Objective Existing hygroscopic and perspirant fabrics have poor moisture conductivity and insufficient wearing comfort. The essence of hygroscopic and perspirant wicking is to use the difference in the absorption of sweat between the inner and outer layers of the fabric to conduct human sweat to the outer side of the fabric and evaporate, so as to keep the surface of the skin dry. In order to meet people's demand for clothing comfort, fabrics with moisture absorption and sweat wicking function have good development prospects and high practical value. In this study, a single wet double-layer fiber membrane with polyvinylidene fluoride(PVDF) as hydrophobic layer and polyacrylonitrile(PAN) and silica as hydrophilic layer was prepared.

Method The hydrophobic PVDF layer and the hydrophilic PAN/SiO₂ layer with orientation structure were prepared by electrospinning technology according to the single guided wetting mechanism of the fiber membrane. The double-layer composite fiber membrane has pore size gradient structure and surface wettability gradient structure. The pore size gradient was constructed by adjusting the thickness of PVDF layer, and the relationship between the thickness and the single moisture index, moisture permeability and mechanical properties of the double-layer composite fiber membrane was analyzed.

Results The spinning time of PVDF layer was adjusted to 2.0,2.5,3.0 and 3.5 h respectively, and the corresponding fiber membrane thickness was 295.1, 305.8, 314.7 and 324.5 μm, respectively, which showed a positive correlation with the spinning time. With the increase of the spinning time of the PVDF layer, the pore size of the hydrophobic layer was decreased and the distribution range of the pore size were narrowed gradually, while the pore size of the hydrophilic layer became much smaller than that of the hydrophilic layer, thus constructing a gradient structure from the hydrophobic layer to the hydrophilic layer. PVDF layer spinning time of 3.0 h showed the best wetting effect, where water was able to penetrate the fiber membrane within 2 s, and the unidirectional transfer index reached 1 778.2%. With the increase of PVDF layer spinning time, the positive AOTC(accumulative one-way transport index) increased from 1 259.6% to 1 778.2%. Therefore, the increase in the thickness of the PVDF layer led to the improvement of the directional transport performance of the liquid. However, when the spinning time of PVDF layer increased from 3.0 h to 3.5 h, AOTC was decreased from 1 778.2% to 1 204.2%, further indicating that Janus membrane with appropriate thickness was more likely to achieve better unidirectional liquid conductivity. Further, the water pressure resistance of the fiber membrane was tested. The positive and negative water pressure resistance of the composite fiber membrane with different PVDF spinning time was significantly different. The positive water pressure resistance was always lower than that of the reverse water pressure, and the water pressure difference showed an increasing trend with the increase of the spinning time of the PVDF layer fiber membrane. The hydrophilic layer with orientation structure showed a core suction height of 10 cm in 10 min, which provides good reverse osmosis performance for the fiber membrane. In addition, when the spinning time of PVDF is 3.0 h, the fiber membrane also has good moisture permeability and air permeability, with the moisture permeability reaching 8.7 kg/(m²·d), and the air permeability is 196.5 mm/s.

Conclusion In this study, PVDF-PAN/SiO₂ double-layer composite micro-nano fiber membrane containing oriented hydrophilic layer was prepared by electrospinning technology, and the effects of PVDF layer thickness on the pore size, single wizard moisture index, moisture permeability and mechanical properties of the composite fiber membrane were investigated. The results show that when the spinning time of PVDF layer is 3.0 h, the fiber membrane has the best single wet performance, and the unidirectional transfer index can reach 1 778.2%. In addition, the fiber membrane has good moisture permeability (8.7 kg/(m²·d)) and excellent air permea-bility (196.5 mm/s). The composite membrane can absorb human sweat and quickly conduct it to the outer layer of the fiber membrane within 2 s, which is much better than the existing single guide wet fiber materials. The double-layer composite fiber membrane prepared in this paper has a broad application prospect in the fields of hygroscopic and perspiratory textiles and medical and health textiles.

Objective The requirements for environmental protection are getting higher and higher, and the use of bio-based polymers to replace petroleum-based polymers is an inevitable development trend. It is hence of interest to develop bio-based photochromic synthetic fibers with good mechanical properties and color-changing effects.

Method With polyactic acid (PLA) was as fiber matrix, polyhydroxybutyrate (PHB) as modified polymer material and phase-change materials (PCMs) as photosensitive indicator, a new bio-based photochromic synthetic fiber with good mechanical properties and chromic effect was prepared using melt spinning technology. The rheological properties of the photochromic PLA/PHB blend were analyzed. The effects of post-drafting process on the structure and properties of fibers were systematically studied.

Results The apparent viscosity of photochromic PLA/PHB blends decreased with the increase of temperature and shear rate, and the decrease was more obvious with the increase of PHB content. The blend is an incompatible system and the PHB is thermally degraded during processing. The cross section and surface of the fibers were smooth, with no obvious structural defects, and the diameter was about 20 μm.When the drafting multiple was 4.0 times, with the increase of the drafting temperature, the breaking strength of the fiber basically remained unchanged, the elongation at break increased, the initial modulus decreased somewhat, and the thermal shrinkage of the fiber decreased. XRD results showed that the addition of PHB and PCMs did not produce new crystal types, and the crystallinity of the fiber decreases and the grain size of the (200 & 110) crystal plane of PLA showed a downward trend. With the increase of the drafting ratio, the breaking strength of the fiber was increased, the elongation at break decreased, and the initial modulus increased. When the drafting ratio was 4.2, the fracture strength of F15-150-4.2 (the PHB mass fraction was 15%, the drafting temperature was 150 ℃, and the drafting multiple was 4.2 times) reached (3.79±0.40) cN/dtex, the elongation at break (25.51±1.72)%, and the initial modulus (20.19±2.51) cN/dtex, indicating the good mechanical properties. The thermal shrinkage rate of blended fiber showed an increasing trend. The crystallinity and grain size of the fibers was increasd, so the fracture strength and initial modulus increase with the increase of the drafting ratio. The fibers began to change color in the first second under the sunlight, from white to light green, and are responsive. After 50 times of ultraviolet illumination, the color difference value hardly changed, and the fiber returned to a color that was difficult to be distinguished by the naked eye in 10 min.

Conclusion The photochromic PLA/PHB blend fibers were successfully prepared by melt spinning technology. The breaking strength of the fibers was (3.09-3.79) cN/dtex, the elongation at break was 21.78%-29.13%, and the initial modulus was (14.29-24.62) cN/dtex. The improvement of fiber properties is closely related to the post-drafting process. With the increase of drafting temperature, PHB forms a large amorphous region inside the fiber and entangles seriously with PLA macromolecular chains. The crystallinity and grain size of the fiber decrease, the thermal shrinkage rate decreases, the fracture strength remains unchanged, the initial modulus decreases, and the fiber flexibility improves. With the increase of the drafting ratio, the axial orientation of the macromolecular chain increases, the crystallinity and grain size increase, the fracture strength of the fiber increases, and the thermal shrinkage of the fiber increases. Photochromic PLA/PHB blend fiber can change color from white to light green in 1 s under the sunlight, and has a sensitive response. After 50 times of ultraviolet illumination, it can still maintain acceptable color difference, and has good light stability and good light recovery. It provides a scientific basis for developing functional bio-based synthetic fibers and expanding the application of PHB in textiles.

Objective In developing textiles, wearable devices, aerospace and other fields, the core element of intelligent temperature regulation function is based on the use of phase change temperature regulating fibers. As the basic unit of intelligent temperature regulating textiles, phase change fibers mainly combine phase change materials with matrix materials through various spinning technologies. With the increasingly serious energy crisis and environmental protection problems, the development of thermal energy storage materials with environmental protection characteristics is very important for the sustainable development of energy. At present, there are limited studies on phase change fibers (membranes) based on biodegradable materials and phase change materials. Therefore, it is of great significance to develop biodegradable phase change fiber materials (membranes) with high latent heat.

Method Polyactic Acid (PLA) nanofiber membrane has good biodegradability, and as a phase change material, disodium hydrogen phosphate dodecahydrate (DHPD) is widely used in the field of thermal energy storage. Through adding phase change materials to PLA nanofibers, the fiber membrane can achieve temperature regulation function. In this study, DHPD was used as a phase change functional material, and PLA was used as a carrier for encapsulating phase change materials. The biodegradable fiber membrane with temperature regulating function was prepared by electrospinning technology. The morphology structure, thermal energy storage performance and thermal regulation performance of the temperature-regulated fiber membrane were analyzed. In addition, the thermal cycle performance, wettability and water absorption performance of the temperature-regulated fiber membrane were evaluated.

Results When the mass fraction of PLA was 8% and the mass ratio of PLA to DHPD was 40∶4, the nanofiber membrane with an average fiber diameter of 342 nm was successfully prepared. The results showed that the fiber surface of the thermoregulated fiber membrane was smooth and continuous, and the morphology of the fiber membrane was also good. The heat storage performance of the temperature-regulating fiber membrane was studied and analyzed, and it was found that after adding DHPD, the thermal properties of the thermoregulated fiber membrane changed significantly. With the increase of DHPD mass, the melting enthalpy and crystallization enthalpy of the thermoregulated fiber membrane were significantly improved. When the mass ratio of PLA to DHPD is 40∶4, the melting temperature of the thermoregulated fiber membrane was 42 ℃, and the melting enthalpy was 1.96 J/g. The temperature-regulated fiber membrane showed an obvious exothermic peak at 31-33 ℃, and 31.85 ℃ was the crystallization temperature, when the crystallization enthalpy was 1.49 J/g. Thermal imaging technology was used to test and analyze the thermal regulation performance of the thermoregulated fiber membrane on human simulated skin. It was clearly observed that the final temperature difference of the thermoregulated fiber membrane with a mass ratio of PLA to DHPD of 40∶0 and a mass ratio of PLA to DHPD of 40∶4 was 0.3 ℃ during the 80 s period. The surface temperature of the thermoregulated fiber membrane with a mass ratio of PLA to DHPD of 40∶4 was increased by only 3.7 ℃. After 50 heating and cooling cycles, the shrinkage of the thermo-regulated fiber membrane decreased with the increase of DHPD mass ratio, indicating that the addition of DHPD had an effect on the thermal stability of the thermo-regulated fiber membrane. Finally, the wettability and water absorption properties of the thermoregulated fiber membrane were analyzed. The results showed that the addition of DHPD had an effect on the hydrophilicity and water absorption of the thermoregulated fiber membrane. When the mass ratio of PLA to DHPD was 40∶4, the water contact angle of the thermoregulated fiber membrane reached 110°, and the water absorption rate reached 689%.

Conclusion In summary, a biodegradable fiber membrane with temperature regulation function was successfully prepared by electrospinning technology in this research with a simple route. When the mass ratio of PLA to DHPD is 40∶4, the heat storage performance and thermal regulation performance of the thermo-regulated fiber membrane are both good. In addition to the unique flexibility of the fiber membrane, this temperature-regulated fiber membrane also has good heat storage performance, thermal regulation, reusability and water absorption. The temperature-regulated fiber membrane prepared by this method also provides a new strategy for the development of environmentally compatible thermal energy storage textiles.

Objective Tissue engineering offers a promising therapeutic approach for chronic and acute skin injuries, primarily repairing and regenerating damaged tissues through artificial scaffolds. The migration of human skin fibroblasts (HSFs) and human umbilical vein endothelial cells (HUVECs) plays a crucial role in tissue repair and regeneration. Meanwhile, adipose stem cells (ADSCs) secrete various pro-angiogenic and anti-apoptotic factors essential for tissue repair and regeneration. Therefore, to investigate the effect of the conditioned medium of ADSCs on cell behaviors, three nanofiber yarn-based mesh scaffolds of different sizes were prepared and co-cultured with ADSCs, and the conditioned mediums obtained were co-cultured with HSFs and HUVECs to explore their regulatory effects on the migration and vascularization of these wound repair related cells.

Method The nanofiber yarn-based meshes with different sizes were prepared by light-welding and electrospinning, and the microstructure of different scaffolds was characterized by scanning electron microscopy (SEM) and digital photography, the welding temperatures of nanofiber yarn-based mesh scaffolds were measured by thermographic camera. ADSCs were cultured on scaffolds of different sizes to obtain different conditioned media, and HSFs and HUVECs were cultured with these different conditioned mediums. Cell viability was detected by CCK-8 kit, and cell morphology was observed by fluorescence microscopy.

Results SEM images and digital photographs showed the different sizes of nanofiber yarn-based mesh scaffolds and the uniform size of nanofiber yarns (257.69 ± 36.87) μm which was achieved at the welding temperature (39.83 ± 3.07) ℃. The viability and migration experiments of HSFs showed that the different conditioned mediums of nanofiber yarn-based mesh scaffolds had little effect on cell viability, but their biocompatibilities were improved over that of the control group. The healing rate of HSFs after scratches of small nanofiber yarn-based mesh scaffolds (SNS) and medium nanofiber yarn-based mesh scaffolds (MNS) was better than that of large nanofiber yarn-based mesh scaffolds (LMN) and control group. There was no significant difference in the effect of 3 different conditioned media on the viability of HUVECs among all groups, SNS group had better effect on the migration of HUVECs and SNS group and MNS group promoted the angiogenesis of HUVECs.

