpet beetle larvae Anthrenocerus australis. Propiconazole provided the most effective protection of wool from this species, with a concentration of approximately 0.4% on mass of wool predicted to give adequate insect resistance. A combination of propiconazole and isoniazid was trialed against Anthrenocerus australis, without any synergistic effect. The antiprotozoal compound pentamidine isethionate had no measurable effect on Anthrenocerus australis larvae, but provided a moderate anti-feeding effect on Tineola bisselliella. Antimicrobial compounds could affect the digestive process of wool-digesting insects either directly or by their effects on any gut flora and/or fauna. Azoles are antifungal compounds, and are likely to disrupt the insect utilisation of cholesterol by inhibiting the cytochrome P450 enzymes. Propiconazole was trialed as a dyebath-applied insect-proofing agent on piece-dyed carpet, showing inefficient uptake onto wool, but good fastness to carpet shampooing and light exposure.
The hydroentanglement process is highly energy intensive compared to other methods of manufacturing nonwoven fabrics. This paper presents an exploratory study on optimizing the usage of hydroentanglement energy so as to lower the processing cost. The experiments were based on a Box–Behnken experimental design (BBD) and multivariate linear regression analysis to model the tensile strength as response to variables. Three variables were selected, namely fabric area weight (150–400 g/m2), machine speed (5–15 m/min) and waterjet pressure (40–200 bars). These parameters were employed in two sets of experiments to achieve maximum tensile strength of viscose nonwoven fabrics. The first experiment was conducted using higher waterjet pressures of 100, 150 and 200 bars, which were proved to have exceeded the optimum levels. The second experiment was conducted at relatively lower waterjet pressures of 40, 60 and 80 bars. The results on tensile strength were analyzed using the SYSTAT 10 software package and response surface plots were prepared. The linear, quadratic and interactive effects of the main variables were shown to be significant. Interactions amongst the variables were found to have either a synergistic (positive) or offsetting (negative) relationship with the fabric tensile strength. The interactions involving machine speed were predominantly offsetting. The 400 g/m2 area weight fabric produced at 80 bars of waterjet pressure achieved a fabric tensile strength of 222 cN, which compared favorably with that of 232 cN obtained at 200 bars of waterjet pressure. In this exploratory study using BBD, linear, quadratic and interactive effects were observed to be significant and the usage of hydroentanglement energy was successfully optimized. This indicates the possibility of achieving high fabric strength but at lower waterjet pressures; in other words, by employing low hydroentanglement energy and thereby minimizing the processing cost.
An earlier study confirmed the influence of cotton fiber length characteristics on the High Volume InstrumentTM (HVI) strength measurement and devised a quantitative correction factor to compensate for the effect. The current paper investigated the validity of two important assumptions utilized in the previous study. Firstly, single fiber testing confirmed that the particular sample preparation method used to generate samples of different fiber length characteristics from a common cotton sliver did not introduce any inherent damage to the fibers (and so this could not be the explanation for the observed trend in measured fiber strength as a function of fiber length). Secondly, the positioning of the jaws relative to the beard in the HVI strength measurement was explored. This positioning was found to be quite variable for replicate measurements on the same cotton being a function of the size of each individual beard. The average positioning between the different samples was found to be similar and this validated the assumption and approach used previously for deriving the correction factor for that particular sample set. Characterizing the position of the jaws was extended using a wider range of cotton samples. The HVI positioning algorithm appears to not simply be a function of the size of the beard (i.e. the ‘amount’ parameter), but is also dependent on fiber length characteristics. It was also observed that the reported HVI elongation values displayed both a significant bias due to fiber length and also a dependence on the size of individual beards tested.
Research in modeling and simulation of woven fabrics has been quite intensive in the past decade. The simulation studies presented confined consideration of crimp and extension roles in the damage deformation process, in particular tensile and puncture. Most simulation works are struggling to relate internal yarn interactions with respective damage modes due to the unit cell approach. Hence, in the present study, an alternative finite element analysis approach was proposed to model yarn crimp and extension response during puncture based on the validated uniaxial tensile and puncture models. Puncture stress–strain, post-impact kinetic energy and damage evolution of full-scale woven fabrics models were evaluated with two impactor shapes and three friction levels. The results show that puncture damage behavior is the critical dependent of the magnitude of impactor shapes and yarn frictional contacts. Good comparisons with the experimental and previous studies demonstrate the approach’s suitability for modeling textile in composites.
Flame retardant polyamide 6 (nylon 6) nanocomposite nanofibers containing montmorillonite clay (MMT) platelets and intumescent non-halogenated flame retardant (FR) additives were processed by electrospinning. Different methods of mixing nano fillers before electrospinning were explored and compared. It was found that high loadings of nanoclay particles affected the electrospinnability of the nanocomposite material. Good dispersion and exfoliation of nanoclay platelets within individual nanofibers was verified by transmission electron microscopy. The degradation temperature of nanocomposite samples was lower than pristine nylon 6 samples. However the degradation of all nanocomposite formulations was overall slower. Moreover, the difference in residual char weight after decomposition was significant. Microscale combustion calorimeter results show that FR particles played a major role in reducing flammability of the material in both solution- and melt-compounded samples, while MMT nanoclay was effective in improving char residue and in reducing flammability in high-shear melt premixed samples.
In this study, conductive fabrics were developed by polymerizing aniline onto polyester (PET) woven fabrics. The fabric treatment was carried out by the chemical polymerization method at 0.5 M, 0.8 M and 1.2 M aniline concentrations. Hydrochloric acid as acidic medium and ammonium persulfate as oxidant were employed during the polymerization process. The polyaniline (PANI)-treated PET fabric structures were fully characterized and evaluated in terms of their electromagnetic shielding effectiveness, absorption and reflection characteristics, and tensile properties. Additionally, the fabrics were examined by scanning electron microscopy for their surface morphology and Fourier transform infrared spectroscopy for their chemical functionality. The electromagnetic shielding effectiveness and absorption and reflection characteristics were determined using a network analyzer with a frequency range from 15 MHz to 3000 MHz. The electrical characteristics were measured by the two-end method. It was concluded that the tensile strength values of the treated fabrics were enhanced when the amount of monomer in the concentrations increased as compared to the untreated fabrics. It is interesting to note that 1.2 M treated fabric had the lowest tensile strength values as compared to the other treated fabrics. It was also found that a 0.5 M concentration of PANI-treated fabric had the lowest surface resistivity since it showed the highest conductivity value. Another important finding is that the 0.8 M aniline-treated fabric had the highest shielding effectiveness.
Analysis of textile materials often includes measurement of structural anisotropy or directional orientation of textile object systems. To that purpose, the real-world objects are replaced by their images, which are analyzed, and the results of this analysis are used for decisions about the product(s). Study of the image data allows one to understand the image contents and to perform quantitative and qualitative description of objects of interest. This paper deals in particular with the problem of estimating the main orientation of fiber systems. Firstly, we present a concise survey of the methods suitable for estimating orientation of fiber systems stemming from the image analysis. The methods we consider are based on the two-dimensional discrete Fourier transform combined with the method of moments. Secondly, we suggest abandoning the currently used global, that is, all-at-once, analysis of the whole image, which typically leads to just one estimate of the characteristic of interest, and advise replacing it with a "local analysis". This means splitting the image into many small, non-overlapping pieces, and estimating the characteristic of interest for each piece separately and independently of the others. As a result we obtain many estimates of the characteristic of interest, one for each sub-window of the original image, and – instead of averaging them to get just one value – we suggest analyzing the distribution of the estimates obtained for the respective sub-images. The proposed approach seems especially appealing when analyzing nonwoven textiles and nanofibrous layers, which may often exhibit quite a large anisotropy of the characteristic of interest.
The purpose of this study was to investigate the effects of wind (0, 1.1 m/s) and clothing apertures (not closed, closed hem, closed hem and neck) and the combined effects of them on local clothing ventilation rates and localized thermal insulation. Nine working jackets with identical design but different garment sizes and fabric permeability were made. The results showed that wind and clothing apertures had distinct effects both on the local ventilation rates and the local thermal insulation. The local ventilation rates of the right arm were largest at 1.1 m/s wind speed with the clothing hem closed. Chest and back ventilation rates were higher at wind than at no wind. Closing the garment hem affected the local thermal insulation of the impermeable garments mostly. In addition to wind and garment apertures, garment sizes and fabric permeability also impacted the local ventilation rates and the thermal insulation.
A shear thickening fluid (STF) was prepared from SiO2/PEG200 by ball-milling and its effect on the sound insulation properties of textile materials investigated. The rheological properties of the STF were evaluated using a high-speed rotary rheometer and a field emission scanning electron microscope. Fabrics based on fibers of profiled cross-section were knitted on a computerized flat knitting machine, then dipped in the diluted STF and the microstructure and the sound insulating properties of the STF-treated fabrics were established using a two-channel acoustic analyzer. It was found that an increase in the SiO2 content of the STF decreased the critical shear rate, and the thickening effect of the STF system became effective once the SiO2 content reached 30 wt%. The sound insulation performance of the STF-treated fabrics was superior to that of the untreated fabrics, and their level of sound insulation level was particularly increased with increasing surface density.
A new objective method has been developed for the identification of animal hair fibres, in particular wool, cashmere and yak. Enzymatic digestion of keratin extracted from these fibres and peptide analysis by ultra-performance liquid chromatography/electrospray–mass spectrometry (UPLC/ESI–MS) allows not only qualitative determination of the presence of fibres derived from these species but also a quantitative assessment of the relative percentages present in blends. Such an analysis will provide reliable objective data about the authenticity of commercial products. The effectiveness of the UPLC/ESI–MS method was assessed by analysing known samples of these fibres and confirmed using unknown wool/cashmere/yak blends, and the results were compared with those obtained by SEM method IWTO 58–00.
The secondary structure and compliance of a novel small caliber (≤6 mm) silk fibroin (SF) tubular scaffold (SFTS) were investigated. Imitating the structure of natural vascular tissue, the SFTS consisted of a silk knit as the medium and a poly(ethylene glycol) diglycidyl ether (PEG-DE) cross-linked silk fibroin (SF) membrane as the intimal and adventitial layers, integrated to form a porous tissue. FTIR and XRD results showed that PEG-DE could induce SF molecules to form β-sheets during the cross-linking reaction process, resulting in improved crystallinity. As a result of the silk knit medium the SFTS had excellent mechanical properties. The intimal layer, which is in contact with a continuous flow of blood, must have adequate compliance. The results showed that the intimal layer of the SFTS had good stress-strain resistance when combined with the silk knit medium. When the SFTS was prepared with 6% SF, its axial breaking strength was >62 kPa and breaking elongation could reach about 33%; the circumferential breaking strength was >10 MPa and breaking elongation was >18%. The results of compression testing showed that the radial compression resilience of SFTS reached 94%, which was a significant improvement on commercial artificial blood vessels prepared from Dacron.
