Table of Content

15 March 2024, Volume 45 Issue 03

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Fiber Materials

Preparation and application properties of dendritic sulfonated polyethersulfone fiber based composite solid electrolyte

YANG Qi, DENG Nanping, CHENG Bowen, KANG Weimin

Journal of Textile Research. 2024, 45(03):  1-10.  doi:10.13475/j.fzxb.20221106101

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Objective The conventional liquid electrolyte is easy to leak and flammable, which brings potential safety risks to the actual application of lithium metal batteries. Replacing liquid electrolyte with all-solid-state electrolyte has become one of the most feasible methods. However, solid polymer electrolytes are limited by low ionic conductivity and poor mechanical strength. For solving the two problems of solid polymer electrolyte at the same time, nanofiber membranes with high strength are used for modification.

Method Dendritic sulfonated polyethersulfone nanofibers (SPES) were prepared by electrospinning technology. They were introduced into polyethylene oxide (PEO) to prepare composite solid electrolytes and applied in high-performance all-solid-state lithium metal batteries. The influences of spinning solution concentration, salt addition, electrospinning voltage and receiving distance on fiber morphologies were explored and analyzed. Moreover, the influences of SPES nanofiber membrane on the crystallinity, ionic conductivity, mechanical properties, and electrochemical properties of composite solid electrolyte were also studied under the optimal spinning process.

Results When the spinning solution concentration was 23%, the electrospinning voltage was 30 kV and the receiving distance was 15 cm, the obtained SPES nanofibers had the best morphology among them. Based on obtaining the optimal spinning solution concentration of ordinary SPES nanofibers at 23%, the influence of ammonium tetrabutyl hexafluorophosphate on fiber morphologies were investigated. It was found that the optimum parameters for preparing dendritic SPES nanofibers were salt dosage of 2%, electrospinning voltage of 30 kV and receiving distance of 15 cm. After the nanofibers and PEO were constructed into the composite electrolytes, both the ordinary SPES nanofibers and the dendritic SPES nanofibers caused the crystallization peak of PEO in the composite electrolyte be smaller than that of pure PEO electrolyte, indicating that the interlaced nanofibers were conducive to destroying the crystallization zone of PEO matrix. The destruction of nanofibers with two structures to the crystallinity of PEO was also reflected by the ionic conductivity of the electrolyte. At 30 ℃, the ionic conductivity of the electrolyte containing ordinary SPES nanofibers was 6.92×10^-5 S/cm. The ionic conductivity of the electrolyte containing dendritic SPES nanofibers was as high as 8.13×10^-5 S/cm at 30 ℃, which is even 1.4 times that of pure PEO electrolyte (5.62×10^-5 S/cm). In addition, the ordinary SPES nanofiber membranes and the dendritic SPES nanofiber membrane can provide skeleton support for the PEO matrix, and the mechanical strength of the electrolyte containing the two types of fiber membranes was as high as 4.8 MPa and 5.1 MPa, respectively. In the lithiumi/lithium symmetric battery, the electrolytes composed of ordinary SPES nanofiber membrane and dendritic SPES nanofiber membrane could maintain the battery cycling for 180 h and 198 h, respectively. But the pure PEO electrolyte had a short circuit during a 65 h cycle at 0.1 mA·h/cm². When LiFePO₄/Li was assembled with an electrolyte containing of the dendritic SPES nanofiber membranes, the electrolyte enabled the battery to maintain a high specific discharge capacity of 128.6 mA·h/g after 400 cycles.

Conclusion From the tested results, it can be seen that both the ordinary SPES nanofiber membrane and the dendritic SPES nanofiber membrane can damage the crystalline region of the PEO matrix to a certain extent, thereby greatly enhancing the ionic conductivity of the prepared composite solid electrolyte. In addition, as the support skeleton of PEO matrix, both fiber membranes can improve the mechanical strength of composite solid electrolyte. However, the modification effect of dendritic SPES nanofiber membrane on electrolyte is more excellent. This is because dendritic SPES nanofiber has more branch fibers than SPES nanofiber, which destroys the crystalline region of PEO to a greater extent and is more helpful for constructing the enough three-dimenstional ion transport pathway. Therefore, the dendritic SPES nanofiber membrane modified electrolyte can better meet the actual application requirements of high-performance all-solid-state lithium metal batteries.

Preparation and performance of electrospun membrane for Cu(Ⅱ) detection

ZHAO Meiqi, CHEN Li, QIAN Xian, LI Xiaona, DU Xun

Journal of Textile Research. 2024, 45(03):  11-18.  doi:10.13475/j.fzxb.20220906701

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Objective Excessive Cu(Ⅱ) content may cause gastrointestinal disorders, liver and kidney damage, and even death. Therefore, the study of convenient Cu(Ⅱ) detection method is significant for maintaining human health. At present, the Cu(Ⅱ) detection is faced with problems of high detection cost, difficult on-site detection and pollution of detection probes. In order to solve the above problems, this study proposed a convenient Cu(Ⅱ) detection material for more intuitively detecting Cu(Ⅱ) content to avoid the inability so as to timely understand the Cu(Ⅱ) content of water that poses potential health risks.

Method In this study, the natural dye lac red (Lac) was used as the Cu(Ⅱ) detection probe, and polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) were used as the carrier of the detection probe, and the Lac/PAN/PVP fiber membrane was prepared by electrospinning method. By means of rotational viscometer, scanning electron microscope, X-ray diffractometer and infrared spectrometer, the influences of spinning solution mass fraction and blending ratio on the structures and properties of fiber membranes were studied, and the Cu(Ⅱ) detection performance of fiber membrane was investigated.

Results When the mass fraction of PAN/PVP in spinning solution was increased from 7% to 19%, the corresponding viscosity was changed from 52.5 mPa·s to 4 316.7 mPa·s. When the mass fraction of PAN/PVP in the spinning solution was 7%, a lot of beads appeared on the surface of the fiber, and the fiber diameter was (102.3±1.8) nm. As the mass fraction of PAN/PVP in spinning solution was increased to 19%, the fiber formation tended to be uniform and smooth, and the fiber diameter increases to (546.3±7.4) nm. The fibers can be formed well at different mass ratios of PAN to PVP. The fiber diameter was decreased from (220.7±2.4) nm when the mass ratio of PAN to PVP was 5∶5 to (113.9±1.3) nm when the mass ratio of PAN and PVP was 9∶1. The water contact angle of the fiber membrane was decreased from 102.2° when the mass ratio of PAN to PVP was 10∶0 to 43.0° when the mass ratio of PAN to PVP was 5∶5. The addition of PVP improved the hydrophilicity of Lac/PAN/PVP fiber membrane. The infrared spectra showed that the absorption peak at 1 041 cm^-1 was enhanced in the Lac/PAN/PVP fiber membrane, caused by the introduction of more hydroxyl groups on the lac red molecule to enhance the stretching of C—O in C—OH. It meant that lac red was successfully mixed into the fiber membrane. Two crystalline structures were found in the Lac /PAN/PVP fiber membrane. The Lac/PAN/PVP fiber membrane had no significant diffraction peaks at 2θ of 32°, 46° and 56°. It was found that the lac red was fully dissolved and evenly distributed in the fiber membrane by electrospinning. Only Cu(Ⅱ) can change the hue value of Lac/PAN/PVP fiber membrane from 338.0° to 22.3°, accompanied by a color response from red to yellow. It showed that the Lac/PAN/PVP fiber membrane has good anti-interference ability. The Lac/PAN/PVP fiber membrane hue value gradually changed from 349.9° red to 38.1° yellow. 0.03 mmol/L Cu(Ⅱ) solution was able to produce an obvious color response of Lac/PAN/PVP fiber membranes, and the color response intensity was increased with the Cu(Ⅱ) concentration from 0.03 mmol/L to 0.09 mmol/L.

Conclusion Lac/PAN/PVP fibers with a good morphology and a diameter of (149.7±0.7) nm were produced when the mass fraction of PAN/PVP was 10% and the mass ratio of PAN to PVP was 7∶3. The Lac/PAN/PVP fibers were able to specifically recognize Cu(Ⅱ) in solutions containing a variety of metal ions, producing a clear color response from red to yellow. Lac/PAN/PVP fiber membranes were capable of detecting Cu(Ⅱ) up to 0.03 mmol/L with the naked eye. The use of Lac/PAN/PVP fiber membranes for Cu(Ⅱ) detection enables the visualization of Cu(Ⅱ) detection and improves the convenience of Cu(Ⅱ) detection. Lac/PAN/PVP membranes have the advantages of good interference immunity and low detection limits, thus has potential applications in the field of Cu(Ⅱ) detection.

Preparation and performance of copper modified antimicrobial and anti-mite polyamide 6 fiber

ZHENG Xiaodi, SHENG Pinghou, JIANG Jiacen, LI Rui, JIAO Hongjuan, QIU Zhicheng

Journal of Textile Research. 2024, 45(03):  19-27.  doi:10.13475/j.fzxb.20220900701

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Objective The application of copper antimicrobial agent in fiber materials is faced with three major problems. Firstly, the functional nano powder has serious agglomeration and poor compatibility with polymer materials, which makes it difficult to disperse evenly. Secondly, copper is easy to be oxidized and discolored, resulting in poor stability and uniformity of fiber color. Thirdly, spinnability and mechanical properties of fiber decrease with the increase of antimicrobial agent content, therefore it is difficult to increase the content of copper antimicrobial agent in the fiber. It is important to improve the dispersion, interfacial compatibility, and antioxidant properties of copper antimicrobial agent in fibers.

Method In this study, the nano spherical copper antimicrobial agent was coated with oleic acid. Two types of copper modified PA6 antimicrobial masterbatch containing 1.1% and 2.1% copper antimicrobial agent were obtained by squeezing granulation. Copper modified PA6 antimicrobial and anti-mite fibers were obtained by melt spinning and composite spinning, respectively. The structure, morphology and interfacial compatibility of copper antimicrobial agent, thermal stability and spinnability of antimicrobial masterbatch, copper content, mechanical properties, antimicrobial, and anti-mite properties of fiber and fabric samples were analyzed.

Results The diffraction peaks were found sharp with no other impurity peaks appearing, indicating that the sample was well crystallized and was still pure after modification. No obvious weight loss is found during the dehydration at about 100 ℃, which indicated satisfactory hydrophobicity of the sample. Sample C1 showed about 0.4% of weight loss at 300 ℃, and its thermal stability met the requirement of melt spinning, and the dispersion was good without large-size agglomeration under the electron microscope and showed good hydrophobicity with water contact angle of 146°, which was consistent with the TG results. Whether it is melted spinning or composite spinning, pre-oriented yarn sample had high fiber yield of 94%. The fiber yield of draw textured yarn sample is 93% and 94%, respectively. The modified spherical copper antimicrobial agent hardly affected the mechanical properties of PA6, which could be attributed to the reduced agglomeration and improved dispersion of the oleic acid modified spherical copper antimicrobial agent, resulting in fewer large rigid particles in the fiber. The interfacial interaction between PA6 and copper particles was enhanced with the help of oleic acid. The elongation at break of the copper modified PA6 fiber was 29.95% and the tensile breaking strength was 4.43 cN/dtex. For Candida albicans, Staphylococcus aureus and Escherichia coli, copper modified PA6 DTY sample (X1') and copper modified PA6 sheath-core DTY sample (X2') both have high bacteriostasis rate of 99%. The bacteriostasis rate was still over 99% after washing for 50 cycles, indicating that the samples had good resistance to washing and superior long-lasting antibacterial performance. After washing, the copper content of the X1' sample was 1.26% and that of the X2' sample was 1.11%. Compared with the copper content of the two fiber samples before washing, the copper content remained basically the same within the allowable testing error. For mixed test, fungi colony consists of Aspergillus niger, Trichoderma viride, Penicillium funiculosum and Chaetomium globosum, the mildew proof grade of the fiber reached grade 0, meaning no obvious mildew colony under magnifier. X2' samples were woven into fabric for the anti-mite performance test. The result showed that the average number of mites in the test group was 22 and that in control group was 194, suggesting the repellent rate of mites of 89%.

Conclusion The dispersibility of oleic acid coated spherical copper antimicrobial agent and its compatibility with PA6 are good. Copper modified PA6 antimicrobial masterbatch has good thermal stability and spinnability. Copper modified PA6 antimicrobial and anti-mite fiber has high fiber yield of 88% and excellent color consistency at a high antimicrobial addition of 1.1%. The mechanical property of the fiber is adjustable. The antimicrobial, mildewproof and anti-mite properties of fiber samples are strong and durable. Therefore, copper modified PA6 antimicrobial and anti-mite fibers have broad industrial application potentiality in military personal protective equipment, fiber products for medical and health industry and textiles for civil clothing and home decoration.

Controllable preparation of cellulose/tea residue composite films and food preservation properties

HAN Junfeng, WANG Yunxia, WU Wei, HU Chaofan, FENG Qichun, DU Zhaofang

Journal of Textile Research. 2024, 45(03):  28-35.  doi:10.13475/j.fzxb.20220906901

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Objective A lot of caffeine and tea polyphenols are contained in the waste tea residue, which have excellent antibacterial effect and are ideal raw materials for the preparation of food preservation films. However, the molecular chain of tea residues is short, and the film formation rate is low. Herein, a phase conversion casting film strategy is proposed, where cellulose and tea residue are dissolved in ion liquids. The caffeine and tea polyphenols are well extracted and dispersed into cellulose, and hydrogen bonds drive cellulose to build films in the ion liquids.