Conclusion The conditioned medium obtained after co-culturing ADSCs with nanofiber yarn meshes could effectively promote in vitro migration and angiogenesis of HSFs and HUVECS. Among them, the SNS scaffold was more effective in regulating cell behavior. The modulation of wound healing-related cell behavior utilizing nanofibrous scaffolds cultured with stem cell-collecting conditioned media is expected to be used in wound healing-related applications, providing new ideas for tissue regeneration and repair.

Objective CO₂ corrosion of the cathode in flexible metal-air batteries severely reduces its electrochemical performance and greatly hinders the further development of flexible metal-air batteries. Existing research shows that the amino functional group in PEI has strong adsorption capacity for CO₂. By increasing the orientation of the fiber membrane, the specific surface area and pore volume of the fiber membrane can be increased, thereby enhancing the adsorption capacity of the fiber membrane. A high degree of orientation can also enhance the mechanical properties of the membrane to a certain extent. However, there are few studies on cathode separators for flexible metal-air batteries offering both excellent CO₂ adsorption capacity and good mechanical properties. As such, this study aims to use electrospinning technology to prepare highly oriented Polyethyleneimine(PEI)/polyacryloni-trile(PAN) composite fiber membrane by adjusting the drum speed, and to characterize its physical properties, mechanical properties and CO₂ adsorption properties.

Method Four different groups of PEI/PAN composite fiber membranes were prepared at the drum rotation speeds of 500, 1 000, 1 500 and 2 000 r/min respectively. Fourier transform infrared spectroscopy, X-ray diffractometer, Scanning electron microscopy, and a flexible electronic comprehensive test platform were used to characterize the physical properties and mechanical properties of the composite fiber membranes. The CO₂ adsorption performance of the composite fiber membranes was characterized by a specific surface area and pore size analyzer and a simultaneous thermal analyzer, and the influence of orientation on the CO₂ adsorption capacity and mechanical properties of the PEI/PAN composite fiber membrane was explored.

Results The results of infrared spectroscopy and scanning electron microscopy show that the PEI/PAN composite fiber membrane was successfully prepared by electrospinning, and as the drum speed increases, the fiber diameter decreases. The rotation speed of the drum greatly affected the orientation of the fibers. When the rotation speed was 1 500 r/min, the orientation of the fibers seemed the best. The high degree of orientation obtained by increasing the rotation speed of the drum can obtain a larger specific surface area and pore volume of the PEI/PAN composite fiber membrane, thus improving its ability to adsorb CO₂. This is mainly due to the smaller fiber diameter and the larger gap formed by fiber stacking between the non-oriented and oriented directions. The increase in fiber orientation also enhances the crystallinity of fibers, which greatly affects their mechanical properties. High orientation caused increase the tensile breaking strength and Young's modulus of the fibers in the longitudinal direction. This is mainly because the nanofibers arew able to withstand greater tensile stress when they are aligned.

Conclusion The PEI/PAN composite fiber membrane prepared by electrospinning at 1 500 r/min has excellent orientation. Compared with the randomly oriented composite fiber membrane prepared by electrospinning at 500 r/min, the CO₂ adsorption capacity of the prepared membrane is increased by 62.06%, the longitudinal tensile breaking strength is enhanced by 178.57%, and the Young's modulus is enhanced by 245.3%. The research reported in this article provides a reference for the preparation of cathode anti-CO₂ corrosion membranes for flexible metal-air batteries.

Objective In making nonwoven fabrics, the needling process can not make the two-component fibers split into ultrafine fibers. Because of this, the splitting effect of high shrinkage polyester (HSPET)/polyamide 6 (PA6) hollow pie-segmented two-component spunbonded needle-punching nonwovens (hereinafter referred to as the HSPET/PA6 needle-punching nonwovens) is poor, resulting in the HSPET/PA6 needle-punching nonwovens can not give full play to offer the expected performance. It is necessary to identify ways of splitting the fibers in HSPET/PA6 needle-punching nonwovens, and to prepare hollow pie-segmented spunbond needle-punching nonwovens with high fiber splitting rates and excellent performance.

Method The two-component spunbonded process was used to prepare HSPET/PA6 hollow pie-segmented spunbonded filaments, and HSPET/PA6 needle-punching nonwovens were formed by mesh lay-up and needle-punching reinforcement. The fiber splitting rates of nonwovens prepared by four different physical fiber splitting processes were compared to find out the optimal process. The softness, mechanical properties as well as air and moisture permeability of HSPET/PA6 needle-punching nonwovens were tested to analyze the effect of the optimal fiber splitting process on the properties of HSPET/PA6 needle-punching nonwovens.

Results It was found that the fiber splitting rate of HSPET/PA6 needle-punching nonwovens was 18.9%, and dry heat treatment to the nowovens did not help the fiber splitting rate. However, the fiber splitting rate of HSPET/PA6 needle-punching nonwovens after hydrothermal treatment, ultrasonic treatment and rotary drum machine washing treatment were found to be 24.0%, 32.6% and 75.5%, respectively. This indicates that the rotary drum washing can effectively improve the split rate of HSPET/PA6 needle-punching nonwovens, so that the two-component fibers split into ultrafine fibers. Subsequently, the changes in the properties of HSPET/PA6 needle-punching nonwovens before and after the fiber splitting treatment were investigated using the rotary drum machine washing treatment process. The fiber splitting rates of HSPET/PA6 needle-punching nonwovens were 57.4%, 75.5% and 80.6% when the rotary drum washing treatment temperatures were ambient, 60 ℃ and 90 ℃, respectively. Considering the fiber splitting rate, production cost and environmental protection, 60 ℃ was selected as the appropriate treatment temperature for rotary drum machine washing. The effect of rotary drum washing treatment times on the performance of HSPET/PA6 needle-punching nonwovens was analyzed at the optimal rotary drum washing treatment temperature of 60 ℃. It was also found that the fiber splitting rate of HSPET/PA6 needle-punching nonwovens was gradually increased with the increase of rotary drum washing treatment time. The softness and mechanical properties of HSPET/PA6 needle-punching nonwovens was improved with the increase of the fiber splitting rate. However, along with the increase in the split fiber rate, the flexural aperture of HSPET/PA6 needle-punching nonwovens became smaller, resulting in a gradual decrease in the air permeability and moisture permeability of HSPET/PA6 needle-punching nonwovens.

Conclusion The rotary drum washing process works well in splitting of two-component fibers during the needle punching process, and the process is simple and pollution-free without damaging the fibers. The rotary drum washing process provides a new direction for the splitting of pie-segmented two-component fibers and the preparation of nonwovens with a high fiber splitting rate. The needling process endows HSPET/PA6 needle-punching nonwovens a three-dimensional mesh structure, and the rotary drum washing treatment splits the two-component fibers into ultrafine fibers. The combination of the two processes gives HSPET/PA6 needle-punching nonwovens structural characteristics similar to those of natural leather, and provides the possibility that pie-segmented two-component spunbonded nonwovens can be widely used in the field of microfiber leather as a microfiber synthetic leather-based nonwovens.

Objective Currently, textile testing technology requires high-quality fiber images as a fundamental condition to observe the fineness and maturity of textiles. However, obtaining high quality fiber images is challenging due to the out-of-focus blurring of overlapping fibers in the visual field during single image imaging. Therefore, achieving the effect of global texture sharpness focusing by multi-focal plane fusion, based on obtaining only the locally clearest source image of overlapping fibers, holds great theoretical significance and application value.

Method To address the problem of defocus blur of overlapping fibers in the visual field during single image imaging, this research proposed a multi-focal plane fusion algorithm based for fibers on focal pixels. Firstly, two locally clearest source images were determined from the overlapping fiber images. Focal pixels were then obtained by multi-scale modified Laplacian algorithm to generate the initial decision map. The intermediate decision map was generated by slice calculation, and the guide filter was used to get the final decision map. Subsequently, the source image was processed with high-pass and low-pass respectively by the nearest neighbor distance filter. Finally, the fusion image was weighted.

Results The fiber multi-focal plane fusion algorithm based on focal pixels was proved suitable for different fiber samples. In the experiment, four types of fiber samples were listed, named as sample 1 (wool), sample 2 (down hair), sample 3 (cotton) and sample 4 (rabbit hair). By comparing the locally out-of-focus fuzzy original images of different samples with the fused images, it was seen that the texture details and edge structures of different samples were very clear after processing by the proposed multi-focal plane algorithm. Overlapping wool fiber samples in the same region were selected to compare the differences among the multi-focal plane fusion algorithm based on focus pixels and multi-mode fusion algorithm, three-layer decomposition sparse fusion denoising algorithm and non-down sampled continuous transformation algorithm. In order to better compare the four algorithms, Subjective evaluations were employed as auxiliary evaluation, and objective evaluation index was established as the evaluation benchmark. Three objective evaluation indexes of image mutual information, peak signal-to-noise ratio and edge information result retention were used to evaluate the algorithms. From the evaluation data, it was found that the evaluation values of each index of the multi-focal plane fusion algorithm were 3.543, 0.624 6 and 29.425 3, respectively. Compared with the other three algorithms, the evaluation value of each index of the proposed algorithm was the largest, and the larger the evaluation value, the better the image fusion. Thus, the superiority of the multi-focal plane fusion algorithm proposed in this paper was verified.

Conclusion The study provided data support and characterization to verify the effectiveness of the fiber multi-focal plane fusion algorithm based on focus pixels to solve the out-of-focus fuzzy problem of overlapping fibers. The factors leading to local blurring of overlapping fibers were analyzed from the perspective of high-power microscopic imaging. The multi-focal plane fusion algorithm was designed according to the characteristics of microscopic imaging to achieve globally clear imaging of overlapping fibers. It has been proven that the algorithm is suitable for different fiber types and has high adaptability. Compared with other multi-focal plane fusion algorithms, the fiber image processed by this fusion algorithm can best achieve the effect of globally sharp texture and focus.

Objective To benefit from the performance advantages of two-component composite staple yarns, a new spinning method for sheath-core staple yarns based on ring spinning machine was developed. The twist distribution in the sheath and core layers of sheath-core staple yarn is studied because it has a significant impact on the settings of spinning process parameters and the yarn properties.

Method The conventional front roller was replaced with the coaxial front roller with different diameters. Two fiber slivers were output with different speeds at the front roller nip. The slow fiber sliver was twisted around its axis, while the fast fiber sliver was spirally wrapped around the outside of the slow counterpart, thus forming a sheath-core structure. Based on the geometry of spinning triangle, the twist in sheath layer was calculated theoretically, and the twist in sheath and core layers of sheath-core yarn were measured by the filament simulated tracer method and image technology.

Results Through the fitting analysis of the twist in sheath and core layers, it is found that the twist in sheath layer is a quadratic function of the setting twist. Additionally, the twist in sheath layer is inversely proportional to the yarn diameter, which is consistent with theoretical analysis. Furthermore, the twist in core layer exhibits a linear relationship with the setting twist. The R² values for all fitted curves exceed 0.95, indicating that the fitting results are highly reliable. The breaking strength and elongation of sheath-core yarn are superior to those of ring-spun cotton yarn. At a twist of 550 twist/m, the breaking strength and elongation of sheath-core yarn with a sheath-core proportion of 65/35 are 68.0% and 85.5% higher than those of ring-spun cotton yarn, respectively. As the setting twist and core proportion increase, the breaking strength and elongation of sheath-core staple yarn increase. This is because as the setting twist increases, the twist in sheath and core layers increase, thereby enhancing the breaking strength and elongation of sheath-core staple yarn. Additionally, it is well known that polyester fibers have superior tensile properties compared to cotton fibers. Therefore, as the core proportion increases, the tensile properties of sheath-core staple yarn improve. The CVm of sheath-core staple yarn decreases as the core proportion increases. At a twist of 550 twist/m, the CVm decreases by 7.2% when the core proportion increases from 25% to 35%. This is because, as the core proportion increases, the width of sheath fiber bundle decreases, enhancing the control over the edge fibers and reducing the loss of edge fibers. The CVm decreases as the setting twist increases. When the sheath-core proportion is 65/35, the CVm decreases by 6.0% as the twist increases from 490 to 550 twist/m. The twist of sheath and core fiber bundles in the spinning triangle increase with setting twist increases. This enhances the cohesion of fibers, reduces the loss of fibers, and thus improves the evenness of sheath-core staple yarn. The harmful hairiness of sheath-core staple yarn decreases with increasing setting twist. When the sheath-core proportion is 65/35, the harmful hairiness decreases by 8.8% as the twist increases from 490 to 550 twist/m. This is because as the setting twist increases, more fibers are involved in the yarn, resulting in reduced hairiness.