The thermal performance of firefighters' protective clothing entrapping multiple air gaps and exposed to low heat fluxes has been studied using a newly designed bench-scale test apparatus. Different air gap sizes (0, 2 and 5 mm), and entrapped positions within the multiple fabric system between the outer shell, the moisture barrier, and the thermal liner, respectively, were investigated at three levels of thermal radiation (2, 5 and 10 kW/m2) over a prolonged period. The effect of air gap size and its position on the heat transfer in a multilayer fabric system are interpreted in terms of a theoretical flat multi-wall structure. The results show that the thermal protective performance of a multilayer fabric system is reduced under low-level heat flux with and without an air gap. It is indicated that the time for skin to burn in direct contact with the inner layer is increased with the size of the air gap, due to an increase in the total thermal resistance of the fabric combination and a decrease in heat radiation between two adjacent fabric layers separated by an air gap. The results also provide an insight into the contribution of the thermal resistance of each fabric layer and each air gap to the overall protective effect of the clothing system. The difference in the received heat flux with different air gap sizes in different positions shows that the effect of air gap size is related to its position.
Helmet security relies on a retention system that is usually manufactured from webbing. In many helmets (e.g. bicycle, climbing) this is polyester or nylon webbing. In UK military helmets, cotton webbing is currently used for the retention system, including the chin-strap. Cotton is the preferred fiber content rather than a synthetic-polymer fiber due to the potential melt hazard of the latter. Whether the retention system of military helmets is strain rate sensitive at quasi-static and dynamic rates and whether the webbing degrades when exposed to ultraviolet radiation (UVR) are of interest with reference to current conflicts. This paper (i) presents data on quasi-static tensile properties at varying strain rates, (ii) describes a method developed to measure the dynamic tensile strain rate sensitivity and (iii) uses that method to determine the effect of simulated UVR exposure on dynamic tensile properties of cotton webbing typical of that used in UK military helmets.
This paper presents an experimental study of the protective properties of warp-knitted spacer fabrics developed for protecting the human body on impact. A drop-weight impact tester was used to test the fabrics in a hemispherical form to simulate the use of impact protectors in real life. The study consists of two parts. The first part, presented in the current paper, focuses on the impact behavior of a typical spacer fabric impacted at different levels of energy. The analysis includes the impact process and the energy absorption and force attenuation properties of the spacer fabric. Frequency domain analysis is also used, to identify the different deformation and damage modes of the fabric under various levels of impact energy. The results show that the impact behavior of the fabric under impact in the hemispherical form is different from that in the planar form. The results also indicate that the curvature of the fabric can reduce energy absorption during the impact process and therefore reduce the force attenuation properties of the spacer fabric. This study provides a better understanding of the protective properties of spacer fabrics. The effect of fabric structural parameters and lamination on the protective properties of spacer fabrics under impact will be presented in Part II.
The aim of this study was to develop three-dimensional (3D) fully interlaced representative circular woven preform structures and to understand the effects of weave pattern and number of layers on 3D circular woven structures. Various 3D circular woven preforms were developed. Data generated from these structures included yarn-to-yarn space, density, yarn angle, yarn length and crimp.
It was shown that the weave patterns affected the 3D circular woven preform structures. The yarn-to-yarn spaces in the 3D fully interlaced circular structures were high compared to the traditional 3D orthogonal circular woven structures in fabric circumference (fabric outside surface) due to the interlacement of the yarn sets. The 3D plain, twill and satin structures resulted in axial angle (a) in fabric length; circumferential angle (c), and interlaced radial angle (ri) in fabric circumference and fabric diameter due to the axial-circumferential and axial-radial interlacements. The weave patterns slightly affected the yarn angles. On the other hand, it was observed that the number of layers considerably affected the radial arc length and the radial length in wall thickness in the 3D circular woven structure.
The interlacement on 3D plain, twill and satin circular woven structures resulted in axial crimp, circumferential crimp and radial crimp. The crimps in the 3D fully interlaced circular woven structures slightly depended on the types of weave pattern and the number of layers.
A new steeping method is put forward in this paper, in which steeping assistant is added into the solution during the vacuum permeation for the treatment of silk slices on small reels. With this new method, the traditional process of steeping raw silk and drying can be omitted. Orthogonal array L16 (43) is used to study the new method. The result shows that the optimal technological parameters are 2 h, 1.25% and five times for balance drying time, assistant concentration and vacuum number, respectively. The test indicates that the properties of silk slices show no significant difference between steeping on small reels and conventional steeping, and the new process of steeping silk slices on small reels can mostly meet the technological requirements of steeping. It is also found that the properties of knitted fabric produced by the new steeping method and conventional steeping method are quite similar to each other. However, some special properties of the former, such as abrasion resistance, bursting strength and draping, are better than the latter. Compared with the conventional steeping of raw silk, the new steeping method has lower cost and higher efficiency.
This study focused on the production of heat storage materials from cotton wastes by incorporating a phase-change material and determination of their thermo-regulating properties. Polyethylene glycol (PEG) was grafted onto a cellulosic cotton backbone to give solid–solid phase change properties. The change in the surface morphology of the fibers was studied by scanning electron microscopy. Chemical characterization of the fibers was carried out using Fourier-transform infrared radiation spectroscopy. Thermal analysis of the modified fibers was performed by differential scanning calorimetry, and the thermal regulating properties of the PEG-grafted fibers were investigated using a thermal history system comprising insulated boxes, temperature sensors and a data-logger. Static thermal insulation measurements were also carried out on the fibers. The PEG-grafted cellulose fibers were shown to absorb up to 33.8 J/g heat at 33.0°C, releasing 31.5 J/g heat at 29.4°C, during the phase transitions. Thermal history results showed that temperature of the box containing PEG1000-incorporated fiber differed by 1–1.5 ± 0.1°C from the temperature of the box containing untreated cotton fibers over 23–25 minutes. Based on these results it is concluded that PEG-grafted cellulose has sufficiently high energy storage properties to be employed as a thermo-regulating material.
Woven cotton fabric was chemically modified by a self-made cationic modifying chicken feather keratin agent (named WLS-10). The dyeing dynamics property and the dyeing effectiveness of the modified cotton fabric dyed with reactive dyes in the absence of salt were explored and compared with that of the unmodified cotton fabric dyed with reactive dyes in the presence of salt. The structures of the WLS-10 agent and the modified cotton fabric were characterized with Fourier transform infrared spectroscopy and scanning electron micrographs. The results showed that the dyeing rate of the WLS-10 modified cotton was higher than that of unmodified cotton dyed with reactive dyes, despite the addition of large amounts of salt in the latter case. In addition, the chemical structure and the surface morphological structure of the modified cotton fabric were different from that of the unmodified cotton fabric.
Apparel fabrics are constructed of large numbers of fibers, spun into thread and woven and treated with sizing into final structures, giving rise to a number of different surface properties. A method to record and analyze the friction sound emitted from model fabrics (uniform, single-fiber polyester meshes) and apparel fabrics was developed and the relationship between microstructure and the sound emitted was established. The effect that surface modification (conditioning) has on sound emission was also investigated.
Fabric sounds were captured as a result of friction, producing sound spectra (frequency versus amplitude), from which total noise could be calculated. This was compared to the fabrics’ microstructure. The shape of the sound spectra varied as a result of the structure of the model fabrics, with experimentally measured frequencies being comparable to predicted frequencies calculated. It is possible to produce a ‘fingerprint’ of acoustics, based on the thread diameter and aperture size of single-fiber structures.
Spectra produced for apparel fabrics were broader than for the model fabrics (possibly as a result of the multifiber structure), and the level of total noise differed between the three fabrics, with total noise being strongly correlated to surface roughness and weight. A relationship between the total frictional noises emitted from surfaces of different materials has previously been investigated.
Conditioning fabrics, no treatment and desizing the fabrics did not have a significant effect on surface roughness, weight or total noise.
The antibacterial activity of ZnO is reported by several authors. We present the preparation and application of inorganic–organic hybrid polymers modified/filled with ZnO nanoparticles of varying particle sizes. Inorganic–organic hybrid polymers employed here are based on 3-glycidyloxypropyltrimethoxysilane (GPTMS). ZnO is prepared by hydrolysis of zinc acetate in different solvents (methanol, ethanol or 2-propanol) using lithium hydroxide (LiOH c H2O). The hybrid materials prepared are applied to cotton (100%) and cotton/polyester (65/35%) fabrics. The antibacterial performance of these sol-gel derived hybrid materials is exemplarily investigated against Gram-negative bacterium Escherichia coli and Gram–positive Micrococcus luteus. Effects of particle size and concentration for the antibacterial performance are examined. Literature discusses various (active) species and processes responsible for the antibacterial action of ZnO. Therefore, particular attention is paid to investigate active species available in the described systems as well as to observe possible interaction between the nanoparticles and bacteria; the first results are presented.
Bast fiber contained in cotton stalk, a residue from the growth of cotton fiber, is available in very large quantities, estimated at more than 15 million tonnes annually. The stalk is currently burnt or buried into soil. In this study, bast fibers were extracted from cotton stalk using a mechanical decortication method. The morphology of single bast fibers, also known as ultimates or ultimate fibers, were characterized by an effective diameter and a cell wall thickening factor (maturity) derived from a concentric circle model reconstructed using an image analysis technique. Fiber cells within the same plant are quite consistent in diameter but can vary considerably in maturity depending on their position in the plant. Eighty percent of the bast fibers were contained in the lower half of the stalk where the fiber maturity was high. Cotton bast fibers are as strong as other bast fibers, such as jute and hemp, and can be used as reinforcement for polymer composite materials.
The effect of different aqueous emulsions of vegetable oils on the wrinkle recovery properties of 100% cotton fabric was investigated. Six vegetable oils (rapeseed oil, olive oil, coconut oil, safflower oil, linseed oil and modified sunflower oil) with different fatty acid profiles were used. The results prove that the fatty acid profile is an important factor affecting the wrinkle recovery properties of treated cotton fabrics. In general, higher concentrations of the active agent (vegetable oil) provide better wrinkle properties for treated cotton fabrics. The results suggest that better recovery from wrinkle deformation is due to the formation of a micro-film around the fibers and yarns that reduces the friction coefficient.
For analysis that better monitors the complex process of fiber relaxation after deformation, an optical wrinkle tester based on grazing light analysis was developed. The technique allows more precise scanning of textile surfaces and measuring of small increments of wrinkle recovery after a spray treatment, for example. The optical wrinkle tester offers the possibility of time-dependent measurements to follow the kinetics of wrinkle relaxation and, for the first time, gives access to kinetic profiles of fiber relaxation.
The yarn suction gun is a kind of fluid machinery using compressed air as power. Airflow geometry in the gun has a significant influence on the airflow distribution, which decides the yarn suction performance. To clarify the effect of the nozzle structure on the yarn suction performance, we designed 16 nozzles, determined yarn suction force F, mass flow rate of compressed air G and analyzed yarn suction efficiency , which is defined as the ratio of F to G. The rational geometrical parameters are obtained as follows: the number of jet orifices N = 3, jet orifice diameter d = 1.6 mm, jet orifice angle = 75° and passage diverging angle of the nozzle = 60°. A smaller N reduces the conflict between jet streams and then increases . Decreasing d contributes to greater but smaller F. In the range of ≤ 75, increasing causes both F and to increase. An appropriate promotes the yarn suction performance by helping the injected air to go forward smoothly and reducing backflow. It is more rational to use to evaluate the yarn suction performance.