Method The cellulose/tea residue composite film was prepared by casting film method. Cellulose and tea residue were dissolved with ionic liquid as solvent, and the mixed solution was obtained by adding glycerol as plasticizer. The composite film precursor was obtained by centrifuging the mixed solution. The precursor was prepared into wet film by phase change method, and then transferred to the mold and air-dried at room temperature to prepare cellulose/tea residue composite film. The mechanical properties and antioxidant properties of the composite films were measured by tensile testing machine and ultraviolet visible spectrophotometer. The food preservation performance of the composite films was determined by plate counting method. The water content, water solubility and mass ratio of the composite film were obtained by measuring the weight change of the composite films in different solution media.

Results The final dissolution temperature of tea residue in ionic liquid ([EMIm]Ac) was 90 ℃, which was lower than the [AMIm]Cl. The DPPH free radical scavenging properties of the cellulose/tea residue composite films was 45.9%, which was increased about 32 times than the pure cellulose film. There was a strong positive relationship between tea residue and moisture content. The moisture content of the composite film was 4.8% higher than that of the pure cellulose film with 80% tea residue, and water solubility decreased to 11%. Moreover, the gas permeability value was also positively correlated with the content of tea residue. The gas permeability value of the composite film with 80% tea residue revised to 7.2 mol·m/(m²·s·Pa), which was about 67% higher than pure cellulose film. The food preservation performance of the cellulose/tea residue composite films was between the pure cellulose film and commercial PE film. When the tea residue content reached 80%, the water loss rate of the fresh beef embedded with the composite film was only 28.9%, which was significantly lower than pure cellulose film (57%). The prepared composite film demonstrated excellent gas permeability. Therefore, the film was able to prolong the storage time of beef for 3-4 d compared to PE film. Tea residue was effectively capable of inhibiting the microbial colonies, which further improved the food preservation performance of the composite films to 12 d.

Conclusion The [EMIm]Ac had the lowest dissolution time and temperature for tea residue, which was the optimal solvent for tea residue. The DPPH free radical scavenging rate of the prepared films was 32 times higher than pure cellulose film, and the antioxidant activity was also significantly enhanced. These were attributed to the large amount of antioxidant active component contained in the tea residue. With the increase of tea residue content, the water solubility of the composite films gradually decreased, and the moisture content was increased. These were mainly attributed to high hydrophobicity of the tea residue, and the network of the prepared films contained massive pores. Compared to commercial PE films, the cellulose/tea residue composite film had an excellent preservation performance, and the preservation time was able to be prolonged by 3-6 d. Therefore, the research opened a new avenue for the utilization of tea residue waste.

Cotton color detection method based on machine vision

BAI Enlong, ZHANG Zhouqiang, GUO Zhongchao, ZAN Jie

Journal of Textile Research. 2024, 45(03):  36-43.  doi:10.13475/j.fzxb.20221006501

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Objective At present, most of the domestic cotton testing instruments are adopted to detect cotton grades, but the specifications of instruments and equipment are expensive and cannot be used in a wider range. At present, fewer methods of using machine vision are adopted to detect the color grade of cotton, and the accuracy is not high. Therefore, in view of the above situation, a cotton color grade detection method based on machine vision was designed.

Method An experimental platform was firstly built. The light source was fixed to the aluminum profile frame and sealed. Cotton was collected in real time through a camera connected to a computer. The collected cotton sample image was transmitted to a computer and preprocessed, and the preprocessed image was cropped using Halcon software and divided into subregions. The albedo (Rd) and yellowness (+b) values of each subregion were calculated by the conversion of color space values, and the color value of each subregion was clustered by the K-means algorithm to obtain the color average of the overall image of cotton. Finally, it was compared with the national standard cotton color grade map to determine the final grade of cotton. Four different color grades of cotton were selected for impurity removal and non-impurity treatment, and the color parameters obtained after impurity removal and without impurity removal were calculated by Halcon software. For the same impurity removed cotton, the Rd value and +b value was calculated, and compared with the detection of MCG-1 detection instrument, the detection results were counted, and scatter plotted by using Origin software to observe the linear relationship between the two detection methods. In order to explore the stability of the test results under different durations, cotton was continuously tested in the time periods of 0 h, 12 h, 24 h, and 36 h in the same environment under the condition that the equipment was not turned off and the lights were not turned off. Finally, in order to explore whether the overall color value of cotton can represent the color grade of the entire cotton sample, two different color grades of white cotton and light yellow dyed cotton were selected for testing, and under the same conditions, the color value of each sub-region of the two cotton was calculated by using software, and the value of each sub-region was placed in the national standard cotton color grade chart for comparison to observe the distribution of the color grade of each sub-region.

Results It is found that the Rd value and +b value detected in the cotton after impurity removal were higher than those detected before impurity removal, but the Rd value increased more and the +b value increased less. For the same cotton, the color value of cotton detected by image processing method was compared with the color value obtained by MCG-1 cotton detector, and the two results were highly correlated and linear, indicating that the results detected by the two methods were consistent. Cotton was continuously tested at different lengths of 0-72 h, and it was found that the test results were stable at each duration, and all were in the same area. Compared with the MCG-1 test results, they were all the same grade cotton. The results of the K-means algorithm were compared with the mean detection, and the results of the K-means algorithm were closer to the results obtained by the MCG-1 cotton detection instrument, and the detection accuracy was better than the results obtained by the mean detection.

Conclusion Using machine vision methods to inspect cotton color grades improves the simplicity, efficiency, and accuracy of inspection. This technology not only solves the problem of expensive cotton testing instruments, but also solves the problem of fewer methods and insufficient accuracy of using image processing to detect cotton grades, and can replace the instrument used in practical cases. With the continuous development and maturity of machine vision technology, the technology could be made more useful in the field of cotton testing in the future, and in machine vision methods for cotton color detection. It is expected that this method can be used as a basis for image processing to detect cotton grades, and can be further improved and optimized.

Textile Engineering

Simulation of accelerating point distribution for floating fibers during dynamic drafting

FAN Jule, ZHANG Yuze, WANG Jun

Journal of Textile Research. 2024, 45(03):  44-48.  doi:10.13475/j.fzxb.20220809101

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Objective The reason for additional unevenness of output slivers after drafting is that the accelerating point of floating fibers fluctuates in a region during the drafting process. However, the existing models could not simulate the influence of the frictional force among fibers on the fiber acceleration process during the dynamic drafting process. In order to study the influence of drafting conditions on the accelerating point distribution of floating fibers, this paper established a dynamic drafting model and simulated the acceleration process of floating fibers with frictional force between fibers during the dynamic drafting process.

Method According to the velocity and the frictional force of fibers, the fibers in the drafting zone were divided into four types: back fiber, slow-floating fiber, fast-floating fiber, and front fiber. Further, back fiber and slow-floating fiber were called slow fiber, and fast-floating fiber and front fiber were referred as fast fiber. The dynamic drafting process of fibers was refined into five stages: entering the drafting zone, leaving the back roller nip line, accelerating, reaching the front roller nip line, and leaving the drafting zone. On this basis, the dynamic drafting process of fibers was simulated by calculating the time interval between adjacent fibers entering the drafting zone and the movement time of fibers at each stage. In addition, the acceleration process of fibers was simulated by calculating the guiding force and control force on floating fibers during the dynamic drafting process. The fibers in contact with floating fibers in the dynamic drafting process were determined by randomly selecting fibers from the drafting zone and calculating the contact length. The guiding force was obtained by calculating the contact length between floating fibers and surrounding slow fibers, and the control force was obtained by calculating the contact length between floating fibers and surrounding fast fibers. During the dynamic drafting process, the control force and guiding force changed dynamically as the floating fiber gradually moved to the front roller nip line. The floating fibers was accelerated instantaneously when the guiding force reached and exceeded the control force. At this moment, the leading end position of the floating fiber was the position of fiber accelerating point.

Results By weighting and cutting the strand in the drafting zone, the distribution of frictional field of simple roller device was calculated. On this basis, the dynamic drafting process with different drafting ratios and fiber lengths was simulated and the accelerating point distribution of floating fibers was obtained. The results showed that with the increase of drafting ratio, the distribution of accelerating points was gradually closer to the front roller nip line, and the distribution range of acceleration gradually reduced. This showed that the greater the drafting ratio, the more concentrated the slow-floating fiber accelerated in the area closer to the front roller nip line, and the longer the fiber length was, the closer the accelerated point distribution was to the front roller, and the smaller the range of accelerating point distribution was. This is because the longer the fiber length was, the shorter distance the fiber moved as floating fiber. In addition, the distribution of accelerating points in the simulation with different drafting conditions was roughly in the form of the normal distribution, which was close to the actual situation.

Conclusion This method could simulate the acceleration process of floating fibers affected by the frictional force among fibers during dynamic drafting process. In addition, the principle of the influence of different drafting conditions on the drafting process could be analyzed through this method because different drafting conditions changed the distribution of floating fiber accelerated points by affecting the frictional force between fibers. Therefore, this method could be adopted to predict the unevenness of the output sliver after drafting, and to design and optimize the process parameters of the actual drafting equipment.

Yarn unevenness measurement method based on multi-view images

FU Caizhi, CAO Hongyan, LIAO Wenhao, LI Zhongjian, HUANG Qixiang, PU Sancheng

Journal of Textile Research. 2024, 45(03):  49-57.  doi:10.13475/j.fzxb.20221003301

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Objective The performance of yarn directly determines the quality of the fabric, and the unevenness of yarn is an important indicator for evaluating yarn quality. Testing and analyzing yarn unevenness is a necessary aspect for controlling and improving yarn quality. However, as a typical linear heterogeneous material, yarn is difficult to accurately characterize its actual performance by simply detecting its volume or single direction projection using existing detection instruments. In order to more accurately represent the three-dimensional features of yarn, a method based on multi-view yarn images is proposed to measure and evaluate the yarn unevenness.

Method An image acquisition device with single camera was constructed to obtain images of yarn from multiple view angles, before the obtained yarn images in four directions were processed sequentially through automatic threshold segmentation, image automatic cropping, rapid removal of hairiness, and removal of isolated areas. A clear and noise-free image of the yarn core was obtained. Single- and multi-view diameters and CV values were read from the yarn core image, and new multi-view unevenness mean (CV_n) indicators and three-dimensional unevenness variation coefficient (S) indicators were proposed based on the elliptical model to characterize yarn unevenness.

Results The unevenness of five cotton ring spun yarns with different linear densities was tested and compared with the test results of Uster tester. The results showed that the difference in yarn diameter detected by the two testing methods is not significant, both illustrating diameter decreases as the linear density was decreased. The average diameters measured from four single perspectives was quite consistent, indirectly indicating that the diameter testing process of the proposed method is correct. The yarn diameter measured by the proposed method was slightly smaller than that measured by the Uster tester, mainly because of the use of image processing operations to remove hairiness. The results also showed that CV 0.3 mm, CV 8 mm under single and multiple view angles was consistent with the results measured by Uster tester. The CV values gradually increase with the decrease of linear density, which was consistent with the theory that says the smaller the linear density, the more uneven the yarn. The proposed three-dimensional unevenness variation coefficient S, regardless of S 1p, S 0.3 mm, or S 8 mm, increased with the decline of yarn linear density, and all conform to the theory that the larger the fiber length, the smaller the CV value. The proposed method approximated the yarn with a regular ellipse for cross-sectional area, and the diameter values of multiple perspectives were multiplied using the ellipse area formula. As the area increases compared to the diameter value, the CV value also increases. Therefore, the measured S values are greater than the Uster tester results at various cutting lengths, thus can characterize the variation rule of yarn thickness.

Conclusion In this paper, a new image processing method and a new indicator for characterizing yarn unevenness are proposed based on a multi-image acquisition device with single camera. The yarn detection results are compared with the diameter and CV values measured by the Uster tester and the proposed method. The results show that in terms of yarn appearance diameter, single-view and multi-view CV, the two methods lead similar results with consistency, which are in line with relevant theory and understanding, suggesting that the method proposed in this paper could be used for detecting yarn unevenness. However, this paper used a rotating camera to capture multi-view images, which caused inefficient. What's more, the yarn cross-sectional area is regarded as a regular ellipse to calculation. After the diameter values of multiple angles are multiplied according to the ellipse area formula, the data base value becomes larger, and then the CV value becomes larger. This is also the main reason why S is too large in this paper. In the future, a multi-camera real-time yarn detection device should be built up to facilitate three-dimensional real-time yarn detection.

Mechanical property analysis of single yarn pull-out from aramid plain woven fabrics

MA Ying, CHEN Ao, HU Yuepeng, PAN Jun, HU Hanjie, LU Sheng

Journal of Textile Research. 2024, 45(03):  58-64.  doi:10.13475/j.fzxb.20221108001

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Objective Aramid fabrics show highly nonlinear and anisotropic behavior under ballistic impact, which brings immense challenges to the study of their mechanical properties. Hence, yarn pull-out, as an important mechanism for dissipating ballistic impact energy, is immerged as a popular research subject. However, in the existing researches, not enough attentions have been paid to the influence mechanism of different factors on the peak pull-out force and the change of pretension. In this paper, the effects of fabric pretension, pull-out speed, fabric dimension, and yarn type on peak pull-out force and pretension is systematically studied under laboratory conditions.

