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    15 January 2024, Volume 45 Issue 01
        
    • Invited Paper
      Dynamic modeling and control of package yarn pulled by mobile manipulator
      XU Gaoping, SUN Yize
      Journal of Textile Research. 2024, 45(01):  1-11.  doi:10.13475/j.fzxb.20231202801
      Abstract ( 198 )   HTML ( 29 )   PDF (7023KB) ( 88 )   Save
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      Objective With the continuous development of robotics and textile industry intelligence, the use of industrial robots to replace manual labor to complete all types of typical textile processing skills operations has become a new trend in the textile industry. However, in complex textile processing environments, the direct manipulation of flexible yarns by robots suffers from yarn morphology perception difficulties and spatial limitations. Therefore, a yarn-pulling manipulation control framework with an integrated robotic obstacle avoidance motion planning strategy is proposed to realize collision-free and smooth pulling manipulation of package yarn on the warping frame by the robot from the starting point to the target point.

      Method First, the dynamics model of yarn on the package surface is constructed; then the motion coupling relationship between the robot and the yarn is analyzed and the motion control equation of the robot pulling the yarn is given; furthermore, the improved adaptive goal-guided rapidly-exploring random trees (AGG-RRT) algorithm based on the axial strain constraints of the yarn is proposed; finally, the motion planning is out carried for the mobile composite manipulator, which prevents the yarn from overstretching while circumventing the obstacles.

      Results In simulation experiment 1, taking the mobile manipulator bypass from the front of the yarn frame to the back of the yarn frame as an example, the robot obstacle avoidance path search is simulated to test the obstacle avoidance ability when facing a large obstacle. The results show that after eight traversal collision detection and correction of the searched robot end collision-free path, a completely collision-free path in the robot joint space is obtained, and the movement process of the robot around large obstacles is shown, and the translation motion curves of the robot's mobile chassis and the joint motion curves of the manipulator are obtained. In simulation experiment 2, taking the mobile manipulator gripping the reserved yarn end of the package and pulling around the obstacle to the target point as an example, the simulation for searching the obstacle avoidance path of the robot pulling yarn is carried out. The results show that after eight traversal collision detection and correction of the searched robot end collision-free path, a completely collision-free path in the robot joint space is obtained, and the translation motion curves of the robot's mobile chassis and the joint motion curves of the manipulator are obtained. Furthermore, the collision-free path of the mobile manipulator is planned in the Cartesian coordinate system using S-shaped velocity curve to obtain the interpolation trajectory of the robot pulling yarn. Then, according to the dynamic model and the motion control equation, the spatial configuration and the overall axial strain of the yarn under each moving time step of the robot are obtained, and the obstacle avoidance motion process of robot pulling yarn is shown. The results show that the absolute value of the overall axial strain of each element of the yarn is smaller than the preset value.

      Conclusion Simulation results validate the ability of the obstacle avoidance algorithm to bypass large obstacles and show its applicability in complex textile processing environments. The successful planning of a collision-free trajectory for the robot pulling yarn and the effective control of the axial strain of the yarn demonstrate the effectiveness of the control framework, which can realize a collision-free and flexible hauling operation of the manipulator for the packaged yarn from the starting point to the target point.

      Fiber Materials
      Study on correlation between charge storage and filtration performance of melt-blown polylactic acid/polyvinylidene fluoride electret air filter materials
      YANG Qi, LIU Gaohui, HUANG Qiwei, HU Rui, DING Bin, YU Jianyong, WANG Xianfeng
      Journal of Textile Research. 2024, 45(01):  12-22.  doi:10.13475/j.fzxb.20230101701
      Abstract ( 161 )   HTML ( 36 )   PDF (16122KB) ( 95 )   Save
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      Objective Under the background of the continuous aggravation of air particulate matter pollution, in order to achieve efficient filtration of PM2.5 and other harmful particulate matters in the air to achieve the purpose of protecting human life and health, polyvinylidene fluoride (PVDF) with good dielectric and polarity was compounded with biodegradable polylactic acid (PLA), so as to prepare an environmentally friendly electret air filter material with fine fiber diameter, small pore size, high filtration efficiency and low filtration resistance. And the influence of PVDF on the crystallization behavior, charge storage performance and the relationship between the mechanism and filtration performance of PLA corona electret air filtration material was investigated.

      Method The melt-blown nonwovens were prepared by melt blending with PLA as the substrate and PVDF as the electret additive material. The convenient and efficient corona electret process was adopted to greatly improve the filtration efficiency of the prepared PLA/PVDF melt-blown nonwovens of through electrostatic adsorption without increasing the filtration resistance. The influence of PVDF on the crystal structure of PLA and the change of crystallinity were studied by X-ray diffractometer. The influence of PVDF on the crystallization process of PLA was studied by hot stage polarizing microscope, and the charge storage performance was studied by thermally stimulated discharge tester.

      Results By introducing an appropriate amount of PVDF (PLA/0.3%PVDF melt-blown nonwovens), the melt-blown nonwovens fiber is more uniform, the fiber network structure is more dense, the pores are more, the pore size is smaller, and the diameter is finer to 2.60 μm. It was found by X-ray diffractometer that the introduction of PVDF made the crystallization of PLA more orderly. The crystallinity of PLA/0.3%PVDF melt-blown fabric was the highest, reaching 16.99%. It was found by hot stage polarizing microscope that the introduction of PVDF significantly accelerated the crystallization rate of PLA. The test results of surface electrostatic meter and thermal stimulation discharge instrument show that the electrostatic potential of PLA/0.3%PVDF melt-blown nonwovens after corona electret can reach more than 3 kV, the peak value of TSD is higher, and the charge storage capacity is significantly improved. It shows that the introduction of PVDF can improve the crystallization properties of PLA and promote the crystallization process of PLA, thereby increasing the charge storage position during corona electret. The filtration efficiency of PLA/0.3%PVDF single-layer melt-blown nonwovens after corona electret reached 85%, and the filtration resistance was less than 40 Pa. Compared with the filtration efficiency of the corona electret melt-blown nonwovens without PVDF, the filtration efficiency was increased by more than 20%. The quality factor was used for comprehensively measuring the effect of air filter materials. It was found that the quality factor of PLA/0.3%PVDF melt-blown nonwovens after corona electret was higher than that of non-electret melt-blown nonwovens from less than 0.01 Pa-1 to 0.046 Pa-1. The filtration efficiency of PLA/0.3% PVDF melt-blown nonwovens decreased from 98% to 80% when the air flow rate increased from 10 L/min to 90 L/min, with the smallest decrease. It is further illustrated that the corona electret melt-blown nonwovens with an appropriate amount of PVDF has the best overall filtration performance.

      Conclusion By systematically studying the relationship between the crystallization behavior, charge storage performance and filtration performance of PVDF on PLA corona electret air filter material, it is found that the introduction of PVDF has an important influence on the crystallization performance of PLA/PVDF melt-blown nonwovens. The introduction of PVDF accelerates the crystallization rate of PLA and increases the crystallinity, which leads to the improvement of charge storage performance of PLA/PVDF melt-blown nonwovens and finally improves the filtration performance. The prepared degradable high-efficiency electret air filter material can effectively cope with the increasingly severe air pollution and the continuous virus prevention and control.

      Properties and filtration mechanism of thermal bonding polyethylene/polypropylene bicomponent spunbond nonwovens
      LIU Jinxin, ZHOU Yuxuan, ZHU Borong, WU Haibo, ZHANG Keqin
      Journal of Textile Research. 2024, 45(01):  23-29.  doi:10.13475/j.fzxb.20220803501
      Abstract ( 110 )   HTML ( 13 )   PDF (3592KB) ( 56 )   Save
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      Objective Bicomponent spunbond nonwovens have many unique advantages by virtue of the combination of two components, and are widely used in medical and health materials, battery separators, filter materials, oil-absorbing materials and other fields. The reinforcement method has a great influence on the properties of bicomponent spunbonded nonwovens. However, most of the previous studies focused on the influence of the process parameters of the preparation process on properties of the material, while the research on the reinforcement technology is still less. Therefore, it is imperative to study the effect of thermal bonding reinforcement on the properties of bicomponent spunbond nonwovens.