Types of fabric movement inside a front-loading washer were analyzed in order to examine their effect on washing performance. A high-speed camera was used to record and track the outlines of the fabric inside a washer, and 13 movement indexes were derived. From this observation, fabric movements were divided into four categories, and the relationship between fabric movements and washing performance were examined. It was shown that the mechanical force from the complex movement where diverse fabric movements were mixed was stronger than that from the simple movement where only single fabric movement appeared. With regard to the detergency, it was also shown that complex movement was more effective than single movement. For fabric with a lower drape coefficient, there seemed to be a greater potential to generate more flexing under similar mechanical action, therefore resulting in higher washing performance.
This paper reports the development of a hexagon resistance model, based on the loop structure of a plain weft knitted fabric. This model is capable of describing the electromechanical properties of conductive knitted elastic fabrics. Based on the relationship between the resistance and the load on the fabric under biaxial extension, the equivalent resistance of the fabric was obtained by solving the circuit network equations. It was found that the circuit network is a multiple circuit parallel to the wale direction whereas it is in series along the course direction. And Holm’s electrical contact theory is used to calculate the relationship between the contact resistance and the contact force in an elastic fabric sensor. The contact load and deformation between two knitting loops are calculated using the classical knitted fabric mechanics model of Kawabata and Popper.
Conductive textiles are fabrics that include conductive yarns woven into or conductive tracks printed on to the textiles. Conductive textiles have attracted significant attention, since they are fundamental for the integration of electronic functions to achieve wearable devices. Screen printing is a well-established and cost-effective fabrication method; it enables a versatile layout of conductive tracks. The limitation of the current screen-printed conductive textiles is low durability to weathering, abrasion and washing. This paper presents a process for producing a waterproof and durable conductive textile using only screen printing. A three functional layer design was used to fabricate the durable conductive tracks. Firstly, an interface layer was printed to provide a smooth surface for subsequent printing, under-side protection and electrical insulation. Next, a silver layer provided the conductive track and finally an encapsulation layer was printed on top to provide upper-side protection and electrical insulation. The printed silver tracks achieved maximum conductivity using a single print. The conductivity of the silver tracks returned to its original value when they were dried after soaking in water continuously for 24 hours.
An optimization design simulating the electro-mechanical property of the conductive elastic knitted fabric is built based on a loops structure under biaxial extensions. A computer program can give the fabric equivalent resistance, which is obtained by solving the circuit network equations. So, it can simplify the computational process immensely. In order to simplify the calculation of the contacting forces on the overlapped yarns, two hooked yarns are used to represent the loop configurations. From the theoretical analysis and experimental investigations, it is found that the resistance changing due to the yarn segment transfer is the key factor for the sensitivity of elastic fabric sensors. This makes the resistance linear increasing with the strain increasing. Analysis of the experimental results show that change in the resistance of a fabric sensor due to the contact resistance has a minor contribution to the sensitivity of the sensor in the large-strain regime. Also, the fabric structure and the yarn elongating affect the characteristics of the fabric sensor.
Wearable textile-based stretch sensors for health-care monitoring allow physiological and medical evaluation without interfering in the daily routine of the patient. In our previous work, we successfully coated viscose and polyester (PES) fibers with the conjugated polymer poly(3,4-ethylenedioxythiophene) (PEDOT), using a chemical vapor deposition (CVD) process. In the present paper we report the possibility of producing a large quantity of PEDOT-coated conductive fibers with acceptable mechanical strength and frictional properties, so that knitted stretch sensors can be produced. In utilizing these knitted structures we have demonstrated the possibility of producing a textile-based monitoring device which is more readily integrated into wearable clothing than the previous metal-containing structures. The performance of viscose and PES knitted structures as stretch sensors has been investigated using a cyclic tester of our own design. For imitation of respiratory and joint movement, the variation in electrical properties of the knitted structures was examined at 5 to 50% elongation, and the performance of knitted viscose and PES structures was then compared on the basis of the cyclic testing results. In order to determine the effect of washing on PEDOT coatings and the knitted structures, two washing cycles were performed. After washing, the persistence of PEDOT coating on knitted structures was investigated using FT–IR spectroscopy and thermogravimetric analysis. In the case of PES fiber, it was revealed that stretch sensing behavior persisted even after the washing cycles. These structures thus have the potential to be utilized in medical textiles for monitoring the physiological activities of patients, such as breathing rate and joint movement.
Current customized fenestrated devices require a fabrication delay of 4–6 weeks and therefore cannot be considered for the treatment of emergent or urgent aortic pathology. A flared textile cuff capable of better sealing the connection between a stent-graft fenestration and a branching stent-graft could bring more flexibility in treating patients with peri- and juxta-renal abdominal aortic aneurysms. Four different flared textile cuff prototypes were fabricated by compression molding of woven fabrics having structure similar to those of commercially available devices. Each cuff comprised a flat collar as a base, an arc as a curved section, and a top as a regular fabric tube. The fabric count, density, and thickness decreased from the first to the third sections and the results differed according to the structure. The physical and mechanical properties of these flared fabric cuffs were similar to those found in commercially available stent-grafts. The flared textile cuffs showed a scope of properties adapted for easier delivery and are acceptable to various sizes and shapes of fenestration. The development of flared textile cuffs represents a considerable advancement in endovascular therapy: (1) allowing a fenestrated solution to be readily available off-the-shelf; (2) providing an adequate seal of the ancillary stent-graft to the main body of the stent-graft.
This paper presents the tensile behaviors of polytetrafluoroethylene (PTFE)-coated fabrics subjected to monotonous and cyclic loading. First, uniaxial tensile tests are conducted to study the uniaxial cyclic behaviors, in which the effects of stress amplitude and temperature on the fabrics are studied. Then, biaxial tests are carried out to analyze the biaxial cyclic behaviors with different stress ratios. Finally, the mechanical properties of PTFE-coated fabrics without initial loading and after cyclic loading are compared. The results show that the tensile behaviors of PTFE-coated fabrics are asymmetric and affected obviously by loading protocols, which are concerned with the woven structure of substrate and properties of yarns. After cyclic loading, the significant stiffness strengthening and the linearity of tensile behaviors becomes obvious, while the discrepancy between the elastic modulus of the warp and the weft decreases. Compared with the new material without initial loading, the material tensile strength after cyclic loading remains almost unchanged, which may be related with fewer cycle numbers. The tensile behaviors under cyclic loading are mainly related with stress amplitude, temperature and woven structure of substrate. With temperature increasing, the degree of stiffness strengthening after cyclic loading increases. The effect of loading history on the mechanical properties of PTFE-coated fabric is obvious, and different constitutive constants should be conducted regarding different design stages.
The effect of laser technological parameters on the color of denim fabric is a topic of research for scientists in various countries. More detailed investigations, which would estimate the effect of several main laser technological parameters on the color, taking into account morphological fabric modifications, have been yet to be performed. Therefore, the aim of this study was to define the effect of laser technological parameters on the color of denim fabric. In the research, denim fabric was used with the following fiber content: 98% cotton and 2% EL, surface density 357 g/m2, weave – twill 3/1. The specimens were treated using a CO2 laser, with changing beam power and motorized drive parameters – the speed and step. Using a spectrophotometer, the change of the fabric surface color, E, and color system, HSB, were determined both before and after laser treatment. Morphological analysis of the fabric was carried out uing a scanning electron microscope. The research showed that the color change, E, of the laser-treated specimens is different in the warp and weft directions. The highest E was reached while changing the beam power. The largest effect on the change of color hue, H, and color saturation, S, amongst all tested laser technological parameters was found for laser power. Color brightness, B, was mostly affected by laser step size, when laser energy density is ~6 mJ/cm2.
Research into new textile transmission lines is currently being conducted. Thanks to the flexibility of textile material used for their construction, these lines can become elements of a textronic system incorporated in modern smart garments to considerably enhance the comfort of its use. Textile transmission lines are required, however, to meet some specific requirements. A properly designed line should assure the minimum of signal losses and reflections. The normalized characteristic impedance of lines is assumed to be 50 ohms. This paper presents a new type of textile transmission lines. A method for measuring the line impedance is discussed. The construction of a measuring stand to be used for testing the electric properties of textile transmission lines is shown. Using artificial neural networks, a model for selected electric properties of textile transmission lines was obtained. The results of a sensibility analysis carried out based on the three-layer perceptron indicates a significant influence of selected model input quantities, such as the width of the inner conductive path, the distance between paths, path surface resistance, path thickness, and the number of warp and weft yarns occurring in a conductive path on the electric properties of textile transmission lines.
The purpose of this study is to fabricate self-cleaning textiles with photocatalyst excited by sunlight irradiation. Self-cleaning textiles were realized by coating carbon nanotube (CNT)-TiO2-acrylate copolymer on cotton and nylon fabrics using the dip-pad-dry process. The effect of CNT addition to TiO2 was observed on the self-cleaning performance and tensile stress of the treated fabrics. The morphology, chemical structure and particle size of acrylate copolymer with CNT-TiO2 and treated fabrics were analyzed using transmission electron microscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and a dynamic particle-size analyzer. The self-cleaning efficiency of the treated samples was examined by decomposition rates of methylene blue in aqueous solution and that of a wine stain under sunlight irradiation. It was found that the decomposition rates both for methylene blue and the wine stain were improved by CNT addition to TiO2 treatment on fabrics. When tensile degradation by photocatalytic reaction was monitored for TiO2 and CNT-TiO2-treated fabrics, the tensile deterioration after 48 hours of irradiation appeared to be mitigated by CNT addition to TiO2 treatment.
The static and dynamic behavior of a developed electrothermal fabric was studied using an electrothermal model that considers the following fabric parameters: thermal conductivity coefficient, specific heat capacitance, fabric mass, and initial temperature. An experiment was set up to measure the average temperature of the knitted fabric of ordinary materials, namely wool, cotton, and acrylic. These materials were knitted with silver-coated conductive yarns in three loop densities each at an applied electric power of 4 W. The calculated coefficient of determination is greater than 0.98, and the fit standard error is smaller than 1.11. Therefore, the analytical equation could accurately model the electrothermal characteristics of the thermal fabrics under an applied electric current and compute the temperature at a certain time for the same fabric using known parameters.
This part aims to investigate the effects of structural parameters and lamination on the impact force attenuation properties of warp-knitted spacer fabrics developed for impact protectors. A series of warp-knitted spacer fabrics was produced on a double-needle bar Raschel machine by varying their structural parameters including spacer monofilament inclination and fineness, fabric thickness, and outer layer structure. The effects of fabric structural parameters, impact energy levels, and laminated layers on the protective performance of the spacer fabrics were tested and analyzed based on the assessment of the peak transmitted force. The results showed that all the structural parameters significantly affect the impact force attenuation properties of the warp-knitted spacer fabrics. It was also found that lamination of the spacer fabrics can effectively improve the force attenuation performance. Three layers of the developed warp-knitted spacer fabrics in a total thickness of about 2.5 cm can meet the requirement of the transmitted force lower than 35 kN at an impact energy of 50 J according to the European Standard BS EN 1621-1:1998.