Method The experimental setup is mainly composed of an automatic centering and fixture, especially designed for yarn pull-out test, attached to an electronic universal testing machine. Two load cells are a installed to measure the pull-out force and pretension. The experiment was divided into 5 groups with a total of 23 experiments. Each experiment is repeated for 4 times to minimize operation error. The change of pull-out force and pretension with respect to displacement is recorded under various conditions to analyze the influence mechanism of transverse pretension, pull-out speed, fabric length, fabric width, and yarn type on pull-out performance.

Results The pull-out force and pretension oscillate sinusoidally with zero phase difference at the same frequency. The peak pull-out force is in direct proportion to the number of yarn cross-over, the tension at the yarn cross-over, and the deformation magnitude. When the initial transverse pretension equals to 100, 200, 300, and 400 N, the peak pull-out force is 5.63, 7.30, 8.85 and 10.58 N, respectively, the increase of transverse pretension was 3.37, 2.92, 2.22 and 1.87 N, respectively, and the decrease of transverse pretension was 15.02, 17.37, 19.55 and 21.94 N, respectively, during the pull-out. When the fabric length was increased from 30 mm to 110 mm, the peak pull-out force was increased from 2.04 N to 6.14 N, the rate of increase, however, was decreased from 93.63% to 7.16%. The increase and decrease amount of transverse pretension during the pull-out increase and decrease, respectively. When the pulled yarn is weft, the density of which is smaller than warp, the peak pull-out force, the increase and decrease of the transverse pretension is 1.13 to 1.21, and 0.90 to 0.99, and 1.36 to 1.93 times that of the warp under the same precondition. When the fabric width was increased from 30 mm to 110 mm, the peak pull-out force was increased from 4.02 N to 4.95 N. When the pull-out speed was increased from 10 mm/min to 400 mm/min, the peak pull-out force is decreased from 6.10 N to 5.00 N.

Conclusion When the initial transverse pretension ranges from 100 N to 400 N, the peak pull-out force is linearly correlated with the transverse pretension, the increase and decrease amount of transverse pretension decreases and increases with the increase of initial transverse pretension. When the fabric length was increased from 30 mm to 110 mm, the rate of increase of peak pull-out force decreased, the increase and decrease amount of transverse pretension during the pull-out increase and decrease, respectively. A smaller yarn density leads to a bigger crimp degree after applied pretension and a bigger peak pull-out force. The fabric width and pull-out speed have little impact on peak pull-out force.

Hexagonal three-dimensional virtual braiding of vascular stent preforms

DING Caihong, GU Xin, LU Chenyu

Journal of Textile Research. 2024, 45(03):  65-73.  doi:10.13475/j.fzxb.20221004001

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Objective The braiding process for braided vascular stent preforms is relatively straightforward and fixed, with drawbacks including weak mechanical qualities and singular applications that cannot satisfy the genuine market needs. Complex correspondence between fabrics and processes, as well as long development cycles, are issues of developing a process by hexagonal three-dimensional (3-D) braider with a variety of braiding processes. Therefore, it is suggested that a simulation technique considers the connection between the hexagonal braiding process and the fabric structure, so as to create a 3-D virtual model of the stents under particular hexagonal braiding processes and to speed up the development of braiding processes.

Method Firstly, the units were mathematically coordinated by building the geometric relationships of the hexagonal braider chassis, so that the yarn movements could be transformed from the braiding process and recorded in matrices. By using matrix operations, the spatial coordinate sets of the yarns were produced, and the related formulas for the yarn trajectory and the fundamental 3-D shape of the stent were then created. The 3-D form of the stent was expanded, and by analyzing the characteristics of the unidirectional fabric, a system of linear equations was applied to solve for the yarns' interweaving points and identify the type of interweaving in conjunction with the yarn movement. Finally, the yarn fluctuation equation was modified to generate formulas for the trajectory with interweaving properties, and the solid model of the holder was constructed and tested against the actual object to verify the correctness of the model.

Results In detail, matrixes were applied to record the information transformed by the hexagonal braiding process, and in combination with the mathematical model of the carrier-suspender-mandrel established, the tangent points of the yarn wound on the mandrel, i.e., the set of coordinates of the spatial trajectory of the yarn, were calculated by matrix operations. The discrete points in the coordinate sets were connected and fitted to create a model of the spatial trajectory of the yarn, which was compared with the trajectory obtained by the numerical calculation, suggesting that the spatial spiral curve could be used to simplify and more accurately show the spatial trajectory of the yarn, and the model obtained by this method was used as the 3-D basic form of the stent. In order to further demonstrate the interwoven form of the stent, the 3-D basic form of the stent was expanded along the z-axis direction, enabling the interweave points to be solved in reduced dimensions. On this basis, calculation of yarn winding tangent point was created to calculate the 2-D coordinates of the yarn interweaving points and to find the 3-D coordinates by means of the z-values. In addition, the z-values enabled information relating to the interweaving of the yarns in the braiding process to be found, which was used to determine the carrier interaction of the inter-weaving yarns, and in turn to apply interweaving principle to determine the change in position of the yarns in the fabric to obtain the fabric in-terweaving type (U∶V) defined. Based on the above, the modified yarn fluctuation equations were applied to obtain the mathematical formulas for left- and right-handed yarns reflecting the type of interweaving of the hexagonal braiding, thus creating a solid numerical model of a virtual fabric with 3-D interweaving characteristics. In order to validate the method above, 3-D virtual braiding experiments were carried out on stents with different hexagonal braiding processes, comparing the type of interweaving and related dimensions of the virtual fabric and the real one, and it was discovered that both were almost identical in terms of morphology and values. By inputting the hexagonal braiding process and dimensional parameters, the method was able to produce a corresponding 3-D model of the virtual vascular stent.

Conclusion The viability and accuracy of the virtual braiding approach for the hexagonal 3-D braiding process of the stent preforms were confirmed through modelling of forms, interwoven manipulation, and solidification of the hexagonal braided stent preforms. This would offer technical assistance for the quick advancement of the hexagonal braiding process and the evaluation of the stent's mechanical characteristics. It was important to note that many companies had concentrated on the structure of stents with variable yarn rotation and superimposed inter-weaving layers and their braiding process in addition to the widely used unidirectional structure of hexagonal 3-D braided stents. As a result, the virtual modelling needs of braided stents had been further broadened and the 3-D virtual braiding algorithm of the stent would also become more complex.

Fabric visualization bending test method

YANG Yang, LIU Chengxia

Journal of Textile Research. 2024, 45(03):  74-80.  doi:10.13475/j.fzxb.20220507801

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Objective Fabric bending is an important attribute that affects the style and appearance of fabrics and directly reflects the magnitude of fabric draping ability, therefore fabric bending evaluation has attracted the attention of many researchers. The fabric is soft and prone to deformation that even test results in the same direction witness considerable variation. It has been necessary to conduct multiple tests to reduce experimental errors. The current bending test standard is to test the warp and weft directions of the fabric for 5 times each, the average of which is taken to characterize the overall bending performance of the fabric, which is cumbersome and time-consuming. Facing this situation, this paper proposes a fast and simple testing method capable of simultaneously obtaining multiple sets of results, which is referred as the sunflower method.

Method In this research, 14 types of woven fabrics were selected as the research objects, and 2 samples were cut from each fabric in two directions, 0° and 90°. Four characteristic indexes were extracted by the new method, which are unfolding area S, unfolding perimeter Z, unfolding length L and sagging height H. The relationship between the new method and the conventional testing methods was explored by analyzing the relationship between four new indicators and bending length C and bending stiffness B. Correlation analysis was adopted to explore the correlation between various indicators. Coefficient of variation was introduced to study the testing stability of the two methods through one-way analysis of variance, such as CV of different directions, fabrics, and textures.

Results Comparing the correlation coefficient values of S, Z, L and H with the bending length and bending stiffness in four directions, it was found that all Pearson coefficient values are above 0.78, except for H at 90°. The negative correlation with conventional indexes was H, and the positive correlation was S, Z and L. Pearson coefficient between Z and L in all four directions was greater than 0.85. All the four new indicators showed good correlation with the bending length and bending stiffness in convenitional methods, proving feasibility of the method proposed in this paper. The CVs of Z of the new method and the bending length of the inclined plane method were both less than 0.1. Single factor analysis of variance is adopted to compare the CVs of the four directions in the new method, and no obvious difference was found. Comparing the CV of the new method for testing the bending properties of cotton and chemical fiber fabrics through single factor analysis showed no significant difference, and there was no significant difference in the CVs of the bending test results of plain and twill fabrics. In other words, the stability of the new method for testing the bending properties of fabrics in different directions was the same. The stability of the bending test results for cotton and chemical fiber fabrics, as well as the stability of the bending test results for plain or twill fabrics, are the same as well.

Conclusion The new method proposed in this paper, named as the sunflower method, showed satisfactory agreement with the conventional bending test method. It can test the bending stability of fabrics in two directions, which can simultaneously obtain 10 test values and 4 characteristic indicators, without the need for multiple cutting and repeated testing. Compared with conventional methods, it has higher efficiency and saved testing time. The data obtained from using the new method can also be adopted to visualize the stability of fabric bending, providing a clear understanding of the differences in fabric bending, which is conducive to material selection in fashion design.

Production scheduling of warping department based on adaptive simulated annealing algorithm

SHEN Chunya, FANG Liaoliao, PENG Laihu, LIANG Huijiang, DAI Ning, RU Xin

Journal of Textile Research. 2024, 45(03):  81-86.  doi:10.13475/j.fzxb.20220905201

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Objective Taking the warping scheduling of weaving enterprises as the research object, the yarn types and order quantities are reasonably configured through intelligent algorithms based on the actual scheduling needs, aiming to achieve the optimization of production scheduling, improve production efficiency, reduce waste of raw materials, and increase production capacity. In order to solve the problems of low production efficiency and low utilization of warping shafts in warping department of weaving enterprises under multiple constraint conditions, the optimization achieved through intelligent algorithms in configuring yarn types and order quantities can significantly enhance the efficiency of the entire process flow, thereby realizing an increase in production capacity.

Method Taking the total number of warp ends, order meters, winding length of warp beam, warp ends per warp beam and others as the constraints, and the number of warp beams and processing time as the objective functions, the master-slave optimization correlation model of production relations in warping department meeting the cylinder assembly conditions was established. A production scheduling scheme of the warping department based on adaptive simulated annealing algorithm was proposed. By introducing an adaptive annealing factor, the shortcomings of conventional simulated annealing algorithms such as low computational efficiency and susceptibility to local optima were effectively overcome.

Results In order to verify that the master-slave model and its solution algorithm of multi-constraints production scheduling are suitable for warp beam preparation, the production order of a certain production cycle in the warping department of a textile enterprise was taked as an example. the adaptive simulated annealing algorithm (ASAA), simulate anneal algorithm (SAA) and genetic algorithm (GA) were adopted to solve the orders. The smaller the number of warp beams, the shorter the processing time and algorithm running time, the better the algorithm optimization effect. According to the data of an individual order, the experimental simulation was carried out with the number of warp beams, processing time and algorithm running time as the objectives. The utilization rate of the warp beam obtained by using the ASAA proposed in this paper was in general better than the other two algorithms, and the solution obtained in 30 experiments was less volatile and more stable. The solution sets of the three algorithms for the 30 experiments with two objective functions as the coordinate axis. Smaller values of the two objective functions would indicate better solution. The solution set of ASAA was more concentrated on the lower left part, showing that the solution set of ASAA yielded smaller objective functions with better performance. It was evident that ASAA outperformed the other two algorithms in terms of computational efficiency when solving the warping scheduling problem. For the same order, in 30 experiments, the ASAA could save an average of 20% of the operation time compared with the other two algorithms.

Conclusion Based on the research on the production scheduling problem in warping department of weaving enterprises, an optimization model of warping production scheduling for multi-constraint conditions and warp beam production is constructed, and simulation experiments are carried out according to the actual production cases of enterprises. The results show that the adaptive simulated annealing algorithm proposed in this paper can effectively improve the efficiency of warping production scheduling in textile enterprises, and improve the utilization of warp beams. However, considering that the actual production process would be much more complex than the experimental environment, and unstable factors such as order insertion, equipment failure, and shortage of raw materials need to be considered, further improvement of the model is an important direction for future research.

Dyeing and Finishing Engineering

Catalytic oxidation of flax with alkaline boiling in one bath degumming process and its properties

YANG Shu, CAO Qiaoli, LI Jiyuan, LI Zhaoling, YU Chongwen, ZHANG Yang

Journal of Textile Research. 2024, 45(03):  87-96.  doi:10.13475/j.fzxb.20230200701

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Objective Flax should be degummed before spinning using cotton spinning system. The degumming process is to remove pectin, hemicellulose, lignin, and other non-cellulosic substances from the raw flax. The whiteness of flax fiber obtained by the conventional alkali degumming process is low, and bleaching is a necessary step. The oxidative degumming process is easy to cause cellulose degradation, which leads to the decrease of fiber breaking strength. Meanwhile, residual oxidized lignin after degumming tends to reduce fiber elongation because of its high lignin rigidity.

Method N-Hydroxy-3,4,5,6-tetraphenylphthalimide (NHTPPI)catalytic oxidation with alkali boiling in one bath was adopeed to degum flax. The NHTPPI catalytic oxidation system selectively oxidizes primary hydroxyl groups at the C6 position of cellulose. This feature was utilized to achieve effective inhibition of the oxidative degradation of cellulose macromolecular chains while removing non-cellulosic material, bleaching fibers, and oxidizing lignin. Finally, the benzene ring and side chain of oxidized lignin were dissolved in sodium hydroxide solution.

