Table of Content

10 April 2024, Volume 32 Issue 4

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Wettability regulation and mechanism study of PLCL microfiber nonwoven materials

ZHU Xueying, DENG Jixia, HUANG Chen

2024, 32(4):  1-9. 

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Electrostatic spinning technology is an efficient method for the preparation of nanofiber materials. The fiber materials produced by this method have high porosity and specific surface area, and their fiber structure can mimic the extracellular matrix, making them an ideal material for promoting repair and regeneration of damaged parts in tissue engineering. PLCL is a synthetic polymer material with high biosafety and degradability, and is widely used in tissue engineering and drug delivery. However, the poor hydrophilicity and poor biocompatibility of PLCL electrospun fiber materials limit their applications. The hydrophilicity of composite or pure PLCL fiber materials is often improved by mixing them with hydrophilic natural or synthetic polymer materials or post-treating PLCL microfiber nonwoven materials, etc. However, the composite fiber material made by the former method is unstable in structure and prone to phase separation, and some of the natural polymer materials have large brittleness and poor flexibility, resulting in poor mechanical properties of the composite material. By contrast, the composite fiber material made by the latter method is unstable in effect, and is prone being hydrophobic from being hydrophilic after a period of use.
By changing the ratios of hexafluoroisopropanol (HFIP) and trifluoroacetic acid (TFA) in the electrostatic spinning solution, the wettability of poly(propylene lactone-caprolactone) (PLCL) microfibrous nonwoven materials was changed in a one-step method without adding any hydrophilic components or finishing. PLCL was dissolved in a solvent mixture of HFIP and TFA and then electrostatically spun, and it was found that the average fiber diameter decreased from 1.036 μm to 0.611 μm with the increase of TFA content from 0 to 100%, and the contact angle decreased from 121° in the droplet method to 46° in the bubble method. The infrared spectra, thermogravimetric curves, X-ray diffraction curves, and nuclear magnetic hydrogen spectra of the materials were further tested to investigate the mechanism of the phenomenon. The experimental results showed that the addition of TFA shortened the chain segment of PLCL macromolecule and reduced the number of hydrophobic ester groups, which led to the decrease of fiber diameter and the increase of hydrophilicity of the material. Nevertheless, the addition of TFA did not change the thermal stability of the material as a whole, and did not produce new chemical structures, and the hydrolysis occurred firstly in the amorphous region of the PCL molecule. It is proved that hydrophilic PLCL microfiber nonwoven materials can be prepared simply and efficiently by changing the solvent ratio.
PLCL microfiber nonwoven materials can be applied to tissue engineering dressings, inoculating epidermal cells or fibroblasts based on the polymer scaffold material can be used to repair patients' wound to increase the degree of active growth factor secretion. Since hydrophilic materials are easier for cell adhesion and biocompatible, improving the wettability of PLCL microfiber nonwoven materials is one of the keys to expanding their applications.


Preparation and application of B-PDA-G/PDMS thermally conductive insulating materials

CHENG Chunfen, PAN Jiajun, TANG Kongke, XIA Zhaopeng, LIU Zhitao

2024, 32(4):  10-20. 

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With the continuous improvement of people's living standards, people have put forward more diverse requirements for the performance of clothing, and it has shown great market prospects. As the future development trend of wearable devices, the heat dissipation of electronic devices has gradually become the key to research and application in various fields, especially in the textile field. If there is no effective heat dissipation, overheating will seriously reduce the performance and reliability of the equipment. Polymers are often used in thermal management materials for their advantages of good processability, high relative molecular mass, low water absorption, high resistivity, high breakdown voltage, corrosion resistance and low cost. However, the inherent low thermal conductivity (0.2~0.5 W/(m·K)) of the polymer matrix generally limits its thermal applications. Usually, thermally conductive fillers such as the inorganic ceramic fillers of aluminum oxide (Al2O3), aluminum nitride(AlN), and zinc oxide(ZnO) are added to the polymer matrix to improve the thermal conductivity of polymers. The addition of these high-density ceramic fillers usually results in low compatibility with the polymer, poor dispersion, high loading, and unsatisfactory improvement of the thermal conductivity of the composites.
To solve the heat dissipation problem in wearable electronic devices, flexible thermal management materials with high thermal conductivity and electrical insulation properties were obtained. Boron nitride (BN) and graphene nanoparticles (GNPs) were selected as hybridized thermally conductive fillers, and B-PDA-G/PDMS flexible thermally conductive and insulating films with different filler contents were prepared by hot-pressing method after surface modification of the hybridized fillers by polydopamine (PDA) and mixing with polydimethylsiloxane (PDMS) matrix. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to investigate the effects of filler B-PDA-G and single BN on improving the thermal conductivity of PDMS membrane materials and to assess the feasibility of their application in the textile field. The results show that the B-PDA-G/PDMS composite membranes can maintain good mechanical properties, electrical insulation and thermal conductivity at low filler filling. When the mass ratio of BN to GNPs is 5:5 and the mass fraction of filler is 30%, the in-plane thermal conductivity of B-PDA-G/PDMS can reach up to 7.63 W/(m-K), which is 2.8 times and 27.3 times higher compared to BN/PDMS materials and pure PDMS materials, respectively. 
By coating the flexible thermally conductive and insulating composites into the electrothermal fabric as the encapsulation coating, it is found that B-PDA-G/PDMS has better heat transfer and dissipation ability compared with BN/PDMS at the safe heating temperature of human body, which demonstrates its broad application prospect in smart wearable products.