Comparative analyses have been completed on hollow and solid E-type glass fibers. Single fiber tensile tests were performed and correlations have been determined between the geometry and the tensile strength of the fibers. The flexural properties of the solid and the hollow fibers have been determined with deflection tests. The hollow glass fibers showed higher tensile strength and flexural rigidity than the solid glass fibers in the case of similar outer diameter. The hollow fibers were filled with the help of capillary effect, and the filling process was examined as a function of the viscosity and the contact angle between glass and fluids. A relationship has been detected between fiber filling speed and the inner diameter of the fibers, and the filling speed was increased by the lower viscosity and contact angle.
The fabric weave pattern recognition process is a structure identification process that detects the yarn location as well as the yarn crossing structure in a woven fabric. A new local orientation feature is proposed for fabric structure detection by using high-resolution images. The detection process consists of two main steps. Firstly, the yarn location is detected through a series of image enhancement techniques and an edge-based projection method. Secondly, the yarn float is recognized with a local orientation detection approach based on Radon transform. Three kinds of yarn-dyed cotton fabrics are investigated in this study, including the single yarn, the double yarn, and the twisted yarn fabric. Experimental results and discussions demonstrate that the research method is effective in detecting fabric structure and yarn float even with long hairiness.
In this study, aluminum (Al) vapor was deposited on the surface of electrospun polyurethane nanowebs in order to improve their thermal comfort while maintaining water vapor permeability. After the deposition, the pore size and air permeability decreased, while the water vapor permeability remained at a level of 5000g/m2·24hr. Because of the reflection of the radiation heat, the thermal resistance increased by 30–40% compared with untreated nanowebs. Evaluation of clothing performance using a thermal sweating manikin demonstrated that the water vapor resistance of the deposited nanowebs was lower and the thermal resistance was higher than existing waterproof–breathable textiles.
A series of polypropylene (PP) nanocomposite fibres containing respectively 0, 0.5, 1, 3, and 5 wt% ZnO nanoparticles (NPs) were prepared by melt spinning. The antimicrobial activity of these fibers against Staphylococcus aureus (ATCC 6538) as a Gram-positive bacterium and Klebsiella pneumoniae (ATCC 4352) as a Gram-negative bacterium was evaluated. It was confirmed by scanning electron microscopy that the dispersion of the NPs within the PP matrix was homogeneous. Although such homogeneity the fibers are unable to exhibit antimicrobial activity. The absorption properties of the fibers was then investigated and found to be inadequate, so cold plasma and chemical finishing were applied to improve their absorptivity. After this treatment the PP/ZnO nanocomposite fibers exhibited increasing antimicrobial effectiveness with filler content. In addition, mechanical and thermal characterization tests showed that increasing concentration of ZnO–NPs improved the mechanical properties of the fiber due to the interface between the matrix and the nanoparticles sharing the stress. The crystallinity of the fibers was found to decrease by about 7% as the level of ZnO increased to 5%. This was attributed to the more rapid cooling experienced in the presence of ZnO particles of high thermal conductivity.
Fibrous textile materials are widely used in acoustic applications. However, the absorption of lower-frequency sound is problematic with fibrous material made up of coarser fibers. For this reason sound absorption materials effective at low frequencies are required. For low-frequency sound absorption the energy of sonic waves is absorbed by a thin nanofibrous layer in accordance with the principle of membrane resonance. This study deals with the acoustic behavior of a nanofibrous resonant membrane produced by needleless electrospinning. Using an experimental set-up involving a high-speed camera, it was attempted to predict the sound absorption behavior of a PVA nanofibrous membrane by determining its resonance frequency. The findings were compared with those from a homogeneous membrane structure in the form of a foil.
Hemp fiber has many superior performances and applications, for instance, the yarns, woven fabrics, knitted fabrics and composite materials. However, there is no hemp nonwoven in the market and in application. Therefore, in order to continue to expand the application fields and increase the additional value of hemp fiber, we developed a hemp/cotton spunlaced nonwoven to research its oil filtration property and verify the filtration mechanisms. The results indicate that the filtration efficiency of a hemp/cotton spunlaced nonwoven increases with the increase in particle diameter and the decrease in filtration time. In addition, compared with the change in filtration efficiency with the increase in particle diameter, it can be found that the filtration time has a relatively smaller influence on filtration efficiency. The experimental results suggest that the filtration efficiencies of direct interception and gravitational deposition are substantially higher than inertia collision, while the filtration efficiency of inertia collision is so low that can be neglected. Through a theoretical analysis of filtration we make a verification of the mechanisms and suggest a new equation to reduce the errors in filtration efficiency between the theoretical results and experimental values. Then, the hemp/cotton spunlaced nonwoven was used to develop two different automobile engine oil filters on an experimental scale.
Solid fats are one of the most difficult stains to remove at low temperatures. Mechanical action is beneficial for stain removal, but the potential and limitations of such an essential part of washing are not known. Fabric abrasion has been studied for the first time in a systematic and controlled manner using a tribometer. The efficiency of cotton–cotton abrasion, to simulate the rubbing of clothes, was studied in the absence of detergents using models of liquid and solid oils (hexadecane, octadecane, and undecanoic acid) and real fats (lard and buttermilk fat). In model oils, abrasion is not very effective at any temperature, whereas in typical fats abrasion significantly improves cleaning in a wide range of temperatures. The different behavior is caused by the temperature-dependent solid fat content of lard and butter. Fluorescence microscopy is introduced as a novel methodology for the quantification of the fat content in soiled fabrics.
Compact spinning with a perforated drum is one of the most important kinds of pneumatic compacting. It utilizes the transverse air force in a perforated drum to condense the fiber bundle in order to effectively eliminate the spinning triangle and improve the qualities of spun yarns. Therefore, the emphasis in research on a flow field in the condensing zone is always on the difficulty of pneumatic compact spinning. In this paper, the three-dimensional flow field of compact spinning of a perforated drum with a guiding device is investigated using Fluent software. First, a three-dimensional model, using AutoCAD Software, of the condensing zone is given. Then, the numerical simulations, by using Fluent software, of the three-dimensional flow field in compact spinning of a perforated drum with three guiding devices (type A, type B, and type C) and without a guiding device are presented, respectively. It is shown that the effective range of the negative pressure in the condensing zone of the compact spinning system with a perforated drum and guiding device increases significantly as compared with that of compact spinning without a guiding device. The flow field distribution is symmetric with respect to the central line of air-suction flume. The fiber strands move toward the center under the left–right symmetric transverse air force, which achieves transverse converging effects. Meanwhile, the static pressure shows a wavy distribution due to the influence of round holes. Furthermore, it is proved that the comprehensive effect of the type C guiding device is the best. Finally, the theoretical results obtained are illustrated by spinning experiments.
Workwears are required to maintain optimum performance during dangerous, exhausting activities (e.g. those involving the fire brigade or police). The purpose of the present study was to compare two workwears (A and B) composed of underwear and outerwear with different fiber blends (A: 100% aramid; B: combination of fire resistant (FR) viscose/merino wool underwear and FR viscose/aramid outerwear) during strenuous physical activity. In a climatic chamber (25°C, 50% RH) participants had to walk on a treadmill until exhaustion occurred. Weight measurements were made for calculating evaporation, sweat residue, and sweat distribution. Endurance performance was assessed by time to exhaustion. Core temperature, heart rate, lactate, thermal comfort, microclimate between skin and underwear, surface temperature of the outerwear, and perceived exertion were also measured. The tested workwears caused no significant differences in time to exhaustion, core temperature, and thermal comfort. Sweat distribution differed significantly in the workwears. The underwear of workwear B caused less moisture accumulation in the outerwear and this may be a beneficial safety feature for the prevention of hazardous burns of the skin. Moisture accumulation in the outerwear may reduce thermal insulation and increase the possibility of evaporation whereby hot steam may move to the skin. The potential protective feature of the FR viscose/merino wool blended underwear and the economical price of viscose support the use of fire resistant (FR) viscose blended fabrics in workwears.
The possible application of conclusions from a published study concerning cottons from West and Central Africa (WCA), involving an evaluation of the within-bale variability of fiber Micronaire, Length, Uniformity, Strength, Reflectance and Yellowness in cottons from Eastern and Southern Africa (ESA) was investigated.
We took eight cotton samples per bale from 240 bales produced by 32 ginning mills in six ESA countries in two crop seasons. Our representative sample comprised 1920 fiber samples that were centrally analyzed under controlled conditions using standardized instruments for testing cotton (SITC). We evaluated within-bale variability levels for both saw- and roller-ginned cottons and checked the applicability of the published conclusions to ESA.
We found that (1) sampling variance levels were comparable in ESA and in WCA for saw-ginned cottons, (2) WCA recommendations for saw-ginned cottons would also apply in ESA for most fiber characteristics measured by SITC, and (3) for roller-ginned cottons, the higher within-bale variability of roller-ginned cotton fibers compared to saw-ginned cotton would require the definition of a specific sampling and testing method based on an experiment to be designed.
A hospital environment may act as a significant reservoir for potential pathogens that can be transmitted with hospital textiles, which could represent a source of healthcare-acquired infections. Quantitative assessment of nosocomial pathogens with real time polymerase chain reaction (qPCR) on textiles can serve to verify the achievement of standards for textile hygiene of hospital laundry that assess the risk for acquiring hospital infection from inappropriately disinfected textiles. The aim of the study was to establish qPCR for quantitative assessment of selected common nosocomial pathogens (Clostridium difficile, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa) on hospital textiles and to compare the efficiency of the molecular method to the standard procedures for evaluating the bio burden of textiles in hospitals. This study demonstrated that presence of nosocomial pathogens on hospital textiles can be confirmed with qPCR even where conventional techniques do not give any results. qPCR offers a possibility to confirm the presence of microorganisms in dead or viable but non-culturable states that cannot be detected by conventional sampling techniques but may still pose a hazard to public health.
Currently, oven drying in air is often utilized to generate the percentage of moisture in cotton fibers. Karl Fischer Titration, another method for cotton moisture measurement, has been compared to the oven drying method. The percentage of moisture as generated by the oven method tracks those of Karl Fischer Titration, but there are differences between the two. In fact, a bias exists in the measured moisture loss employing the standard oven drying method. In addition, the moisture data collected via Karl Fischer Titration demonstrates smaller variances than those data collected in the oven. The aim of this study is to determine what is causing those differences. In the current report, particulate matter formation and browning of oven-treated cotton samples have been observed, suggesting visible indirect evidence that cotton oxidation may be occurring. It is noteworthy that three types of oxidation processes may be occurring during the current study: heating in air, scouring and bleaching, and periodate-driven processes. The first two oxidative processes yield non-specific products, whereas the periodate-driven oxidative products are well-defined in the literature. Thus, a method was needed to gain direct evidence for this postulated cotton oxidation that may be contributing to the bias in the standard oven drying method used to calculate moisture loss in cotton. Thus, this preliminary study employed Attenuated Total Reflectance/Fourier Transform Infrared spectroscopy to determine if direct evidence for oxidation can be observed for oven-treated cotton samples.