Results Single-factor tests were carried out on the concentration of NHTPPI, 9,10-anthraquinone and hydrogen peroxide, pH value, reaction temperature and sodium hydroxide. The results of the single-factor tests showed that the optimum concentrations of hydrogen peroxide was 9 g/L, the reaction temperature was 80 ℃, the pH value was 10.5, the amount of catalyst NHTPPI was 0.6 g/L, the concentrations of co-catalyst 9,10-anthraquinone was 0.5 g/L and the concentrations of sodium hydroxide was 5 g/L. Influences of the factors on the flax fiber breaking strength and whiteness after degumming were then investigated using SPSS statistical analysis software. The results showed that the concentrations of hydrogen peroxide had an extremely significant effect on the flax fiber breaking strength and whiteness. The reaction temperature had a highly significant effect on flax fiber breaking strength and whiteness, and the sodium hydroxide concentration had a significant effect on flax fiber breaking strength and whiteness. It was found that the pH had no significant effect on flax fiber breaking strength and whiteness, the NHTPPI concentration had no significant effect on flax fiber breaking strength and whiteness, and the 9,10-anthraquinone concentration had no significant effect on flax fiber breaking strength and whiteness. A preliminary single-factor test was conducted to determine the ranges of these significant variables, that hydrogen peroxide concentration was in the range of 6-12 g/L, reaction temperature was in the range of 60-100 ℃ and sodium hydroxide concentration was in the range of 2-8 g/L. Their interaction effects and optimization of the reaction conditions were investigated using a central combined design CCD. Response surface analysis was carried out using Design-Expert to obtain the optimum process for flax degumming by NHTPPI catalytic oxidation and alkali boiling in one bath. The results showed that the optimum process for the catalytic oxidation of flax and the degumming in one bath by alkali boiling was as follows: NHTPPI concentration of 0.6 g/L, 9,10-anthraquinone concentration of 0.5 g/L, pH value of 10.5, hydrogen peroxide concentration of 10.35 g/L, reaction temperature of 83.6 ℃, sodium hydroxide concentration of 5.67 g/L. SEM, FT-IR and ¹³C NMR characterizations showed that after catalytic oxidation with alkali boiling in one bath, most of the non-cellulose components in the flax fiber were removed, the surface was smooth, carboxyl groups were generated on the fiber and only primary hydroxyl groups at the C6 position of flax were selectively catalytically oxidized, which could effectively inhibit the oxidative degradation of the cellulose macromolecular chain and enhance the fiber breaking strength. Compared with the three processes of catalytic oxidation with alkali boiling in one bath degumming, oxidative degumming with sodium periodate and conventional alkali degumming with hydrogen peroxide bleaching, catalytic oxidation with alkali boiling in one bath degumming of flax fiber had the highest breaking strength and the shortest reaction time. The length of fibers obtained by the three processes was about 28 mm, and the whiteness was all over 70%.

Conclusion The average breaking strength of the refined flax fiber prepared in repeat validation tests using the optimum process was 4.39 cN/dtex and the whiteness was 70.53%, which are very close to the predicted values of the CCD model (4.38 cN/dtex, 71.25%). The results show that the CCD model has good predictability for NHTPPI catalytic oxidation and alkali boiling one bath degumming process, and the fine of flax obtained conforms to the national standard. The process has a broad application prospect in the field of flax degumming.

Influences of pigment and linear density on spun-dyed polyester staple fiber and yarn

LU Yunjing, WANG Xue, QI Yuanzhang, SONG Lin, LIAN Zhijun, LI Xin

Journal of Textile Research. 2024, 45(03):  97-105.  doi:10.13475/j.fzxb.20230200201

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Objective The large-scale application of spun-dyed fiber corresponds to multi-spes and differentiated fiber production. However, a long transition cycle when changing the fiber color type or pigment content generates a large amount of transition material or waste in this process due to the generally large capacity of the device. Therefore, it is necessary to understand the influences of pigment type, content, and fiber linear density on the color of spun-dyed fibers, as well as the color variation from fiber to yarn, so as to guide more effectively the development and application of spun-dyed staple fibers.

Method The influences of pigment content (0.3%, 0.9%, and 1.5%) and fiber linear density (1.56, 2.78, 3.89 dtex and 6.11 dtex) on the chromaticity values of semi-dull spun-dyed polyester staple fibers red, yellow, and blue were systematically investigated. In parallel, the variation of chromaticity values from fiber to yarn (linear density of 20 tex, twist factor of 300) was examined and compared with specific specifications of semi-dull dyed staple fibers and bright spun-dyed staple fibers.

Results The results showed that the variation of pigment content significantly affected the chromaticity values of the semi-dull fibers, especially from light-color fiber to medium-color fiber, which is twice as much as between medium-color fiber and dark-color fiber. The chromatic aberration ΔE_CMC(2:1) for yellow fibers was 21.8 and 8.4, respectively, which is about three times higher than that for red and blue, mainly because of the contribution of the hue difference ΔH. The influence of fiber linear density variation on ΔE_CMC(2:1) was not significant, and the higher the linear density, the weaker the effect. Similarly, the ΔE_CMC(2:1) of yellow was more obvious than the other two colors. When producing products such as yellow, especially fine denier fibers, adjusting the linear density required reconfirming the pigment formulation. In general, the variation of chromaticity values from semi-dull spun-dyed staple fiber to yarn was not significant, with ΔE_CMC(2:1) in the range of 0.8-2.6. On contrast, the variation of chromaticity values of yellow semi-dull dyed staple fiber to yarn was large, with ΔE_CMC(2:1) in the range of 3.4-3.9. On further examination, the change rate of ΔE_CMC(2:1) for dyed fibers was 1.8-6.5 CMC(2:1)/dtex, which was significantly higher than that of spun-dyed fibers. It was also evident that the ΔE_CMC(2:1) of dyed fibers did not show a significant decrease in the change rate of ΔE_CMC(2:1) with the increase in the linear density of the spun-dyed fibers. The variation of chromaticity values from bright spun-dyed polyester staple fibers to yarn was similar to that of semi-dull dyed staple fibers, and ΔE_CMC(2:1), ΔL, ΔC, and ΔH were basically the same meaning that for specific color types, the yarn color matching experience of dyed fibers did serve as a reference.

Conclusion The chromaticity values of semi-dull staple fibers vary greatly with pigment types and content ranges. When the pigment content needs to be changed significantly during the production process, the masterbatch should be reformulated. Different fiber linear density ranges have different influences on the chromaticity values of the fibers, and the normalized results suggested that the smaller the linear density, the greater the change rate of ΔE_CMC(2:1). Among them, the change rate of ΔE_CMC(2:1) is most obvious for yellow, which is mainly due to larger ΔH, indicating that the adjustment of linear density requires reconfirmation of the masterbatch formulation when producing products such as yellow, especially fine denier fibers. For conventional linear density of semi-dull spun-dyed fibers, the color variation from fiber to yarn is not obvious. However, when the fiber linear density is small enough, such as ultrafine fibers prepared by composite spinning, this result needs to be re-examined. Overall, the change rate of ΔE_CMC(2:1) of dyed fibers is significantly higher than that of spun-dyed fibers, mainly due to the different chromophores of dyes and pigments. The color variation from fiber to yarn for the bright spun-dyed fibers is essentially the same as that for the semi-dull dyed fibers, implying that the color variation law from semi-dull dyed fibers to yarn can be utilized to guide the yarn color matching of the bright spun-dyed fibers.

Tea pigment dyeing of cotton fabric modified with polydopamine/chitosan and its antibacterial and anti-ultraviolet properties

LI Lili, YUAN Liang, TANG Yuxia, YANG Wenju, WANG Hao

Journal of Textile Research. 2024, 45(03):  106-113.  doi:10.13475/j.fzxb.20221201901

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Objective Plant dyes have attracted widespread attention in the textile industry due to their environmental and functional health benefits. To improve the dyeing durability and functionality of fabrics treated with plant dyes, chemical crosslinking agents or mordants are often used, which is harmful to the environment and human health. It is necessary to develop eco-friendly methods of plant dyes for fabric finishing, imparting fabrics good color fastness and multifunctionality.

Method Polydopamine/chitosan (PDA/CS) modified cotton fabrics were prepared by using chitosan (CS) finishing after rapid polymerization and deposition of dopamine (DA) on the fabric surface under CuSO₄/H₂O₂ oxidation system, and then dyed with tea pigment. The structure and morphology of the fabrics before and after modification were characterized and analyzed through scanning electron microscope, Fourier transform infrared spetroscopy and X-ray photoelectron spectroscopy. The color fastness, antibacterial and UV resistance properties of different modified cotton fabrics dyed with tea pigment were compared and analyzed.

Results The effect of various factors on the dyeing performance of the modified cotton fabrics during the rapid polymerization and deposition of DA were investigated, and the better process conditions were obtained: CuSO₄ concentration of 3 mmol/L, DA concentration of 2.0 mg/mL, H₂O₂ concentration of 13 mmol/L, and deposition time of 2 h. The K/S value of the PDA/CS modified cotton fabrics after dyeing reached 6.21. The fiber morphology and structure showed that the surface of PDA modified cotton fiber was obviously covered with a layer of PDA coating, which made CS uniformly film on the fabric surface, and the surface substance of PDA/CS modified cotton fabrics was further increased after dyeing with tea pigment. The chemical structure analysis showed that the intensity of the characteristic absorption peaks near 3 342 cm^-1 of the PDA modified cotton fabrics increased significantly after CS treatment, indicating that hydrogen bonding between PDA molecules and CS molecules was generated on the surface of the cotton fabrics. The intensity of the absorption peaks of the modified fabrics after dyeing in the interval of 1 455 to 1 210 cm^-1 were increased, indicating that the tea pigments were successfully adsorbed on the surface of the modified fabrics. Elemental composition analysis showed that compared with raw cotton, there was a new Nls absorption peak at 403.4 eV in the full spectrum of PDA modified cotton fabrics, and the N element content of PDA/CS modified cotton fabrics increased from 3.84% to 4.12%. The color fastness to soaps (discoloration) of PDA/CS modified cotton fabrics after dyeing was 3-4, and the color fastness to rubbing, soaps(staining) and artificial light reached 4 or above. The UPF value reached 312, and the transmittance of UVA and UVB bands were less than 1%. In addition, the inhibition rate of Staphylococcus aureus and Escherichia coli were 91% and 90%, respectively.

Conclusion Under the CuSO₄/H₂O₂ oxidation system, DA rapidly polymerized to form PDA polymer. Cotton fabrics were composite modified by PDA and CS, and then dyed by the natural plant dye tea pigment without any chemical crosslinking agent or mordant. Modified fabrics after dyeing have good color fastness, as well as dual effects of antibacterial and anti-ultraviolet properties, which promoting the high-quality production of cotton textiles. It is expected to be developed as a short process technology for the integration of plant dye dyeing and finishing, providing a theoretical basis for the use of natural dyes in textile dyeing and finishing technology and the development of ecological textiles.

Preparation and application properties of chitosan fluorescent anti-counterfeiting printing coating

LI Manli, JI Zhihao, LONG Zhu, WANG Yifeng, JIN Enqi

Journal of Textile Research. 2024, 45(03):  114-121.  doi:10.13475/j.fzxb.20230202401

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Objective In order to tackle the low fluorescence intensity and photobleaching resistance of organic fluorescent anti-counterfeiting printing coatings commonly used in textile printing and dyeing industry, aggregation-induced emission (AIE) fluorophore-tetraphenyl ethylene (TPE) labeled chitosan (CS) fluorescent anti-counterfeiting coatings were prepared and their application properties were investigated.

Method The typical AIE monomer-tetraphenyl ethylene-isothiocyanate (TPE-ITC) was synthesized initially. The TPE-ITC product was characterized by Fourier transform infrared spectroscopy (FT-IR) and MALDI-TOF mass spectrometry (MS). The study took CS as the representative of bio-based polymer paints, labeled different amounts of TPE fluorophores onto CS using the TPE-ITC as fluorescent monomers, and prepared a series of TPE-CS fluorescent paints with different degrees of labeling (DL). The series of TPE-CS products were characterized by FT-IR and ¹H-nuclear magnetic resonance (¹H-NMR) to confirm the labeling of TPE fluorophores. Main application properties of the TPE-CS paints, such as fluorescence intensity, photobleaching resistance and thermal stability, were evaluated. Anti-counterfeit printing on cotton fabric was carried out using the TPE-CS coatings and the common color fastness of the printed fabric was tested systematically according to the national standards.

Results FT-IR and MS spectra confirmed that the synthetic product was the expected AIE fluorescent monomer TPE-ITC. FT-IR and ¹H-NMR spectra proved that TPE fluorophores were successfully grafted onto the molecular chain of CS. The higher was the feed concentration of TPE-ITC monomers, the higher was the DL of TPE-CS. TGA thermograms illustrated that TPE-CS (DL of 2.56%) had nearly the same thermal stability with unlabeled CS. With the increase in the DL, the fluorescence intensity of TPE-CS showed a gradual increase, reflecting its unique AIE advantage. The TPE-CS coating was colorless and thus its printing pattern on the fabric had good concealment in the sunlight. On the contrary, because of the high fluorescence quantum yield of the AIE fluorophores, the TPE-CS coating was found to emit blue fluorescence under ultraviolet light, and the printing pattern on the fabric could be easily recognized with the naked eye. With the increase in the DL of the TPE-CS, the fluorescent intensity of the printing patterns on the fabric kept increasing. Compared with aggregation caused quenching (ACQ) fluorophore labeled CS, the anti-counterfeiting TPE-CS coatings exhibited superior fluorescence intensity and photobleaching resistance. Even if the DL of TPE-CS was only 1.43%, the relative fluorescence intensity of the anti-counterfeit coating solution (1 000 mg/L) could exceed 1 090. After exposure to high-intensity ultraviolet light for 1 h, the relative fluorescence intensity of the solution still reached 94.9% of that before photobleaching. The common color fastness ratings for the fabric printed by TPE-CS 3^# were all above level 3.