Simulation analysis of the influence of mechanical properties of fillers on cushion comfort

XIAO Keying, CUI Siyi, LIN Shaowu, WANG Xueqin,

2024, 32(4):  21-28. 

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Based on the background that the majority of the population spends more time in a seated position and the demand for cushion products is increasing, the selection of cushion products with a high level of comfort has become the focus of consumer attention. In this paper, for the 50th percentile male representative group in China, three kinds of materials, namely warp-knitted spacer fabrics, sponges with a medium density of 28 kg/cm³, and sponges with a high density of 50 kg/cm³ were selected as the filler of cushion products to obtain three kinds of cushion materials.
We explored the mechanical characteristics of the three types of materials and the methodology and effectiveness of finite element simulation, and established relevant material microelement models to assist design prediction. The results show that the intrinsic model with the highest compression-strain fit (99.24%) among sponges with a medium density of 28 kg/cm³, sponges with a high density of 50 kg/cm³ and warp-knitted spacer fabrics is LOW DENSITY FOAM. Meanwhile, the mathematical model of the relationship between deformation of warp-knitted spacer fabrics and the amount of compression force applied, as well as the thickness of the material was obtained by using the quadratic polynomial surface fitting of MATLAB.
Subsequently, the process of contact between human body and three different cushion products in sitting posture was simulated by finite element simulation in ABAQUS software to analyze the comfort of the products according to the distribution of body pressure on the cushion surface, and the validity of the simulation experiments was verified by using a body pressure tester. It is found that the peak value of the elastic cushion surface of the warp-knitted spacer fabric is larger than that of the elastic cushion surface of sponges with a medium density of 28 kg/cm³, and smaller than that of the elastic cushion surface of sponges with a high density of 50 kg/cm³, and the distribution of the overall cushion surface is more homogeneous than that of the sponge cushion; and the body pressure tester verifies that the simulation data are less than 5% of the actual test data, which proves the feasibility of the simulation experiment.
Warp-knitted spacer fabrics exhibit better support and breathability than sponge materials. Combined with the results of objective data analysis, it is believed that as these materials continue to evolve, they can provide more choices for future elastic cushion products.


Preparation of a titanium-phosphorus catalyst and its application in PET

ZHU Haixin, WANG Yongjun, LÜ Wangyang, CHEN Wenxing

2024, 32(4):  29-37. 

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Titanium-based catalysts have the advantages of green and high efficiency, and have broad prospects in replacing antimony-based catalysts. To investigate the stability and catalytic properties of a self-made titanium-phosphorus catalyst during the polycondensation of polyethylene terephthalate (PET), the structure of the catalyst was tested with ultraviolet visible spectrophotometer (UV-Vis) and Fourier transform infrared spectroscopy (FT-IR). The esterification products of purified terephthalic acid (PTA) and ethylene glycol (EG) were used for polycondensation to verify the hydrolysis resistance of the catalyst, and to make the catalyst more evenly dispersed and the reaction situation more suitable for actual production. It is also possible to achieve a longer period of polycondensation to prepare PET with high intrinsic viscosity. In addition, the molecular structure and properties of PET synthesized over titanium-phosphorus catalysts were characterized by ultra high performance polymer chromatography, multi angle laser light scattering instrument, differential refractometer (APC-MALLS-RID), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TG). 
We made a comparison between the titanium-phosphorus catalyst and the antimony-based catalyst, and added a catalyst before esterification. The addition amount of titanium-based catalyst was 5 ppm, and the addition amount of antimony-based catalyst (antimony trioxide) was 180 ppm. The prepolymer was placed in a multifunctional polycondensation reactor, and PET was synthesized through polycondensation at a temperature of 270 ℃ and a vacuum of 20–60 Pa. The results show that the titanium mass fraction of the self-made titanium-phosphorus catalyst was 17.10%. In the FT-IR spectrum, there are symmetric and antisymmetric stretching vibrations of the ester group (C=O) at positions 1,567 cm-1 and 1,438 cm-1, and the stretching vibration peak of the hydroxyl group (−OH) appears near 3,424 cm-1, indicating a strong interaction between Ti ions and ligands in the catalyst. The above indicates that Ti ions are well coordinated and the catalyst has been successfully prepared. After 103 min of esterification, the titanium-phosphorus catalyst catalyzes the polycondensation of the prepolymer for 180 min to obtain PET with an intrinsic viscosity of 0.907 dL/g and a weight average molecular weight (Mw) of 57,240 g/mol. Its catalytic activity is still higher than that of antimony-based catalysts, and exhibits good catalytic stability, which also indicates that the catalyst has good ability to prepare high viscosity PET. The polydispersity index of titanium-phosphorus PET is higher than that of antimony-based PET at the same polycondensation time due to the fact that titanium-phosphorus catalysts lead to more side reactions, fewer additions, and fewer active sites compared to antimony-based catalysts. After 120 minutes of reactive polycondensation of esterification products catalyzed by the titanium-phosphorus catalyst, the rate of broadening the molecular weight distribution of the products increases, while the degree of yellowing of PET increases. Therefore, the polycondensation time should be controlled within 120 minutes as much as possible in the process. 
In terms of thermal properties, the melting peak temperature of titanium-phosphorus PET and antimony-based PET increases to the highest value at 90 min of polycondensation, with titanium-phosphorus PET being at 250.9℃ and antimony-based PET being at 249.8 ℃. And then, the melting peak temperature  gradually decreases. After 180 min of polycondensation, the temperature of 5% thermal weight loss for titanium-phosphorus PET and antimony-based PET is 413.3℃ and 412.3 ℃, respectively. The thermal stability of the titanium-phosphorus catalyst for synthesizing PET is better than that of antimony-based PET.