      Method Polyethylene/polypropylene (PE/PP) sheath/core bicomponent spunbond nonwovens were successfully prepared by bicomponent spunbond technology with PE as the sheath component and PP as the core component. By means of scanning electron microscope, the longitudinal and sectional morphology of sheath core fiber was observed. With the help of filter material automatic tester, pore size tester, multi-function electronic fabric strength tester, thickness gauge, water permeability tester, air permeability tester, etc., the structure and performance of the spunbond nonwoven materials with different reinforcement methods were tested and characterized.

      Results The surface morphology of the bicomponent fiber is smooth and the core are completely covered. The cross section of the bicomponent fiber presents sheath/core type, and the interface between the sheath component and the core component is obvious. After calender bonding, the rolling point area of the surface bonding of the bicomponent spunbond nonwoven material forms a "filmed" state, while the fibers that are not bonded by the rolling point still maintain the original shape. The bicomponent fibers reinforced by through-air bonding are melted and consolidated at the junction point, and the sheath component PE is melted and bonded with each other under high temperature airflow, while the core component PP still maintains its supporting role. The direction (MD) strength of calender bonding bicomponent samples is greater than the cross direction (CD) strength, while the elongation of CD is greater than the MD elongation. With the increase of surface density, the average pore diameter of the five kinds of spunbond nonwovens with surface density of 20, 35, 50, 65 and 80 g/m2 decreased successively, which were 49.24, 40.37, 34.89, 27.92 and 25.74 μm, respectively. It shows that the stacking of multilayer fiber web increases the number of fibers in unit volume, resulting in smaller pores between fibers. Considering that the porosity will affect the air permeability and water permeability of the material, the air permeability and hydrostatic pressure resistance of the sample are also tested and analyzed here. The results show that with the increase of the surface density of the sample, the air permeability is 3 501.65, 3 389.77, 3 226.64, 2 743.38, and 2 513.20 mm/s, respectively, showing a gradually decreasing trend. The hydrostatic pressure resistance of the five materials is 0.39, 0.92, 1.37, 1.90 and 3.14 kPa respectively, which increases with the increase of area density, which obviously conforms to the influence law of pore diameter change. The through-air bonding bicomponent spunbond nonwovens perform better than the calender bonding samples in terms of low resistance, high dust volume and quality factor. When the test flow is 32 L/min and the median mass diameter of NaCl aerosol is 0.26 μm, the filtration efficiency of through-air bonding bicomponent spunbond nonwovens with a surface density of 80 g/m2 after corona charging treatment is 76.62%, while the filtration resistance is only 15.85 Pa, and the dust holding capacity is 4.82 g/m2. The phenomenon of "growing dendrites" formed by particles trapped and accumulated during the filtration of through-air bonding bicomponent spunbond materials.

      Conclusion This paper mainly analyzes the influence of two kinds of thermal bonding reinforcement methods on the properties of the sheath/core bicomponent spunbonded nonwovens, and studies the fiber morphology, mechanical properties, pore size, hydrostatic pressure resistance, permeability, filtration performance and other indicators. Moreover, the filtration mechanism of the bicomponent spunbond nonwovens was analyzed. The filtration performance of the fiber filter material is closely related to the porosity. The larger the porosity, the smaller the filtration resistance and the higher the dust content. It is hoped that this study can provide a reference for the production and performance analysis of bicomponent spunbond nonwovens, and provide a new idea for the design of fiber filter materials.

      Preparation and fast wettability of polylactic acid micro-nanofibrous dressing by melt blowing process
      WANG Rongchen, ZHANG Heng, ZHAI Qian, LIU Ruiyan, HUANG Pengyu, LI Xia, ZHEN Qi, CUI Jingqiang
      Journal of Textile Research. 2024, 45(01):  30-38.  doi:10.13475/j.fzxb.20220807101
      Abstract ( 154 )   HTML ( 16 )   PDF (7330KB) ( 51 )   Save
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      Objective Polylactic acid (PLA) micro-nanofibrous nonwovens have weak hydrophilicity and low cell adhesion, adversely affecting wound healing, and are more likely to cause inflammation when used for preparing dressings. This considerably limits the effective use of PLA micro-nanofibrous nonwovens in the healthcare sector. Therefore, it is necessary to modify PLA hydrophilicity to improve its use in healthcare applications.

      Method Polyethylene glycol (PEG), sodium dodecyl sulfate (SDS) and polylactic acid are fused and blended. PLA blending raw materials with the SDS mass ratio of 0%, 0.3%, 0.6%, 0.9%, 1.2% and 1.5% are fed into screw extruder to melt. The melt is quantitatively transported to the spinneret hole of the die head by the pump and extruded in the form of melt stream through the spinneret hole. PLA micro-nanofibrous are formed by melt microflow under the action of high temperature and high-speed air flow at the die, which are then collected on the receiving screen after drafting and self-bonded to form PLA micro-nanofibrous nonwovens. Finally, the PLA micro-nanofibrous dressing is prepared by thermal lamination of the PLA micro-nanofibrous nonwoven and the viscose spunlaced nonwoven.

      Results The contact angle of the sample free of SDS was 116° (>90°) and did not change with time. With the increase of SDS ratio, the wetting time of the sample was gradually shortened. When the SDS ratio reached 1.5%, the droplets could be completely spread on the material in 0.06 s, and the sample showed super hydrophilic effect at this time. The absorption intensities of infrared curves at 1 080 and 1 750 cm-1 were enhanced after SDS addition, indicating that the ester group of PLA fiber increased after SDS addition, so the dynamic contact angle of the sample with SDS addition decreased at the same time, and the liquid conductivity of the sample was enhanced compared with that without SDS addition. The diffusion area of liquid on PLA micro-nanofibrous nonwovens increased from 36.05 cm2 to 78.26 cm2, which increased by 117.08%. The wetting time of the surface layer and bottom layer of the sample decreased from 5.34 and 3.75 s (3-5 s is fast) to 2.91 and 2.81 s (≤3 s is the maximum speed), respectively. The water absorption rate increased gradually from 4.38%/s and 4.31%/s (0-9%/s is extremely slow) to 9.15%/s and 9.39%/s (9%-29%/s is slow), respectively. The diffusion velocities of liquid water in the surface layer and bottom layer increased from 2.21 and 2.77 mm/s (2.0-2.9 mm/s is medium speed) to 8.34 and 8.11 mm/s (≥4.0 mm/s is the maximum speed). At this time, the liquid absorption rate reaches 429.94% and the liquid retention rate reaches 359.42%. According to the observation, the PLA micro-nanofibrous nonwoven with SDS has a significant influence in preparing wound dressing guide liquid, and can be naturally degraded after use, which is in line with the current characteristics of green environmental protection.

      Conclusion PLA micro-nanofibrous nonwovens with rapid liquid conduction characteristics were prepared by melt blowing technology. A small amount of SDS can reduce the composite viscosity of PLA and make the polymer fluidity better. The rheological property of the polymer with SDS is better, causing the melt to be more easily drawn, so the diameter of the ejecta fiber is smaller. The addition of SDS will increase the ester group of PLA fiber, facilitating the rapid liquid conductivity enhancement of PLA micro-nanofibrous nonwovens. Moreover, the prepared PLA micro-nanofibrous dressings can be naturally degraded after use, which is in line with the characteristics of current green environmental protection, and has good research significance in the field of medical nursing.

      Preparation and performonce of cotton stalk bast microcrystalline cellulose/modified graphene oxide composite flame-retardant fiber
      GU Jinjun, WEI Chunyan, GUO Ziyang, LÜ Lihua, BAI Jin, ZHAO Hanghuiyan
      Journal of Textile Research. 2024, 45(01):  39-47.  doi:10.13475/j.fzxb.20220903801
      Abstract ( 100 )   HTML ( 10 )   PDF (10520KB) ( 52 )   Save
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      Objective Cotton stalk bast microcrystalline cellulose (MCC) is microcrystalline cellulose extracted from waste cotton stalks. MCC fiber prepared from MCC has outstanding performances in coloration and moisture absoprtion. However, the flame retardant performance of MCC fiber is unsatisfactory, which limits the continued development of MCC fiber. The surface grafting method was adopted to modify graphene oxide (GO) by adding phosphorus. The modified GO was mixed with MCC to prepare composite fibers to improve the flame retardant performance of MCC fibers.