Textile coatings with electrical conductivity were obtained by the addition of poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) and ethylene glycol (EG) to a polyurethane (PU)-based coating formulation. Variations of the coating formulation, the coating amount and the drying conditions, as well as the absence of an annealing step, were investigated. The coated fabrics were evaluated for tear strength and bending rigidity as well as surface resistivity and appearance before and after Martindale abrasion. A high proportion of PEDOT:PSS dispersion in the formulation and the presence of EG provided low surface resistivity. This composition resulted in softer samples with higher tear strength than those containing more PU-binder. All coatings proved to withstand abrasion to a similar extent. The surface resistivity increased gradually with the abrasion, about one half order of magnitude, except for those coatings that had been subjected to a faster drying process, where the surface resistivity increased somewhat faster.
The multifocal phenomenon is a common problem when viewing a thick nonwoven sample under a light microscope. Multi-focus image fusion is a technique used to combine a series of partially focused images of the same scene into one fully focused image, and permits the accurate measurement of object features within the scene. This paper presents a region-based image fusion algorithm based on the fact that multi-focus images contain compensatory focused regions that can be selected to create a merged image. The process starts with the selection of a few reliable points with the highest local sharpness values and where there is coherent edge information (object features). Regions are then formed through diffusion or expansion of these selected source points. The final coupled boundaries among the diffusing sources are determined using the distance transform. Once the new image is divided into a number of regions, each region is filled with the corresponding region selected from one of the multi-focus images that possesses the highest average sharpness value among the entire set. The sharp image facilitates accurate detection of fiber edges in a nonwoven structure. Two orientation distribution parameters are used to describe fiber and web orientations and are evaluated with the two tensile tests on three different nonwoven webs.
The colorimeter method is widely used to identify the color and grade of a cotton sample, but this method does not give information about the variation of color within the sample. We have conducted an investigation using an image analysis method to study the intra-sample distribution and variation in cotton color. High-resolution color images of cotton samples were obtained using a color scanner. For each image the Rd and +b values of the image and specific sub-areas within it were computed to analyze the color distribution. Intra- and inter-sample variations in Rd and +b values and color grade were compared with those obtained by the HVI system. The results show that for the same cotton substrate, although the variations among the color grades of different samples (replicates) may be very small, intra-sample color variations are evident, the colors of the sub-areas being distributed over a range of areas of the cotton color chart. In other words, cotton samples of the same overall color grade may exhibit different intra-sample color variations and distribution. A description of the intra-sample color variations and distributions obtainable using an image analysis method may allow a more comprehensive evaluation of color characteristics on cotton.
TiO2/MgO core–sheath structured nanofibers (NFs) were fabricated through co-electrospinning (i.e., coaxial electrospinning), and then the long TiO2/MgO NFs were converted into short TiO2/MgO nanorods (NRs) by ultrasonic treatment. Based on the TiO2/MgO NRs, two novel technical textiles, that is, a photovoltaic smart textile integrating flexible dye-sensitized solar cells and a photocatalytic functional textile immobilizing photocatalyst, were developed. The effect of the insulating MgO sheath on the semiconducting TiO2 core was discussed. Compared with the pure TiO2 NR counterparts, the TiO2/MgO NR-based photovoltaic and photocatalytic textiles exhibit better performances. The common reason for the performance enhancements is that the charge recombinations occurring in both photovoltaic and photocatalytic processes are greatly suppressed when TiO2 is coated by MgO. Finally, the potential applications of these two types of textiles were proposed. This work offers a unique insight into the development of special textiles through the combination of new energy and environmental technologies and traditional textile research.
In order to avoid using polyvinyl alcohol (PVA), an eco-friendly sizing technology with atmospheric pressure plasma treatment and green sizing recipes has been developed and evaluated with respect to sizing properties and desizing efficiency. The results show that the eco-friendly sizing technology can endow cotton yarn with better sizing properties, including significantly improved size-pick-up, breaking strength, breaking elongation, abrasion resistance and substantially reduced yarn hair, than the traditional sizing technology with the use of PVA. Compared with a typical traditional sizing technology using PVA and modified starch, the optimized eco-friendly sizing technology can impart the yarn an increase of 19.4%, 5.3%, 3.4% and 169.2% for the size-pick-up, breaking strength, breaking elongation and the abrasion resistance time, respectively, and a reduction of 59.3% for the yarn hairiness index value at level 1. The sizing properties can be obviously improved by the atmospheric pressure plasma treatment, which can roughen the fiber surface, etch away the hydrophobic cuticle layer and introduce polar groups. The glycerol in the green sizing recipes can effectively reduce the yarn hairiness and increase size-pick-up and abrasion resistance. The eco-friendly sizing technology has no observable negative influence on desizing of cotton fabrics. Furthermore, a better water diffusion in the fabric can be achieved because of the improved hydrophilicity by using the plasma treatment.
Viscose non-woven was treated by NH3 plasma. Different exposure times were used in order to find the optimum conditions for simultaneously improved hydrophilicity and antimicrobial activity, as desired effects by wound dressings. Both chemical and morphological modifications were studied by X-ray photoelectron spectroscopy and atomic force microscopy, respectively, revealing functionalization with nitrogen groups as well as formation of rich morphology at sub-micrometer scale. The wetting rise curves increased from 0.04 g2 s–1 for non-treated material to 1 g2 s–1 after prolonged treatment. The water contact angle decreased almost linearly with treatment time from 90° for non-treated samples to about 40° for samples treated for 140 s and remained rather constant thereafter. The AATCC 100–1999 standard test revealed reduction on all used bacteria, more pronounced for Gram-negative, that is, E. coli and P. aeruginosa, then for Gram-positive, that is, a significant for S. aureus and a marginal for E. faecalis.
In this paper, we propose a new approach to intelligently segment jacquard warp-knitted fabric images by combining wavelet texture decomposition, multiresolution Markov random field (MRF) modeling and Bayesian parameter estimation. Firstly, we use a flat scanner to capture eight-bit grayscale images of jacquard fabrics and adopt the Gaussian low-pass filter to decrease pixel variation due to discordant light reflection arising from uneven jacquard fabric surface. To overcome the incapacity of single resolution, multiresolution wavelet texture decomposition is employed, inspired by human visual sense procedure. Next, both intra-scale and inter-scale information are taken into account by the MRF model, in which a modified feature field model of the MRF, containing spatial noise with zero-mean Gaussian distribution, is presented in light of the inherent characteristics of jacquard warp-knitted fabric image. Afterward, an adaptive weighting function is used to weaken the defect of the potential parameter set empirically during the process of parameter estimation and image segmentation. Experimental results, used to verify the performance of the proposed algorithm especially the main novelties, prove that the approach is feasible and applicable.
Linen fabrics are known for their superior comfort properties over fabrics of other origins. However, they have a very high tendency to wrinkle during use and laundry. In order to overcome this problem, easy-care finishes are applied on linen during or after fabric production. These chemicals are partially released during use and washing. Moreover, strengths of fabrics are affected negatively. Increasing ecological concerns and public awareness bring the need for an environmentally friendly alternative process. Delicate washing may decrease the number of wrinkles on fabrics but the functions used in the new-generation washing machines regarding the wrinkle reduction do not provide the expected results on linen fabrics. In this study, the wrinkling behavior of linen fabrics encountered during washing action in washing machines with steam generators is improved by selection of proper levels of processing parameters, including temperature, rate of mechanical action (ED), revolution per minute (rpm) and water amount applied during laundering. In order to further improve the wrinkling behavior of linen fabrics while still maintaining the gentle washing action, steaming steps were inserted into the laundering process between the adjacent laundering steps. The shrinkage and wrinkling characteristics of laundered linen fabrics were measured and analyzed. The best four profiles amongst others were chosen, and will be used for the development of a laundering process specializing in gentle washing linen products.
The aim of this study was to develop three-dimensional (3D) fully interlaced and semi-interlaced representative woven preform structures and to understand the effects of weave pattern and number of layers on 3D woven structures. Various 3D woven preforms were developed. Data generated from these structures included yarn angle, yarn-to-yarn space and density, yarn length and crimp. It was shown that the weave patterns affected the 3D woven preform structures. The yarn-to-yarn spaces of the 3D fully interlaced and semi-interlaced structures were high compared to the traditional 3D woven structures (orthogonal, through-the-thickness and angle interlock) in fabric width due to the interlacement. The 3D plain, twill and satin structures resulted in warp angle (w) in fabric length and filling angle (f), and interlaced z-yarn angle (zi) in fabric width due to the warp–filling and warp–z-yarn interlacements. The weave patterns slightly affected the yarn angles. On the other hand, it was observed that the number of layers considerably affected the z-yarn arc length and the z-yarn length in thickness in the 3D woven structure. The interlacement on 3D plain, twill and satin woven structures resulted in warp crimp, filling crimp and z-yarn crimp. The crimps in the 3D structure fully interlaced and semi-interlaced woven structures slightly depended on the types of weave pattern and the number of layers.
As the use of fabrics containing spandex for apparel applications is expanding, developing eco-friendly technologies to recycle the industrial as well as post-consumer waste for spandex blended fabrics becomes increasingly important. As is known in the industry and demonstrated in this study, spandex may be removed from blended fabrics by dissolving it in solvents such as N,N-dimethylformamide, but the use of such solvents is undesirable for economical and environmental reasons. The main focus of this study was to develop an alternative process for removing the spandex component in a nylon/spandex blended fabric (NSBF) by selective degradation so that the nylon component can be recovered for recycling. In this process, the fabric first underwent a heat treatment step, followed by a washing process. For the heat treatment, the effect of temperature, water-to-fabric ratio, and pressure were studied. Treatment at 220°C for 2 hours under atmospheric pressure was found to be very effective, allowing the degraded spandex residues to be readily washed off in ethanol, while the nylon component retained its original morphology. With the removal of spandex in NSBF, a decrease in -CON- absorption peaks in the Fourier transform infrared–attenuated total reflectance spectra of the fabrics was observed.
The EMI shielding composites consisted of carbon fabric and nonwovens were developed based on needle punching and thermal bonding techniques, and their static and dynamic puncture resistances were also evaluated to resist against different puncture behaviors. The result shows that, needle-punched density and thermal bonding correlate with the EMI shielding effectiveness (SE) at particular medium and high frequency range, and respectively has interaction effect with number of layers. The mechanism of EMI shielding is reflection and absorption loss in medium-frequency, and only absorption loss in high-frequency. The static and dynamic puncture resistances improve linearly with number of layers, but both display an upward and then downward trend at increasing needle-punched density. After thermal bonding, the influence of thickness on static puncture resistance becomes significantly but on dynamic puncture resistance insignificantly. The resultant composites are expected to be used as wall interlayer and package interline in the future.