Conclusion A method of one-step spinning sheath-core staple yarn based on ring spinning machine was developed. The spinning efficiency of this method is high, and the yarn spun by this method has good properties. In addition, the relationship between twist in sheath and core layer and setting twist was established by combining theoretical modeling with experiment. The results show that the twist in sheath layer has a quadratic function relationship with setting twist, and the twist in core layer is positively linearly correlated with setting twist. The breaking strength and breaking elongation of cotton/polyester sheath-core staple yarn are better than those of cotton ring yarn at the same linear density and twist.

Objective Sirospun is only suitable for two sets of rovings with similar fiber length, while fibers with different lengths require different gauges during the drafting process. In this study, cotton and wool rovings were fed into a double apron drafting device, and segment colored yarn and AB yarn were produced by intermittent and continuous feeding separately. In this research, cotton/wool segment colored yarns and AB yarns were prepared based on the double apron drafting ring spinning machine. However, when spinning conditions were the same, the CV and strength of cotton/wool segment colored yarn were worse than those of AB yarns. This paper reports on the development of a method for reducing the performance gap between two types of yarns.

Method Aiming at the unevenness caused by the retraction of the roving at the front roller nip, the principle of alternating advance-feeding of two rovings was proposed in such a way that when the front middle roller stopped feeding the cotton roving, and the back middle roller kept feeding the wool roving. When the cotton roving broke at the front roller nip, the gripping force by the front roller would disappear. The cotton roving was held by apron on the front middle roller, and the fore-end of the roving retracted from the front roller nip. Before the wool roving stopped feeding, the cotton roving was fed into the front roller nip in advance, so that when the cotton roving resumed feeding, they are perfectly connected to the wool roving, avoiding weak points in the yarn due to the shrinkage of the roving. The advance-feeding of wool roving was carried out in the same way as for the cotton roving.

Results Cotton/wool segment colored yarn showed pure color segments as well as mixed color segments. The lengths of the mixed color segment of the yarns with advance-feeding of 0, 0.1, 0.2, 0.3, 0.4, and 0.5 mm were 28.5, 30.9, 32.7, 35.1, 37.1, and 39.8 mm, respectively. As the advance-feeding amount increased, the length of the cotton/wool mixed color segment gradually increased too, but the lengths of the mixed color segment of the yarns were only below 17% of that of the yarns produced by coaxial back roller method. As the advance-feeding amounts increased, the unevenness, coarse and fine knots, breaking strength, and harmful hairness of cotton/wool segment colored yarns were improved firstly but then deteriorated. When the advance-feeding amount was 0.3 mm, the CV and coarse/fine knots were found minimized. The shrinkage of the rovings during the spinning process was compensated by the advance-feeding amount, thereby improving the evenness of the yarn. When the advance-feeding amount is above 0.4 mm, the advance amount exceeds the shrinkage amount, and the evenness of cotton/wool segment colored yarn became worse. As the advance-feeding amount was increased from 0 to 0.3 mm, breaking strength of the yarn was increased, but when the advance feeding amount was increased from 0.4 mm to 0.5 mm, the breaking strength of the yarn was decreased. When the advance-feeding amount wasis 0.3 mm, the breaking strength of cotton/wool segment colored yarn was 1.38 times than that of yarn made without advance-feeding, reaching 96% of the breaking strength of AB yarn with cotton/wool 30/70. The number of harmful hairiness in cotton/wool segment colored yarn was found higher than that of pure cotton, cotton/wool AB, and pure wool yarns, indicating that the two rovings can easily form harmful hairiness when breaking alternately at the front roller nip.

Conclusion Cotton/wool segment colored yarns with shorter mixing color segments can be produced by proper advance-feeding amounts. The unevenness of cotton/wool segment colored yarn can be reduced by applying an appropriate advance-feeding amount, hence improving the breaking strength and reducing harmful hairiness. The three indexes of the segment colored yarns are improved to match those of the cotton/wool 30/70 AB yarns. Due to higher distribution of wool fibers in the outer layer, the yarn has a strong wool appearance, thereby improving grading of the fabric. Cotton components in the yarn can improve the breaking strength, save usage of wool fibers, and reduce costs. The cotton/wool segment colored yarns has potential application in the field of fancy yarns. In the future, the performance of segment colored yarn can be further increased by improving the mechanical accuracy of the cotton/wool intermittent feeding transmission.

Objective In order to improve the quality of yarn and textiles, this study tests and characterizes the fiber hook in chemical fier slivers, which is one of the most important internal performance indicators of fiber slivers, in order to explore the benefits to yarn producers in setting up production processes and optimizing spinning production parameters.

Method In this study, the cellulose fiber and polyester fiber were selected to be the research objects, and the tracer fiber method was used to evaluate the fiber hooks in the corresponding raw fiber slivers, head slivers, and end slivers. Firstly, the fluorescent fiber was made and mixed with the raw material for making the raw slivers. The specific forms of the hook fibers were defined, the state of various fibers in the sliver was observed, and the proportion of the hook fiber in each state was obtained according to the hook fiber definition.

Results In this study, the real state of fluorescent fibers in the viscose and polyester raw slivers, head draws and end draws was observed and analyzed, and various forms of fluorescent fibers were defined and classified. The fibers in the yarn sliver were divided into straightened fibers, broken fibers, zigzag fibers, 0-degree back/front hooking fibers, acute angle back/front hooking fibers, obtuse angle back/front hooking fibres, 2-end folding fibers, and 2-end acute angle hooking fibers. According to these 18 types of observed fluorescent fiber states, and the proportion of various forms of fibers was obtained, the results showed that the proportion of posterior hooking fibers in the green sliver was the largest, and more than 50% of the fibers were shown as posterior hooking fibers, and the proportion of front hooking fibers was about 10%, which was much lower than that of the back hooking. This was due to the configuration of the comb needle between cylinder and doffer and the relationship between specifications and carding, and therefore the probability of various fibers on the cylinder to be transformed to the upper back hook of the doffer was greater than that of the front hook, causing the directional problem of more back hooks in the green sliver. Due to the drafting effect, the straightened fibers in the head drawing were significantly increased, and when the back hooking fibers in the green sliver was transfered onto the cylinder and then led out to feed the head, they became the front hooking fiber. In this process, part of the hooked fibers were drawn and straightened, resulting in the reduction of the front hooking fibers in the head drawing compared with the amount of back hooking fibers in the green sliver. The hooked fibers in the end draw was straightened again, and the front hooking fibers in the head draw was encircled into the sliver and then led out to feed the second draw, hence forming the back hooking fibers.

Conclusion The tracer fiber method can not only accurately reflect the various stages of the fibers in the sliver, but also accurately calculate the proportion of fibers in various stages in the sliver produced by this process through the observation of a certain number of slivers. By making fluorescent fibers, the state and number of fibers in the sliver can be accurately recognized and measured by using tools such as fluorescent light boxes. This study reveals that the ratio of fluorescent fibers to raw materials was 1/1000 under the condition that the observation results were not affected, and a mixing method of "small batches and multiple batches" was established to allow the fluorescent fibers and raw materials to be mixed evenly. At the same time, the morphological characteristics of various hooking fibers in the yarn sliver are defined in detail, and the observed data results also provide a more detailed and comprehensive original data accumulation for the follow-up research on the final yarn quality and the relationship between the hook.

Objective The fabric strain sensor made of silver-coated nylon yarn has the problem of coating oxidation corrosion, which affects the measurement accuracy and can cause the sensor failure. In order to improve the environmental stability of fabric strain sensor, a new design concept is proposed in this paper, where TPU/CB/PA conductive yarns with polyamide(PA) yarn as core layer and polyurethane (TPU) and carbon black (CB) composite material as core sheath structure were prepared based on coaxial wet spinning technology. Then the conductive yarns were knitted together with finished spandex yarns to form a knitted fabric strain sensor. Due to the absence of active chemical elements, this type of sensor theoretically has the advantages of oxidation resistance, corrosion resistance and sweat resistance.

Method TPU/CB/PA conductive yarns with polyamide (PA) yarn as core layer and polyurethane (TPU) and carbon black (CB) composite material as core sheath structure were prepared based on coaxial wet spinning technology. The conductive yarn was knitted together with spandex yarn as an inlaid part for fabric strain sensor. The sensor samples were prepared with four types of knitted structures, namely plain grain, 1×1 rib, double rib, double reverse, four different Mosaic schemes and different densities. When the external strain was applied to the sensor, the conductive part of the coil was deformed, so that the sensor resistance changed, and the received mechanical signal was converted into an electrical signal output. Different strains made the degree of deformation of the coil different. In this paper, the resistance change of the sensor under 5%-50% tensile strain is measured to study the performance of the sensor and its influence parameters.

Results The prepared conductive yarn skin and core layer were tightly bonded. The resistance value of the 5 cm length of the yarn was within 27-31 kΩ, indicating relatively stable resistance, and the resistance value met the requirements of the preparation of the sensor. The sensor properties of the four types of structures prepared by inlay scheme 2 were better than those prepared by other inlay schemes. The relation between the resistance change rate and strain of the four types of structures sensor samples prepared under the strain of 5%~50%. The resistance change rate of the ribbed sample began to decrease after 45% strain, the resistance change rate of plain sample began to decrease after 40% strain, the resistance change rate of double-reverse sample fluctuated after 25% strain, and the resistance change rate of double-ribbed sample fluctuated after 35% strain. The repeatability range of the sensor stable resistance of the four types of structures of the embedded scheme 2 was 35%-50% for the rib sample, 30%-50% for the plain sample, and the double reflex 2 and double rib samples were stable under the strain of 45%-50%. The ribbed sensor sample passed 500 fatigue tests. On the basis of the ribbed sensor sample, the density of the fabric was reduced, and the effective strain range of the sensor was expanded to 20%-50%, and the life fatigue reached at least 500 times. The ribbed sample was sewn on the elastic belt, which initially achieved the monitoring of human respiration and joint movement.

Conclusion A conductive yarn with a skin core structure is prepared by using wet spinning technology to wrap a conductive layer of polyurethane/carbon black on nylon yarn, and the prepared conductive yarn is further used for the preparation of sensors. Based on the characterization of the sensor properties, It can be concluded that the sensor properties of the four types of structures prepared by inlay scheme 2 are better than those prepared by other inlay schemes. In the four types of knitted fabric, plain, 1×1 rib, double reverse, double rib, the effective strain range of the sensor sample of plain and 1×1 rib is 30%-45%, and the fatigue life is at least 500 times. Plain grain and 1×1 rib are more suitable as knitted fabric for preparing strain sensors. The density of the fabric sensor coil is found to affect the stability of the sensor. When the density of ribbed sensor samples is reduced, the effective strain range of the sensor is expanded from 35%-45% to 20%-50%. However, when the density decreases, the relative resistance of the sensor also decreases. It is a problem to balance the effective strain range and the relative resistance change. The sensor can effectively monitor breathing, joint movement, and other signals, and has a good development prospect in the field of flexible intelligent wearable.

Objective Conductive cardiac patches play a crucial role in the treatment of myocardial infarction (MI). Anisotropic microstructures such as oriented fiber structures have been designed to mimic the directional structure and electrical conductivity of natural myocardial tissue. However, existing conductive fiber-based myocardial repair materials are non-stretchable and can rupture under deformation, hindering the reconstruction of the conductive microenvironment. Therefore, the development of stretchable conductive myocardial patches with anisotropic properties and stable electrical conduction during heartbeats is crucial for effective myocardial repair.

Method Polypropylene (PP) patches were immersed in a dopamine solution, followed by treatment with pyrrole and FeCl₃·6H₂O to obtain PP/PPy samples. Morphological observation was conducted using a stereomicroscope and scanning electron microscope, while chemical composition analysis was performed using a Fourier-transform infrared spectrometer. Mechanical properties were evaluated using a universal material testing machine, and electrical conductivity was measured using a source meter. The resistance changes of patches under stretching strain were assessed using a multi-modal tester. The viability of human foreskin fibroblast cultured with the patches was evaluated using the CCK-8 assay to evaluate the biotoxicity of the patch.