      Methods In this paper, 9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide (DOPO) was used as the modifier to modify graphene oxide (GO) by electrophilic substitution. In the process of GO modification, P—H in DOPO molecule opens the epoxy ring on the surface of GO, so that P forms a covalent bond with C on the epoxy ring on the surface of GO, and was grafted with GO. The phosphorus-containing flame retardant DOPO-GO prepared in the previous process was added to the MCC spinning liquid by physical blending, and DOPO-GO was uniformly distributed in the spinning liquid by ultrasonic dispersion, and MCC/DOPO-GO fiber with good flame retardant performance was prepared by wet spinning. The mechanical properties, thermal properties and flame retardant properties were analyzed.

      Results DOPO was successfully grafted onto graphene oxide, decreases the DOPO-GO particle diameter,and destroys the arrangement regularity of GO lamellar, which was conducive to reducing GO agglomeration and improving the dispersion uniformity of GO in the spinning solution, and increases the break strength of MCC/DOPO-GO fibers by 450%. The enthalpy values of MCC/GO and MCC/DOPO-GO fibers are increased by 916.2 and 1 280.2 J/g, respectively, compared with MCC fibers. It shows that the thermal stability of the fiber is improved, indirectly showing that GO and DOPO-GO can improve the flame retardant properties of the fibers. The flame retardant DOPO-GO contains the green flame retardant element P, and the P element is evenly distributed in the fiber cross section, which can greatly improve the flame retardant performance. The intensity D-peak/intensity-G-peak (ID/IG) of the residual carbon after combustion of MCC/GO and MCC/DOPO-GO fiber decreased by 4.0% and 34.2%, respectively, compared with that of MCC fiber. In other words, DOPO-GO flame retardant can form a denser carbon layer, which can effectively prevent high-temperature ablation and further improve the flame retardant property of the fiber. When the dosage of flame retardant DOPO-GO was 7% of MCC, the limiting oxygen index LOI value of MCC/DOPO-GO fiber reached 27.3%, which was 66.5% higher than that of MCC fiber 16.4%, and the fiber changed from flammable fiber to refractory fiber.

      Conclusion The thermal stability and mechanical properties of the MCC/DOPO-GO fibers modified by DOPO-GO are greatly improved, and the flame retardant performance of MCC/ DOPO-GO fibers changes from flammable to refractory. This study provides a new idea for the study of flame retardant performance of cotton straw husk microcrystalline cellulose.

      Preparation and antibacterial performances of silver-copper bimetallic nanoparticles/polylactic acid composite nanofiber membranes
      RONG Chengbao, SUN Hui, YU Bin
      Journal of Textile Research. 2024, 45(01):  48-55.  doi:10.13475/j.fzxb.20220906401
      Abstract ( 146 )   HTML ( 13 )   PDF (5776KB) ( 79 )   Save
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      Objective In the past few decades, the increase of bacterial antibiotic resistance worldwide has posed a serious threat to public health. The research aims to develop green, safe and durable polylactic acid(PLA)antibacterial textiles to protect wounds from the influence of drug-resistant bacteria. In order to develop a green, safe and durable antibacterial textile, PLA were blended with silver-copper bimetallic nanoparticles (Ag-Cu NPs) to prepare Ag-Cu NPs /PLA composite nanofiber membranes with different composition.

      Method Silver and copper nitrates first were reduced using ascorbic acid by green synthetic method to obtain Ag-Cu NPs. Then, Ag-Cu NPs were blended with PLA spinning dope to prepare Ag-Cu NPs /PLA composite nanofiber membranes with different compositions by electrostatic spinning. The morphologies, structures, hydrophilicities and antibacterial properties of Ag-Cu NPs/PLA composite nanofiber composites were characterized and analyzed by using scanning electron microscopy, X-ray diffraction, Flourier transform infrared spectroscopy, water contact angle testing and antibacterial testing.

      Results Ag-Cu NPs presented an irregular spherical shape with a particle size of about 32 nm. PLA electrospun nanofibers had a uniform diameter and a large number of tiny pores appeared on the fiber surface. Compared with PLA nanofibers, the average fiber diameter of Ag-Cu NPs/PLA composite nanofiber membrane decreased, and the average fiber diameter increased with the increase of Ag-Cu NPs concentration. Ag and Cu elements appeared on the surface of the composite nano-electrospinning membranes and uniformly distributed along the fiber diameter direction, indicating that Ag-Cu NPs were encapsulated by PLA matrix. Compared with PLA, the XRD diffraction peaks belonging to Ag and Cu appeared in the XRD patterns of Ag-Cu NPs/PLA composite nano-electrospinning membranes. The FT-IR spectrum of PLA electrospun nanofiber membrane showed the typical characteristic peaks of PLA. The infrared spectra of Ag-Cu NPs/PLA composite nanofiber membranes were similar to the pure PLA electrospun nanofiber membrane, indicating that there exists only physical interaction between Ag-Cu NPs and PLA matrix. The pure PLA electrospun nanofiber membrane with a water contact angle (WCA) value of about 135° displayed the poor hydrophilicity. The WCA value of Ag-Cu NPs/PLA composite nanofiber membranes slightly decreased compared with pure PLA electrospun nanofiber membrane, meaning the hydrophilicity of the composite nanofiber membranes increased. Pure PLA electrospun nanofiber membrane showed very limited antibacterial ability against Staphylococcus aureus and Escherichia coli. The antibacterial efficiencies of the Ag-Cu NPs /PLA composite nanofiber membranes against these two bacteria were significantly increased with the increasing of Ag-Cu NPs concentration. When the dosage of Ag-Cu NPs was 7%, the composite nano-electrospinning membrane showed high antibacterial activity, and the antibacterial efficiencies for both Staphylococcus aureus and Escherichia coli reached 99%.

      Conclusion Ag-Cu NPs/PLA composite nanofiber membranes had excellent antibacterial activity against Staphylococcus aureus and Escherichia coli. When the Ag-Cu NPs dosage was 7%, the antibacterial efficiencies of Ag-Cu NPs /PLA composite nanofiber membrane against both Escherichia coli and Staphylococcus aureus could reach 99%. It is expected that our studies may provide some theoretical reference for the application of PLA nanofiber membrane on the biomedical field.

      Preparation and air filtration performance of electrospun polyamide 6/polystyrene composite membranes
      CHEN Jiangping, GUO Chaoyang, ZHANG Qijun, WU Renxiang, ZHONG Lubin, ZHENG Yuming
      Journal of Textile Research. 2024, 45(01):  56-64.  doi:10.13475/j.fzxb.20220801601
      Abstract ( 128 )   HTML ( 11 )   PDF (7062KB) ( 63 )   Save
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      Objective Particulate matter in the air poses a significant health risk to humans. Utilizing fibrous materials to filter fine particles is the most prevalent method for golving the problem. Most filtration media struggle to achieve a balance among filtering efficiency, pressure drop, and service life. In order to create effective air filters, the fiber structures must be precisely designed. High-specific-surface-area nanofibers offer better filtering efficiency but greater air resistance. Beaded fibers provide abundant open spaces between fibers and lower air pressure as well as increasing service life. However, few studies have considered the influence of varied fiber sizes and morphologies, and fiber deposition order on filtering performance.

      Method By controlling the mass concentrations and types of polymers with mass concentrations of 20% polyamide 6 (PA6), 20% polystyrene (PS20), and 30% PS (PS30), respectively, the single nozzle electrospinning technique was adopted to produce PA6 nanofibers (referred to as PA6 mono-membrane), PS beaded nanofibers (referred to as PS20 single fiber membrane), and PS microfibers (referred to as PS30 single fiber membrane), as well as composite fiber membranes with varying single fiber membrane deposition sequences. A sequentially deposited PA6/PS20/PS30 membrane, a reverse-deposited PS30/PS20/PA6 membrane, and a three-nozzle electrospun PA6-PS20-PS30 membrane were presented. The produced fibrous membranes were tested for initial filtration, filtration performance under variable face velocity, and dust holding.