In this paper we propose a highly efficient novel algorithm named Automatic Feedback Error-Correcting Color-Weave Pattern Recognition algorithm (AFEC algorithm). This algorithm is capable of simultaneously recognizing the color and weave pattern of yarn dyed fabric. The AFEC algorithm consists of three main components: 1. Color pattern recognition, 2. Weave pattern recognition, and 3. Feedback error correction. The last two each include one additional sub-algorithm, namely, the Infill algorithm and the Rectification algorithm. The first component focuses mainly on using the simplest method to reduce the time demand of color pattern recognition. With this objective we have adopted an X-means clustering algorithm which has less time complexity than other common algorithms used in this field. Furthermore, since the detection of the yarn edge and color classification in this component are designed to be independent of one another, to save time they can be run in parallel. In the second component weave pattern is detected, based on the color pattern obtained in the first component. In the second component the Infill algorithm can identify the logic embedded in the incomplete weave pattern, and hence fill in the gaps to form a complete pattern. By contrasting the color and weave patterns of the fabric, the third and final component uses a Rectification algorithm to correct errors in the recognition of color and weave pattern that may have occurred in the earlier components. Theoretical analysis, and experiments conducted during the present study, indicate that without prior knowledge the AFEC algorithm can improve the accuracy and runtime required for recognizing the color and weave pattern of yarn-dyed fabrics.
This paper presents the fabrication of polydioxanone weft-knitted stents and the mechanical properties optimization on process parameters. The stents can be used for treatment of intestinal obstruction and stenosis. Patients diagnosed with different phases require different mechanical stents. So, the mechanical properties of stents, radial force and circumferential strength are important for the safety and efficiency of stents. The aim of this paper was to identify the effect of process parameters on the mechanical properties of stents using the statistical modeling method, then propose optimum parameter settings. The intra-abdominal and intra-intestinal pressures of the human intestine were investigated through an intestine physical model; a full factorial experiment was employed to identify the most suitable factors and find the optimum processing parameters according to the two pressures identified. The results showed that optimum stents with radial force in the range of 1.3–2.5 cN/mm and circumferential strength in the range of 20–50 cN/mm could be obtained at a stitch cam setting ranging from 3.2 to 3.4 mm, with fabric tension in the range of 140–160 cN if the yarn tension and yarn linear density were held at 1.2 cN and 150 tex, respectively. The model validation results showed that stents with different mechanical properties could be tailored through the statistical method and proposed model. In conclusion, such stents, and optimization method, may find broad applications clinically.
We evaluated the feasibility of producing biodegradable mulch fabrics from bast fibers using a low-cost nonwoven fabric production process. Commercially available low-cost hemp and linseed flax fibers were carded, lightly needle-punched and then consolidated using a hydroentanglement process to produce fabrics around 200 g/m2 and 0.5 mm thickness. The hydroentanglement process liberated micro and nanofibers that formed a continuous fibrous network entangling and linking the parent fibers to produce fabrics with good tensile properties. Preliminary field trials of the fabrics demonstrate that they can be used to suppress weeds when colored with a commercially available carbon black-based mulch colorant. When in contact with soil the fabric biodegraded and lost strength in a matter of a few months.
This study explores the influence of cotton fiber length characteristics on the High Volume Instrument (HVI) strength measurement. A set of cotton samples cut at different lengths from a common parent sliver was used. HVI strength data exhibited a consistent trend as a function of the fiber length properties. This data was analyzed using the working hypothesis that the HVI estimates the total mass of fiber at a position between the jaws, rather than the true mass, which contributes to the breaking force. A quantitative model was developed to correct for this overestimation based on the shape of the Fibrogram. It was demonstrated that the Fibrogram can be adequately modeled as a straight line in the region of the HVI strength measurement. Based on this, it was found that the required correction factor is a function of the mean fiber length and various geometrical parameters of the HVI instrument (i.e. (a) the distance from the base of the beard to the inside edge of the clamp nearest the base of the jaws, and (b) the actual position of the beard's fiber length determination relative to the clamping jaws). Importantly this correction factor is independent of the shape of the fiber length distribution. Application of this correction factor approach was able to remove the effect of fiber length on the corrected strength values. The same model was also applied to other published data and, again, a simple correction factor based on mean fiber length adequately ‘removed’ the observed bias.
Through nonwoven hydroentanglement of greige cotton blends with polyester and nylon, varying degrees of fiber surface polarity, swelling, and absorbance can be achieved. Electrokinetic properties of nonwoven blends made with Ultra CleanTM cotton (100% greige or virgin cotton) and polyester or nylon in 40:60 and 60:40 ratios demonstrated distinct differences in charge, swell, and per-cent moisture uptake capability. An electrochemical double layer analysis of charge based on a pH titration (pH 1.5–11 in 1 mM KCl) was employed to measure the relative fiber and fabric surface polarity (plateau), which ranged from –60 to –26 millivolts. A linear relationship of fiber swelling () and per cent moisture content is apparent when greige cotton and synthetic fibers are blended. Water contact angles revealed that the cotton/synthetic fiber blends were hydrophobic (contact angle >80°) while retaining significant absorbency. The greige cotton/synthetic nonwoven materials, however, possess absorbent properties characterized by varying degrees of moisture uptake, fiber polarity, and swelling attributes similar to absorbent fluid transport materials present in the layers of incontinence products. Electrokinetic properties of the blended greige cotton/synthetic nonwovens are correlated to absorbent incontinence materials.
The influence of the calendaring process of nonwoven geotextiles on the water permeability normal to their planes, including influence of different loads, as well as pore characteristics investigated by two different methods has been studied. Methods of pore characteristics differ in obtaining different pore parameters. Two groups of samples were produced whereas first group is bonded by needle punching, while second group is needle punched samples taken from first group and additionally bonded by calendaring. Mass per unit area for both groups is in range of 150 to 500 g/m2, with increasing by 50 g/m2 for the next sample within groups. Calendaring process decrease water permeability of geotextile, but also decreases interval of geotextile water permeability change due to the applied pressure. Calendared geotextiles have controlled and predictable compressibility, respectively structure which will not significantly change in the practical application.
Hot liquid hazards present in work environments are well known to be a considerable risk in workplace safety for numerous industries. In this work, the effects of different liquids and temperatures on penetration performance of fabrics were investigated, and the influence of impingement angle on protective performance of liquid penetration was also studied. Several kinds of fabrics for protective clothing were used to characterize the penetration behaviors of protective materials. The results showed the liquid temperature had a significant impact on the stored and penetrated amount of liquids. Different liquids can lead to distinct damage to fabrics. The impingement angle affects liquid transfer (storage and penetration) through the fabric. The addition of a thermal liner or moisture barrier can sharply decrease the penetration. The results provide new insights into the development of functional garments/materials and better methods for evaluating the performance of these materials under hazardous work environments.
Textiles with dynamically color-changing effects depending on the observation angle were achieved by applying a coating paste containing multicolor effect pigments using a knife-over-table coating method. Black and white textile substrates with different structure characteristics depending on yarn type (multifilament and spun) and thread count (high and low) were studied and compared to a paper test chart as a smooth reference. The influence of surface structures on effect pigment coatings were investigated and compared with TiO2 coatings. Scanning electron micrographs showed that the substrate surface roughness increased when constructed of multifilament yarns with high thread count, spun yarns with higher thread counts and spun yarns with lower thread counts. Multi-angle spectrophotometer measurements of effect pigment-coated samples showed that the color differences in form of the CIE L*a*b*-coordinates varied to great extents, depending on detection angles, surface roughness and color of the substrates, compared to TiO2-pigment coatings with insignificant color-changing effects. The parallel alignment of effect pigment platelets was more easily achieved on the test chart. As a result, the color-changing effect was less intense on coated textiles. The effect were approximately reduced by half when coated on a substrate constructed of spun yarns compared to one made of multifilament yarns.
In online transactions of textile products, fabric hand was thought to be inaccessible to consumers. Recently, much effort has been made to study the feasibility of providing consumers with a real sense of fabric through a virtual experience. The current paper proposes to extract fabric hand information from the perspective of visual perception. Two sensory experiments are conducted according to the standardized sensory evaluation procedures on a set of representative textile fabrics by two trained panels. The first experiment is aimed to measure how much fabric hand can be perceived through fabrics’ visual displays. On the basis of the positive results obtained, the second experiment is carried out to further investigate the interactive mechanism between samples’ visual features and their tactile properties. A novel algorithm based on rough set theory and fuzzy set theory is proposed in order to quantitatively measure relations between different sensory information.
We have reported recently that fibers with surface roughness can be produced through the melt spinning of polyamide 6 (PA6) blended with 20 wt% of poly(ethylene terephthalate) (PET) if the extrusion temperature is lower than the melting temperature of PET. This technology is applicable for the production of fibers for artificial hair. Three kinds of optical equipment, including an optical microscope, were applied for the quantitative evaluation of the surface roughness of PA6/PET blend fibers. There was a good correlation between the roughness values evaluated using the edge-detection type diameter monitor (EDDM) and the back-illumination type diameter monitor (BIDM), even though resolution of the BIDM is lower than that of the EDDM. Through the on-line measurement of spin-line diameter performed at various positions along the spin-line using the BIDM, it was revealed that roughness developed with the increase of distance from the spinneret.
Different ways are presented of modifying cellulosic non-woven substrates, which can serve as potential wound dressings with satisfactory antimicrobial and hydrophilic properties. For safe attachment of silver particles without a measurable release from the used materials, a sol–gel derived process was used. Alkaline and oxygen plasma treatments were used to improve the hydrophilicity of the materials. Their efficiency was determined by measuring contact angles and water retention values. Scanning electron microscopy (SEM) was used for determination of sample morphology prior to and after treatment. The efficiency of silver attachment and activity was evaluated by in vitro release studies and antimicrobial tests. Atomic force microscopy (AFM) and SEM, combined with dynamic light scattering, were used for determination of silver particle size. Additionally, we evaluated the influence of treatment on technological parameters, important for application performance, i.e. mechanical properties and air permeability.
In this study, sodium alginate (SA) and xanthan (XG), selected as two typical pastes, were intensively investigated by steady, transient, and dynamic rheological methods. Compared with SA, in the steady-shear tests it was found that XG showed a prominent shear-thinning feature at low shear rates and low concentrations. In addition, the transient tests suggested that XG had more remarkable hysteresis thixotropy and that the structural viscosity needed more time to return to its original level after shears. What is more, two pastes in the same concentration performed totally different viscoelastic behaviors from the dynamic tests. SA exhibited more viscous behavior and XG more elastic behavior. Furthermore, experimental data have been correlated with different models: flow curves with the Cross and power-law model, mechanical spectra with the Friedrich–Braun model and Generalized Maxwell model. The relationship between dynamic and steady-shear properties (Cox–Merz rule) was satisfactory for SA while undesirable for XG. Through the rheological properties, it may be inferred that those who show weaker elasticity, stronger viscosity, relatively steady viscoelasticity, and the structural viscosity liable to restore the original level after shears may be more appropriate as the pastes to achieve better printing qualities on cotton printing with reactive dye.