Results Optical microscopy images of the knitted patches with different mesh structures were shown (single denbigh stitch, double denbigh derivative tricot stitch with lapping and three denbigh weft laid-in stitch). Scanning electron microscopy (SEM) images reveal the surface morphology of the PP monofilaments before and after PPy coating. The untreated PP monofilaments have a smooth surface, while the PPy-coated PP monofilaments showed roughness due to particle deposition, indicating successful PPy coating. The characteristic peak at 1 045 cm^-1, attributing to the absorption peak caused by the in-plane C—H vibration of PPy, also confirmed the successful coating of PPy on the PP patch surface. These mesh structures provided flexibility and stretchability to the patches, with fracture elongation exceeding 100%, making them suitable for cardiac applications. Statistical analysis showed no significant differences in fracture strength and elongation between the PP patches and PP/PPy patches, suggesting that the PPy coating had no significant impact on these properties. The double denbigh derivative tricot stitch structure with lapping showed an increase in Young's modulus for the PP/PPy patches compared to the PP patches, attributed to the higher stiffness of the PPy coating. The single denbigh stitch and three denbigh weft laid-in stitch structures had lower Young's modulus, as more filaments oriented along the stretching axis instead of being stretched. There were no significant differences in Young's modulus between the PP and PP/PPy patches with single denbigh stitch and three denbigh weft laid-in stitch structures. The conductivity range of the patches was consistent with that of native cardiac tissue, indicating their potential to restore the damaged conductive microenvironment in the infarcted area. The anisotropic electrical conduction ability of the PP/PPy patches with three denbigh weft laid-in stitch structure further aligns with the anisotropy ratio range of native cardiac tissue, enhancing their effectiveness in restoring directional conductivity. Furthermore, the conductive patches demonstrated stable electrical conductivity under tensile strain, which is important for maintaining their performance during cardiac contraction. The PP/PPy patches with single denbigh stitch and three denbigh weft laid-in stitch structures exhibited lower relative resistance change compared to the patches with double denbigh derivative tricot stitch structure with lapping, indicating their superior structural deformation capability. Importantly, the conductive patches showed no cytotoxicity in co-culture experiments with HFF-1 cells. This finding provides assurance for their biocompatibility and supports their potential use in cardiac repair and regeneration applications.

Conclusion In conclusion, stretchable conductive patches with different mesh structures were successfully developed using warp knitting technology and in-situ polymerization. The PP/PPy patches with single denbigh stitch and three denbigh weft laid-in stitch structures effectively prevented rigid conductive coatings on the flexible patches, while maintaining good conductivity and stability. Furthermore, the PP/PPy patches exhibited excellent biocompatibility with HFF-1 cells. These findings provide new insights and directions for the design and application of conductive cardiac patches, offering promising options for cardiac repair after myocardial infarction.

Objective In order to form near-net tapered axisymmetric preform for radome using three-dimensional angular interlocking structure, a layer calculation model and a warp yarn adding model under the assumption of elliptical yarn cross section are put forward based on the analysis of the characteristics of variable thickness and variable cross section of the radome, and a fabric preform of variable thickness rotary cover is woven by combining the three-dimensional weaving technology.

Method The three-dimensional characteristics of tapered axisymmetric body with variable thickness were analyzed, and the mathematical model for calculating thickness (weft skew) and number of layers and the warp yarn adding model were established. Firstly, the simulation experiment of warp and weft extrusion state was established, and the regression equations for yarn long and short diameter (a, b) were obtained by response surface analysis. The unit thickness (single layer warp and weft thickness) model along the weft oblique direction was modified. Then, the mathematical model of layers and the model of warp yarn addition were established. Finally, the two models were used to design the number of layers, layer reduction scheme and warp yarn adding scheme of the radome fabric, and the fabric was practically woven to verify the feasibility of the fabric structure design scheme.

Results According to the analysis and calculation of the three-dimensional structure of the radome and the fineness as well as density of the selected warp and weft, four symmetrical 2.5D looms were used for weaving. In the weaving process, the regression equations of the long and short axes a and b of the yarn are obtained by determining the working conditions and inputting the horizontal coding of the corresponding factors, and then the number of weft layers was calculated according to the modified unit cell thickness model. When calculating the number of layers, it was determined that the position where the fineness of the warp yarn was reduced was the second weft according to the warp yarn difference rate f, and the number of layers after the thinning of the warp yarn needs to be equal to or less than that of the previous weft yarn due to the difficulty in adding layers. In the case that the predicted value of fabric fiber volume content is much different from the specified value, the yarn fineness would be redesigned. The warp and weft yarns with varying fineness gradient were used to improve the phenomena of "tight inside and loose outside" and uneven density of the fabric with variable thickness, and to reduce the friction at the yarn connection and reduce the fuzzing phenomenon. After weaving, the cover fabric was scanned in three coordinates, and the obtained three-coordinate scanning map showed 97.36% similarity with the cover model, and the error between the measured value and the predicted value of fabric fiber volume content was as small as 1.84%. The cured fabric was cut to obtain yarn sections in the variable thickness area and the equal thickness area.

Conclusion Based on the assumption of elliptical yarn cross-section, this paper makes a geometric analysis of the radome fabric preform with diagonal interlocking structure according to the two characteristics of variable thickness and variable cross-section. Combined with the regression equations of long and short diameters of yarns, the unit thickness model along the weft skew direction is modified, and then establishes the mathematical calculation model of thickness (weft skew) and number of layers and the warp and weft yarn adding model are established, dividing the warp and weft yarn distribution in detail. Through the actual weaving on the machine, the design effect of the model is verified, and the results show the feasibility of the structure and process design of the fabric preform with variable thickness. It can realize the integrated near-shape weaving of the radome of hypersonic aircraft and improve the overall performance of the radome.

Objective Based on the resin transfer molding process, Shear deformation will change the fabric structure, which directly reduced the fiber bundle spacing and porosity and affected the permeability and main permeability direction of the fabric. In order to ascertain the governing principles. the effect of shear deformation on the principal permeability component of anisotropic fiber fabrics, permeability anisotropy, principal permeability direction, inlet pressure, and the time required for filling and infiltration is investigated to lay the foun-dation for practical applications and verified with numerical simulations.

Method An experimental measurement system for the radial flow of a low-viscosity liquid (corn oil) under constant flow conditions was designed and set up using a plain glass woven fabric (fabric face density of 0.482 kg/m² and glass fibric density of 2 500 kg/m³. The warp and weft yarn density was 1 105 tex,while the warp density was 30 pieces/(10 cm) and the weft density was 22 pieces/(10 cm)) with rectangular pores. The principal permeability component was obtained using the permeability formula for anisotropic fabrics and the inlet pressure change was recorded by the pressure transducer in the process of filling and infiltration.

Result As the shear angle was increased from 0° to 30°, the internal porosity of the fabric was decreased and the fiber volume fraction was increased. At shear angles between 10°-20°, the fiber volume fractions obtained from the theoretical equations were basically the same as the experimental values; while at the shear angle of 30°, the theoretically predicted fiber volume fraction was about 0.8% higher than the experimentally tested value. With the increase of the shear angle, the magnitude of the principal permeability K₁ and K₂ showed a significant decreasing trend, in which K₁ decreased from 20.20 × 10^-10 m² to 11.44 × 10^-10 m² and K₂ from 16.1 × 10^-10 m² to 6.31 × 10^-10 m², the degree of anisotropy of the fiber fabric increased by 1.6% and 12.0%, and the anisotropy of the fabric was increased by 1.6%, 12.0%, and 44.8%. The direction angle of the principal permeability was decreased by about 29°, 39°, and 46°. At shear angles of 0°, 10°, 20°, and 30°, the time required for the elliptical flow front to fill and infiltrate along the long axis is 39.0, 37.0, 36.0, and 32.0 s, respectively, and the time required for the fabric to be completely filled and infiltrated is 45.0, 48.0, 49.0, and 54.0 s, with the maximum values of the inlet pressures being 23.2, 30.0, 33.0, and 38.9 kPa, respectively. Comparing the different inlet pressure curves, the length of the long and short axes of the flow front, and the contour of the flow front obtained from the experimental and numerical simulations were in excellent agreement, and the time error of long axis full infiltration was 4.0%. the total wetting time error was 2.4%, the maximum inlet pressure error was 7.9%. The numerical simulation could accurately predict the change of inlet pressure during the filling and wetting process, and this method could be used to study the wetting characteristics of different fabrics after shear deformation.

Conclusion In radial flow experiments, an increased fiber volume fraction leads to a reduction in the principal permeability (K₁, K₂) of the fabric and alters both the anisotropy degree (K₁/K₂) and the orientation of the primary permeability. The fitting formula obtained from the experiments effectively predicts the direction of the principal permeability of the fabric after shear deformation, providing a solid foundation for subsequent investigations into changes in the directional principal permeability of the fabric. The augmentation of fiber volume fraction results in an elevation of inlet pressure and an increase in the time required for complete filling and infiltration of the fiber fabric during the liquid filling process, making the filling process more challenging. Numerical simulations offer a more economi-cally and conveniently prediction of the liquid filling and infiltration process in fiber fabrics. Subsequently, numerical simulations can serve as a basis for studying the wetting characteristics of different fiber fabrics.

Objective As a healthy and environmentally friendly cotton fiber product, cotton nonwoven fabrics have been widely applied in various fields. All natural cotton fiber contains pigment impurities and needs to be scoured and bleached. Hydrogen peroxide (H₂O₂) bleaching is usually carried out in high-temperature and strong-alkali environment. The H₂O₂/activator system can effectively reduce the bleaching temperature and alkalinity. However, partial activators possess ecotoxicity. This research aims to explore for cleaner and more effective scouring and bleaching methods.

Method Firstly, the cotton nonwoven fabric was pre-treated with a plasma cleaning machine for 5 min. Subsequently, the fabric was immediately immersed in H₂O₂/PAG bleaching solution for treatment at 70 ℃ for 30 min in a constant-temperature dyeing machine. After the treatment, the fabric was squeezed and laundered thoroughly before being air-dried. The solution mentioned above contained H₂O₂, PAG, NaHCO₃, and EDTA-2Na. The fabric's whiteness and hydrophilicity were tested to evaluate the bleaching and scouring performance, respectively. The influences of plasma treatment on the chemical structure of cotton fiber were analyzed using X-ray photoelectron spectrum, scanning electron microscopy, and X-ray diffraction.

Results For achieving comparable bleaching effect via the NaOH and H₂O₂ routes, the H₂O₂/PAG system was able to reduce the bleaching temperature by 20 ℃ and to maintain the pH value at 5-7. On this basis, the introduction of plasma was shown to further reduce the H₂O₂ concentration by 50% or shorten the bleaching time by half, and the degree of polymerization was decreased by 3.6%. Plasma treatment significantly improved the hydrophilicity of cotton nonwoven fabrics. Specifically, the contact angle of water droplets reduced from 106.7° to 38.1°, and the wicking height within 30 min increased from 0 to 5.7 cm. Analysis of the X-ray energy spectrum indicated that both the content of oxygen elements and the number of polar oxygen-containing groups on the fiber surface increased after plasma treatment. Some grooves on the plasma-etched fibers were observed by means of scanning electron microscope. The results of the X-ray diffraction test showed a reduction in the cotton fiber's crystallinity by 13.4% compared with the untreated original fiber. The results of single-factor experiments demonstrated the following. Prolonging the plasma treatment time had little effect on the whiteness and yellowness of the nonwoven fabrics, but it evidently enhanced their hydrophilicity. An increase of H₂O₂ and PAG concentration produced more peracetic acid, contributing to an increase in whiteness and a decrease in the pH of the solution. The pH medium created by 30 mmol/L NaHCO₃ was suitable for the complete perhydrolysis of PAG, resulting in a near-neutral environment and desired bleaching results. Temperature was a significant factor affecting the whiteness of bleached fabrics. Fabrics' yellowness increased instead when the bleaching temperature exceeded 70 ℃. The whiteness showed a rapid increase within the scouring and bleaching duration of 0 to 30 min, indicating the high efficiency of the plasma/H₂O₂/PAG system. Further extension of time did not result in significant whiteness improvement.

Conclusion Approximate whiteness enhancement is obtained from plasma/H₂O₂/PAG and H₂O₂/NaOH system. However, 50% H₂O₂ concentration, 20 ℃ temperature, or 50% bleaching duration can be saved when using the front system. Moreover, plasma/H₂O₂/PAG system can provide a near-neutral pH environment. Thanks to the mild bleaching environment, the polymerization of cotton fiber only decreases by 3.6%. Plasma treatment increases the number of oxidation groups on the surface of the cotton fiber, induces physical etching on its surface, and improves the proportion of the amorphous zone. Above changes in fiber's structure achieves an apparent improvement in hydrophilicity of cotton non-woven fabric. As a result, the penetration and oxidation efficiency of the bleaching agent towards pigment impurities are correspondingly improved. When the optimal process parameters are applied (with concentrations of H₂O₂, PAG, and NaHCO₃ at 30, 7.5, and 30 mmol/L respectively, and plasma treatment for 5 min, followed by 70 ℃ bleaching for 30 min), the whiteness of the fabric can reach 82.1%, which is 23.8% higher than untreated fabric.