      Results PA6 nanofibers had greater filtering efficiency (99.18%) and larger pressure drop (85 Pa). PS20 beaded nanofibers could balance the contradiction between filtration efficiency and air resistance, with the highest quality factor (with filtration efficiency of 78.47%, air resistance of 20 Pa, quality factor of 0.079 4 Pa-1) among the three mono-membranes. The pressure drop of PS30 microfibers was the lowest among the three, which was 10 Pa. None of the three mono-membranes can solve the problem of reduced filtration efficiency at extremely high wind speed. The filtration efficiency and air resistance of the three composite membranes were approximately the same, however the filtration performance was different when dust was loaded. In the 30 min dust loading test, the air resistance of PA6/PS20/PS30 membrane increased faster, whereas that of PS30/PS20/PA6 membrane grew slowest. It is speculated that this is related to the size of the fiber structure on the windward side and the pore structure between the fibers. From SEM images before and after dust collection, it is seen that a large number of coarse fibers and holes existed on the wind side of PS30/PS20/PA6 and PA6-PS20-PS30 membranes, which are conducive to the entry of fine particles into the membranes and delay the formation of "cake-layer filtration". In addition, as the upwind side of the PA6-PS20-PS30 membrane comprised nanofibers, microfibers, and beaded fibers simultaneously, filtration efficiency and air resistance can be maintained at severe wind speeds. The most penetrating particle size (MPPS) of PA6 mono-membrane under the challenge of 30-500 nm monodisperse particles was around 90 nm, with a filtration efficiency <70%. The MPPS of PS20 single fiber membrane was 30 nm, and the minimum filtering efficiency was 80.21%. The size fraction filtering efficiency of PA6/PS20/PS30 composite fiber membrane was more than 94%, and the MPPS was around 90 nm. Its filtering performance was superior to that of PA6 and PS20 single fiber membrane. Thus, owing to the diversity of fiber diameter and shape, the composite fiber membrane may demonstrate higher filtering performance under diverse particle sizes.

      Conclusion By depositing PA6, PS20, and PS30 single fiber membranes in various sequences, composite fiber membranes with a beaded structure and nano-to microscale fibers were produced. Due to the complementary of fibers with various diameters and morphologies, the composite fiber membranes' initial filtration efficiency, dust-loading capacity, and filtration efficiency in the presence of high wind speeds are significantly increased. The wind side of the composite fiber membrane with an open pore structure permitted fine particles to enter the filter, hence delaying the increase in air resistance over time and prolonging the service life of the air filters. The PA6-PS20-PS30 membrane has a filtration efficiency of 93.13% and a pressure drop of 30.67 Pa, which is superior to the H10 commercial glass fiber filter. Thus, multi-nozzle electrospinning composite fiber membranes have greater potential for real-field filtration.

      Migration properties of commercial polyethylene terephthalate staple fiber oligomers and influencing factors thereof
      XIE Yanxia, ZHANG Weiqiang, XU Yaning, ZHAO Shuhan, YIN Wenxuan, ZHANG Wenqiang, HAN Xu
      Journal of Textile Research. 2024, 45(01):  65-73.  doi:10.13475/j.fzxb.20220903701
      Abstract ( 118 )   HTML ( 9 )   PDF (5677KB) ( 51 )   Save
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      Objective With the development of fine denier and high-speed spinning technology, the phenomenon of oligomers migration and powders shedding from the surface of polyethylene terephthalate(PET) fiber became more and more serious, which would greatly impact on the production efficiency, quality and workers' health during the spinning and dyeing processes. It is necessary to solve the problem by exploring the migration mechanism and the structure-activity relationships of oligomers during staple fiber processing, and thus adjust the production conditions to prevent the migration.

      Method Two types of commercial PET staple fibers with obvious difference in white powder shedding properties were extracted and thermal induced to obtain extractive fibers, thermally induced fibers and oligomers, respectively. The thermal induction temperature was determined on the practical process of the post-spinning process. Scanning electron microscopy, differential scanning calorimetry(DSC), ultraviolet-visible spectrophotometry and X-ray diffractomety (XRD) techniques were carried out to analyze the structural constituent, precipitate law and precipitate mechanism of the oligomers.

      Results The main components of the oligomers derived from these two fibers were both cyclic trimers (C3) and a small amount of PET microcrystalline polymers (PET microlite). The fibers which shed more powders (HM) detected few oligomers with high melting point should be assigned to the C4 polymers. The C3 oligomers and PET microlites were of relatively high melting temperature at 173.5 and 146.7 ℃, respectively, and the melting temperature for C4 was around 274.6 ℃. While the C3 and PET microlites for the fibers which shed less powders (LM) have low melting temperature around 171.8 ℃ and 139.0 ℃, respectively. The C3 in PET staple fiber, solvent extraction substance and pyroprocess existed as A type, B type and A/B mischcrystal type, respectively. The melting temperature of A type C3 and B type C3 from HM polymers were 173.5 and 314.5℃ while the A type C3 and B type C3 from HM polymers were relatively lower, at 171.8 and 312.6 ℃, respectively. The HM and LM fibers showed similar oligomers mass ratio as 1.37% and 1.42%. Compared with the no shedding PET fiber, the shedding powder fibers contained significantly higher amount of oligomers and the crystallinity was 57.73% (11.25% lower). Moreover, the HM fibers maintained relatively small amount of A type trimer whose melting point was 1.7 ℃ higher, and B type trimer was about 1.9 ℃ higher, and relatively higher amount of cyclic polymers containing diethylene glycol residues. It is found that when the two fibers were subjected to thermal induction in hot air from 140 to 200 ℃ for 1h, the oligomers migrated from the two of fibers possesses point-like crysta at 140, 160 and 180 ℃, and the amount of oligomers increased with the rise of temperature, on the other hand, the low powder shedding fibers migrated less oligomers. When the induction temperature reached 200 ℃, the oligomers migrated from the surface of these two fibers were mainly multi-sided crystal type, the amount of precipitation increased rapidly compared with that at 140-180 ℃, and the crystal type and quantity tended to be the same quantity.

      Conclusion The powders shedding phenomenon during staple fiber processing has no corresponding relationship with the mass ratio of total oligomers, however, it holds a positive relationship with the quantity of oligomers migrated on the fiber surface, and thermal induction is an important factor affecting the migration of PET staple fiber oligomers. Fibers heat treatment process in post-processing, the crystallinity of the fibers, and the mass ratio of ethylene glycol to terephthalic acid during polymerization may be the influencing factors affecting the powder shedding properties of oligomers. The temperature during fibers post-processing, cooling craft and the mass ratio of ethylene glycol in polymerization could be effective methods to prevent fibers from shedding powders.

      Textile Engineering
      Preparation and strain sensing properties of yarn sensor prepared by in-situ freezing interfacial polymerization
      AI Jingwen, LU Dongxing, LIAO Shiqin, WANG Qingqing
      Journal of Textile Research. 2024, 45(01):  74-82.  doi:10.13475/j.fzxb.20221001701
      Abstract ( 114 )   HTML ( 17 )   PDF (14852KB) ( 64 )   Save
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      Objective In order to solve the problems of poor flexibility and limited working range of conventional rigid sensors, smart sensoring devices are constantly shifting to miniaturization, flexibility and portability. Flexible wearable sensors can monitor human signals accurately and quickly, facilitating fitting into the human body or combine with clothing. The yarn-based flexible strain sensors have attracted much research attention to the engineering of flexible strain transducers taking advantages of their processability, high elasticity and wide adaptability.

      Method With polyester-coated spandex yarn as the substrate, a layer of polydopamine (PDA) was deposited on the surface of the substrate by impregnation to improve the adhesion of polypyrrole (PPy) to the substrate. Then, PPy was synthesized by in-situ freezing interface polymerization to effectively avoid unfavorable cross-linking or branching in the polymer, improve the conductivity, and obtain a flexible yarn strain sensor aiming for excellent tensile strain sensing performance. The conductive yarn's microscopic morphology and chemical structure were characterized by scanning electron microscopy, X-ray spectroscopy and Fourier transform infrared spectroscopy.