Analysis of oligomer composition in polyethylene terephthalate by double detectors with chromatography

LI Lina, GAO Feng, WANG Yongjun, CHEN Wenxing, LÜ Wangyang

2024, 32(4):  38-44. 

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Polyethylene terephthalate (PET) is widely used in textile fibers, packaging materials, industrial films and other fields because of its chemical stability, good resilience and high strength. The rapid development of polyester products in all walks of life has also worsened energy shortage and environmental pollution problems. Research on recycled polyester in recent years has contributed to sustainable development. However, oligomers contained in polyester materials can be migrated to fiber surface or deposited on the machine during the production process, affecting product performance and production efficiency. In this study, a method for determining the composition of oligomers in polyester was established, which provides a technical basis for further research on oligomers in recycled polyester. 
In this study, photo-diode array (PDA) and refractive index detector (RID) were connected in series on advanced polymer chromatography (APC) to analyze the mixture standard sample according to the principle of them, and the standard curve and linear equation of each composition oligomer were established by the external standard method. At the same time, we verified the feasibility of the method by repeating experiments. The oligomer content in recycled polyester and virgin polyester was calculated by the linear equation and compared to characterize the differences. It is found that more sensitive and accurate information can be obtained by selecting chromatography at the maximum absorption wavelength of 240 nm. According to the spectral information obtained by RID and PDA, the standard curves plotted have a good linearity within a certain range. It can be seen from the repeatability test that the method is stable and efficient, and is suitable for the detection of oligomers in PET. With the help of standard curve and linear equation, the content of each oligomer in the regenerated and virgin PET fibers was calculated, and it could be seen that the oligomer compositions in PET fibers include cyclic dimers, cyclic dimers containing a diethylene glycol, cyclic trimers…cyclic dodecamers and above. There are many oligomeric species that can be extracted by the one-step precipitation method. Cyclic trimer and cyclic tetramer are the main compositions of PET oligomers, with a relative content of about 60% and 17%, respectively. The total amount of oligomers contained in physically recycled PET is 22.64 mg/g, which is higher than that of virgin PET at 21.03 mg/g, and the total amount of oligomers in chemically recycled PET is 20.73 mg/g, which is lower than that of virgin PET. It is in accordance with the physical and chemical recovery processes. 
In this study, PDA was coupled with RID on APC to extract chromatogram information at 240 nm; the standard curve of each composition oligomer was ploted, so as to establish the quantitative detection method of oligomers in PET. The method is simple and efficient, with better stability. From the calculation results, it is clear that different recovery methods of PET affect its internal oligomer content. Therefore, for different product performance requirements, the selection of suitable PET recovery methods is crucial for its high quality.


Parallel Electrode Electroluminescent Yarn Construction Molding and its Water Rescue Wearable Application

ZHAO Shikang, WANG Hang, TIAN Mingwei

2024, 32(4):  45-51. 

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Electroluminescent yarn has been a research hotspot in recent decades due to its extensive prospect in the field of intelligent display applications, such as human-computer interaction and emergency warning. The basic principle of electroluminescence is the phenomenon of electric current excitation to produce light, specifically when the current passes through some specific materials, it will excite the electronic energy level transition in the material, thereby emitting visible or near-infrared light. However, the DC drive mode of organic light-emitting diodes and quantum dot-based light-emitting diodes limits their practical application. This is because unidirectional DC flow can lead to unfavorable charge accumulation at high current densities. In addition, power loss is unavoidable. Therefore, AC-driven electroluminescent devices have attracted attention for various applications.
At present, the main preparation methods of luminescent fibers include integrated circuit method, spraying method and intercalation method. The integrated circuit method is mainly achieved by integrating luminescent materials, electrode fibers and other components; The spraying method is to spray the luminescent material in the form of a solution or powder on the conductive wire, and encapsulate it with an insulating material; The embedding method is mainly prepared by embedding luminescent materials into yarns. However, in the molding process of light-emitting optical fiber, there are inevitably shortcomings such as time-consuming production process and high cost, which greatly limits the large-scale production of outgoing light-emitting optical fiber and restricts its practical application. Therefore, there are still significant challenges in developing a cost-effective and feasible method to manufacture luminescent fibers/yarns.
Therefore, in this paper, a parallel electrode electroluminescent yarn structure is designed, and a parallel electrode electroluminescent yarn is prepared by using zinc sulfide doped copper (ZnS: Gu) electroluminescent composite material as the luminescent layer and conductive silver-plated yarn as the flexible electrode. The luminous yarn can reach a brightness of up to 161.71 cd/m2 (700 V, 8 kHz), and PELF  - 60%has good wearing performance and water insulation properties, which can be used for water rescue and warning clothing, and has a broad application prospect in visual interaction and environmental warning.