Objective The annual production of waste textiles is enormous, and the existing treatment routes such as chemical incineration and physical landfill are commonly employed to deal with waste textiles. These methods not only severely pollute the environment but also result in significant resource waste. Therefore, recycling waste textiles is crucial for conserving resources and reducing pollution. Color stripping is a prerequisite for recycling the colored waste textiles. However, conventional color stripping processes are characterized by high energy consumption, low efficiency, and operational complexity. This research aims to develop an environmentally friendly color stripping process that is both low in energy consumption and easy to operate as an alternative to the conventional color stripping methods.

Method A reduction-oxidation stripping system, employing thiourea dioxide (TD) as the reducing agent and sodium persulfate (Na₂S₂O₈) as the oxidizing agent, was used to strip the dyed cotton fabrics colored with Reactive Blue KN-R. The influences of stripping agent concentration, alkali concentration, stripping time, and temperature on the color stripping rate and the strength retention rate of the fabric were investigated. After stripping, the K/S values of the fabrics were measured using spectrophotometers to determine the color stripping rate. The strength retention rate was measured using an electronic fabric strength tester. All samples were measured three to five times to obtain an average value.

Results In the reductive color stripping process, the concentration of NaOH significantly affected the removal of dye molecules. When the concentration of NaOH was increased from 1 g/L to 6 g/L, the stripping rate increased from 73.09% to 86.95%. Excessive dosage of TD resulted in slight decreases in both color stripping rate and strength retention rate, indicating that excessive TD concentration is not conducive to colorant removal. The color stripping rate increased with time but showed minimal improvement beyond 20 min. Higher temperatures improved the color stripping rate but also caused a notable decrease in strength retention rate. When the temperature of the stripping system reached 70 ℃, after stripping for 20 minutes, the fabric strength retention rate dropped below 90%. In the oxidative stripping process, the stripping rate was higher than 90.00% with the dosage of NaOH being more than 1 g/L. A gradually increasing tendency was also obtained as the concentration of the oxidant Na₂S₂O₈ being increased from 1 g/L to 6 g/L. Similarly, the color stripping rate was increased within 20 minutes and stabilized afterward. Higher temperature also increased the color stripping rate but damaged the cotton fabrics, reducing the strength retention rate. After TD reduction stripping and Na₂S₂O₈ oxidation stripping, the fabric color changed from blue to purple and eventually to white. Additionally, the sequential reduction-oxidation stripping system effectively stripped fabrics dyed with other reactive dyes. For fabrics dyed with Reactive Red M-3BE, Reactive Red X-3B, Reactive Blue KN-G, and Reactive Blue M-BE, the initial reductive color stripping rates were 91%, 93%, 64%, and 78%, respectively. The subsequent oxidative stripping further improved the rates to 97%, 98%, 83%, and 96%, respectively.

Conclusion The sequential stripping system of TD reduction and Na₂S₂O₈ oxidation can serve as an alternative to conventional color stripping methods. For the cotton fabrics dyed with Reactive Blue KN-R, the stripping rate can reach 96% under low-temperature conditions, while the strength retention rate remains above 90%. The optimized TD reductive stripping process includes a thiourea dioxide concentration of 2 g/L, NaOH concentration of 6 g/L, stripping time of 20 minutes, and stripping temperature of 60 ℃. The optimized Na₂S₂O₈ oxidative stripping process includes a sodium persulfate concentration of 6 g/L, NaOH concentration of 4 g/L, stripping time of 20 minutes, and stripping temperature of 60 ℃. Compared to traditional color stripping processes, the new method causes less fabric damage, uses fewer stripping agents, requires shorter stripping times, and operates at lower temperatures. Moreover, the sequential reduction-oxidation stripping system is applicable to a wide range of reactive dyes.

Objective Diacetate fiber is a kind of synthetic fiber which can be naturally degraded, and it is widely used in fashion clothing fabrics. Digital printing technology is an important technical means to broaden diacetate fiber fabrics. Digital printed diacetate fiber fabrics was mainly achieved through high temperature steaming fixation, which was energy and water consuming and also may cause damage to the diacetate fabrics. In order to achieve water and energy saving digital printing process for diacetate fabrics, alternative baking fixation technology for the diacetate digital printing process was put forward.

Method Three printing thickeners were used to pretreat the diacetate fabric. After inkjet printing, the printed fabric was baked at different baking temperatures and times. Through testing the surface contact angle of the pretreated diacetate fiber fabric and the color yield (K/S value) of the printed fabric, the type and amount of pretreatment additives, the baking temperature and time were determined. Confocal Raman imaging technology was used to observe disperse dye diffusion in the diacetate fiber to investigate effect of curing temperature and pretreatment additive concentration on the diffusion of disperse dyes in diacetate fibers. Finally, color management and fastness test of printed products were carried out in the digital printing process under the condition of baking and fixing process.

Results The color yield of baking printed diacetate fabric reached and exceeded that of steaming printed products. Pretreatment of diacetate fiber with thickener KF-388 made the pretreated fabric obtain the same surface contact angle as that of printing paste thickener pretreated diacetate fiber. Laser Raman imaging proved that more dyes diffused into the diacetate fiber when the baking temperature of the printing diacetate fabric exceeded 200 ℃ and above. The fastness test also showed the disperse dyes did not diffused into the fiber when the printing diacetate fiber fabric was baked at 170-190 ℃. Most of disperse dyes exfoliated from the surface of the fiber during the soaping test. The soaping fastness grade of printed fabrics through baking at low temperature was nearly 2-3 which is intolerable to be the luxurious digital printing products. The baking process has a certain negative effect on the hand feeling and other properties of printed fabrics, such as whiteness and strength retention rate and so on. The determination of baking temperature needs to combine the color yield and the performance of printed products. The color management for the diacetate fiber fabric printing process is also key to get an expected color yield. The K/S value of CMYK color pattern after color management almost doubles that of CMYK color pattern before color management.

Conclusion In order to achieve non-steaming and no-washing printing for diacetate fiber fabric, KF-388 is found to be a suitable pretreatment additive, the dosage of which should be more than 2.0%, with the baking temperature of printing being kept at 200 ℃ for 60 s. The printed fabric can obtain the required color yield, hand feeling, whiteness and strength retention rate comparable to the steaming printing process for the diacetate fiber fabric. Laser Raman imaging technology are used to analyze the diffusion of disperse dyes in acetate fibers. The soaping fastness of printed products can be maintained above grade 4. The color management of the digital printing process for diacetate fabric adjusts the total ink output and the linearization of printing process, so as to ensure the quality of diacetate digital printing to achieve what you see is what you get.

Objective Metallized carbon nanotube (CNT) yarns are prepared and studied, which require the use of precious metals or complex processes to achieve satisfactory surface topography, resulting in high production costs. However, the mechanical properties of the metallized CNT yarns significantly are decreased while achieving the improved electrical conductivity. Therefore, it is necessary to find solutions that will enable metallized CNT yarns to have both satisfactory mechanical and electrical properties at low-cost.

Method This paper employed chemical deposition and electrochemical deposition methods to deposit metals on the surface of CNT yarns. Nickel served as the interface layer and oxidation-resistant layer in the metallized CNT composite yarns, while copper acted as the conductive layer. By adjusting the process parameters, controlling the process flow and adjusting the structure of the composite yarns, we successfully prepared high-performance Ni/Cu/Ni-CNT composite yarns. This paper conducted tests and characterizations on the mechanical, electrical, and processing properties of the composite yarns and discussed the influence of the nickel interface layer on the mechanical and electrical properties of the composite yarns.

Results The optimal electrochemical deposition was carried out at 5 mA/cm² for 180 min. The surface of the original CNT yarns exhibited prominent grooves, and the yarn surface was covered with metal, resulting in a significant reduction in the grooves after metal deposition. In the absence of a nickel interface layer, the surface of the composite yarn showed visible metal particles, with some copper loosely adsorbed onto the CNT yarns in the form of loose particles, leading to a rough and porous coating. However, with the presence of a nickel interface layer, the surface coating of the composite yarns became uniform and refined. The Ni/Cu/Ni-CNT composite yarns demonstrated a thicker coating compared to the Ni/Cu-CNT composite yarns without the nickel interface layer. However, the decrease in tensile strength of the Ni/Cu/Ni-CNT composite yarns was smaller than that of the Ni/Cu-CNT composite yarns, with an improved elongation at break. These findings indicate that the porous structure causes stress concentration, weakening the overall load-bearing capacity of the composite yarns and resulting in the deterioration of its mechanical properties. The nickel interface layer was introduced before the copper plating forms a robust CNT-Cu interface, for the purposes of enhancing the load efficiency between the CNT yarns and copper, improving the quality of the copper-plated layer, and creating tightly structured composite yarns with staisfactory mechanical properties. After copper plating, the electrical conductivity of the CNT yarns was significantly improved, with the Ni/Cu/Ni-CNT composite yarns exhibiting the best conductivity, which is 44 times higher than the original CNT yarns and 1.4 times higher than the Ni/Cu-CNT composite yarns. After 100 friction cycles, the surface of the Ni/Cu-CNT composite yarns suffered severe damage, with needle hook friction causing noticeable fractures in the metal coating. By contrast, the Ni/Cu/Ni-CNT composite yarns only exhibited micron-level cracks on the surface while maintaining a good surface topography. This indicates that the nickel interface layer significantly improves the wear resistance and knittability over the CNT/Cu composite yarns. After simulating 100 knitting cycles, the tensile strength of the composite yarns was slightly decreased, while the elongation at break got higher. The conductivity loss of the Ni/Cu-CNT composite yarns was 46%, while the Ni/Cu/Ni-CNT composite yarns showed a conductivity loss of 38%. Nonetheless, the conductivity loss was still 28 times higher than that of the original CNT yarns. Even after 100 friction cycles, the electrical conductivity of the composite yarns remained satisfactory.

Conclusion The Ni/Cu/Ni-CNT composite yarns prepared by chemical deposition and optimal electrochemical deposition exhibit excellent morphology, mechanical properties, and electrical properties. The surface coating of the Ni/Cu/Ni-CNT composite yarns is uniform and refined. Compared to the original CNT yarns, the Ni/Cu/Ni-CNT composite yarns show a 44-fold improvement in electrical performance while maintaining 90% of its tensile strength. The Ni/Cu/Ni-CNT composite yarns also demonstrate outstanding wear resistance and knittability. The nickel interface layer effectively enhances the adhesion of the copper-plated layer to the surface of the CNT yarns. After 100 friction cycles, only micron-level discontinuous cracks are observed on the yarn surface, and the tensile strength and electrical conductivity are maintained at 91% and 62%, respectively.

Objective Lyocell fibers belong to regenerated cellulose fiber family with excellent comfort, breathability and biodegradability, which is widely used in clothing, bedding, furniture and other fields. However, the limiting oxygen index (LOI) of lyocell fiber is only 19%, indicating high flammability with a great threat to people's life and property safety. In addition, the hygroscopicity of lyocell fabrics provides suitable conditions for the propagation of microorganisms, which adversely influences human health. Therefore, the flame retardant and antibacterial modification for Lyocell fabrics is worthy of attention.

Method Aminoazole-based cyclotriphosphazene (HATA) is rich in phosphorus and nitrogen, which can achieve efficient flame retardant for fabrics. Besides, tannic acid (TA) belongs to biomass, which has a wide range of sources. Glycidyl trimethyl ammonium chloride (GTA) was utilized to improve the loading of tannic acid on the fabric, amnd triethoxyvinylsilane (VTEO) was selected to endow the fabric hydrophobicity. A multifunctional lyocell fabric was prepared by the dip-drying method, and the flame retardant, UV resistance, hydrophobicity and antibacterial properties were investigated by vertical flame tests (VFT), limiting oxygen index (LOI) evaluation, microscale combustion calorimetry (MCC), anti-UV performance test, contact angle test, and oscillating method of antimicrobial test.

Results In this study, control lyocell was burned out with little char residue during the VFT. However, treated Lyocell passed VFT with self-extinguish behavior and the char residue was only 5.5 cm. Besides, treated Lyocell after 5 laundering failed to pass VFT, but remained a little char residue. Compared with the control lyocell, the LOI value of treated Lyocell increased from 19.0% to 29.4%. MCC test showed that the peak heat release (PHRR) and total heat release (THR) of treated Lyocell decreased 74.9% and 65%, respectively. Moreover, TG resulted that the introduction of the coating reduced the maximum decomposition rate (R_max) and the temperature at the maximum decomposition rate (T_max) obviously, improving the char residue rate from 14.3% to 40.3%. The above results indicated that the coating played an important role in promote the formation of char layer to protect the fabrics. Meanwhile, through SEM, the micromorphology of control lyocell, treated lyocell, and the char residue of treated lyocell was examined. The char residue of treated Lyocell remained the original woven structure and had some noticeable bubbles. To detect the UV resistance of treated Lyocell, ultraviolet spectrophotometer was used to test the UV protection factor (UPF) of samples. The UPF value of treated lyocell increased from 7.69 to 64.04, which was over 40. According to the standard of GB/T 18830-2009, the treated lyocell can be defined as "anti-ultraviolet production". In addition, the water connect angle (WCA) of treated lyocell was 116°. When various liquids, such as coke, milk, juice, and tea, were applied on the surface of the treated lyocell, the droplets maintained stable spherical shape for an extended period. To evaluate the antibacterial property of treated lyocell against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), the shaking flask method was used to determine the antibacterial rate, the antimicrobial rates of the treated lyocell against S. aureus and E. coli reached 99.99% and 99.88%, respectively.