      Results The characterization results all proved the successful load of PDA and PPy. After PDA modification, a uniform and uneven PDA coating layer was formed on the surface of the yarn, and the hydrophilicity of the fiber surface was greatly improved. After in-situ polymerization of PPy, a granular PPy conductive layer was observed on the surface of the yarn, forming a conductive path. With the optimal ratio of n(pyrrole)/n(ferric chloride) of 1, the yarn resistance value was the lowest at 0.33 kΩ/cm. Weights of different mass were loaded on the same section of the yarn, and as the weight mass increased, the tensile deformation of the yarn gradually increased, resulting in a gradual increase in the yarn resistance value. Three stages of the main resistance were observed in the diagram of relative resistance and strain. In the first stage, the relative resistance change increased very rapidly at a strain of 0% to 6%, with a gage factor (GF) value of 4.039. In the strain range of 6% to 18%, the relative resistance change increased gradually slowing down as the strain increased, and the GF value was 1.006. At 18% to 30% strain, the relative resistance change increased slowly, and the GF value was 0.318. The change in resistance was attributed to the deformation and movement of polyester fibers after tensile strain. The prepared strain sensor simultaneously achieved a broad working range of 60%, a fast response time of 166.67 ms, which is of almost frequency-independent reliability, and stable cycle durability over 1 000 cycles. In addition, human activity could be detected when the yarn sensor was connected directly to different body parts, such as the mouth, abdomen, fingers, and knees. In the example, the yarn sensor was fixed beside the mouth, and when the tester spoke different words such as "Jiangnan", "Zhongguo", "Shaxiang" and so on, the yarn sensor recorded a specific waveform signal for each vocalization because of the different amplitudes and patterns of the mouth opening and closing. The sensor recorded almost the same waveform when the same words were repeated. Connecting the yarn to the human abdomen the sensor detected the slight deformation caused by different shades of breathing state. All these verified that the PDA/PPy/polyester-coated spandex conductive yarn had good sensitivity.

      Conclusion PDA/PPy/polyester-coated spandex conductive yarns have excellent stability, sensitivity, durability and repeatability to meet the requirements of wearable strain transducers. In addition, conductive yarns can be combined into woven, knitted and embroidery fabrics to monitor human joint activities in real time and have great potential in speech recognition, rehabilitation training, monitoring of respiratory. The outcome of the research demonstrate potentials in helping patients with joint injury and monitoring vital vegetative signs.

      Color prediction of fiber-colored fabrics based on Neugebauer equation
      YANG Liu, LI Yujia, YU Yan, MA Lei, ZHANG Ruiyun
      Journal of Textile Research. 2024, 45(01):  83-89.  doi:10.13475/j.fzxb.20220603301
      Abstract ( 121 )   HTML ( 11 )   PDF (2334KB) ( 56 )   Save
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      Objective Fiber-colored fabrics are woven from a variety of colored fibers, and the fabric color prediction is complicated. According to the stacking of color fibers and the interaction between fiber and incident light, color prediction models convenient for color calculation were established based on the Glassmann' color mixing theory and Neugebauer Equation, and the model was further optimized to predict the color of fabrics for accuracy and efficiency.

      Method Color prediction was discussed in two cases: one was depended on the surface layer of colored fibers, and the other was depended on the interaction of the top two-layer fibers. When considering the top two layers of fibers that were superimposed on each other, the mutual stacking was simplified as stacking with the same color or stacking with another color regardless of the number of primary fibers in the fabric. Color prediction models were established according to different calculation methods, and the model with the minimum color difference was selected and optimized.

      Results According to different calculation methods, three color prediction models were set up. When the color of fiber-colored fabrics was depended on the surface layer of colored fibers, model 1 was used based on the mixing primary faber colors and the average color difference for all the fabrics was 12.39. When the color of fiber-colored fabrics was depended on the interaction of the top two-layer fibers, models 2 and 3 were used. In this case, considering that the top two layers of fibers were superimposed on each other, the mutual stacking was simplified as stacking with the same color or stacking with another color, regardless of the number of primary fibers in the fabric. The color of fiber-colored fabrics was mixed by 6 primary units in model 2, and its average color difference for all the fabrics was 7.83. The color of fiber-colored fabrics was mixed by 9 primary units in model 3, where unit A+B is different from the unit B+A, but is the same as A+C and B+C. The average color difference using model 3 for all the fabrics was 9.49. Model 2 achieved the smallest average color difference, meaning that when the color of fiber-colored fabrics was depended on the interaction of the top two-layer fibers, the stacking sequence has no effect on the color value of the primary units. This model was optimized by linear regression and the proportion coefficient of each primary unit in the model can be better adopted to predict the color value of fiber-colored fabrics. The new model was named model 4, and its average color difference for all the fabrics was 3.38. The new model 4 was proven to be convenient for prediction of the surface color of fiber-colored fabrics, and could be used as a reference for predicting the color of two-color or three-color mixed fabrics.

      Conclusion Based on the Glassmann' color mixing theory and Neugebauer equation, three color prediction models were set up. Model 2 is associated to the smallest average color difference and is further optimized by linear regression. The new model 4 is convenient for predicting the surface color of fiber-colored fabrics, and can be used as a reference for predicting the color of two-color or three-color mixed fabrics. The De Mitchell equation was dupted to calculate the proportion coefficient of the primary units in the Neugebauer equation, and it was found difficult to calculate and required assumptions, resulting in theoretical errors. In this research, the primary units was simplified according to different assumptions, also generated theoretical errors, resulting in model 4 predicting higher color difference than the 1 color difference unit. The primary units of the fiber-colored fabrics is expected to be optimized in future research, fully considering the theoretical error when calculating the primary units proportion.

      Thermal and moisture comfort of polybutylene terephthalate/polyethylene terephthalate weft-knitted sports T-shirt fabrics
      YAO Chenxi, WAN Ailan
      Journal of Textile Research. 2024, 45(01):  90-98.  doi:10.13475/j.fzxb.20221006301
      Abstract ( 101 )   HTML ( 12 )   PDF (4587KB) ( 62 )   Save
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      Objective Leisure, sports, and fitness have become a life fashion. Increasing number of people participate in sports and fitness, and as a result people's requirements for sports and leisure clothing fabrics are gradually changing. Lightweight, permeable, soft, and comfortable sports fabrics with features such as diverse styles, environmental friendliness, and health benefit are favored by consumers. As people pay more attention to human health and comfort, textiles with thermal and moisture comfort performance have gained attention in the global market, and attracted research attention. The wearing comfort is largely affected by the thermal and moisture comfort performance of the fabric. Air permeability, moisture permeability, thermal resistance, water evaporation rate, and liquid moisture management ability are considered to be the key factors affecting the wearer's thermal and moisture comfort performance.

      Method In order to study the thermal and moisture comfort performance of sports and leisure T-shirt materials, 13 kinds of polybutylene terephthalate/polyethylene terephthalate(PBT/PET) weft knitted sports T-shirt fabrics with different structure parameters were developed. By using a fabricair permeability tester, fabric moisture permeability tester, thermal resistance, moisture resistance tester, and liquid moisture management tester, five indexes of the polybutylene terephthalate/polyethylene terephthalate 13 kinds of PBT/PET weft knitted sports T-shirt fabrics, which are air permeability, moisture permeability, thermal resistance, moisture evaporation rate, and liquid moisture management ability, were tested. The influences of fabric structure and monofilament size on fabric thickness, surface density, porosity, and thermal and moisture comfort performance were investigated. The thermal and moisture comfort performance of 13 kinds of weft knitted single-side knitted fabrics was evaluated through gray cluster analysis based on five individual indexes.