Performance of antibacterial clothing fabric with the composite functions of thermal-moisture comfort

LIU Xiaohan, WANG Yuxuan, XIE Wen, ZHANG Hongxia

2024, 32(4):  52-59. 

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In recent years, multi-functional composite healthy and comfortable fabrics are the development direction of current fabrics. Under the high temperature in summer, the human body will produce a lot of sweat after exercise. As a product in direct contact with the human body, clothing is easy to attach to the skin surface and form a high temperature and humidity climate environment with it, and produce sticky, stuffy and airtight feeling. And because of the porous structure and large specific surface area, it is easy to absorb sweat and a large amount of oil secreted by human metabolism, providing a good environment for the attachment and reproduction of bacteria and other microorganisms. The pungent odor and indirect transmission produced in the process of reproduction are also important sources and transmission routes of diseases, thus bringing hidden dangers to human health. In summer activities and work, a long time of humid and sultry environment will make the skin more prone to allergy and other inflammatory reactions and accelerate skin aging. The development of multi-functional composite fabrics with moisture absorption and quick drying, antibacterial and thermal comfort has a certain market prospect.
At present, the thermal-moisture comfort function of fabric is relatively simple, and there is little research on the multifunctional composite of fabrics realized by functional fiber mixing. The fabric modification for the hot and humid environment is mainly for the improvement of the functions such as moisture absorption and quick drying, antibacterial and heat transfer. To develop healthy and comfortable clothing fabrics under humid and hot conditions, a total of 16 types of fabrics, including A and B series, were woven with mulberry silk as warp and a blend of honeycomb antibacterial polyester fibers, tencel, honeycomb UV resistant polyester fibers, and honeycomb jade polyester fibers as weft. By testing the performance of moisture absorption, quick drying, antibacterial and heat transfer, the heat and humidity comfort was evaluated by fuzzy comprehensive analysis. The results show that the moisture absorption and quick drying properties of the yarn is related to its type, weave and density. The inhibitory effect of fabric on S. aureus and E. coli is positively correlated with the content of cellular antibacterial polyester fiber in latitude yarn, and the inhibitory effect of S. aureus is better than that of E. coli. The thermal resistance of fabric decreases with the increase of tencel content in yarn, and the heat transfer performance of fabric is best when honeycomb jade polyester fiber is contained. The results of fuzzy comprehensive analysis indicate that in the A series, the fabric woven with tencel/honeycomb antibacterial polyester fiber/honeycomb ultraviolet resistant polyester fiber (30/60/10) as weft and 16 reinforced weft satin has the best comprehensive performance; the comprehensive performance of the fabric in the B series is the best when the weft density is 46 roots/cm.
We explore the influence of fiber content ratio, fabric weave and fabric weft on the antibacterial, thermal-moisture comfort of the blended yarn, and the research results can provide reference for the design and development of multi-functional fabrics, contribute to the development of composite functional fabrics with better comprehensive performance, and promote the development of clothing fabrics in a more high-grade, more accurate and more scientific direction.


A multi-direction visual bending test method of fabrics based on 3D scanning

JIANG Xina, LIU Chengxiaa, b

2024, 32(4):  60-67. 

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The bending property of the fabric is one of the mechanical properties of the fabric to be evaluated. It affects the formability, drapability, and crease recovery of the fabric to some extent. It also plays a key role in determining the stiffness and softness of the fabric, as well as in the performance of the garment shaping. If the fabric bending stiffness is low, clothing will appear easy to arch, easy to wrinkle, and not easy to recover. On the contrary, if bending stiffness is high, the body fit will be poor. So far, traditional fabric bending performance testing mostly relies on repeated labor. In addition, the existing fabric bending test methods can only test the bending properties of a single direction each time, and it is difficult to directly observe the differences in the bending properties of fabrics in each direction.
In view of the above situation, a multi-direction visual bending test method of fabric based on 3D scanning was proposed, and three characteristic indexes representing fabric bending were extracted, namely, the projection perimeter of fabric splines in different directions, the projection area and the overall cross-sectional area of fabric. The projected perimeter and area are measured by the projection formed by the bending shape of the fabric specimen in each direction under gravity conditions. The section area is the area formed by the fitting curve of the point cloud section at 1/4, 1/2, 3/4, and the bottom of the three-dimensional point cloud of the fabric. Using three-dimensional scanning technology can better show the bending shape of fabric. Not only can the whole bending property of the fabric be obtained, but also the fabric samples in different directions can be compared and analyzed. The study shows that the results measured by the new method have better correlation coefficients than the results of the conventional cantilever method. The correlation between the projection circumference and the bending length is higher than the projection area, and the section area of the bottom has the highest correlation with the bending length among the four positions.
Although there are a lot of bending test methods, only the bending result of a single direction of the fabric can be obtained from each test. By contrast, the bending results of three directions of the fabric and the bending indexes of the five specimens in each direction can be obtained. At the same time, the bending differences between different fabrics and different directions of the same fabric can be obtained more intuitively. The research results of this paper can provide a more efficient testing method for the field of textile testing, and the testing efficiency is 15 times that of the existing methods, which has good theoretical significance and practical value.


Development of fabric style and thermal-moisture comprehensive evaluation system

TIAN Yuan, DU Zhaoqun, ZHENG Dongming, ZOU Haochen

2024, 32(4):  68-75. 