Conclusion Labeling AIE fluorophore TPE onto CS macromolecule is one of the effective methods to prepare high-performance organic polymer fluorescent anti-counterfeiting printing paint. The high heat stability of CS is not affected by the labeling of TPE group. The TPE-CS anti-counterfeiting coating within the appropriate range of the DL is sufficient to withstand the baking temperature during printing. In addition, the fluorescence emission intensity of TPE-CS is much higher than that of F-CS after UV photobleaching with the same time and intensity. The use of TPE-CS fluorescent anti-counterfeiting coatings can solve the problems of the ones labeled by ACQ fluorophore, such as low fluorescence emission intensity and weak photobleaching resistance. Taking the application properties and preparation cost into serious consideration, TPE-CS with the DL of 1.43% shows good fluorescence emission performance and high photobleaching resistance and thus the DL value is appropriate. The fabric printed by the TPE-CS coating possesses high fastness to sunlight. Therefore, it can compensate for the lack of sunlight resistance of ACQ fluorescent paints and is suitable for long-term outdoor use. The AIE fluorophore labeled bio-based polymer has great potential to be widely used in the field of textile fluorescent anti-counterfeiting printing as a kind of environment-friendly coating with extensive sources and excellent performance. The preparation and application of TPE-CS fluorescent printing coating can overcome the defects of commonly used fluorescent paints and can be used as an important reference for the preparation of other kinds of AIE fluorophores labeled bio-based fluorescent coatings, such as starch, cellulose, and protein.

Conductivity and electrical heating properties of reduced graphene oxide modified silk fabric by screen printing

CHEN Kun, XU Jingying, ZHENG Yiqian, LI Jialin, HONG Xinghua

Journal of Textile Research. 2024, 45(03):  122-128.  doi:10.13475/j.fzxb.20221104501

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Objective As a natural material with good mechanical properties and piezoelectricity, silk is widely used in the field of intelligent textiles. However, the development of intelligent wearable textiles is limited due to its inability for normal machine washing. Therefore, it is necessary to study the washing resistance of silk-based intelligent textiles. In order to study the washing resistance and electric heating properties of silk-based wearable fabrics, this work explores the influences of screen-printing times and fabric structure on fabric conductivity, washing resistance and electric heating performance.

Method In this study, graphene oxide (GO) was repeatedly finished on the surface of silk fabrics with satin, twill and backed weaves by screen printing, and then reduced graphene oxide (RGO) modified silk fabrics were prepared by reducing agent. The apparent morphology and crystal structure of the prepared RGO modified silk fabric were analyzed by scanning electron microscope and X-ray diffractometer. The surface resistance of the sample was tested by VC890D digital multimeter, and the samples were washed according to the standard of GB/T 8629—2017. The electrical heating properties of samples were tested by infrared thermal imager.

Results The spacing between the yarns in the satin silk fabric is obvious, and the RGO sheet structure on the surface is easily interrupted. Although many RGO layers adhered on the surface of RGO modified twill silk fabric, it is prone to large voids in the warp direction. RGO modified backed weave silk fabric has a large area of RGO layer in both warp and weft directions. The untreated silk fabric and the prepared RGO modified silk fabric have basically the same characteristic peak positions in the X-ray diffraction pattern. The preparation method used in this paper has no obvious effect on the original crystal phase structure of silk. With the increase of screen-printing times, the resistance of the fabric surface gradually decreases. When the number of screen-printing times is the same, the backed weave fabric has the minimum fabric surface resistance, and which is 0.539 kΩ·cm when the fabric is screen-printed for 6 times. The minimum change in the surface resistance of the fabric after washing is achieved by screen printing for 5 times. After 9 cycles of washing, the fabric resistance of each of the three fabrics is 1.427 kΩ·cm (satin weave), 1.061 kΩ·cm (twill weave), 0.797 kΩ·cm (backed weave), respectively. Accordingly, the RGO modified satin silk fabric has good electrical heating properties, reaching a stable temperature of 96 ℃ at a current of 0.025 A, and the maximum heating rate is 10 ℃/s. When the input current value is the same, the saturation temperature of RGO modified twill silk fabric is greater than that of RGO modified backed weave silk fabric. When the input current is 0.03 A, the saturation temperatures of the RGO modified twill weave silk fabrics is 69 ℃, and RGO modified backed weave is 39.8 ℃, and the heating rates are 9.7 ℃/s (twill weave) and 4.5 ℃/s (backed weave).

Conclusion Under the same preparation conditions, the resistance of RGO modified backed weave fabric is the smallest. In addition, the resistance of RGO modified silk fabric with 6 screen-printing times is higher than that of RGO modified silk fabric with 5 screen printing times after washing. Among the RGO modified silk fabrics with three different structures, the satin weave showed better electrical heating properties. This paper shows that RGO modified silk fabric prepared by screen printing has good washing resistance and electrical heating properties, and has good application potential in the field of intelligent wearable textiles.

Synthesis and application of microfiber leather impregnated with waterborne polyurethane

LI Chen, WANG Dong, ZHONG Hongtian, DONG Peng, FU Shaohai

Journal of Textile Research. 2024, 45(03):  129-136.  doi:10.13475/j.fzxb.20230303001

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Objective As an artificial leather product, impregnated microfiber leather owns excellent thermodynamic properties, rebound resilience, softness, and fullness. However, the main material for its production is solvent polyurethane, which causes serious environmental pollution. Whereas waterborne polyurethane, an environmental-friendly material, brings problems of surface cracks and poor texture when applied to the impregnation of microfiber leather. In order to solve these problems, a particular waterborne polyurethane emulsion was designed and synthesized by referring to the solvent polyurethane with large molecular weight and small particle size, and then successfully applied to the production of impregnated microfiber leather.

Method The prepolymer method was adopted to synthesize the target waterborne polyurethane emulsion by using isophorone diisocyanate (IPDI) as the hard segment, polycarbonate diol (PCDL) as the soft segment, 2,2-bis(hydroxymethyl) propionic acid as the hydrophilic chain extender, and 1,4-butanediol as the flexible chain extender, trimethylolpropane (TMP) as internal cross-linking agent, and ethylenediamine as post chain extender. The relative molecular weight and emulsion particle size of waterborne polyurethane were controlled by adjusting the relative molecular weight of PCDL and the content of TMP, the waterborne polyurethane emulsion with the optimal formula was applied to the production of impregnated microfiber leather.

Results Firstly, emulsion tests were conducted to explore the influences of PCDL relative molecular weight and TMP content on the waterborne polyurethane emulsion in different aspects. According to the results, the relative molecular weight and emulsion particle size of the waterborne polyurethane emulsion was increased with the rising of the PCDL relative molecular weight, and the emulsion particle size decreases first and then increases sharply with the growth of TMP content. When the PCDL relative molecular weight reached 500, the emulsion would be cured smoothly to form a film, and when the PCDL relative molecular weight exceeds 3 000, the emulsion doesn't emulsify but disperses in a flocculating form due to the overlong molecular chain segment. When the TMP content surpasses 3%, the waterborne polyurethane emulsion obviously begins to precipitate due to excessive long-chain network structures and seriously intertwined segments. When the PCDL relative molecular weight amounts to 2 000 with a 3% TMP mass fraction, the synthesized waterborne polyurethane demonstrates a strong storage stability with a relative molecular weight of 5.93×10⁴ and a particle size of merely 89.54 nm. After DSC, DMA, and mechanics property analysis tests on the cured films of the above waterborne polyurethane, it was concluded from PCDL molecular weight that the storage modulus and loss modulus of the films at high temperature can reach 2 837.57 MPa and 278.87 MPa, while the breaking strength was 3.725 MPa with an elongation at break of 763.99%. The target product was obtained by adopting the above waterborne polyurethane to produce the impregnated microfiber leather. Its cross-sectional SEM images showed that the internal bonding and curing of waterborne polyurethane were significantly improved with even and stable distribution. It was observed from the tensile diagrams of the microfiber leather that the surface cracks were also resolved.

Conclusion A waterborne polyurethane emulsion which had large molecular weight and small particle size was produced, with both its emulsion state and physical and chemical properties showing stability. While applied to the production of impregnated microfiber leather, it was observed that the obtained waterborne polyurethane demonstrated high performance as well as the possibility of large-scale production. The curing condition inside the microfiber leather has been improved by enhancing the wettability and bonding property of the substrate in the real application, thus effectively reducing surface cracks, and retaining a good texture and elasticity.

Preparation and photocatalytic properties of N-TiO₂/ polypropylene melt-blown nonwovens

CHEN Rongxuan, SUN Hui, YU Bin

Journal of Textile Research. 2024, 45(03):  137-147.  doi:10.13475/j.fzxb.20220907601

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Objective Titanium dioxide (TiO₂) has non-toxicity, low cost, and high photocatalytic activity. However, the photocatalytic ability of TiO₂ itself cannot reach the application level, and the powdered TiO₂ is difficult to recycle and reuse.Thus, it is difficult for TiO₂ to be practically applied in industrial fields. Polypropylene (PP) melt-blown nonwoven material with good chemical stability, low price, and simple manufacturing process has been widely used in air filtration, medical protection, and other fields. However, its single function limits its application. This research aims to improve photocatalytic ability and to tackle the recycling of TiO₂ by doping N with TiO₂ and then loading N-TiO₂ nanoparticles on the surface of PP melt-blown nonwovens.

Method N-TiO₂ photocatalyst was first prepared by sol-gel method, and the optimal doping amount of N was determined by studying the surface morphology, microstructure, chemical structure, and photocatalytic performance of N-TiO₂. The N-TiO₂ photocatalyst with the best performance was loaded on the surface of PP melt-blown nonwovens by ultrasonic impregnation method. The surface morphology, chemical composition and structure, and photocatalytic properties of N-TiO₂/PP composite melt-blown nonwovens with different N-TiO₂ loading concentrations were studied. The photocatalytic mechanism of N-TiO₂/PP composite melt-blown materials for organic dyestuff was verified and analyzed by free radical capture experiments.

Results The particle size of N-TiO₂ reached about 10 nm. N-TiO₂ with N doping amount of 1% was found to have the best photocatalytic performance for MB. After loading the optimal N-TiO₂ on the surface of PP melt-blown nonwovens, N-TiO₂ were found uniformly wrapped on the surface of PP fibers. The agglomeration of N-TiO₂ on the surface of PP fibers occurs when the loading amount of N-TiO₂ exceeds 30 mg. Compared with PP melt-blown materials, the water contact angle of N-TiO₂/PP composite melt-blown materials was significantly reduced, and the thermal stability was also improved. When the N-TiO₂ loading amount is 30 mg, the photocatalytic degradation rate of N-TiO₂/PP composite melt-blown material for MB reached 98% under the conditions of 30 min dark adsorption and 90 min photocatalysis. After trapping superoxide radicals (· {\mathrm{O}}_2^{-}) and hydroxyl radicals (·OH), the photocatalytic MB degradation efficiency of N-TiO₂ with 1% N doping were decreased by 22% and 23%, respectively. After being first used for the MB photocatalytic degradation, the crystalline structure and morphology of N-TiO₂/PP composite melt-blown nonwovens remained the same. After the fourth MB photocatalytic degradation, the photocatalytic degradation efficiency of the composite melt-blown material for MB was about 58%.

Conclusion Low N doping amount can effectively improve the photocatalytic performance of TiO₂. N-TiO₂/PP composite melt-blown material has proved to effectively degrade methylene blue dye. The composite melt-blown material has good stability and is recyclable. The research provides reference for expanding the application of PP melt-blown materials in the water treatment industry.

Apparel Engineering

Simulation prediction of lower limb clothing pressure using ANSYS

ZHU Yuanyuan, DAN Rui, JIN Jiaqin, LEI Yuteng, YU Miao

Journal of Textile Research. 2024, 45(03):  148-155.  doi:10.13475/j.fzxb.20221006601

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Objective In order to study the mechanism of interaction between clothing pressure and various layers of lower body tissues, including skin layer, other soft tissue layer and muscle layer, a finite element layered model was established using ANSYS to predict the deformation and stress distribution of each layer tissue under clothing pressure.

Method Two-dimensional tomography images of human lower limbs was obtained by CT scanner, and a three-dimensional layered model of human lower limbs by Mimics was established and was imported into ANSYS to improve the model. Material properties of the model were defined, and boundary conditions were set to obtain finite element prediction models. In order to verify the accuracy of the model, 44 collection points were selected in the lower limbs to collect the measured clothing pressure data, and SPSS were utilized to analyze the correlation between the predicted data and the measured data,useing multiple correlation coefficient R to measure the model fit degree. The closer the R value was to 1, the higher the accuracy of the model was proved.