      Results Using SPSS statistical software to conduct a one-way analysis of variance and correlation score, it was found that fabric structure and raw material monofilament size affected fabric porosity, and the correlation coefficients were 0.831 and 0.757 (p<0.05), respectively. Fabric thickness and surface density were also important factors affecting the porosity. The correlation coefficients were -0.768 and -0.710 (p<0.05). The microstructure and filament size were also found to affect the fabric's porosity, thickness, and surface density, and then affect the fabric's thermal and wet comfort properties such as air permeability, moisture permeability, thermal resistance, water evaporation rate, and liquid water management ability. The fabric structure was significantly correlated with the fabric's air permeability, moisture permeability, and thermal resistance, and the correlation coefficients were 0.783, 0.631, and 0.684, respectively. The thickness of fabrics was significantly correlated with the moisture permeability and thermal resistance of the fabrics, and the correlation coefficients were 0.771 and 0.761, respectively. The air permeability, water evaporation rate, and overall water management ability of fabrics were significantly correlated with the monofilament size, and the correlation coefficients were 0.544, -0.628, and 0.692, respectively. The porosity of fabrics was significantly correlated with the air permeability, thermal resistance, and overall water management ability of the fabrics, and the correlation coefficients were 0.654, 0.748, and 0.735, respectively. The surface density of fabrics was significantly correlated with the air permeability and overall water management ability of the fabrics, and the correlation coefficients were -0.688 and 0.709, respectively.

      Conclusion The gray cluster analysis was adopeed to comprehensively evaluate the thermal and moisture comfort performance of the 13 weft knitted sports T-shirt fabrics, and it was concluded that the single-sided weft knitted sports T-shirt fabrics with single jersay, jacquard (1) and single-bead mesh had better thermal and moisture comfort performance, which was more suitable for the sports and leisure field.

      Dynamic deformation simulation of weft knitted fabrics based on improved mass-spring model at interlacing points
      CHANG Chenyu, WANG Yuwei, YUAN Xuyang, LIU Feng, LU Zhiwen
      Journal of Textile Research. 2024, 45(01):  99-105.  doi:10.13475/j.fzxb.20221002201
      Abstract ( 109 )   HTML ( 12 )   PDF (3647KB) ( 164 )   Save
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      Objective Because of the diversity of loop unit combination, the threading relationship and the pulling effect between different loops, weft knitted fabric structure are prone to deformation, thus achieving a rich fabric appearance. In order to dynamically simulate the deformation process of weft knitted fabric composed of different basic loop structure units, the overall structure of the fabric was controlled and the details of the loop structure were described, so as to further reduce production cost, speed up production efficiency and improve production quality.

      Method Interlacing points in the fabrics were represented by a three-dimensional structure model of the loop, as an improvement to the traditional mass-spring model. In order to associate the loop structure model and the mass-spring model with the interlacing point as the link, Non-uniform rational B-splines(NURBS) curves were to simulate the loop centerline, and the mass position through internal force analysis and dynamic solution were constantly updated through. Finally, computer tools were adopted to show the dynamic simulation effect of the associated model.

      Results The three-dimensional structure model of the loop and weft plain knitted fabric was established, involving the interlacing points and the type value points, as well as the loop distance, loop height and loop thickness. On this basis, the relationship between the type value points of the loop centerline and the interlacing points were obtained, and the three-dimensional structure model of other loops and composite fabrics through deformation were also achieved.

      The mass-spring model unit more suitable for the loop structure unit was established, and the improved mass-spring model was formed. On this basis, the mass-spring model of the corresponding fabric was obtained by changing and adjusting the model unit according to the change of the loop type.

      The connection between the loop structure model and the mass-spring model was established by using the interlacing point as the link, and the loop centerline used to describe the geometric path of the loop structure model was generated by fitting based on the principle of NURBS curve inverse calculation problem, as well as the mass positions in the mass-spring system were constantly updated through internal force analysis and dynamic solution.

      The dynamic deformation simulation of weft knitted fabric was achieved by using computer tools. An example was given to show the simulation effect of the associated model. As well as an example, the simulation effects of fabric deformation including multiple different types of loops were shown.

      Conclusion The loop structure model and mass-spring model of weft knitted fabric were established based on the interlacing point, and the relationship between them was created. The loop centerline simulated by NURBS curve was basically consistent with the geometric structure of the fabric. After reasonable internal force analysis and dynamic solution, the mass positions in the mass-spring model system were constantly updated. The dynamic simulation process of weft knitted fabric was realized.

      Construction and implementation of multilayer mass-spring structure model for weft-knitted two-side transfer fabric
      ZHANG Jing, CONG Honglian, JIANG Gaoming
      Journal of Textile Research. 2024, 45(01):  106-111.  doi:10.13475/j.fzxb.20220708501
      Abstract ( 113 )   HTML ( 14 )   PDF (4933KB) ( 50 )   Save
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      Objective The technological structure of weft-knitted two-side transfer fabric is complex and changeable, and the existing system is difficult to intuitively display the structural characteristics of the fabric during design and development. A multilayer mass-spring structure model suitable for weft-knitted two-side transfer fabric is proposed to simulate the structure of weft-knitted two-side transfer fabric.

      Method Firstly, the geometric structure models of looping, tucking and transfering are established, and then the structural characteristics of weft-knitted two-side transfer fabric are analyzed. Based on the conventional mass-spring model, the multilayer mass-spring model is constructed. Then the final position of the multilevel mass-spring model is solved by Newton's second law and Velocity-Verlet numerical integration method. Finally, an algorithm flow of weft-knitted two-side transfer fabric structure simulation is proposed.

      Results An ideal loop model is established for the basic unit of weft-knitted two-side transfer fabric, including looping, tucking and transferring. According to the documents and the actual fabric characteristics, the relevant parameter relationships of the ideal looping model are as follows: w1=4w2=1.3w3=2w4,h1=0.4h2=1.2h3. According to the different types of loops, the parameter values of each type value point will change. By adjusting the model parameters of the looping, the loop models of the tucking structure and the transferring structure are obtained. Among them, the model parameter T of the transferring coil is the sum of the total width of the loop w1 and the distance between the vertical lines of the positive and negative adjacent loop. The actual shape of the loop in the weft-knitted two-side transfer fabric were designed and woven, the position of the loop in the fabric loop shifting, and the structural features of looping, tucking and transferring in the fabric is analyzed. At the same time, the force of the adjacent loops in the fabric changes, causing the deformation of the surrounding loops. The multillayer mass-spring structure model is established and the appropriate numerical integration method is selected to solve the dynamic equation, and the loop structure deformation of weft-knitted two-side transfer fabric is analyzed. Finally, the simulation algorithm flow of weft-knitted two-side transfer fabric is put forward to determined the final position of each particle in the multi-layer spring-mass model, combined with the loop structure model of weft-knitted two-side transfer fabric, it realizes the structure simulation of weft-knitted two-side transfer fabric using Visual Studio, and the simulated fabric pattern is clear, with obvious concave-convex effect.

      Conclusion In this paper, according to the loop structure characteristics of weft-knitted two-side transfer fabric, three eight-point loop geometric structure models of looping, tucking and transferring are fitted by NURBS curve. Based on the analysis of the structural characteristics of weft-knitted two-side transfer fabric, a multilayer mass-spring structure model reflecting the connection of loops in series in three-dimensional space is constructed on the basis of the conventional spring-mass model. According to Newton's second law, the force analysis of the multil ayer mass-spring structure model is carried out, the Velocity-Verlet numerical integration method is adopted to solve the dynamic equation, and through collision detection, the phenomenon of unreasonable string between loops in the structure simulation of weft-knitted two-side transfer fabric is effectively prevented. The structure simulation of weft-knitted two-side transfer fabric is realized by using the model and the applied method.

      Single soldier camouflage small target detection based on boundary-filling
      CHI Panpan, MEI Chennan, WANG Yan, XIAO Hong, ZHONG Yueqi
      Journal of Textile Research. 2024, 45(01):  112-119.  doi:10.13475/j.fzxb.20230103301
      Abstract ( 121 )   HTML ( 19 )   PDF (6143KB) ( 92 )   Save
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      Objective In the automatic detection of siagle soldier camouflage, it is necessary to detect the targets at a long distance. In this scenario, the small size of the camouflaged target and the intensification of background fusion substantially increase the difficulty of detection. Therefore, a deep learning approach to tackle this challenge is proposed based on the deep learning network architecture and module structure.

      Method The original dataset was extended using data augmentation and the network architecture was designed based on the BGNet model. SCNet was used for feature extraction of images, and EAM (edge-aware module) was used for detecting target edges. EFM (edge-guidance feature module) made use of the output of EAM to guide the network to locate and identify targets, NCD (neighbor con-connection decoder) was used for fusing the features from EFM output, and the CAM (context aggregation module) was employed to aggregate multi-level features to obtain the final output.