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People have five senses, namely vision, touch, hearing, smell and taste. In real life, when consumers choose clothing, the senses that express the fabric style are mainly visual, tactile and auditory senses, which is a process of multi-sensory integration. However, the evaluation of fabric style is mostly tactile style, that is, hand feeling. The thermal-moisture comfort of fabrics  depends on the permeability, hygroscopicity and thermal conductivity of the fabric. Fabric style and thermal-moisture evaluation are two important aspects of fabric quality evaluation. When selecting fabrics, in addition to considering the style, people should pay attention to the characteristics related to thermal-moisture comfort such as air permeability and moisture absorption of fabrics, so as to ensure that fabrics suitable for specific environments and needs are obtained. The fabric style and thermal-moisture comfort affect each other and restrict each other, which need to be considered comprehensively.
To comprehensively evaluate the fabric style and thermal-moisture comfort, a comprehensive evaluation system of fabric style and thermal-moisture comfort was designed and developed based on the test principle of CHES-FY textile hand feeling evaluation instrument. Combining the multi-sensory style of the fabric and the combination of style and thermal-moisture comfort evaluation, a comprehensive evaluation system of fabric style and thermal-moisture was developed to evaluate the fabric. Five fabrics with obvious differences were selected and tested on standard instruments such as Datacolor 850 desktop spectrophotometer, YG461G automatic air permeability meter, YG606E textile thermal resistance tester, YG601H computer fabric moisture permeability meter, and KES-F7 IIB contact cold and warm feeling tester, and compared with the test results of fabric style and thermal-moisture comprehensive evaluation system. The results show that the fabric style and thermal-moisture comprehensive evaluation system can not only test the multi-sensory style of textiles, but also combine the three senses of vision, touch and hearing, provide a variety of combination information, and enhance the usability of the instrument. The structural characteristics of textiles can also be obtained, and a number of thermal and moisture indexes between different fabrics can be simply tested and compared. Compared with the basic thermal and moisture comfort test results, it is found that the difference between fabrics can be well reflected, which provides a new idea for the design of fabric evaluation instruments.


Effect of Pretreatment with Polar Solvent on Dyeing and Mechanical Property of Meta Aramid

SONG Jixian, ZHANG Sijia, JIANG Hua

2024, 32(4):  76-83. 

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Meta aramid fiber is known to be difficult to dye because of its high crystallinity and compact structure. Pretreatment with polar organic solvents can well swell meta aramid fiber, thus facilitating the dyeing process. Reported papers usually proceed the pretreatment at high temperature, leading to a severe fabric shrink accompanied with a remarkable decline of mechanical property. Therefore, it is important to balance the relationship between dyeing performance and mechanical property. The aim of this paper is to explore the feasibility to decrease the fabric damage by studying the effect of pretreating/dyeing process on dyeing/mechanical properties.
 In this paper, the mechanical property of a meta aramid fabric was assessed by shrinkage rate, breaking strength and elongation values, while the dyeing property was evaluated in terms of dye exhaustion, color depth as well as color fastness. The pretreating and dyeing processes were optimized. The effect of pretreating temperature and time on mechanical property was investigated, and the effect of dyeing temperature on dyeing performance was studied. Besides, 15 disperse dyes were applied to dyeing meta aramid fabric at optimized pretreating and dyeing condition. Moreover, scanning electron microscope (SEM) was also used to analyze the fiber surface.
 Pretreatment with polar organic solvents, such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), etc. were confirmed to efficiently improve the dyeing performance of meta-aramid fabrics, while DMSO was demonstrated to be the best solvent when compared with others at the same pretreating condition. When dyeing the pretreated meta aramid fabric using C.I. disperse red 167, the dye exhaustion value largely improved as increasing the pretreating temperature and prolonging the pretreating time. A temperature of 55 ℃ and a time of 30 min were optimized for the pretreating process. Further investigation of dyeing process indicated that a dyeing temperature of 80 ℃ and a time of 60 min were enough to obtain a high dye exhaustion value of 95.1%. Under the optimized pretreating and dyeing conditions, result of dyeing experiment suggested that azo type disperse dyes generally exhibited better dyeing performance than anthraquinone or heterocycle type disperse dyes. The dyed meta aramid fabrics also showed good to excellent color fastnesses to soaping, rubbing and sublimation of higher than grade 4. In term of mechanical property, the pretreating temperature was found to be the primary key factor. High temperature would help the polar solvent penetrating into meta aramid fiber, breaking down the hydrogen bonds, thus swelling the fiber. In particular, when pretreated at 55 ℃ for 30 min, the shrinkage rate of a meta aramid fabric could decline to less than 10% with a breaking strength of 950 N and elongation value of 36%. SEM image analysis further showed that pretreatment at relatively low temperature would effectively avoid solvent erosion on fiber surface. In addition, most of the dyed meta aramid fabrics exhibited breaking strengths of 956~1110 N, showing a comparative mechanical property as the untreated fabric.
 Based on the above results, it was concluded that the damage of mechanical property of a pretreated meta aramid fabric could be well reduced by using a low-temperature pretreating process. Therefore, it was feasible to obtain a dyed meta aramid fabric with both satisfactory dyeing performance and mechanical property. 