Results The least obvious part of the skin layer was found to be the medial front of the calf, the least obvious part of the other soft tissue layer was basically the same as the skin layer, and the least obvious part of the muscle layer was the medial front of the calf. The most obvious deformation part of the skin layer was basically the same as that of other soft tissue layers, which was on the upper part of the inner middle of the thigh. The maximum shape variations were 2.73×10^-2 mm and 5.19×10^-4 mm, respectively, with a difference of nearly two orders of magnitude. The muscle layer deformation mainly occurred in the inner thigh, front internal, back internal and back leg. The most obvious part of the deformation was in the middle of the inner thigh, with a maximum value of 7.30×10^-5 mm. By comparing the skin layer with other soft tissue layers, it was found that in the area where the skin layer shape variation is less than 2.73´10^-3 mm, the other soft tissue layers hardly deformed. Compared with the deformation prediction curve and stress prediction curve, although there are some differences between them, the inflection point was basically the same. When the stress reached the peak, the deformation also reached the maximum value, and when the stress dropped to the trough, the deformation is also at the minimum value, indicating that the deformation was affected by the change of stress and was positively correlated with the stress. On the whole, the thigh deformation was more obvious than the calf deformation, the middle thigh deformation difference was the largest, the ankle deformation difference was the smallest.

Conclusion By comparing the prediction results of clothing pressure of skin layer, other soft tissue layer and muscle layer, it is found that the pressure of clothing pressure on each layer of human lower limbs gradually decreases from the outside to the inside, and the influence of clothing pressure on muscle layer is little, and the main object of clothing pressure is skin layer and other soft tissue layer. In a certain range, the body surface shape variations are affected by stress changes and maintain a positive correlation with stress. The surface stresses of human lower limbs are inner, rear, front and outer in order from large to small. The goodness of fit of multiple correlation coefficients between the predicted clothing pressure data and the measured data R is 1, indicating that the layered clothing pressure prediction model can be used to study the deformation prediction of skin, other soft tissues and muscles under clothing pressure. In practical application, this finite element prediction model can be used to obtain the appropriate garment pressure comfort threshold, reduce muscle fatigue, improve exercise efficiency, and provide theoretical guidance for the product development of functional tight sports pants.

Smart clothing design for autistic children with distance monitoring and auxiliary prompt functions

WANG Xinyu, TIAN Mingwei

Journal of Textile Research. 2024, 45(03):  156-162.  doi:10.13475/j.fzxb.20230202801

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Objective Social and emotional disorders are the core issues that affect the normal life of autistic children. Two sets of smart clothing that meet patients' needs for wearing were designed in this study, i.e., sensory integration, psychological identity and aesthetic preference, and social distance monitoring and auxiliary prompting functions. This study integrated the concept of traditional Chinese medicine in functional clothing design, expecting to help develop the auxiliary therapy and smart wearable research and application direction of autistic children.

Method The clothing needs of autistic children were firstly summarized in three aspects: wearing, feeling and psychological identity using questionnaire survey and field interview. Ultrasonic distance sensor technology was adopted to realize social distance monitoring. Flexible pneumatic air bags and heating carbon fiber were adopted to simulate traditional Chinese medicine (TCM) massage therapy for autism, and heat and pressure were adopted to stimulate wrist acupuncture points to achieve certain goals of intervention and auxiliary prompting of patients.

Results Children with autism need clothing with clear signs to guide them put on and take off with easy ways of fastening and undressing. Study indicated that they preferred soft and non-irritating fabrics and clothes with regular patterns and cool colors. Concealed intelligent controls with auxiliary debugging functions were more in line with the psychological identity needs of such children and their families. Reasonable social distancing is helpful to maintain patients' psychological sense of security. In combination with social distancing and epidemic prevention suggestions, the monitoring distance selected was 0.5-3 m. The ultrasonic distance sensor has high precision with small shape and dirt resistance which could effectively identify social distance when embedded in clothing, and the effective monitoring range was within 0.2-3 m. Statistics of TCM treatment of autistic children showed that stimulation of acupoints could effectively relieve the emotional disorder symptoms of patients. Multiple effective acupoints were distributed centrally at the wrist. Combined with the convenience of clothing, flexible air bags were placed at the cuff position to simulate the effect of TCM massage. The data showed that appropriate clothing pressure was helpful to release pressure, no more than 7.90 kPa at the arm. CLO3D software was adopted to simulate the pressure of the cuff on the wrist when the airbag was not inflated, and the pressure on the wrist after inflation. When a patient was in the unsafe social distance, the flexible air bag and the heating carbon fiber inside the clothing were triggered, and the pressure and heat stimulate the wrist acupuncture point to stimulate the patient so as to relieve anxiety. According to the survey results of patients' clothing needs, the smart children's clothing was designed as H/A shape with zipper fastening, cool colors, and geometric pocket design. The fabric was designed with two layers, where the inner layer is soft and comfortable, and the outer layer has certain support to adapt to functional accessories.

Conclusion The ultrasonic distance sensor is connected with the flexible air bag and the heating carbon fiber to achieve multiple functions of social distancing monitoring, air bag massage and heating, which can not only play the effect of auxiliary reminder secretly, but also properly relieve the emotional disorders of children with autism to a certain extent, and meet the physical and mental needs of patients and caregivers. The integration of TCM treatment concepts into clothing has a huge market prospect and is of great significance for the improvement and application of smart clothing and adjuvant therapy effect for autistic children and other special groups.

Analysis of newly revised national standard for chemical protective clothing

YANG Guang, YANG Xiaobing, LI Li, YAO Zhifeng, ZHOU Chuan, ZHANG Mingming

Journal of Textile Research. 2024, 45(03):  163-168.  doi:10.13475/j.fzxb.20221005201

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Objective This paper aims to clarify the situation after the revision of the national standard for chemical protective clothing to enhance correct understanding the new specifications of chemical protective clothing. It is expected that this work will help engineers make scientific and reasonable selection of chemical protective clothing from the perspectives of protective performance and service performance based on the hazard degree of chemicals in different job sites, to ensure the personal health and life and property safety of users.

Method During developing the new national standard of chemical protective clothing in China, references were made to some foreign standards of chemical protective clothing, including International Organization for Standardization (ISO), European Committee for Standardization (CEN) and National Fire Protection Association (NFPA). Focusing on the changes in the revised GB 24539—2021 "Protective Clothing: Chemical Protective Clothing", this paper interprets the standard from the aspects of classification, performance requirements and test methods.

Results It is found that GB 24539—2021 integrated GB 24539—2009 "Protective Clothing: General Technical Requirements for Chemical Protective Clothing", GB 24540—2009 "Protective Clothing: Chemical Protective Clothing against Acids and Alkalis" and GB/T 29511—2013 "Protective clothing: Chemical Protective Clothing for Solid Particles", and the classification of chemical protective clothing was greatly adjusted and updated by deleting the non-airtight chemical protective clothing-ET, and by adding the airtight chemical protective clothing, limited liquid spray chemical protective clothing and woven material liquid acid and alkali chemical protective clothing. Accordingly, the performance requirements were also changed greatly, these mainly including the overall protective performance of clothing, the protective performance of clothing fabrics and the physical and chemical properties of clothing fabrics. Among them, liquid leakage performance in the overall protective performance of clothing was deleted, and inward leakage rate, limited liquid-tight spray performance and practical performance were added. New requirements for the protective performance of clothing fabrics were put forward in combination with various types of protective clothing which were reorganized. The grading indexes of wear resistance and flex resistance for physical and chemical properties of clothing fabrics were adjusted to better suit the actual situation of most protective clothing fabrics at present. Test methods in GB 24539—2021 mostly followed the test methods in the previous relevant standards, but they were also improved and perfected accordingly, including the sample pretreatment conditions and test environment conditions, the test method of inward leakage rate of chemical protective clothing, the test method of liquid tightness of chemical protective clothing, the test method of wear resistance of chemical protective clothing fabrics and the test method of bending resistance. Among them, the sample pretreatment conditions, and test environment conditions were added in the new revision which had not been unified and made clear in the previous standards. The test method of inward leakage rate of chemical protective clothing is a new content in this standard revision to evaluate the overall protective performance of airtight chemical protective clothing more comprehensively. The liquid tightness test of chemical protective clothing in the revised standard includes three test methods, which are respectively suitable for the liquid tightness test of jet liquid-tight chemical protective clothing, spray liquid-tight chemical protective clothing and limited liquid spray chemical protective clothing. As for the testing methods for abrasion resistance and flex resistance of chemical protective clothing fabrics, the qualitative evaluation method of visual observation was improved and two quantitative evaluation methods, i.e., the pressure tank method and hydrostatic pressure method, were added.

Conclusion The revised national standard of chemical protective clothing will play an important role in promoting market development, improving product quality, and protecting users' personal health and life safety.

Optimization of mixed production line layout for collaborative clothing suspension system

TONG Xiyu, ZHENG Lu, YANG Jinchang, HU Jueliang, HAN Shuguang

Journal of Textile Research. 2024, 45(03):  169-176.  doi:10.13475/j.fzxb.20221204501

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Objective In order to adapt to the transformation and upgrading of clothing manufacturing enterprises, and quickly respond to market demand, most clothing manufacturing enterprises had introduced many intelligent production equipment such as clothing suspension systems to replace conventional backward bundled assembly line production. In order to apply new production equipment in the actual production, some problems were identified for the mixed assembly line in the clothing manufacturing workshop such as unreasonable suspension system material transmission path, time consumption and energy consumption, uneven workload time of each workbench, long processing cycle, and waste of processing equipment resources. The optimization of workshop assembly line layout considering the collaboration of clothing suspension systems was carried out aiming to effectively solve the above-mentioned problems of clothing production lines.

Method Because of the involvement of multiple disciplines such as clothing, logistics, and operations research, as well as the complexity of the production process, it was necessary to conduct on-site investigations, observe the production line process of clothing production, analyze the production process diagram of clothing production enterprises and the raw data in MES systems. Based on the constraints of the clothing production process, limited workbench resources and processing equipment quantity, and rational production rhythm, a dual objective mathematical programming model was established to minimize material transmission distance and smoothness coefficient. The non-dominant sorting genetic(NSGA-II) algorithm was designed and applied to solve the production lines of multi-style clothing.

Results From the optimization objective iteration curve generated using NSGA-II algorithm, it was found that the algorithm had a good optimization effect on the green mixed clothing assembly line, and the total distance and smoothness coefficient of material transmission had converged to a stable level in over 300 generations. Based on the production data examples, the Pareto optimal solution set was obtained. Because of the two objectives of the total distance of material transmission and the smoothing coefficient, a non-dominated solution with the best total distance and the non-dominated solution with the best smoothing coefficient were extracted from the solution set for analysis. When 12 workstations are operational and 21 processing devices are utilized, the average idle time per workstation amount to 42.2 s, resulting in an optimal total distance of material transport measuring 82 m. However, the smoothness coefficient stands at 55.86 and the compilation efficiency is merely 75.2%. Conversely, when operating with only 10 workstations and utilizing 18 processing devices, each workstation experiences an average idle time of approximately 16.6 s while achieving a smoother coefficient of 24.104. This leads to an improved compilation efficiency of up to 90.2%, albeit at the expense of increased material transport distance reaching a value of approximately 100 m. The total distance of material transmission in the minimum production cycle was 82 m, with a smoothness coefficient of 55.86, and 12 workstations were needed with 21 processing equipment. The average idle time of each workbench was 42.2 s, and the staffing efficiency was 75.2%. The total transmission distance of the material was 100 m, and the smoothness coefficient was 21.977. It was necessary to operate 10 workstations with 18 processing equipment. The idle time of each workbench was 16.6 s, and the staffing efficiency was 90.2%. The Gantt chart of the work tasks for each workstation in the mixed clothing assembly line were generated according to the scheme. In order to verify the effectiveness of the model, NSGA-II algorithm and multi-objective particle swarm optimization(MOPSO) algorithm were compared, and the result showed that NSGA-II algorithm produced closer simulation results.

Conclusion Faced with the transformation of the clothing industry structure, the design of the entire production line plays a crucial role in intelligent clothing manufacturing. The optimization of workshop assembly line layout considering the synergistic effect of clothing suspension system helps promote the transformation and it is useful for upgrading of China's clothing and textile industry from labor-intensive to less labor intensive or unmanned production. This study provides some theoretical reference for the promotion of green and intelligent manufacturing in the clothing enterprises.

Machinery & Equipment

Optimization of gear transmission mechanism of detaching roller for comber

LIU Jinru, LI Xinrong, WANG Jiankun, WANG Hao, SHI Shuaixing, WANG Biao

Journal of Textile Research. 2024, 45(03):  177-184.  doi:10.13475/j.fzxb.20221102401

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Objective With the increase of combing speed, the internal excitation frequencies of the hybrid-driven gear transmission mechanism of the comber detaching roller will increase. When it approaches the natural frequencies of the transmission mechanism, the mechanism will have resonance, causing damage to some components. Therefore, in order to master the dynamic performance of the transmission mechanism and avoid resonance, it is necessary to study the influence of the change of mechanism parameters on the inherent characteristics and then optimize the design of the transmission mechanism.

Method A hybrid-driven gear transmission mechanism of the comber detaching roller was designed. The lumped-mass method was adopted to establish the natural frequency model of the transmission mechanism, and the excitation frequencies of the transmission mechanism at different comber speeds were calculated. Then, the sensitivity model of the natural frequency of the transmission mechanism to moment of inertias was obtained by derivative method. Finally, by optimizing the number of teeth of each gear in WW differential gear train of the transmission mechanism to change the moment of inertia, the first order natural frequency was increased.