      Results The quantitative results of the proposed model and the other models showed that PFNet performed poorly in this small target detection, and SINet-V2 and C2FNet had higher recognition rates but with lower recognition accuracy, indicating poor detection accuracy although they intersect with the true values. On the other hand, the BGNet model had lower recognition rates but with higher accuracy and structural similarity. The BFNet proposed in this paper was improved based on the BGNet, and after the improvement, the recognition rate was increased. At the same time, other indices measuring detection accuracy and object similarity were also improved. The proposed BFNet was found to be able to take both recognition rate and accuracy rate into account, and identify targets more accurately and comprehensively. The quantitative evaluation of the ablation experiments was carried out, and it showed that the modified EFM improved the recognition rateIby 1.35%, indicating that more targets are able to be recognized after the improvement. The modified CAM improved the recognition rate I by 0.51%, indicating that the improved CAM further improved the recognition rate I, while S, a measure of structural similarity, and the adaptive F value Fad were also hoisted, indicating that the recall rate was also improved considering the accuracy. With the modified EFM and CAM, the detection accuracy pA was slightly decreased, but the I value is improved by 1.87%. After modifying EFM and CAM, the accuracy pA was improved by 1.74% using SCNet (self-calibrated networks) as the backbone model, proving the SCNet model compensation for the decrease in accuracy caused by the improved module structure. The results of the final improvement scheme showed that the improvement rate of pA was 0.74% and the improvement rate of I was 1.35%, while the adaptive E metric Eϕadand weighted F-measure Fwβ were improved by 0.85% and 0.71%, respectively. The qualitative comparison of the proposed model with other models is shown. The baseline model could barely recognize small targets, while the improved model performs well in small camouflage target recognition task.

      Conclusion The experimental results show that the proposed model performs well in the automatic detection tasks of single soldier camouflage, which indicates that the detection model in COS (camouflage object segmentation) task is suitable for single soldier camouflage detection, and the improved model offers higher the recognition rate, especially for detecting small target. The detection algorithm can be used as an aid for combatants and also provides an effective means to evaluate camouflage designs.

      Dyeing and Finishing Engineering
      Application of methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate in supercritical carbon dioxide fluid dyeing with disperse dyes
      GE Huaifu, WU Wei, WANG Jian, XU Hong, MAO Zhiping
      Journal of Textile Research. 2024, 45(01):  120-127.  doi:10.13475/j.fzxb.20230300101
      Abstract ( 108 )   HTML ( 5 )   PDF (2533KB) ( 67 )   Save
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      Objective Supercritical carbon dioxide fluid (ScCO2) dyeing of disperse dyes with low energy consumption and no effluent discharge in the dyeing process is an advanced industrial technology in line with sustainable development. However, some problems associated with the disperse dyes in this process, such as low dye uptake and incomplete dye chromatography caused by low solubility, greatly limit their further development. In view of these problems, this paper proposed to add appropriate cosolvent to the ScCO2 to improve its solubility, so as to reduce the impact of these problems on the dyeing process.

      Method Based on the interaction forces between disperse dye molecules and cosolvent molecules, a green cosolvent (methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate) with high solubility for disperse dyes, high boiling point and non-volatile and non-toxic was selected as a dyeing auxiliary. Disperse yellow 163 and Disperse Blue 60 were selected as experimental dyes. The dyeing rates and K/S values of disperse dye filter cakes and disperse dye filter cakes with cosolvent blends were tested under different process conditions to evaluate their dyeing effects. The mechanical properties and color fastness of the dyed yarns were characterized to assess the effect of the cosolvent addition on the yarn properties.

      Results The influence of cosolvent on the fabric was studied through the reflectance curve of the dyed fabric. The results showed that the selected cosolvent has a significant influence on the brightness of the fabric, but it will not change the color and saturation of the fabric. With the addition of cosolvent, the K/S value of fabric dyed by Disperse Yellow 163 increased from 4.5 to 12.0, and that of fabric dyed by Disperse Blue 60 increased from 5.9 to 12.2, indicating that this cosolvent could be used in supercritical carbon dioxide fluid dyeing with disperse dyes. By changing the mass ratio of disperse dyes to liquid cosolvent, dyeing temperature and pressure, the influence of process conditions on the dye uptake of disperse dyes was investigated. The dye uptake of disperse dyes increased significantly after adding the cosolvent. When the mass ratio of dye and cosolvent was 1∶20, the dyeing rate of Disperse Yellow 163 and Disperse Blue 60 reached 57.62% and 70.97%, respectively. With the increase of temperature, the dye uptake increased first and then decreased after adding cosolvent, reaching the maximum at 130 ℃. With the increase of pressure, the dye uptake of disperse dyes increased slightly. The dye uptake did not change significantly with the dyeing pressure above 27 MPa, and the optimum dyeing pressure was 27 MPa. The mechanical properties and color fastness of four different yarns were characterized. The breaking strength and the elongation at break did not change significantly, and the breaking strength of yarns is all about 250 cN and elongation at break is all about 20%. Color fastness to rubbing, color fastness to sunlight and color fastness to soaping of the yarn were all above 4 levels. Properties of yarns dyed with cosolvent met the production requirements.

      Conclusion In this study, methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate was used as a dyeing cosolvent to effectively improve the dyeing rate of Disperse Yellow 163 and Disperse Blue 60 in the supercritical CO2 fluid dyeing process from a practical production problem. Meanwhile, the addition of the cosolvent only affected the brightness of the dyed yarn, and had no significant effect on the color phase and saturation. A suitable dyeing process was determined by the subsequent experiment conditions, i.e., the mass ratio of dye to co-solvent was 1:20, the dyeing temperature was 130 ℃, and the dyeing pressure was 27 MPa. After the addition of cosolvent, the resulting fabric with increased color depth, no significant loss of mechanical properties, and excellent color fastness performance met the requirements of national standards. In summary, the addition of cosolvent caused no significant effect on yarn properties while improving the dyeing rate of disperse dyes with good application prospects in the field of ScCO2dyeing.

      Multi-objective optimization design method for optimal hydroxyl substitution position in anthraquinone dyes
      YAN Suyin, ZHOU Lichun, ZHENG Ting, JIN Fujiang
      Journal of Textile Research. 2024, 45(01):  128-135.  doi:10.13475/j.fzxb.20221100101
      Abstract ( 85 )   HTML ( 10 )   PDF (3567KB) ( 53 )   Save
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      Objective With the increase of molecular weight, the chromatographic depth of dyes increases, but the solubility of dyes in supercritical carbon dioxide decreases. In order to design a dye molecular whose solubility and chromatographic depth meet the requirements, the above contradiction between solubility and chromatographic depth must be solved.

      Method In this research, the two objective optimization problems about dye solubility and chromatographic depth were transformed into a single objective 0-1 programming problem. Among the problem, dye molecular solubility was regarded as the optimization objective function, and the chromatographic depth function was regarded as the constraint. In the program, the dye solubility was expressed by cohesive energy, and the model of cohesive energy and hydroxyl substitution position was established. The chromatographic depth of the dye was expressed by the maximum absorption spectral intensity in the visible light band. According to the geometric characteristics of the molecular structure of anthraquinone dyes, molecular symmetry was used as a heuristic rules to eliminate repeated substitution positions and reduce feasible paths, and the implicit number method was used to iteratively calculate the optimal substitution position of hydroxyl group.

      Results The 5,7,12,14-pentaphentetra ketone molecule was taken as example for research. The cohesive energy and light absorption strength were calculated by the computer molecular dynamics simulation platform and relevant analysis software. Based on the above data, an optimization model was constructed, and the optimal molecular structure was obtained by solving the model. In order to determine whether the chromatographic depth of the optimal dye met the requirement, the UV absorption spectra about two molecular structures were compared. The light absorption intensity of the dyes substituted at positions 1, 4, and 6 was obviously higher than that of the dyes inserted with hydroxyl groups at other positions. Therefore, the chromatographic depth of the optimal dye met the requirement. Through molecular dynamics simulation of the optimal dye molecular structure and the actually produced Disperse Violet 26, the difference between the cohesive energies obtained from the two experiments was compared. It was seen that the designed optimal dye has greater cohesive energy and better solubility than Disperse Violet 26. The effectiveness of the design method was thus proved.