The luminescent properties of ACQ and AIE polymeric nanoparticles and their applications in inkjet printing

LIANG Xiaoqin, LIANG Lihua, ZHU Jinshun, MA Mingyue

2024, 32(4):  84-92. 

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Different from the aggregation-caused quenching (ACQ) effect of traditional fluorescent dyes, aggregation-induced emission (AIE) dyes have become a research hotspot in recent years due to their unique luminescence behavior. The applications of AIE polymer nanoparticles (AIE-PNPs) have gradually expanded from the fields such as cell imaging and chemical sensing to textile printing and dyeing fields. The research on ACQ-PNPs has been ignored for a long period. It is undeniable that a large number of ACQ dyes such as Nile red (NR) and fluorescein possess advantages of stable photophysical chemical properties, high quantum yield and so on, although the fluorescence of dyes would be weaken even quenched when the concentration reaches a certain value. Additionally, not all fluorescent polymer nanoparticles (FPNPs) need to load dyes at a high concentration in many practical applications. Therefore, it is of great importance to conduct in-depth analysis of the discrepancies of the luminescence performance between ACQ-PNPs and AIE-PNPs, and to explore the practical application value of ACQ-PNPs and AIE-PNPs simultaneously.
Enjoying the advantages of green, simple and efficient preparation process, miniemulsion polymerization technology can be used to prepare various FPNPs flexibly. To compare and analyze the luminescent properties of ACQ-PNPs and AIE-PNPs, and further explore their applications in inkjet printing, PMMA/NR NPs and PMMA/TPE NPs were prepared through encapsulation of ACQgen dyes, NR and AIEgen dyes, tetraphenylethylene (TPE) in water-borne miniemulsions, respectively. Influences of the amount of dyes on the final monomer conversion, particle size and luminescent properties of PMMA/NR and PMMA/TPE NPs were investigated and analyzed. The results show that the maximum content of NR and TPE dyes is 1.5wt% and both NR and TPE dyes have negligible influence on the final monomer conversion and particle size. Within the range of 0–1.5% of fluorescent dyes, the photoluminescence (PL) intensity of PMMA/NR NPs shows a trend of first increasing and then maintaining unchanged with the increase of NR content, without fluorescence weakening or quenching phenomenon, whereas the PL intensity of the PMMA/TPE NPs increases linearly with the increase of TPE content. When the content of florescent dyes is higher than 1.5%, the PL intensity of PMMA/NR NPs begins to decrease while that of PMMA/TPE NPs keeps increasing with the increase of the fluorescent dye’s content. Therefore, the critical concentration of dyes to avoid the weakening of fluorescence of PMMA/NR NPs is 1.5%. Furtherly, in order to improve the film-forming and inkjet printing performance of FPNPs, poly(MMA-co-20%BA)/NR and poly(MMA-co-20%BA)/TPE NP emulsions were prepared through miniemulsion polymerization at 1.5% content of fluorescent dyes. After diluting, adding surfactants and filtering, poly(MMA-co-20%BA)/NR and poly(MMA-co-20%BA)/TPE NP inks were prepared and used for inkjet printing on cotton fabrics. Under incandescent light, the printed fabrics with poly(MMA-co-20%BA)/NR and poly(MMA-co-20%BA)/TPE NP inks display the same appearance as the pristine fabric, but display a bright red and blue pattern under UV light, respectively. 
This paper unveils the relationship of the amount of dyes and luminescent properties of ACQ-PNPs and AIE-PNPs, and further demonstrates both NR-based ACQ-PNPs and TPE-based AIE-PNPs emulsion prepared through miniemulsion polymerization have great potential in inkjet printing application with a suitable amount of fluorescent dyes. Research results can provide reference for the development of photochromic inkjet ink.


Clothing image classification algorithm based on improved MobileNet v2#br#

LI Linhonga, b, YANG Jiea, b, JIANG Yanxuana, b, ZHU Haoa

2024, 32(4):  93-103. 

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With the continuous development of Internet technology, online clothing shopping has become one of the mainstream ways for people to shop. Consumers can easily browse and purchase various types of clothing from e-commerce platforms at home, without the need to visit physical stores in person. At the same time, online shopping platforms also offer more choices and competitive prices, which is one of the main reasons why people choose to shop for clothing online. According to market research data, as of 2021, the consumption scale of online clothing shopping in China had reached 3.7 trillion yuan, accounting for nearly half of the entire online shopping market, and this number is still growing. However, quickly and accurately classifying a large number of clothing images is a challenging task. Traditional clothing classification requires a lot of time and labor to classify, sort, and label, consuming a lot of manpower and time costs. Moreover, with the annual increase in the volume of online shopping orders, traditional manual classification methods are difficult to handle large amounts of data and cannot meet the needs of rapid classification and processing. On the contrary, clothing classification methods based on deep learning can learn more features and patterns through a large amount of data and iterative training, achieving higher accuracy without human intervention. Therefore, this article proposes a clothing classification algorithm based on improved MobileNet V2.
The improved algorithm mainly embeds channel and spatial attention mechanisms into the basic unit of MobileNet V2 to form an attention mechanism basic unit, giving useful features greater weight, suppressing useless features, and enhancing the network's feature extraction ability. In addition, transfer learning is used to optimize the model parameters, and enhance the model's generalization ability and stability, so as to further improve the classification accuracy. Experimental results on the Fashion MNIST dataset show that the improved algorithm achieves an average accuracy rate of 93.16%, which is respectively 1.73%, 1.22%, 3.74%, and 3.05% higher than that of the Resnet50, Efficientnet v2_l, Shufflenet v2, and Mobilenet v2 models, effectively improving the problem of low accuracy in clothing image classification.
The algorithm proposed in this article achieves high-precision clothing classification, which not only provides consumers with a better shopping experience but also provides e-commerce platforms with more accurate clothing recommendation services, and has high application value. However, the algorithm in this study focuses on single-label clothing image classification, and there are some limitations in recognizing multiple objects within a single image. Future research will emphasize expanding the clothing image classification task to multi-label classification, and further exploring how to handle multiple clothing categories in the same image, in order to apply it to a broader range of clothing classification scenarios.