Conclusion A multifunctional coating, including the flame retardant, antibacterial, hydrophobic and anti-ultraviolet functions, was prepared by using the hydrogen bonding between HATA and TA, resulting in the formation of a water-insoluble precipitate. Furthermore, the introduction of VTEO provides hydrophobicity to the fabric. The treated Lyocell fabric passed VFT with self-extinguishing behavior, increasing the LOI value from 19.0% to 29.4% and the water contact angle to 116°. According to MCC test, the TA/HATA coating reduced the HRC, PHRR and THR values of lyocell fabrics. The TG results demonstrated that TA/HATA coating significantly improved the thermal stability and char residue rate of lyocell, and decreased the initial decomposition rate. Moreover, the coating endowed lyocell excellent antibacterial properties, hydrophobicity and UV resistance. This method provides a new strategy for constructing multifunctional fabrics.

Objective To address the issue of indoor fire alarms caused by flammable cotton fabrics, MoS₂/MXene flame retardant gas sensitive cotton fabrics were prepared with dual functions of active early warning response and passive flame retardant protection. It is significant for protecting personal and property safety by detecting characteristic CO₂ gas in the early stages of a fire and preventing the spread of flames.

Method Phytic acid-doped polypyrrole modified cotton fabrics were prepared using in-situ polymerization with phytic acid as dopant. Meanwhile, MoS₂/MXene hybrid nanomaterials were synthesized via a hydrothermal method and then assembled onto the modified fabrics by impregnation method to obtain CO₂-responsive flame retardant cotton fabrics. The thermal stability, flame retardant performance and CO₂ gas sensitivity were evaluated by thermogravimetric analysis, an FTT micro calorimeter and a digit multimeter, respectively.

Results MoS₂/MXene flame retardant gas sensitive cotton fabrics were successfully prepared. The surface of the pure cotton fabric was initially smooth, but after modification with phytic acid-doped polypyrrole, it became rough and covered with numerous particles. This change is due to the in-situ synthesis of the doped polypyrrole particles adhering to the cotton fabric. After dipping, the surface of flame-retardant cotton fabric became even rougher with regular folds, indicating successful adsorption of the MoS₂/MXene nano-hybrid material. The MoS₂/MXene flame retardant coating reduced the maximum weight loss rate of cotton fabric by 55.2% and increased the residual carbon content from 9.6% to 21.7%, enhancing thermal stability. Additionally, the coating decreased the peak heat release rate and total heat release by 83.5% and 68.7%, respectively, from 235.8 W/g and 26.7 kJ/g to 38.9 W/g and 8.0 kJ/g. This improvement is attributed to the P-N synergistic flame retardant effect of the doped polypyrrole and the barrier effect of MoS₂/MXene. The fabrics also exhibited high sensitivity to CO₂ gas, with a significantly higher resistance change rate compared to fabrics treated only with MoS₂ or MXene. At a CO₂ concentration of 180 mg/m³, the resistance change rate was as high as 49.9%, allowing for early detection of CO₂ changes during the initial stages of a fire. The presence of P-N heterojunctions in the MoS₂/MXene flame retardant gas sensitive cotton fabrics increased the concentration and migration rate of carriers in the channel, thereby enhancing the sensitivity of MoS₂/MXene flame retardant gas sensitive cotton fabrics to CO₂ gas. In addition, MoS₂/MXene flame retardant gas sensitive cotton fabrics provide more adsorption sites for CO₂ gas, further improving the sensitivity.

Conclusion MoS₂/MXene flame retardant gas sensitive cotton fabrics were successfully synthesized, demonstrating dual functionality of active early warning response and passive flame retardant protection. Compared to pure cotton fabrics, the MoS₂/MXene flame retardant gas sensitive cotton fabrics show significant improved flame retardant efficiency, with an 83.5% reduction in the peak heat release rate and a 68.7% reduction in total heat release. This performance is mainly due to the P-N synergistic flame retardant effect of phytate-doped polypyrrole and the barrier effect of MoS₂/MXene. In addition, MoS₂/MXene flame retardant gas sensitive cotton fabrics exhibit high sensitivity to CO₂gas, capable of monitoring sudden change of CO₂ at the initial stage of a fire. This study shines a new light on fire prevention and control.

Objective The breeding and spread of bacteria on medical and hygienic materials are a major threat to human health. Therefore, it is of great significance to develop bacteria detective textile materials with high efficiency and performance. Prussian blue (PB) is a coordination compound with a redox potential high enough to react with proteins and mediators of the bacterial electron transport chain. Besides, it has a high extinction molar coefficient, distinct color change after reduction, which can be used as an indicator of bacterial reduction metabolism. Polypropylene (PP) spunbonded nonwovens have good chemical stability and are not easy to chemically react with Prussian blue or other substances tested, and the large surface area and pores of PP spunbonded nonwovens contribute to the loading of Prussian blue nanoparticles (PB NPs). In this paper, PP spunbonded nonwoven and PB NPs were employed as substrate and coating material respectively to prepare functional nonwoven with bacterial detection function by acoustic chemical coating technology.

Method PB NPs were firstly prepared by using polyethylpyrrolidone and potassium ferricyanide as raw materials. Then, polyvinyl alcohol modified PP nonwoven (PP/PVA) was prepared by hydrophilic modification. As the last step, PB NPs were combined onto PP/PVA nonwoven by means of acoustic chemical coating technology to obtain PP/PB nonwoven. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to characterize the morphology, chemical and crystalline structures of PB NPs, PP, PP/PVA and PP/PB nonwovens. Especially, the bacterial detection performance of PP/PB nonwoven was evaluated by oscillating method.

Results It was evident from the SEM image that the prepared PB NPs had a regular cubic structure with uniform particle size distribution. The fibers of pure PP nonwoven were arranged dandomly and the fiber surface was smooth and free of impurities, while obvious particles and network adhesion were found on the surface of PP/PVA nonwoven and PP/PB nonwoven, respectively. The infrared spectra of different samples showed that PP/PB nonwoven retained the characteristic absorption peaks of PP/PVA and PB NPs, indicating that PB NPs was successfully loaded on PP nonwoven. XRD patterns of different samples show that PP/PB nonwoven demopnstrated diffraction peaks of PP (2θ=14.18°, 17.05°, 18.64°, 21.36° and 25.37°) and PB NPs (2θ=35.42°, 39.76°, 43.74°, 50.95°, 54.29° and 57.49°), implying that PB NPs were successfully loaded onto PP nonwoven by acoustic chemical coating technology. Finally, the bacterial detection performance of PP/PB nonwoven was investigated. With the increase of the concentration of PB NPs solution, the color of the solution gradually deepened. After 24 h of incubation in the bacterial solution containing Staphylococcus aureus and Escherichia coli, the color of the samples changed from blue to white, indicating that PP/PB nonwoven fabric could detect these bacteria through its color development reaction. Therefore, it is possible to applyPB NPs to medical and hygienic materials such as surgical gowns and masks to achieve the detection and early warning of bacteria through the color reaction, so as to effectively avoid adverse effects caused by bacteria.

Conclusion The PP/PB nonwoven fabric with PB NPS coating were prepared by acoustic chemical coating technology, which has excellent bacterial detection performance. After inoculation with Staphylococcus aureus and Escherichia coli, the color of PP/PB nonwoven fabric changed from blue to white. It can be applied to medical care products such as surgical gowns and masks to realize the detection and early warning of bacteria through color reaction, so as to effectively avoid the adverse effects of bacteria.

Objective It is true that the function requirements on female sports underwear are getting higher and higher. In order to improve the thermal and wet comfort of sports underwear, a fine thermal and wet partition design for sports underwear was carried out, combined with flat braid technology to reduce the seam of sports underwear and improve the comfort.

Method Based on the study of the distribution of thermat and humidity in women's upper body, a thermat and humid partition model for forming sports underwear was constructed. At the same time, using DTY as raw materials, eight types of structures suitable for flat knitting sports underwear were designed and developed, and their moisture permeability, moisture absorption, sweat drainage and air permeability were tested. Based on the experimental results, the thermal and humid comfort of the eight structures was evaluated by fuzzy comprehensive evaluation method, and the order of thermal and humid performance was obtained.

Results Through the analysis of thermal and humid distribution in the upper body of the human body, it is found that the heat in the upper chest, the middle chest and the back is the highest and the distribution of sweat glands is the most dense. The chest heat is higher, but the distribution of sweat glands is less than the upper chest, the middle chest and the back. Underarm heat is relatively low but sweat glands are densely distributed; The distribution of heat and sweat glands in abdomen and back triangle was medium. The remaining areas are at the edges of the body, where they emit less heat and have fewer sweat glands. The thermal and humid test results show that the moisture permeability of the fabric is inversely proportional to the total density of the fabric. This is because the greater the total density of the fabric, the tighter the water vapor will pass through the pores of the fabric, which will also lead to more contact points between water vapor and the fabric, resulting in poorer moisture permeability of the fabric. The moisture absorption and perspiration of the fabric is determined by the number of connecting channels between the front and back of the fabric.The more connected channels, the better the moisture absorption and perspiration, because these connected channels will form a microporous structure on the surface of the fabric, giving it a good single guide wet performance, and promote the improvement of the moisture absorption and rapid drying of the fabric. The air permeability of a fabric is mainly determined by the size and distribution of pores in the fabric. The larger and more pores, the better the air permeability of the fabric, because when the fabric is larger and more pores, the looser its structure, the easier the flow of gas inside the fabric, resulting in a higher air permeability of the fabric.

Conclusion According to the analysis of thermal and humid distribution of female upper body, the thermal and humid partition model of formed sports underwear is constructed, which is divided into five zones. Zone I is high thermal and high humid partition, II for high thermal and humid areas, III is medium thermal and high humid area, IV is area of moderate heat to moderate humidity, and V is the area of low thermal and low humidity. Through fuzzy comprehensive evaluation analysis, it can be seen that the comprehensive thermal and humid performance of the double-layer tissue is better than that of the single-layer tissue, and the honeycomb mesh tissue in the double-layer tissue has the best thermal and humid performance, which is mainly caused by the number of connecting channels between the front and back of the double-layer stitch. A flat knitting sports underwear was designed and developed by combining the thermal and humid zoning model and the comprehensive evaluation results of the tissue structure, and the function of improving the heat and humidity balance of human body was verified by infrared thermal imaging test.

Objective In order to improve the communication efficiency and optimize the customization experience during the process of customizing Hanfu for users, an intelligent customization recommendation method based on an improved stack-generative adversarial network is proposed, relying on the technology of text generated images. Using this method, the user's customized requirement text will be directly generated into Hanfu sample images for reference, efficiently achieving personalized recommendations based on the user's customized needs.

Method The improvement method consisted of a two-stage model. In the first stage, a demand text encoding model based on Embeddding and Long Short-Term Memory (Embedding-LSTM) was constructed to address the problem of sparse and isolated text encoding in the original model. In the second stage, residual structures were introduced to optimize the feature extraction and transmission capabilities of Hanfu text images, providing better guide to the the second stage training process based on the primary features learned in the first stage. Then, the average absolute error was used to construct a loss function to optimize the learning process, thereby improving the consistency between text description and generated images.

Results A dataset comprising 8 156 Hanfu item images was established through data collection and enhancement techniques. By further subdividing the traditional Hanfu into 70 subdimensions based on 7 attributes, which are dynasty, category, collar shape, sleeve shape, color scheme, season, and image presentation, a learning and mapping model was established from customized demand text to Hanfu images. To determine the authenticity of the generated Hanfu images, the Inception V3 model was utilized to calculate the FrÉchet Incepton Distance(FID value). To effectively evaluate the quality of the generated Hanfu images, the pretrained Hanfu fine-grained classification model was used to calculate the second FID value. The objective evaluation results revealed that after the improvement of the model, the differences between the two FID values dropped from 35.86% to 10.59% respectively, indicating that the Hanfu images generated by the improved model had stronger discriminability and were closer to real Hanfu compared to the original model. 38 respondents were invited to participate in a subjective evaluation, and it was found that the Hanfu images generated by the improved model scored higher than the real images in terms of similarity, structural integrity, overall beauty, and text matching. This indicated that the images generated by the improved model were more realistic and favored than those generated by the original model, with more complete and aesthetic style results and higher compatibility with text labels. Comparative experiments were conducted with large model methods such as the Transformer-based ERNIE ViLG diffusion model, the U-Net convolutional neural network-based Composer, and traditional Diffusion Models. The results showed that the improved method proposed in this research had higher FID values when calculated using the Inception V3 model, while the FID values calculated using the Hanfu fine-grained classification model had the lowest scores. This indicated that the Hanfu generated by the proposed method contained more traditional Chinese clothing elements, suggesting that the proposed method was more suitable for the generation of traditional Hanfu.