Fiber-reinforced plastics (FRPs) with adaptive properties make lightweight structures feasible that not only possess a high mechanical force absorption but are also able to adapt their mechanical characteristics, such as geometry and rigidity, to external influences. Within the framework of the basic research presented here, new adaptive FRPs are developed on a basis of textile reinforcement semi-finished products integrated with actuators made from shape-memory alloys (SMAs). The realization of adaptive FRPs requires not only knowledge of the material-specific actuatory properties of the functional materials. It also necessitates the development of textile-technical solutions fully exploiting the actuatory potential of the SMAs within the composite. Promising approaches are hybrid yarn structures based on friction spinning technology. In order to reduce the great experimental effort, modeling and simulation of the SMA's material behavior and of the adaptive FRPs' complex composite behavior are carried out by means of finite element methods. It is shown that the developed actuators generate sufficiently high tensions of about 700–800 N/mm2, to bend the FRP specimen up to 45°.
A nonwoven fabric, three foams and leather, commonly used as fabrics for shoe manufacturing, were doped with microcapsules containing phase change materials (PCMs) and also with carbon nanofibers (CNFs) in order to improve the thermal comfort provided by the shoes. The maximum microcapsule content that can be incorporated and the influence on the weight, thickness and the thermal properties and behavior of the fabrics were evaluated. The resulting materials showed a thermal energy storage (TES) capacity up to 13.74 J/g and a maximum thickness increase of the composite fabric of 0.6 mm. The PCMs addition promoted a slight modification of the steady-state temperatures of the fabrics subjected to heating or cooling processes and the stored and released heats confirmed that PCMs work in a reversible way. On the other hand, the addition of CNFs compensated for the insulating effect of the PCMs. Finally, it was found that footwear containing these materials could hold the foot temperature for a longer time than parent fabrics.
Tissue regeneration relies on building carefully crafted scaffold material in the micron–submicron scale and imparting specific functionality in order to best mimic the in vivo environment in terms of chemical composition, morphology, and surface functional groups. Fibrous meshes with structural features at the micron to submicron level for ideal three-dimensional tissue regeneration scaffolds can be an inexpensive scale-up option. Bio-inert polymers lack the functional motifs for specific bioactivity; however, functionalization of the scaffolds can provide biological functions to actively induce tissue regeneration and promote cell adhesion by targeting specific cell–matrix interactions. It is therefore important to characterize the scaffolds and understand the relationship between the efficacy of the functionalization, the surface properties of the scaffolds, and their biological performance. This paper is a comprehensive review of the current understanding in functionalization and characterization of fibrous scaffolds and their biological efficacy. We begin with a compilation of various functionalization schemes including physical adsorption, co-electrospinning, wet chemical techniques, and surface graft polymerization methods and their application to fibers. After a critical literature review, the state of the art for characterization of these functionalized nano-fibers is then discussed. We emphasize the importance of covalent binding of biomolecules and the subsequent need for characterization of functional group distribution, or local density of functionalization, on the scaffold surface. Current challenges and future directions are outlined so that quantitative characterization of scaffold surfaces can aid in the development of next generation scaffolds.
The spinning triangle is a critical region in the spinning process of yarn. Its geometry influences the fiber tension distribution and thus affects the properties of spun yarns. In conventional ring spinning, on the one hand, the spinning triangles are often asymmetric due to the frictional contacts of fibers with the bottom roller, which interferes with the twist propagation into the spinning triangle zone, and thus leads to the migration of the axis fiber at the front roller nip. On the other hand, the yarn spinning tension has an obvious angle with the vertical axis perpendicular to the nip line. Therefore, in this paper, a theoretical model of the fiber tension distributions in the general spinning triangle has been proposed by considering both the inclination angle of the spinning tension and the migration of the axis fiber at the front roller nip according to the principle of minimum potential energy. Two shape parameters were introduced to describe the skew level of the geometry of the spinning triangle in the analysis. The effects of shapes of the spinning triangle on the fiber tension distributions were investigated. The results show that the fiber tension distribution at the spinning triangle tends to more non-uniformity with increasing the asymmetry of the spinning triangle. The effects of both shape parameters on the fiber tension distributions are similar under the assumption that the spinning triangle height <inline-formula id="ilm1-0040517513481867"><inline-graphic xlink:href="10.1177_0040517513481867mml-inline1"/>H</inline-formula> is constant. In addition, a more long-narrow shape of the spinning triangle shows more uniform fiber distributions.
Silver (Ag) nanoparticles (NP) and poly(lactide acid) (PLA) granules were microcompounded to form a nanocomposite. A series of PLA nanocomposite fibers containing, respectively, 0, 0.5, 1, 3 or 5 wt% Ag were produced and their antimicrobial activity against Gram-negative and Gram-positive bacteria evaluated. It was found that the PLA/Ag nanocomposite fibers exhibited increased antimicrobial activity, depending on the filler content. On the other hand, mechanical and thermal characterization tests, including thermogravimetric analysis, differential scanning calorimetry and tensile testing, showed that increasing concentrations of Ag hindered the mechanical properties of Nanocomposites due to partial agglomeration, leading to the generation of flaws. The crystallinity of the fibers was found to decrease by about 23% if the Ag content was increased to 5%. This could be attributed to a more rapid cooling rate resulting from the high thermal conductivity of the Ag particles.
The present study focuses on surface tailoring and water barrier attributes of zinc oxide (ZnO)-polyester composite textile materials. The surface properties, such as surface topography and roughness, composite compositions as well as thermal stability of ZnO-100% polyester textile composite materials treated through a padding process with different concentrations of ZnO dispersions as active agent in water and methanol were studied. The results show that 3% ZnO-textile composite material have enhanced water barrier properties compared with the other compositions; a fact which promises improved properties in terms of comfort. ZnO modification of polyester surfaces leads to a dramatic decrease in their thermal stability.
This paper investigates textile-based energy storage devices fabricated with poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as an electro-active polymer and conductive yarns as the electrodes. The conductive yarns are sewn into a textile substrate and then coated with PEDOT:PSS systematically. Two different sets of devices were made. A comparison of the devices made with silver coated polybenzoxazol filament yarns and the devices made with pure stainless steel filament yarns is performed. The devices were charged and their self-discharge was measured by voltage decay. A study of the influence of charging time on the decay and the effect brought by various load resistors on the voltage decay is also performed. In this research, the devices with electrodes of pure stainless steel filaments yarns performed better than the devices with silver coated yarns; this outcome has been reported as standard by various researchers.
In this research, the effect of centipede yarn production parameters – band yarn count and chain number – on drape and crease recovery behaviors of woven fabrics produced with these yarns were investigated. Polyester centipede yarns were produced on a Crochet machine with three different count (150, 300 and 600 denier) band yarns and three different chain numbers (10, 12 and 14 chain/cm). The centipede yarns were used as filling in the woven fabric construction. Drape coefficients of the fabrics were calculated from the drape measurements and the crease recovery angles of the fabrics were measured in the weft and warp directions. According to the analysis of variance results, it was proved that the drape and crease recovery behaviors of the woven fabrics from centipede yarns were affected by the centipede yarn structural parameters. Drape coefficients and crease recovery angles in weft and warp directions of the fabrics increased with the selection of higher chain numbers and coarser band yarns. Also correlations were determined between centipede yarn bending length, yarn-to-yarn friction and measured physical behaviors of the fabrics. The results of this study could provide researchers with information on how to determine the centipede yarn structural parameters for producing woven fabrics of centipede yarns with desired aesthetics and functionality.
The paper presents computational fluid dynamics-based numerical simulation of the through-thickness air permeability of woven structures, applying the theory of jet systems. The flow through the interstices between the warp and weft threads is modeled as an "in-corridor"-ordered jet system, formed by nine jets, issuing from nine pores of the woven structure. Fifteen cases were simulated and three different turbulence models were applied in the simulation: k-, k- and Reynolds stress model. The five simulated woven structures were manufactured and their air permeability was measured experimentally. The performed validation of the numerical results with the experimental values of the air permeability showed very good correlation with the experimental results. The analysis and the verification showed that the method can be applied for further investigation not only of the woven fabrics’ air permeability, but also for investigation of the flow after a textile barrier of a woven type.
The aim of the research published in the paper was to study the role of the false-twister in the formation of wrap yarns on a hollow spindle machine. Three cases were investigated as follows: without use of false-twister, with single wrapping around the false-twister, and with double wrapping around the false-twister. Wrap yarn structure, geometrical characteristics, and mechanical properties were analyzed. The results obtained showed some discrepancies with former statements in literature, but demonstrated the significant importance of the false-twister for the morphology and properties of the plain wrap yarns.
In this paper the influence of calender temperature on the crystallization behavior of polylactide (PLA) non-woven fabrics during their manufacturing by the spun-bonding technique is described. Non-woven samples were studied by wide-angle X-ray diffraction, differential scanning calorimetry and birefringence. In addition, physical–mechanical properties of the non-woven fabrics were determined. The results are discussed in terms of structural changes of PLA and meso-phase content during the calendering process in the temperature range 70–130°C. The rebuilding of the supermolecular structure of the investigated samples of PLA fabrics under the influence of increasing calender temperature is observed in terms of the disorder-to-order phase transition ( to α form) during heating around 110°C, and increased degree of crystallinity up to 100°C. The presented structural rebuild of PLA explains observed changes of physical–mechanical properties of the non-woven fabrics obtained at different calendering temperatures. During calendering above 100°C, thermal degradation of PLA occurs at the point of contact between the non-woven fabrics and the calender rollers.
In the hydroentanglement process, high velocity multiple waterjets are generated through the nozzles before impinging on the hydroentangling belt or fibre-web and exert an impact force. In this study, a technique to measure important characteristics of the waterjets, namely, the coefficient of velocity, Cv, and coefficient of discharge, Cd, is proposed. The technique offers a simple and practical method to determine the energy transfer efficiency from the manifold to the waterjets. The measured Cv and Cd values were observed to decrease with an increase in waterjet pressure, which implied higher energy losses at higher waterjet pressures. These results were then used in the next experiment to measure the waterjet impact force. The waterjet impact force was measured using a Tensiometer-R2000 fixed on a vibration-free stand at different waterjet pressures, varied from 30 to 120 bar. It was observed that the waterjet impact forces were equal across the width of the machine at a given pressure, but increased proportionally with the increase in the waterjet pressure. When the empirical relation was fitted between experimental and theoretical values of waterjet impact force, it was found that theoretical values were overestimated.