Results The natural frequencies of the transmission mechanism were divided into two types according to the number of multiple roots: single root frequency and N-1 multiple root frequency. With the increase of the number of double planetary gears, the single root frequencies changed, while the N-1 multiple root frequencies were independent of the number of double planetary gears. When the speed of the combing locomotive was 300, 400 and 500 nips/min, the internal excitation frequency of the transmission mechanism did not intersect with the natural frequency, and the mechanism operated normally without resonance. However, when the speed of the combing machine was increased to 600 nips/min, the meshing frequency of the gear pair c-d intersected the first order natural frequency (points A and B), and the mechanism may resonate at these two points. Then, the first order natural frequency decreases with the increase of the moment of inertia of each component. Among them, the first order natural frequency showed the highest sensitivity to the moment of inertia of planetary gear p, and was almost insensitive to the moment of inertia of planetary carrier h and gear b. With the increase of the rotational inertia of planetary gears p and q, the first order natural frequency was decreased rapidly at the initial stage and then decreases gently. With the increase of the rotational inertia of sun gear s and a, the first order natural frequency was decreased gradually with almost constant slope. After parameter optimization, the first natural frequency of the transmission mechanism became 1 259.28 Hz, 43.44% higher than the original, which would avoid the intersection of the internal excitation frequency and the natural frequency of the mechanism when the combing locomotive speed was raised to 600 nips/min, ensuring that the transmission mechanism operates normally without resonance.

Conclusion The method of concentrated mass is adopted to establish the natural frequency model of the hybrid-driven gear transmission mechanism of the comber detaching roller. The relationship between the natural frequency and the excitation frequency of the transmission mechanism under different comber speeds are calculated, and the number of teeth of each gear of WW differential gear train in the transmission mechanism is optimized according to the sensitivity analysis. Further experiments will be carried out in the future to promote the progress of combers.

Algorithm for detecting yarn bobbin margin based on inverse projection transformation

WANG Junru, WANG Hongpeng, RU Xin, CHEN Zhifeng, SHI Weimin

Journal of Textile Research. 2024, 45(03):  185-193.  doi:10.13475/j.fzxb.20220710001

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Objective The detection of bobbin yarn margin is an important part of the automatic production process in the textile industry, of which the design of an image algorithm is a key part for facilitating the automatic bobbin change system. Because the bobbin installed on the take-up bar rotates in two directions and the front image of the bobbin is oval, it is necessary to design a bobbin yarn margin detection algorithm suitable for the actual production situation.

Method In view of the special imaging effect of the bobbin and considering the actual production situation, the inverse projection transformation algorithm was designed based on the multi-point perspective model. The initial inverse projection transformation matrix was calculated according to the spatial position relationship between the bobbin and the camera, and then the bobbin area was segmented to obtain the inner and outer bobbin areas of the bobbin and calculate the position information of the inner and outer bobbin areas. The compensation matrix was set, and the transformation matrix was optimized according to the position information of the inner and outer bobbin and the element transformation characteristics of the transformation matrix. The polar coordinates of the image were expanded after the inverse projection transformation and the bobbin yarn margin was calculated according to the set yarn margin calculation criteria.

Results The processing effect of this method and the experimental results were discussed in detail. The inverse projection transformation effect of the algorithm was compared with that of the conventional three-point perspective model. It was seen that the conventional inverse projection transformation was difficult to consider the transformation effect of the inner and outer cylinders, and the yarn width in the same direction of the yarn area was not equal or even different. Therefore, the compensation matrix was set based on conventional inverse projection transformation to optimize the effect of inverse projection transformation. The element value of the compensation matrix was determined according to the position relationship between the inner and outer barrels of the bobbin. Therefore, the inner and outer barrels of the bobbin were first segmented, and the contour of the inner and outer barrels was fitted. The position information of the inner and outer cylinder, such as roundness, direction angle and area size, were calculated by obtaining the contour of the inner and outer cylinder. The compensation matrix was solved according to the element transformation characteristics of the compensation matrix after obtaining the position information of the inner and outer drums and the yarn area width at the inner and outer drums. Taking the square calibration board as an example, the transformation characteristics of the compensation matrix elements were shown in compensation matrix factor transformation effect. The fifth bobbin was selected to calculate the compensation matrix, and the product of the initial transformation matrix and the compensation matrix were as the inverse projection transformation matrix. Considering the limitations of the transformation effect, the conventional ellipse polar coordinates were optimized, and the angle information of the ellipse was added to the polar coordinate transformation to obtain the polar coordinate expansion diagram of the corrected bobbin image. The yarn margin of the bobbin was obtained according to the specified yarn margin calculation criteria. The objective in this paper was to determine different types of yarn bobbins under the sampling angle, so that the two types of yarn bobbins could be considered separately in the experiment. The test results of partial yarn margin of cylindrical bobbin were shown in margin detection results. It was seen that the test error was mostly within 5 mm, but it reached over 10% under some circumstances. In fact, although the error of the bobbin with large margin is relatively large, it will not have a significant impact on the actual production. This is because the main purpose of this algorithm is to provide warnings when there is less yarn surplus. Therefore, as long as the yarn surplus is detected before it is used up, the system can calculate the remaining usage time based on the yarn usage speed. The test results of part of the yarn margin of the cone bobbin were shown in margin detection result. The test error was within 4 mm, the error accuracy was about 95%, and the yarn width of the sample with large error was within 40 mm.

Conclusion In order to solve the problems of poor transformation effect and high requirement of experimental conditions in general inverse projection transformation algorithm, this paper proposes a yarn margin detection algorithm based on inverse projection transformation based on multi-point perspective model. The experimental results show that the algorithm proposed in this paper can obtain good transformation effect of inner and outer bobbin at the same time for different types of bobbins under the determined sampling angle, and the detection error of yarn margin is within 5 mm, which meets the practical production requirements. Compared with other inverse projection transformation algorithms, this algorithm is simpler to implement and has higher detection efficiency. In the future work, the bobbin at different angles and different distances, and design filters to further reduce the interference of external environmental factors on the algorithm will be further studied, to enhance the detection accuracy of the algorithm.

Interaction between weft deformation and synthetic airflow from multiple multi-hole array relay nozzle

FANG Jingbing, SHEN Min, LI Junxiang, WANG Zhen, YU Lianqing

Journal of Textile Research. 2024, 45(03):  194-201.  doi:10.13475/j.fzxb.20230103401

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Objective In air jet looms, the weft yarn is propelled through a profiled reed channel by means of a synthetic airflow from a main nozzle and multiple relay nozzles. The structure of the relay nozzle directly affects the airflow speed, weft direction, and breakage rate during the insertion process. Although many researchers studied the fluid characteristics of single-hole relay nozzles, most of the published works ignored the interaction between airflow and the weft yarn. This paper aims to study the influences of structure parameters of multi-hole relay nozzles on the dynamic behavior of a clamp-free fiber bundle transformed by unsteady airflow in the profiled reed.

Method Three types of multi-hole array auxiliary nozzles were designed. The Arbitrary Lagrangian-Euler method (ALE) was employed to simulate fluid-solid interaction between the unsteady airflow and an elastic fiber bundle. The three-dimensional transient airflow has been simulated using ANSYS Fluent 2020, in which the fiber bundle is solved simultaneously using coupled scheme. Then, the motion displacements of fiber bundle were captured by a high-speed camera to confirm the accuracy of the numerical simulation. The image capture rate was adjusted to 10 000 frames's to capture the motion of the yarn. The influences of outlet shape, array layout, and inlet pressure of the auxiliary nozzles on the airflow velocity pulsing and the bending deformation of the fiber bundle were revealed.

Results The simulation results for the airflow velocity and bending deformation of fiber bundle were presented. In order to validate the numerical scheme, the motion deformation of the fiber bundle captured by the high-speed camera was compared with numerical simulation. As observed, a good agreement existed between the numerical and experimental values. Synthetic flow field-weft yarn coupling contour showed the velocity contour of synthetic airflow and motion deformation of the fiber bundle in different time steps for three types of relay nozzles. The influences of the outlet shape and array on airflow velocity and vortex formation were depicted. The influence of the relay nozzle on the fiber deformation was illustrated, the elastic fiber bundle was completely bent along the axial direction due to the friction force of the airflow. Moreover, the displacement value of fiber was the minimum with the three-round hole central array relay nozzle.

Conclusion The two-way fluid-solid coupling simulations have been presented. The simulation results of the fiber motion have been verified with experiments. Firstly, the deformation of fiber is minimum in the synthetic airflow generated by the three-round-hole central array relay nozzle. Secondly, the velocity gradient of synthetic airflow is minimal in this relay nozzle. Thirdly, with the increasing bending deformation of the fiber bundle, the velocity gradient of synthetic airflow along the axis of the fiber increases significantly. The proposed multi-hole relay nozzles could be applied to any type of air jet looms. Especially, the circle-round central array relay nozzles could reduce the weft breaking rate at high speed.

Gradual failure detection of piezoelectric needle selector based on stochastic resonance-BP algorithm

QI Yubao, RU Xin, LI Jianqiang, ZHOU Yuexin, PENG Laihu

Journal of Textile Research. 2024, 45(03):  202-208.  doi:10.13475/j.fzxb.20220804401

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Objective Piezoelectric needle selector is the driver of jacquard needles. Its performance is related to the quality of jacquard knitting production during the process of needle hooking and looping. Aging of piezoelectric crystal or peeling off intermediate bonding layer would cause gradual failure of the actuator. Once the needle selector fails to act normally during knitting process, it would lead to defects such as off-pattern, holes in cloth surface, and even machine failures e.g., pin impact and pin breakage. The existing piezoelectric needle selector uses open loop control, and the results of needle selector would not be perceived. Hence, the control system would not be able to judge whether the action of the knife head of the needle selector is accurate, and the abnormal operation of the piezoelectric needle selector often causes mechanical failure or abnormal jacquard knitting.

Method Given the difficulty in identifying fault characteristics of the piezoelectric needle selector during the jacquard process, a gradient failure detection scheme based on the stochastic resonance-BP (SR-BP) algorithm for the piezoelectric needle selector was proposed. The study investigated the motion state of the driving component: the twin-crystal piezoelectric cantilever beam during the jacquard process of the piezoelectric needle selector, as well as the electric signal generated by its dual-directional piezoelectric effect. For the internal electric signals of the piezoelectric ceramic driver in a gradient failure state, SR fault diagnosis was conducted, and the SR-BP model was established. By extracting the time-domain and frequency-domain parameters of the vibration sequence and SR parameters to generate training samples, the algorithm was made to match the feature parameters to obtain the optimal SR parameters. The vibration signal of the piezoelectric needle selector was mixed with the noise signal into the nonlinear system formed by the SR parameters, and the time-domain and frequency-domain changes of the system output was observed to achieve the purpose of rapid fault detection.

Results An experimental platform and testing system were considered, and the SR-BP analysis on 1 000 sets of data was conducted. The results show that when the SR-BP samples were fewer than 200, the accuracy was below 75%. However, as the number of samples increased, the network accuracy of SR-BP continuously got risen, exceeding 95% when samples exceeded 1 000. The network accuracy of SR-BP primarily depended on the sample size, and the larger the sample size the higher the prediction accuracy. Simultaneous tests on the influence of different feature parameters on testing accuracy and signal-to-noise ratio (SNR) were conducted. With only three induced parameters, nine time-domain feature parameters and SNR, the network accuracy reached 95.4%, with an SNR of 6.91 dB. In the analysis using three induced parameters, three frequency-domain parameters, and SNR, accuracy reached 94.6%, with an SNR of 5.54 dB, showing a decline in accuracy and SNR compared to time-domain parameters. Hence, time-domain features could enhance network accuracy. This is because time-domain parameters can effectively describe the local features of the original vibration signal, better representing the original signal. Frequency-domain parameters reflected the statistical measure of the original signal over an extended time scale, making it a challenge to differentiate the signal's local features. After considering both time and frequency-domain characteristics, the SR response fault features were more pronounced, indicating optimal fault feature extraction with an accuracy of 97.5% and an SNR of 7.36 dB. The combination of time-domain and frequency-domain features provided the best fault diagnosis results. In conclusion, as the number of feature parameters increased, the predictive accuracies of SR parameters and the SNR were both improved. The signal and SR response characteristics in the samples acted as constraints in network training, and as these constraints increased, training results were gradually improved. Optimal SR could only be achieved by thoroughly extracting signal features and inputting them into BP.

Conclusion After in-depth research and experimentation, it is confirmed that the piezoelectric picker's gradual failure detection scheme based on the SR-BP algorithm possesses an extremely high level of accuracy under large sample conditions, reaching an accuracy rate of 97.5%. Compared to conventional diagnostic methods, this approach is more efficient and rapid, significantly enhancing the reliability of fabric quality. This research suggests that combining time-domain and frequency-domain characteristics can achieve the best fault diagnosis results. In the textile field, applying this method can notably reduce quality problems caused by picker faults, bringing tangible benefits to weaving enterprises. It is recommended that future researchers explore more feature parameters and more complex neural network models to further improve diagnostic accuracy. With technological advancements and increasing data volumes, it is predicted that the accuracy of this detection method will further improve, offering more innovative opportunities for the textile industry.