The impact of virtual apparel on physical apparel consumption from a sustainable perspective

LU Chenga, b, CHEN Ziye

2024, 32(4):  104-113. 

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The post-epidemic era has witnessed a rapid shift in consumption patterns towards online channels. The convergence of information technology and the fashion industry has given rise to the virtual apparel. Virtual apparel, which is rooted in a digital creation mode, possesses various advantages such as creativity, inclusivity, and sustainability. Consequently, it has garnered significant attention from capital investors, and numerous traditional apparel brands to launch virtual apparel lines. The investment potential and sustainable value of virtual apparel are highly anticipated. Nowadays, virtual apparel has diversified its forms, extending beyond the realm of traditional virtual try-on experiences. Photo modeling and other forms of social media dissemination have attracted widespread public attention and generated intense discussions. These developments offer new opportunities for brand promotion and the expansion of consumer groups. However, it should be noted that the virtual trading market is still in its nascent stages, and brands' profitability continues to rely on the sale of physical products. As a result, many brands are currently focusing on leveraging virtual apparel for publicity and promotional purposes. Nevertheless, this marketing strategy is still in its early exploratory phase, and it remains uncertain whether virtual apparel can effectively drive brand promotion and physical product sales. Additionally, while existing literature has analyzed the value system of virtual apparel and acknowledged its role in brand promotion and sustainable value, most of these discussions are theoretical in nature and lack empirical research to substantiate their claims.
We aimed to explore the commercial value of virtual apparel in physical apparel consumption and facilitate the sustainable development of the industry. Firstly, we conducted a comprehensive review of the research progress on virtual apparel both domestically and internationally since the 20th century to identify the current hotspots and deficiencies in related research. Secondly, based on product attributes and technology acceptance model, we used physical apparel attitude as a predictor variable of physical apparel purchase intention, introduced the two variables of aesthetic and technology attributes of virtual apparel, and discussed the influence factors of the attributes of virtual clothing on the attitude of physical clothing. Additionally, we verified the chain mediating role of perceived usefulness, perceived ease of use and brand attitude. Finally, we conducted a questionnaire survey to collect relevant data based on the model assumptions, analyzed their reliability and validity, and employed regression analysis to verify the assumptions and provide theoretical support for brand to design and applicate the virtual apparel. This research not only expands the scope of applied research of the technology acceptance model but also enriches the research perspective of virtual apparel. Additionally, it provides empirical evidence for the sustainable value of virtual apparel and fills the gap in empirical research regarding the exploration of the commercial value of virtual apparel. The study results indicate that virtual aesthetics and technology have a significantly positive effect on physical apparel attitudes. This effect is mediated by perceived usefulness and brand attitudes, with appearance consistency playing a positively moderating role in the relationship between brand attitudes and physical apparel attitudes. This study affirms the marketing value of virtual apparel in facilitating brand promotion and promoting physical consumption. According to the results, when designing virtual garments, brands should fully leverage their digital creation advantages to enhance consumers' perception of the usefulness of virtual garments in terms of both aesthetics and technology. Moreover, brands should pay greater attention to the technological content of virtual apparel rather than the aesthetic effect, so as to give it more digital vitality and highlight its digital technology characteristics. Meanwhile, traditional fashion brands should focus on the simulation of virtual apparel to enhance the realism of its appearance. This method can drive profitable growth in physical garment sales and reduce the consumption of physical materials in traditional brand promotions. 


Research progress in moisture-absorbing and quick-drying materials

ZHANG Yuexuan, LIU Ya, ZHUANG Xupin, QIU Mengying

2024, 32(4):  114-124. 