The chemical modification of cellulose (Cs)-chitosan (Ch)-electrospun non-woven (ESNW) composite fabrics is described. Since the as-spun Cs/Ch-composite ESNW (Cs : Ch = 4 : 6) deforms in water, an insolublilization procedure using an alkaline-ethanol solution was developed to extend the applications in an aqueous environment. The fine fiber surface was modified with bifunctional isocyanate in order to introduce the -NCO groups on the ESNW surfaces. The -NCO groups were condensed with N,N-(diethyl)ethylene diamine to generate a cationic diethylaminoethyl (DEAE)-ESNW. An enzyme, aminoacylase-I, was immobilized onto the cationic matrix under mild conditions. The immobilized enzyme was subjected to the stereo-specific recognition of Nα-acetyl-methionines. The results suggest that the chemically modified Cs/Ch-ESNW is a useful support matrix for biological catalysts.
Viloft is a special regenerated cellulosic fiber with a flat cross-section and crenulated surface that maintains air gaps in the yarns that help to improve the thermal properties of the fabrics. This fiber is mainly used for underwear, socks and sportswear fabrics and blends of Viloft with polyester or cotton are commonly preferred in the market. In this study, thermal-related characteristics, such as the thermal conductivity, thermal diffusivity, thermal absorptivity, thermal resistance, moisture and air permeability, of Viloft/cotton and Viloft/polyester blended knitted fabrics were investigated. For this purpose, 100%–0%, 67%–33%, 50%–50%, 33%–67% and 0%–100% blends of Viloft/cotton and Viloft/polyester slivers were produced and spun as 19.7 tex on a ring spinning system. In addition, single-jersey and 1 x 1 rib fabrics were produced and the comfort properties of these fabrics were measured using the Alambeta, sweating guarded hotplate, Permetest and air permeability testing devices. A simplex lattice design for the blended fabric properties was also developed and statistical analyses were carried out. According to the results, Viloft-rich blends, in general, improved the thermal properties of the fabrics. However, the relative water vapor permeability of Viloft/polyester blended fabrics was found not to be significant and only small significances were present for cotton blended ones, statistically.
A three-step plasma treatment, including surface activation with argon, surface functionalization with oxygen and then thin film deposition using a pulsed plasma polymerization of hexamethyldisiloxane (HMDSO), was used in low-pressure plasma to improve the pilling resistance of knitted wool fabric. The pilling propensity of the treated samples was investigated and compared with the pilling propensity of untreated, argon activated and oxygen functionized samples and argon and oxygen plasma-treated samples that were afterwards subject to continuous wave plasma polymerization of HMDSO. With the three-step treatment, a pilling grade of four was achieved for the treated wool fabric, while that of untreated and other plasma-treated was two and three, respectively. For the three-step plasma-treated sample, a uniform HMDSO polymer coating of 300 nm thickness was obtained; X-ray photoelectron spectroscopy (XPS) showed the presence of the silicone element, and Fourier transform infrared (FTIR) spectroscopy confirmed the chemical structure of the coating. No apparent differences were found in the whiteness index between the treated and untreated wool knits, but there was deterioration in the bursting strength and handle of the plasma-treated wool samples.
In this paper, we present a new fabric defect detection algorithm based on learning an adaptive dictionary. Such a dictionary can efficiently represent columns of normal fabric images using a linear combination of its elements. Benefiting from the fact that defects on a fabric appear to be small in size, a dictionary can be learned directly from a testing image itself instead of a reference, allowing more flexibility to adapt to varying fabric textures. When modeling a test image using the learned dictionary, columns involving anomalies of the test image are likely to have larger reconstruction errors than normal ones. The anomalous regions (defects) can be easily enhanced in the residual image. Then, a simple threshold operation is able to segment the defective pixels from the residual image. To adapt more defects, especially some linear defects, we rotate the test image by a slight degree and re-analyze the rotated image. Compared to the Fourier method, experimental results on 47 real-world test images with defects reveal that our algorithm is able to adapt to varying fabric textures and exhibits more accurate defect detection.
Meso-scale finite element modeling of textiles and textile composites at the scale of the unit cell of the textile structure is a powerful tool for the homogenization of mechanical properties and the study of stress–strain fields inside the unit cell. This paper discusses modeling and the issues involved in building finite element models of triaxial woven structures (geometry, meshing, boundary conditions), interpretation of the results, and verification of the models. The idealized unit cell structure is analyzed for axial and planar deformations. The prediction is in good agreement with actual experimental results for the parent fabrics. In-plane shear resistance is very high for these structures for application to thin composites. The yarn geometry and structural parameters of the reinforcement material each need precise calculation in order to predict the performance of composite materials in engineering applications.
Time survivor or time kill studies are commonly used to investigate the efficacy of antimicrobial agents in homogeneous solutions. Such a study was attempted via a textile treated with an antimicrobial agent. For this study, a finished undyed cotton fabric and a commercially available antimicrobial agent, polyhexamethylene biguanide, were used. The release of the antimicrobial agent from the cotton fabric when submerged in water with a liquor-to-cloth ratio of 20:1 was evaluated. The antibacterial agent-treated cotton fabric was also tested according to the JIS L 1902 absorption antibacterial testing method at various agent concentrations applied to the fabric and incubation times. The treated textile showed a quick release of agent when submerged in water and the results of the antibacterial tests showed increasing antibacterial activity with increases in concentration, as has been found in homogeneous solutions. Fabrics treated with lower concentrations of the agent show bacteriostatic action. A regrowth of microorganisms was additionally noted at certain incubation times.
To investigate the high-velocity impact response and damage evolution of the triaxial braided composite fan case, a series of ballistic impact tests using blade-like projectiles were conducted. Cylindrical projectiles of the same cross-section perimeter were also employed to identify the influence of projectile geometry. In addition, satin woven composites were tested for comparison with respect to failure modes and damage shape. Experimental results indicate that the main failure modes for the two different fiber reinforcement architectures are similar, that is, fiber shear failure and matrix crush failure in the impact surface and fiber tensile failure, fiber pull-out, matrix cracking, and delamination in the exit surface. The damage area in the exit surface is diamond-shaped for satin woven composites while rounded or elliptic for triaxial braided composites according to projectile geometry. The triaxial braided composites have an improved ballistic resistance and higher ballistic limit than satin woven composites. Based on damage area and failure modes observed from experiments, ballistic behavior was predicted using an analytical model, which proves to be accurate enough.
A series of ballistic tests on triaxial braided carbon/epoxy composites were described in Part I of this paper. In this part, numerical simulations were carried out to investigate the impact response, damage evolution, and penetration mechanisms of these composites. A continuum finite element model was developed to obtain the time history of the projectile velocity, displacement, penetration resistance force, and energy absorption during the impact process. By fitting the numerical data, the ballistic limit velocity can be obtained. Good agreements were achieved between numerical results and experimental results. Numerical predictions for ballistic tests of the composites indicate that, based on variations of damage mechanisms and failure features, the impact process can be subdivided into three stages, i.e. phase I – shock compression, phase II – bulge deformation, and phase III – penetration process, among which phase II consumes most of the projectile kinetic energy. The differences between a blade-like projectile and a cylindrical projectile in the impact process are also addressed in detail.
A theoretical analysis is presented for the estimation of the number of contacts between fibers in random multilayer nanofibrous assemblies with arbitrary fiber diameter and orientation. The statistics of fiber contacts for single-layer nanofiber mats were considered first, and the equations were developed for three-dimensional multilayer nanofibrous assemblies by considering the superposition of the single-layer assemblies. Based on the theoretical approach presented here for multilayer nanofibrous networks, the network porosity, mean fiber diameter and a function of fiber aspect ratio contribute to a model to determine the average number of fiber contacts per unit fiber length in multilayer nanofibrous mats.
The theory is studied parametrically and results compared with the work of a model presented by Samson. It is shown that the presented model compared to the existing models is more sensitive with the fiber diameter in the nano-scale. It is also believed that the presented theory for fiber-to-fiber contacts is more realistic and useful for further studies of multilayer nanofibrous assemblies.
The aim of this study was to characterize modified basalt fabrics as semi-finished articles for application in personal protective equipment (PPE), i.e. protective gloves. Resistance to the thermal properties for three fabrics made of basalt fibers differed in the aspect of mass per square meter and thickness as well as for the aluminized modifications presented. The modifications were obtained by gluing aluminum foil to the fabric with two kinds of glue. The results of the measurements are presented in the form of tables and figures. The study focused on the elaboration of the optimal textile modification designed for use in protective gloves against thermal and mechanical risks. According to the specifications of related European standards, only one way of proposed modification meets the requirements and can be successfully used for manufacturing the final product.
Two novel antibacterial materials were prepared by immobilizing antibacterial peptides protamine sulfate and polymyxin sulfate on polyethylene terephthalate (PET) non-woven fabrics in this study. The fabrics were surface modified by a chemical procedure to create carboxyl groups followed by grafting coupling agent and immobilization of peptide. Scanning electron microscopy images showed that there were no changes on the surface of the fabrics after treatment. X-ray photoelectron spectroscopy confirmed that protamine and polymyxin were successfully grafted on the surface of the PET fabrics. Antibacterial testing using the liquid droplet method showed that fabrics treated with both peptides had excellent antibacterial activity against Escherichia coli and Staphylococcus aureus.
In an effort to provide a technology platform for the mechanical analysis of the clothing pressure on the bust and to investigate the relationship of clothing pressure on the bust and garment bust strain, and Young’s modulus of fabric, accurately, a finite element model of the standard female body bust cross-section was created. The model was composed of skin, soft tissue and bone. The clothing pressure exerted on the busts by 10 elastic sports vests of two types of extensibility in fabric with different bust girth and identical style was measured, then the pressure was taken as load and applied to the model. The bust strain of 10 sports vests after wearing was calculated based on the finite element model. The data from eight out of the 10 vests was chosen to find the linear equation of the relationship between the clothing pressure exerted on the bust, the vest bust strain and Young’s modulus of fabric. The data from the other two vests were used to verify the equation, and results indicated that the calculated clothing pressure was very similar to that measured, proving that the equation can provide a database for the design, from bust size, of functional pressure comfort tight-fit garments.
This study focused on the use of subjective and objective evaluation methods to determine the peak-trough threshold of the drape fabric node. Nineteen different dynamic drape images of fabric, obtained using a dynamic drape instrument with a maximum rotation speed of 450 rpm, were used to evaluate the fabric node number and the fabric drape coefficient. After the ANOVA and the Duncan analysis, 13 consistent evaluators for determining the subjective fabric node number were selected from 19 candidates. The mean values of the subjective node numbers were then used as a basis for determining the peak-trough threshold of the drape fabric node. The fabric drape image plot was obtained by a self-devised dynamic drape instrument for fabric, and then converted to a drape waveform diagram. When the mean value of the drop-height between the outward protruding and adjacent dent positions on the drape waveform diagram at rotation speeds from 175 rpm to 450 rpm was taken as the test value, then the 1 % confidence lower limit of the mean drop-height could be used to obtain fabric node numbers which were subjectively and objectively consistent. This meant that the difference in the distance from peak and trough to the center point in the drape profile was 0.30 cm, which was defined as the peak-trough threshold of the node of a fabric drape image plot. The greater the rotation speed, the greater the drape coefficient of wool woven fabric. The smaller the distance from the peak and trough to the center point, the smaller the node number.