Progress of research and application in air-jet vortex spinning machine and key technologies

SHAO Yinghai, ZHAO Yeping, HAN Xianguo, CAO Jipeng, ZHANG Mingguang, CHEN Wen

Journal of Textile Research. 2024, 45(03):  209-218.  doi:10.13475/j.fzxb.20220906602

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Significance Air-jet vortex spinning machine (AVSM) is an spinning equipment with high spinning speed and efficiency in achieving high quality of multi-variety yarns, which is developed on the basis of jet spinning technology. AVSM is employed by more textile enterprises and has a profound scope for spinning of medium and long lengths staple cotton and blended yarns. But the technology of AVSM has its disadvantages and limitations of significant fiber loss, 100% short fiber loss for cotton yarn spinning. The limitation of the spinning range can be expected to overcome by the market leading enterprises of AVSM. Thus, in order to understand the current application, research development and present problems in AVSM by domestic and foreign spinning enterprises, a comprehensive analysis of the results of research and patent design achieved in AVSM is presented.

Progress Modern air-jet vortex spinning (AVS) technology is basically a new spinning technology developed on the base of the Murata AVSM. The key technologies and principle related to the AVS process include cotton guiding and feeding, sliver drafting, conveying, AVS device, yarn winding, and yarn packaging. The AVS device is the core device of AVSM, and the earliest version was manufactured by Murata. Later Gernot from Rieter proposed another AVS device, which is with different designs for the spindle, needle guider, and nozzle block. The research on in two types of AVS device have been made in the aspects of structure optimization, CFD simulation of three-dimensional air flow field inside of AVS device. Some improved structures of AVS device were proposed for reducing rate of short fiber falling, and for increasing the spinning rate. Huayan in Shaanxi designed two-split structure of AVS device controlled by pneumatic cylinder for opening and closing of the upper and the lower branches. The double AVS devices composed of the upper and lower branches was design to prevent fibers to be taken away from the airflow for improving the spinning rate. There are a few designs of the needle block with special features, i.e., the movable needle with adjustable axial position, or adjustable angle between guide hole and needle, the more guide holes and heating function. In nozzle block, some improved designs were made such as four adjacent spiral vortex grooves on chamber wall, three-stage structure, the surrounding spiral pipe on the outer surface for further improving the spinning effect.

Conclusion and Prospect For understanding the main application and research status of AVS technology, the relevant patents and research papers are reviewed. The research shows that the main research content of AVSM and its key technology are developed by some Chinese spinning enterprises and textile research institutes such as Huayan in Shanxi, Jiangyin Huafang New Science and Technology Ltd. Co. and so on with many related patents mainly focusing on the improved structural design of the AVS device and its related components. Overseas large-scale production of AVSM is mainly made from Murata and Rieter. Global research is also focused on the content of AVS of Murata, and more researches carry out simulation analysis on AVS device and on the spinning performance. In comparison with the early development of AVSM from Murata and Rieter, the relevant achievements of application and research progress of AVS technology are not noticeable. At present, the nozzle chamber of AVSM is often designed as the conical frustum model, in which the working principles of setting multiple air-jet vents in tangential direction of the chamber surface for producing the swirling air flow to make fiber false twisting has not changed. Looking forward to the future, CFD analysis and experimental research of AVS device will be needed aiming at the design of chamber structures, the production of higher strength yarn and the optimization of twisted vortex for improving the performance of AVS, meeting the production of multifunctional yarns and manufacturing yarns from short cotton fiber. In addition, with the progress of science and technology, more and more automation and intelligence control systems will be developed and applied in the AVSM such as electronic yarn cleaner, detection and control of foreign fibers, short fibers diagnosis, visualization, and others.

Review on non-compatibility blend melt blowing nonwoven process

QIN Zixuan, ZHANG Heng, LI Han, ZHAI Qian, ZHEN Qi, QIAN Xiaoming

Journal of Textile Research. 2024, 45(03):  219-226.  doi:10.13475/j.fzxb.20221004802

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Significance Melt blowing method is a one-step preparation process for preparing microfibers nonwovens, which has attractive advantages of high production efficiency, low energy consumption, and low cost. The melt blown nonwovens show a diversified and functional application trend, such as medical protection, air filtration, and oil-water separation, owing to the increasing requirements of the good life. Blending modification is the main strategy to improve the performance of melt blown nonwovens, and the non-compatibility blend melt blowing nonwoven process using the raw materials of polymer with different solubility parameters, is an effective method of structure regulation, including adjusting the fiber diameter distribution and pore morphology, helps expand the application of microfibers materials. This is because the structure paraments of the microfiber materials are affected by the viscosity of the polymer melt and the phase separation during the melt blowing process. In addition, the phase separation is more obvious in the case of high-speed hot air drafting, because of the solubility parameter difference between components in the melt. However, to our best knowledge, there are limited reports about the review on the non-compatibility blend melt blowing nonwoven process. Thus, clarifying the phase separation mechanism and regulation rules of the microfiber material structure in the non-compatibility blend melt blowing nonwoven process help expand the industrialization of melt blowing nonwoven technology.

Progress Starting from the mechanism of non-soluble phase blending melt blowing, this paper presents that the blending system formed by different types of polymers is affected by the forces of each component between polymers during the melt blowing process, and the forces at different positions are different in the drawing process, thus enabling the formation of microfiber materials with large differences in fiber diameters. Thereafter, this paper reviews the performance enhancement of microfiber materials after using different types of polymer ratios. Firstly, the non-soluble phase blending of polymers with different ratios can enhance the toughness of the materials. Meanwhile, the melt blowing non-soluble phase blending can produce microfiber materials with large differences in fiber diameters, which can effectively enhance the filtration performance of the materials. In addition, inspired by the phase separation of components in melt blowing nonwoven materials, the removal of one of the components in the ultrafine fiber material can provide ideas for obtaining nanoscale ultrafine fiber materials. Finally, this paper reviews the functional application forms and fields of non-soluble phase co-blended melt blowing microfiber materials and discusses the current problems and future development directions of non-soluble phase co-blended melt blowing, in order to provide references for further research on the preparation of microfiber materials by co-blended melt blowing nonwovens technology.

Conclusion and Prospect Considerable efforts have been developed in the non-compatibility blend melt blowing nonwoven process. Selecting appropriate polymer types and proportions based on functional applications to form an effective polymer matching system for non-compatibility blend melt blowing nonwoven process are the main measures taken, despite a wide variety of polymers that can be used. The effective selection of raw material and process optimization during the non-compatibility blend melt blowing nonwoven process is not only good for obtaining large scale fiber diameters distribution, but also useful for gain a variety of micro/nano fiber network structures such as horizontal branching and three-dimensional embedding. Thus, toughness and filtration and separation capabilities of microfibers materials are improved. Besides, the combination of non-compatibility blend melt blowing process and etching process can selectively remove a certain component of the melt blown nonwovens, thereby a nanofiber network structure and rough groove morphology was obtained. However, the green, and effective one-step preparation process still needs further research. Although the functional application in the fields of toughness enhancement, filter materials and oil-water separation has been made, the further application in the fields of smart wearables, construction and energy still needs to develop.

Research progress in applied research on click chemistry for preparation of functional textiles

FANG Jin, ZHANG Guangzhi, XU Zhenzhen

Journal of Textile Research. 2024, 45(03):  227-235.  doi:10.13475/j.fzxb.20230202302

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Significance Click chemistry is a novel synthetic chemistry method that allows the rapid and reliable chemical synthesis of various molecules in a short period of time through the stitching of small units to obtain required functions. Click chemistry provides a powerful and efficient tool for the rapid synthesis and precise modification of functional textiles and shows great potential and advantages in the preparation of functional textile materials. A detailed review of recent research on click chemistry for preparation of functional textiles would be helpful to promote the application of click chemistry to textiles and further explore the potential of click chemistry and broaden its application in other fields, such as hydrophobic, antibacterial, and other speciality-functional textiles.

Progress Despite the short history, click chemistry has made some progress in the field of textiles with its unique advantages. By means of click chemistry, functional monomers or polymers can be cleverly grafted onto the surface of textile fibers to impart specific functionalities, thus improving the functional durability that is lacking in the traditional "pad-dry-cure" processing method. The main types of functionalized surface modification of textile materials by click chemistry are thiol-ene, thiol-epoxides, thiol-halogens, thiol-isocyanates, and thiol-maleimides and azide-alkynes. The reaction mechanism of each type of click chemistry is listed, which provides more possibilities for the preparation of functional textiles. The functional textiles constructed by click chemistry in the current literature can be broadly classified into types such as superhydrophobic, antibacterial, electromagnetic shielding, environmentally responsive (shape memory, pH responsive and photochromic), anti-felt shrinkage, anti-wrinkle, conductive, moisture wicking and photocatalytic. Most of the functional textiles prepared based on click chemistry in the literature mainly focus on superhydrophobic fabrics, and the raw materials used are mainly acrylic (fluorine) esters, long-chain thiols, siloxanes, and mixtures containing both fluorine and silicon, and all of them show good functionality, durability, and chemical and mechanical stability.

Conclusion and Prospect The development of ecologically safe and high value-added functional textiles using high technology is an important future development of the textile industry. Efficient click reactions make it possible to modify carriers with multiple functional groups at the same time, providing a feasible way to design and construct multifunctional textiles. However, there are limitations at this stage that still need research attention. Click chemistry-based research is still at the experimental stage and has not yet achieved large-scale practical application or industrialization, and the occurrence of click chemistry requires the participation of specific reactive groups, and the modification of reactive groups on textile materials is tedious and time-consuming. The types of click chemistry reactions are relatively few, and most of the reported reactions are azide-alkyne cycloaddition and thiol-ene addition reactions, and the efficiency of click chemistry in grafting functional monomers on textiles is low. In addition, click reactions may have different effects on fabric whiteness, stiffness and other taking indexes, and thiols have unpleasant odor, which will undoubtedly limit their applications. Therefore, in view of the above problems, there is an urgent need to develop more economical, efficient, green, and safe types of click chemistry reactions, so that click chemistry can be studied more deeply in the field of textiles. It is believed that there is still a great deal of related work to be explored in the future, with the main challenges focusing on designing more novel functional textiles, optimizing the modification of reactive groups and reducing the impact on the properties of textiles themselves, developing more specialized types of reactions, improving the bonding efficiency of functional molecules, preparing greener and safer precursor substances for reactions, and improving and accommodating the multifunctionality of textile materials.

Progress and trends in application of wearable technology for elderly population

LIU Huanhuan, MENG Hu, WANG Zhaohui

Journal of Textile Research. 2024, 45(03):  236-243.  doi:10.13475/j.fzxb.20230206202

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Significance In order to provide a more secure and healthy life for the elderly population increasing, innovative wearable products with the advantages of real-time, continuity, and environmental awareness are developed to support older people's health monitoring, well-being, and independence. It promises to be an effective way to alleviate the issue of social stress at old age. However, there are significant restrictions on creating intelligent wearable designs for seniors. For instance, most wearable devices are not truly created with the needs of the elderly in mind. As an important aspect, smart wearables should be made to take care of the unique needs of the elderly population. It is hoped that this study will, to a certain extent, contribute to the innovation and development of age-friendly smart wearable technology devices and provide a theoretical basis for optimizing services for elderly users in the context of an aging population.

Progress The current situation of age-friendly wearable research in recent years is reviewed. A framework diagram of age-friendly innovative wearable research development is proposed, including the human body layer, product layer, functional layer, and industrial ecology layer. Firstly, the human body layer outlines the changes in the characteristics of the elderly group from 3 perspectives: physiological, psychological, and social attributes. As people age, their bones, bodies, and physical abilities change. They also become more susceptible to negative emotions, and their social roles alter, affecting their mentality and ideas about consuming. Then, concerning the current state of research on intelligent wearable products for the elderly, the vital technical approaches to research age-appropriate innovative wearable products are analyzed from the product level. The seven dimensions are sensors, materials, morphology, structure and interaction methods, functional algorithms, and evaluation methods, of which the most important are sensor type and placement structure and interaction methods. Secondly, the existing research on smart wearable designs suitable for the elderly population is summarized in five functional layers: physiological system, neurological system, motor system, emotional system, and spatial mobility system, and the current design paradigms of age-friendly smart wearable products are summarized based on the current development status of the six industrial ecological layers.

Conclusion and Prospect From a review of relevant researches, researchers have paid attention to the use of wearable technology to improve the quality of aging development. However, the following areas for improvement still exist in the current research. Few wearable products are genuine "age-friendly" in design, and they do not fundamentally focus on the needs of the elderly. The design of wearable products for the elderly, the integration of electronic components with the human body and the comfort and convenience of wearing them still need further research. At the same time, more wearable products are currently designed to meet the physical health needs of the elderly, with less attention paid to mental health. Therefore, efforts can be made in the following aspects of future research. (1) The functions of wearable devices for the elderly should be from the perspective of the practical needs of the elderly and have a certain degree of relevance. (2) The accuracy and real-time requirements of intelligent wearable devices for information collection are the most important, which is the root cause of the absolute practicality of the product. (3) Older people can only replenish their power supply energy sometimes and anywhere, thus posing new challenges to the endurance of intelligent wearable devices. (4) Older users must be allowed to always wear the device independently while meeting the needs of older people who can easily and quickly understand its use. (5) Privacy and security. How to ensure the privacy and security of the elderly population during use is a crucial focus for future research. (6) Most of the consumers in the elderly group have the concept of frugal consumption, so the design and production of wearable products should be reasonably priced to reduce the burden of use on the elderly consumer group.