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The market size of moisture-absorbing and quick-drying materials is increasing day by day. To develop moisture-absorbing and quick-drying materials that better meet market demand and expand their application fields, we analyzed moisture-absorbing and quick-drying materials from several aspects. Firstly, we made a detailed introduction to the mechanisms of moisture-absorbing and quick-drying materials, including differential capillary effect, wetting gradient structure, and biomimetic transpiration, and listed corresponding models developed in recent years. Then, we divided the common moisture-absorbing and quick-drying fibers in the market into natural fibers and chemical fibers, and stated the characteristics, advantages, disadvantages, and application scope of different fibers. Additionally, we listed the current moisture-absorbing and quick-drying standards of common countries and standard organizations, as well as the main performance grading of moisture-absorbing and quick-drying materials in China's moisture-absorbing and quick-drying standards, and listed some problems in the standards and operational plans that can be implemented.
We divided moisture-absorbing and quick-drying materials into moisture-absorbing and quick-drying woven fabrics, knitted fabrics, and non-woven materials. We introduced the research achievements and development status of various materials in recent years, including: woven fabrics prepared by Tao Fengyi et al. by using viscose fibers and honeycomb microporous polyester fibers as raw materials, and changing the arrangement of fiber materials in the thickness direction of the fabric to present different moisture-absorbing effects on the inner and outer layers of the fabric. Wang Yue et al. used green and environmentally friendly Tencel and recycled polyester to design a new type of three-dimensional moisture conductive double-sided knitted fabric that accelerates the passage of gas and liquid, effectively reducing the contact tightness between the fabric and the skin, ensuring moisture absorbing and quick drying, while improving the lightness and comfort of the fabric. Finally, we summarized the existing problems and possible solutions of moisture absorption and rapid drying based on the post-processing technology. In terms of non-woven materials, in addition to arranging and combining various new environmentally friendly fibers with traditional non-woven processes such as water spunlace, needle punching, and hot air to obtain moisture-absorbing and quick-drying materials, there are various materials produced by electrospinning technology. For example, Song et al. prepared a non-woven material with a wetting gradient structure composed of hydrophobic chitosan fibers and hydrophilic adhesive fibers through water spunlace technology. When 90% of the fibers are hydrophobic and the hydrophobic layer exceeds a high thickness of 1.6mm, the material can still achieve anisotropic water penetration and has high wear resistance and environmental friendliness.
We summarized and classified the moisture-absorbing and quick-drying finishing processes into plasma treatment, photochemical treatment, electrostatic spraying, and laser processing. By depositing low surface energy materials on hydrophilic fabrics, the material surface underwent oxidation, cross-linking, chemical bond breakage, etc. under sunlight or ultraviolet radiation. Under high potential, very fine droplets were sprayed from the tube to control the coating thickness. Laser processing was used to change the micro nano scale morphology and other finishing processes, which can accurately change the moisture-absorbing and quick-drying rate of the material.
Finally, we explored the development potential of current moisture-absorbing and quick-drying materials. In response to the current situation of moisture-absorbing and quick-drying fibers, we proposed three problems to be solved from the perspective of fibers and two problems to be solved from the perspective of materials, and provided possible solutions. There is no complete conclusion on the study of the interaction between fibers and water molecules, the influence of the depth and quantity of irregular cross-section fiber grooves used in moisture-absorbing and quick-drying materials on differential capillary effect, and the application should shift towards the development of green and environmentally friendly fibers, as well as more research and development of natural fibers with high moisture-absorbing and quick-drying performance. In terms of materials, simple and effective methods should be developed to achieve low-cost industrial production of moisture-absorbing and quick-drying materials. In the meanwhile, various post-processing technologies that combine green environmental protection performance, good mechanical performance, and stable and efficient moisture-absorbing and quick-drying performance should be more closely combined with the preparation of moisture-absorbing and quick-drying materials.


Research progress of fabric friction performance test system

TIAN Yuan, DU Zhaoqun, ZHENG Dongming, ZOU Haochen

2024, 32(4):  125-140. 

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Friction performance is an important index to measure the friction behavior of fabric materials, which is of great significance for the design, production and application of textiles. With the development of textile science and technology, the research and improvement of fabric friction performance test system has attracted more and more attention, because friction determines the quality of fiber products processing links such as spinning, weaving, knitting and finishing. As one of the most basic mechanical properties of the fabric, the friction performance of the fabric surface affects the fabric style and wearability. Fabric style is the comprehensive effect of the inherent properties of the fabric itself on the human senses. The surface friction performance of the fabric affects the tactile style evaluation of the smoothness, slipperiness and waxiness, and clamminess of the fabric, and gives the fabric a rich surface handle. In order to better evaluate the performance of the fabric in the friction process, the friction performance of the fabric was quantitatively and qualitatively evaluated. The research and development of the fabric friction performance test system were reviewed. The research background, friction mechanism and research process of fabric friction were introduced. Starting from the material of the friction part in contact with the fabric, the fabric-metal friction, fabric-fabric friction and fabric-skin/skin-like fabric surface friction performance test devices were introduced.
When friction occurs within or between fabrics and between fabrics and other substances, there will be low-frequency vibration, which will produce a sound spectrum and affect the fabric’s acoustic style. More and more people have realized that fabric sound is one of the key factors that determine the performance of fabrics. By studying the sound generated by fabric friction, the acoustic characteristics related to fabric structural factors and auditory sensation are determined to meet the growing consumer demand for fabrics’ auditory properties affecting clothing comfort. The test method of fabric friction sound was introduced, but there is no universal test instrument for fabric friction sound test device in the world.
The research of the fabric friction performance test system aims to accurately and reliably evaluate the friction performance of fabric materials, provide scientific basis for textile design and application, and is of great significance in the field of textile science and technology. The surface friction performance of the fabric will also affect its wearability, that is, the comfort of the fabric, and the surface friction performance of the fabric will also have a certain impact on the post-processing and some special functions. Through in-depth understanding of the friction behavior and performance characteristics of fabrics, it can provide scientific basis for the design, production and application of fabric materials, and promote the development and innovation of the textile industry. However, further research and improvement of test methods are still needed to improve the accuracy and practicability of the test system to meet the needs of the developing textile industry.