Conclusion This research focused on Hanfu customization recommendation and proposed an intelligent recommendation method based on an improved stack-generative adversarial network. Research has shown that the improved method is able to produce more realistic and high-quality Hanfu images, and performs better in matching requirement texts, demonstrating the effectiveness and applicability of the proposed method in generating Hanfu images. This study only selected traditional Hanfu as the research object. In future research, more comprehensive Hanfu text and image data will be collected and organized to improve the robustness and diversity of model generation, enhance Hanfu recommendation satisfaction, and optimize customization experience. In addition, future research can also consider combining improved methods with large-scale modeling techniques to continuously optimize and improve Hanfu customization recommendation technology.

Objective The study aimed to assess the dynamic aethetics of pleated skirts, a hallmark of Chinese tradition celebrated for their fluid and elegant movement. Recognizing the gap in scientific methods for measuring the beauty of traditional ethnic garments in motion, it leveraged machine vision technology and high-speed photography to develop quantifiable visual feature indices and a comprehensive mathematical model.

Method The study utilized machine vision technology integrated with high-speed cameras to evaluate objectively the dynamic aesthetics of pleated skirts. A custom dynamic image capture device was designed, incorporating a rotating display platform and multiple high-speed cameras positioned at different angles to capture dynamic images of the skirts at various rotational speeds. Multi-angle image capture was firstly carried out at different rotational speeds to ensure a comprehensive recording of the dynamic process. Subsequently, machine vision algorithms were applied to process and analyze these images, extracting key dynamic visual features such as projected contour area, lateral expansion area, skirt width, expansion angle, and liveliness. These features were systematically quantified to assess the dynamic aesthetics of the skirts under different speed conditions.

Results This study conducted an in-depth analysis of the dynamic aesthetics of pleated skirts using machine vision technology and high-speed cameras, uncovering the relationship between motion and perceived beauty. A custom dynamic image capture device was utilized, equipped with a high-speed industrial camera capable of capturing up to 245 frames/s, and a dynamic display platform that allowed for precise control of the skirt's rotational speed. The study extracted and quantified dynamic visual characteristics such as projected contour area, lateral expansion area, skirt width, expansion angle, and liveliness using this setup. Based on these quantified dynamic features and subjective evaluations from experts, regression analysis was employed to develop a mathematical model capable of objectively assessing skirt aesthetics. Within the rotational speed range of 24 r/min to 48 r/min, various dynamic characteristics of the skirts were extracted and quantified, where the projected contour area were considered between 2 281.9 cm²and 8 253.0 cm², the lateral expansion area from 4 112.3 cm² to 6 278.3 cm², skirt width from 36.427 cm to 51.178 cm, the expansion angle from 32°to 101°; and the liveliness index from 60.2% to 79.1%. These data indicate significant differences in the dynamic performance of pleated skirts at different rotational speeds. Subjective evaluations of the dynamic aesthetics of pleated skirts were carried out by fashion professionals at different rotational speeds using five main aesthetic criteria, which are drape, overall aesthetics, contour curve aesthetics, airiness, and pleat uniformity, using a scoring scale from 1 to 10. For overall aesthetics, the average score was 6.569 with a standard deviation (SD) of 1.963, wheras the average score for drape was 6.053 (SD 1.873), the average score for contour curve aesthetics was 6.224 (SD 1.955), the average score for airiness was 6.211 (SD 2.121), and the average score for pleat uniformity was 5.629 (SD 2.220). The entropy method was employed to calculate a weighted summation of these scores, yielding the final subjective aesthetic score. Pearson correlation analysis revealed a strong correlation between the dynamic visual characteristics of the skirts and the final aesthetic scores obtained from the subjective evaluation. Within the rotational speed range of 24 r/min to 48 r/min, changes in projected contour area showed the strongest correlation with aesthetic scores, with a correlation coefficient as high as 0.893 for flowing elegance and 0.882 for overall aesthetics, underscoring its critical role in visual appeal. Lateral expansion area and expansion angle also exhibited significant positive correlations with aesthetic scores, with correlation coefficients of 0.741 for lateral expansion area and airiness, and 0.740 for expansion angle and overall aesthetics. In contrast, liveliness displayed a weaker correlation but still had some influence, such as a correlation coefficient of 0.644 with drape. Skirt width showed a negative correlation with aesthetic scores, with relatively low correlation coefficients across all aesthetic criteria, such as -0.486 with overall aesthetics, indicating that within a certain speed range, wider skirts may detract from their dynamic aesthetic appeal. Regression analysis was performed, using the final aesthetic score as the dependent variable and the quantified dynamic visual indices as independent variables, resulting in the establishment of a mathematical model for evaluating the dynamic aesthetics of skirts. The regression analysis revealed significant differences in the impact of the main visual indices on aesthetic scores. The non-standardized coefficient for the constant term was 4.519, with a very high level of significance (P < 0.001). Among the indices, the projected contour area had the highest standardized coefficient of 0.563, indicating the greatest influence on aesthetic scores (P < 0.001). The lateral expansion area followed, with a standardized coefficient of 0.294 (P < 0.001), also showing a significant impact. The influence of dynamic skirt width was minor, with a standardized coefficient of 0.036, and was not significant (P = 0.660). The adjusted R²of the regression model was 0.811, indicating that the model explained 81.1% of the variance in aesthetic scores, and the overall regression model was highly significant (F = 78.224, P < 0.001), demonstrating a high level of fit. These findings further validate the effectiveness of the machine vision-based method for objectively evaluating skirt aesthetics.

Conclusion This study developed an analysis device based on machine vision technology, capable of accurately identifying and quantifying the dynamic visual characteristics of skirts. By leveraging machine vision, the device effectively addresses the challenge of accurately measuring skirt parameters in dynamic conditions, significantly improving both measurement efficiency and precision. Moreover, it mitigates the subjective limitations of traditional manual evaluation of skirt aesthetics. The regression model, constructed using data obtained from this device in combination with subjective assessments, exhibits a high degree of fit, further demonstrating the feasibility of using this device for dynamic evaluation of skirts. The objective evaluation mathematical model established from this foundation also contributes to the standardization and quantification of aesthetic evaluation in the fashion industry. This research not only pioneers a new method for evaluating the dynamic aesthetics of skirts but also provides valuable data references for skirt design. In the future, the device and evaluation model can be further optimized to accommodate a wider variety of garments. Additionally, by integrating artificial intelligence, it will be possible to explore the variations in garment aesthetics under diverse environmental conditions, thereby enriching the breadth and depth of research in garment aesthetics.

Objective Rotor spinning is based on the transportation of fibers using airflow as a carrier. However, the core spinning assembly is a closed entity, and the spinning process cannot be directly observed. With the help of numerical simulation, the movement behavior of fibers in the spinning machine can be observed and analyzed in order to address the instability of the spinning process and provide optimization solutions, and to reduce fiber waste in production. This study is also an effort yo enhance the understanding of the theoretical basis for rotor spinning of yarns.

Method The fiber motion trajectory was modelled using the Lagrangian-Euler method by considering the airflow as a continuous phase and the fibers as discrete phases. 3D modeling software SolidWorks 2021 was used to establish a model for the rotor spinning assembly, and the numerical analysis was carried out using Rocky DEM 2022R1 and ANSYS Fluent 2022R1. The airflow field was selected using the Standard k-epsilon turbulence model, Standard Wall Function (SWF), and SIMPLE algorithm. The fiber model was modelled a rod-chain structure, made of cotton fiber with a length of 28 mm.

Results The velocity of the fiber in the fiber transport channel was chosed to be (22-27.4) m/s, with a small increase in velocity and acceleration. The velocity and acceleration were gradually increased along the fiber movement direction. The velocity of the fiber on the slip surface of the rotor was set in the range of (27.4-61.1) m/s. After the fiber tip contacts the slip surface of the rotor, the velocity was increased rapidly. The increase in normal contact force was found to be the main reason for the increase in fiber acceleration. After entering the coagulation tank, the velocity of the fibers was further increased as indicated by the fiber acceleration. After reaching the maximum value of 115.5 m/s, the velocity remained stable.

When the fibers were located in the fiber transport channel, they basically maintained their morphology at the entrance and did not undergo significant morphological changes. After the fiber contacts the sliding surface of the rotor, it moved at a certain angle on the sliding surface and gradually slided towards the condensation groove. When the fiber first entered the condensation tank, it exhibited a multi segment small amplitude bending shape. The small segment bending tended to converge into a large amplitude bending, and was gradually straightened and pressed against the wall of the condensation tank.

Conclusion Numerical simulation software Rocky DEM 2022R1 and ANSYA Fluent 2022R1 were used to simulate rotor spun yarn formation from fibers with cotton fibers of 28 mm in length and 20 μm in fineness. The movement of the straightened cotton fibers in the channel of the rotor spinner was studied, and the velocity distribution, motion trajectory, and morphology of a single fiber at different positions were obtained. Combining theoretical formulae, the reasons for the velocity change of a single fiber were revealed, and the motion and morphology changes of the fibers in the rotor spinner were deeply explored. The results of this study provides some theoretical guidance for design and optimization of rotor spinning production, and has certain reference significance for the design of key components such as the fiber conveying channel and rotor in rotor spinning.

Objective Vortex spinning has been developed rapidly in recent years due to its unique advantages. However, the issue of excessive energy consumption of the vortex spinning nozzle is still unresolved. In order to reduce the energy consumption during the vortex spinning process without significantly influence the yarn strength, this study investigates the effect of the nozzle pressure (P) and the number of the injectors (N) on the air consumption of the nozzle and the strength of vortex spun yarn.

Method The computational fluid dynamics (CFD) method was adopted to simulate the airflow characteristics inside the nozzle. The air consumption and the yarn tenacity were predicted based on the static pressure and mechanical energy of the airflow. The air flow rate and yarn strength were experimentally measured to verify the numerical results.

Result Due to the pressure difference between the nozzle inlet and the vortex chamber, the mechanical energy of the airflow slightly increased in the fiber guiding passage. The mechanical energy of the airflow reached its maximum value in the region around the spindle tip with the influence of the air-jet. Then the mechanical energy of the airflow exhibited a decreasing trend in the annular region between the spindle and the vortex tube along the positive Z-axis. With the increase of nozzle pressure from 0.4 MPa to 0.6 MPa, the static pressure in the vortex chamber and the annular region between the spindle and the vortex tube generally showed a decreasing trend, as the static pressure at the injector exits was increases. The pressure difference between the air reservoir and the injector exits was further increased along with the increase of the nozzle pressure, resulting in the increase of air consumption. The mechanical energy of the airflow in the vortex chamber was slightly increased with the increase of the nozzle pressure, resulting in an increased efficiency of fiber separation. The mechanical energy of the airflow was increased significantly in the annular region between the spindle and the vortex tube, resulting in an initial increase followed by a decrease in the twisting efficiency. With the increase of the number of injectors, the static pressure was first decreased and then increased in the vortex chamber, while the pressure in the annular region between the spindle and the vortex tube was decreased. There was negligible variation in the static pressure at the injector exits, this gaving an insignificant difference in the flow rate through a single injector. The mechanical energy of the airflow in the vortex chamber was first increased and then decreased with the increase of the number of injectors, while the mechanical energy of the airflow in the annular region between the spindle and the vortex tube was increased monotonously. It is crear that either an excessive or an insufficient number of injectors was favorable for fiber separation and twist insertion. The experimental measurements showed that the flow rate of the airflow entering the nozzle exhibiteds an increasing trend as P increases, while the yarn tenacity was initially increased and then decreased. With the increase of N, the flow rate of the airflow entering the nozzle tended to be directly proportional to the number of injectors, while the yarn tenacity was first increased followed by a decrease.

Conclusion The mechanical energy of the airflow is low in the vortex chamber and the yarn passage, while was relatively high in the annular region between the vortex tube and the spindle. With the nozzle pressure was increased from 0.4 MPa to 0.6 MPa. It was found that the air consumption of the nozzle is positively related to the number of injectors. The prediction of air consumption is generally consistent with the experimental measurement of the flow rate. The mechanical energy of the airflow in the nozzle was increased as P increases, and as N increases, the mechanical energy of the airflow in the vortex chamber initially is increases and then decreases. The prediction of yarn strength is consistent with the experimental measurements. Overall, considering the requirement for yarn tenacity, the air consumption of the nozzle is the minimum when P=0.45 MPa and N=4.

Significance Metal-organic frameworks (MOFs) have garnered extensive attention owing to their highly structural design, large specific surface area, and abundant porosity, which are now recognized as one of the most promising nanomaterials and are favored in many fields such as catalysis, gas storage and separation, energy storage, antibacterial, sensing, drug delivery, and hydrophobicity. Fiber/fabrics modified with MOFs as a matric material can greatly extend the application of MOFs to overcome MOFs poor processability, and create MOFs fiber/fabric composite materials with predetermined functions. In order to further improve the practicability and efficiency of functionalized fiber/fabric modified with MOFs, research process in the preparation and application of these modified fiber/fabrics is reviewed.

Progress The processing of traditional polymeric fiber materials is to melt-extrude polymer slices and obtain the final product through a series of post-processing processes. However, in the process of combining MOFs nanomaterials with polymer fiber substrates, problems such as nanoparticle agglomeration and embedding are often encountered, which hinters their specific functions. Therefore, various new preparation processes have been developed in recent years to ensure that MOFs are uniformly dispersed on the fiber surface. Based on the synthesis process of fiber/fabric modified with MOFs, these methods can be classified into two categories, i.e., the prefabrication method and in-situ method. The prefabrication method combines the pre-synthesized fiber/fabric with MOFs by blending or post-finishing, while the in-situ method introduces additional nucleation active sites on the surface of inert fiber/fabric and allow MOFs structures to grow on the fiber/fabric surface directly. The microscopic mechanisms and advantages and disadvantages of different preparation methods are analyzed. In addition, the application of new technologies such as sorption-vapor method and fiber-intercepting-particle method in the preparation of fiber/fabric modified with MOFs is briefly described. The aforementioned methods for preparing MOFs fiber/fabric are widely used in various fields. For example, MOFs exhibit catalytic effect similar to that of metal oxidants, which can promote the decomposition of some toxic and harmful compounds. The polarization effect produced by MOFs can be used to adsorb particulate pollutants in the air and heavy metal ions in wastewater. Its high porosity structure and large specific surface make them suitable for drug delivery and the preparation of high-capacity energy storage electrodes. In addition, when MOFs are combined with fiber/fabrics, the contact with the reactants can be increased, thereby improving the reaction efficiency.

Conclusion and Prospect MOFs modified fiber/fabric integrate the advantages of both MOFs and fabrics. The fabric/fiber substrate improves the deficiencies of MOFs stability, mechanical properties and functional durability, and MOFs also endow fiber/fabrics with multifunctionality. In addition, many MOFs can be prepared using low-cost solution methods, offering high cost-effectiveness. At present, however, most of the preparation and application of fiber/fabric modified with MOFs remain in the laboratory, and their industrialization and large-scale promotion are still restricted. At the same time, the preparation method of fiber/fabric modified with MOFs is usually complicated and cumbersome, and the reaction conditions are harsh. The molecular structure of the fabric substrate will be destroyed due to temperature and pressure, causing it to lose its original mechanical properties. The application of fiber/fabric modified with MOFs in many fields is also affected by factors such as preparation process and raw material cost. It will take some time for them to be promoted and applied on a large scale. In addition, there are still some limitations that need to be solved before these fiber/fabric samples can be applied, these including the precise control of pore size of MOFs to improve their separation performance, and improvement of the durability of MOFs modified fiber/fabrics against wear and wash.

Significance Wearable flexible strain sensors can facilitate all-round monitoring of human activities and thus have broad application prospects in fields such as healthcare, public health and human-computer interaction. Compared with traditional embedded rigid strain sensors, textile structures become an ideal structural platform for flexible strain sensors with the advantages of flexibility, comfort and hyperbolic effect. However, since the raw materials used in traditional textiles generally have electrical insulating properties, they should be modified into electrically sensitive materials before being used to construct flexible strain sensors. In addition, the textile structure design is targeted on the basis of the strain sensing mechanism. Although there are some basic researches on the application of textile technology in the field of smart wearables, it is still in its infancy in the actual market application. In order to further promote the development and application of smart wearable textiles and make full use of the textile structural advantages, this paper summarizes the design concepts and preparation methods of flexible textile-based strain sensors based on the current research progress. The paper is organized on progress made in fibers, yarns and fabrics.

Progress For fiber-based strain sensors, integrating fibers with electrically sensitive materials to achieve conductive fiber preparation is the primary issue which needs to be addressed in the preparation of strain sensors. Currently, there are three mainstream technologies to prepare fiber materials with good electrical conductivity which are fiber spinning, fiber surface coating and carbonization modification of fibers. Compared to fiber-based strain sensors, yarn-based sensors pay more attention to the macroscopic structural design to assemble multiple functional materials, achieving multi-dimensional upgrading of sensing performance. Yarn spinning technology, on the other hand, is an effective way to integrate functional fibers into yarns to achieve a good combination of structure and function. Spiral yarn and core-spun yarn are two commonly used yarn structures in strain sensors. Different fabric structures have their own advantages and disadvantages for creating strain sensors. Knitted fabrics have high stretchability, which can meet the size change ability required for strain sensors, but the structural stability is relatively poor. In comparison, woven fabrics have stable structure but the deformation is limited. The most common method for preparing strain sensors with braided structure is to use elastic yarns as core and conductive yarns as the braided sheath. Nonwoven structures provide an ideal template for the deposition of conductive materials, which can effectively construct three-dimensional interconnected conductive paths. The disadvantage however is that the strength is low and thus nonwoven fabrics are rarely used as a separate substrate for strain sensor. Finally, embedding flexible conductive yarn into textiles through the sewing process is also one way to prepare textile-based strain sensors. In principle, it can be embedded anywhere in clothing, providing preparation flexibility and potentially reducing costs.

Conclusion and Prospect Although significant progress has been made in the research of textile-based strain sensors, there are still some key issues that need to be further investigated in terms of structural design, mechanism analysis, and performance optimization before academic research can be used for practical applications. 1) In order to meet the requirements of high sensitivity and large strain range of sensors, the design concept is that any slight deformation will cause changes in the conductive network inside the material, and the conductive network is always connected under different strain levels. At the same time, the interfacial properties of the conductive filler and the substrate need to be improved to ensure the repeatability and stability of the sensor. 2)The inherent insulation, viscoelasticity, and complexity of the multi-scale structure make the mechanism study of textile-based strain sensors very complex. Establishing a theoretical relationship between the multi-scale structure and the sensing performance is a necessary foundation for optimization design and performance improvement of textile-based strain sensors. 3) The performance improvement of materials in terms of washability, comfort, and adaptability with the human body is an important research direction. It is also a key issue to fully leverage the structural and performance advantages of textile materials, and consequently promoting the practical application of textile sensors in the field of wearable electronics.

Significance Automatic fabric defect detection is one of the key aspects of digital quality control in the textile industry. At present, the domestic fabric defect detection is mostly based on manual detection, but the traditional manual detection success rate of only 60%-75%, indicating that the method can't meet the demand for high-quality products. To overcome the drawbacks of manual defect detection, researchers have proposed a variety of learning-based defect detection algorithms. Compared with the manual detection, machine learning methods demonstrate a high detection rate, good stability and other characteristics. Bacause of the superiority of deep learning technology in defect detection, this technology is also used for fabric defect detection. In order to improve the efficiency of the application of deep learning technology in defect detection and to achieve digital quality control in the textile industry, the current status of research on deep learning technology in defect detection is discussed.

Progress Although traditional algorithms have achieved imroved results in some specific applications, there are still limitations when dealing with complex fabric textures. With the upgrading of computer hardware, the technology is superior in the fields of target detection and image classification, and is utilized in textile quality inspection. Since the introduction of deep learning, great breakthroughs have been made in target detection, which can be categorized into one-phase detection model and two-phase detection model in textile defect detection, both achieving better results in detection speed and detection accuracy. Due to the excellent feature extraction capability of neural networks, convolutional neural network (CNN) based classification networks are widely used for surface defect detection and classification, which can automatically learn different types of fabric defects and accurately categorize them into different classes. Various deep learning methods are superior to manual detection. Due to the difficulty in obtaining fabric datasets, research based on unsupervised learning and semi-supervised learning is gaining popularity, which trains on unlabeled data and a small amount of labeled data and reduces the dependence on labeled data. It can effectively deal with unlabeled datasets or situations where labeled data is scarce or unavailable, and it greatly reduces the working time compared to supervised learning where training is performed on labeled datasets.

Conclusion and Prospect This paper reviews the application of deep learning techniques to fabric defect detection. First, publicly available defect datasets are organized and analyzed. Secondly, the principles, advantages and disadvantages, and the scope of application of deep learning techniques for defect detection are summarized from three perspectives, i.e. supervised learning, semi-supervised learning and unsupervised learning. In addition, the commonly used speed and accuracy evaluation metrics in defect detection are sorted out. Finally, the experimental results of different deep learning networks in the detection task are objectively compared and analyzed, and the future development direction of fabric defect detection is envisioned. Supervised learning-based defect detection requires a large number of datasets, and the available public data resources are relatively scarce. Relying solely on manual labeling of fabric defects is not only time-consuming but also inefficient, therefore, automatic labeling of fabric defects and detection methods that do not require data labeling have become an important direction for future research. Currently, defect samples face many challenges in terms of data scarcity, labeling difficulty, and uneven data distribution, so unsupervised learning, weakly-supervised learning, zero-sample learning, and small-sample learning are receiving more and more attention in defect generation and detection. On the other hand, solving the data problem and developing defects with fabric texture characteristics is also one of the focuses of future research. Currently, most network structures are still designed manually. However, with the development of automatic machine learning techniques, more and more machines will be able to search and generate network architectures automatically, gradually replacing the traditional manual design.

Significance Perfluoroalkyl and polyfluoroalkyl substances (PFAS) have been widely used in various industries, particularly textiles, due to their remarkable stability and water- and oil-repellent properties. However, their extensive use in industrial and commercial settings over the past six decades has raised concerns about potential risks to human health and the environment. As research on PFAS continues to deepen, a more comprehensive understanding of these substances has emerged, leading many countries, regions, and international bodies to establish policies aimed at restricting the use, import, and export of PFAS. By highlighting the ubiquity of PFAS in the environment, their bioaccumulation in humans, the associated health and environmental risks, and the wide range of industrial applications, the need and urgency to minimize or substitute PFAS is emphasized to raise awareness of the human health risks posed by PFAS. It also calls on various industries to proactively engage in the research, development and production of fluorine-free additives as viable alternatives to PFAS.

Progress Numerous studies have demonstrated the remarkable bioaccumulative and toxicological properties of PFAS. These substances have become widely distributed in the environment due to their involvement in various industrial sectors. PFAS can be found not only in various consumer products manufactured by industry, but also in the natural environment, including the atmosphere, soil, surface water, and groundwater. This widespread distribution leads to the accumulation of PFAS, which in turn affects wildlife in the ecological system, disrupts the ecological balance, and affects agricultural practices. Bioaccumulated PFAS can enter the human body through direct or indirect exposure via the environment or the food chain, and their persistence makes them difficult to degrade, posing risks to human health. Recent research has identified the presence of PFAS in human biological samples, such as blood, urine, and other tissues, and linked their presence to a range of health problems, including endocrine disruption, cardiovascular and cerebrovascular disease, developmental abnormalities in infants and young children, various metabolic disorders, and immune system dysfunction. As a result, both national and international regulations governing the production and use of PFAS have been tightened. PFAS are commonly used as additives to improve water, oil or stain resistance in textiles and other industries. Despite the beneficial properties of PFAS, researchers are exploring the use of fluorinated additives to create textiles with enhanced performance. Strategies to mitigate the adverse effects of PFAS include minimizing their use, substituting short-chain PFAS, and developing fluorine-free additives, although these approaches present challenges that require further attention.

Conclusion and Prospect This article provides an in-depth analysis of the use, distribution, and hazards of PFAS and their regulation in China. Following the lead of European countries, which have banned certain PFAS under the Stockholm Convention since 2014, China has made significant progress in establishing a comprehensive regulatory framework and implementing a set of testing standards at the local and national levels. These efforts are aimed at strengthening the monitoring and control of chemicals in the country. To address the challenges associated with PFAS contamination, efforts are being made to improve the situation. Short-chain fluoroalkyl substances are increasingly being used as substitutes for PFAS. Although they are considered less toxic and more readily metabolized, they spread more rapidly in the environment, resulting in longer persistence, particularly in aquatic systems, and are more difficult to degrade. Therefore, the search for non-fluorinated alternatives to replace PFAS is critical. While the development of fluorine-free functional materials is still in its early stages, the need for non-fluorinated alternatives to PFAS is clear. It is our scientific belief that as social awareness continues to grow, along with the advancement of scientific research and the improvement of industry infrastructure, the adoption of environmentally friendly, fluorine-free materials will become the future direction of development.