      Conclusion With the increase of benzene rings in dye structure, more functional groups can be inserted into the molecular structure and it highlights the advantages of optimal design despite the longer reaction period. Symmetry is adopted to eliminate symmetrical positions, making the optimization calculation simpler. Another achievement from the research is the use of the implicit method to calculate the optimal number of functional groups and replacement positions at one time, which is more efficient than the combination optimization. Areas for improvement are also identified for future research. Firstly, plane symmetry is adopted to find symmetry points in this research, but the plane symmetry of anthraquinone dyes is directly related to many variables such as the intermolecular interaction, the state of molecular plane motion, cohesive energy and solubility. In order to improve the efficiency and accuracy of design, it is possible to establish the model of symmetry and state of molecular plane motion, the model of cohesive energy and solubility to design optimal dyes from molecular geometric structure. Secondly, the part of validation in this research is completed on the molecular dynamics platform. When solubility and chromatography are verified by actual dyeing experiments after the optimal dye is synthesized and manufactured, the conclusion of this research would be further proved.

      Preparetion and application of silicones Pickering emulsion synergistically stabilized with surfactant and nanoparticles
      FAN Aoyun, SHEN Junyan, YANG Lei, LI Jianhao, ZHANG Zhijian
      Journal of Textile Research. 2024, 45(01):  136-145.  doi:10.13475/j.fzxb.20230201601
      Abstract ( 104 )   HTML ( 6 )   PDF (4951KB) ( 35 )   Save
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      Objective Silicones having low surface energy, excellent lubricity, thermal stability, and hydrophobicity, are widely used as finishing agents for endowing the finished fabrics with softness, fluffiness, smoothness, as well as other special features. Silicones must be pre-homogenized into emulsions before application. However, higher emulsion stability means higher content of surfactants for even more than 50% of the silicone mass. Consequently, the higher content of surfactant not only increases the cost of emulsion production but also hinders the silicone adsorption onto the fabrics, resulting in the low efficiency of these additives. While the high concentration of additive residues causes COD to increase in the working liquid, the processing burden of contaminated water treatment also got increased. Hence, it is extremely urgent to develop a highly efficient and feasible stabilization system for silicones.

      Method Isooctyl acrylate (EHA) and hydrophilically modified isooctyl acrylate (HPEHA) copolymer latex particles were prepared by semi-continuous seed emulsion polymerization, which were used as Pickering particles. A series of silicone oil/water (O/W) emulsions dosage co-stabilized by Pickering particles were prepared, aiming at development of stabization system with reduced dosage of surfactants. The Pickering particle co-stabilized emulsions were adopted to finish fabrics. The influence of philically modified isooctyl acrylate (PEHA) particle size, dosage, and surface hydrophilic modification on the dispersion stability of the emulsions, as well as Pickering particles on the surface friction coefficients of the finished fabrics and COD values of wastewater, were investigated.

      Results PEHA and the hydrophilically modified PEHA (HPEHA) latex were dried in the first stage. The resulted latex films were analyzed with infrared spectrometer and video contact angle measuring instrument. The results demonstrated the successful hydrophilic modification of PEHA. In order to obtain a stable emulsion, the dosage of surfactant to stabilize the emulsion was as high as 21% of the mass of silicone. When synergistic stabilization system composing of 7% of 180 nm-PEHA and 5% of PEHA was applied, the silicones emulsion exhibited excellent stability, indicating high stabilization efficiency of the synergistic stabilization system. Compared to the smaller PEHA particles, PEHA with larger size showed enhanced stabilization capacity as indicated by the requirement of less PEHA. The stabilization efficiency could be further improved by application of Pickering particles with water contact angle close to 90°(for example HPEHA). In terms of the synergistic stabilization system, with the decrease of (H)PEHA particle size and increase of the (H)PEHA dosage, the droplet size of silicones emulsion decreased accordingly. When the Pickering particle size, as well as dosage, was nearly the same, the droplet size of the silicone emulsion was much smaller when replacing PEHA with HPEHA. The stabilization system also exerted significant effects on the COD values of the residual working fluid, and the slippage of the finished fabrics. When the emulsion was stabilized by surfactant alone, with the increase of surfactant dosage in the emulsion, the COD values of the residual working fluid increased sharply. It demonstrated that the method to enhance the dispersion stability of the emulsion by increasing the amount of surfactant caused a large amount of silicone to remain in the residual liquid, which not only caused the waste of additives and the burden of sewage treatment, but also caused the deterioration of the slippage of the finishing fabrics. By replacing the surfactant-stabilized system with synergistic stabilization one, the finished fabric would have a lower coefficient of surface friction and higher slippage, and the COD values of the residual working fluid would be much lower. The reason could be ascribed to the cationic HPEHA particles adsorbed on the surface of the emulsion droplet, which enhanced the positive electricity of the droplet and promoted the adsorption of the droplet to the negatively charged polyester fabric.

      Conclusion Pickering particles that were adopted to stabilize silicones emulsion could be obtained by emulsion polymerization. The particle sizes and surface of Pickering particles were successfully tailor-made by emulsion polymerization recipes and post-addition of hydrophilic monomers at the final stage of reaction, respectively. When the contact angles between the Pickering particle latex films and water were close to 90°, the stabilization efficiency of the synergistic stabilization system would be significantly improved, leading to the reduction of the dosage of surfactant and Pickering particles up to 60% and 90%, respectively. With the increase in the dosage of Pickering particles, the stability of the silicone emulsions was improved, and the average droplet size got decreased. The larger Pickering particles led to the silicones emulsions with enhanced stability and increased average droplet sizes of emulsions. Compared to that in the emulsion stabilized by surfactant alone, silicone in the synergistically stabilized Pickering emulsions showed higher adsorption efficiency on fabrics, which produced fabrics with lower surface friction coefficient and waste water with lowered COD value.

      Preparation and adhesion properties of propionylated-tertiary aminated starch sizing agent
      ZHANG Yue, LI Wei, WU Yujie, CHENG Xuedong, MENG Xiang
      Journal of Textile Research. 2024, 45(01):  146-151.  doi:10.13475/j.fzxb.20230202501
      Abstract ( 69 )   HTML ( 4 )   PDF (3319KB) ( 19 )   Save
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      Objective As is well known, natural starch presents an inadequate adhesion to fibers, due to numerous hydroxyls and cyclic structure on the starch chains. The adhesion has the main function of enhancing yarn strength by bonding the fibers in the warp yarns and lessening warp surface hairs by more than 80% by bonding the hairs onto warp body. Therefore, this study aims to improve the adhesion of starch to cotton and polyester fibers by using a new starch derivative, propionylated-tertiary aminated starch (PTAS), for promoting sizing quality of the warp yarns with the new starch derivative sizing agent (PTAS).

      Method A series of PTAS samples with different total degrees of substitution were prepared by propionylation-tertiary amination of acid-hydrolyzed starch (AHS) with propionic anhydride (PA) as esterifying agent and 2-dimethylaminoethyl chloride hydrochloride (DMC-HCl) as etherifying agent, and with the method of fixing the amount of PA as well as altering the amount of DMC-HCl, under weak alkaline and low temperature conditions, in an aqueous medium. In order to reveal the successful preparation of PTAS, the chemical structure of PTAS was characterized by Fourier transform infrared (FT-IR) spectroscopy, while its elemental analysis was carried out by a X-ray energy spectrometer. The surface morphology of PTAS particles was observed and analyzed by a scanning electron microscope, and the effect of modification on the surface morphology of PTAS granules was clarified. The modification levels of propionylation and tertiary amination were determined by titration analysis and Kjeldahl method, respectively. The effects of modification on the adhesion between starch and polyester, polyester/cotton and cotton roving, and the surface tension of starch paste, were also investigated, and the adhesion was investigated by a Chinese standard method (FZ/T 15001-2008) via measuring the bonding strength of slightly sized roving. The measurement mainly includes three processes: (a) forming a starch, (b) immersing the roving and then air-drying, and (c) conducting tensile test of sized roving.

      Results FT-IR analysis found that a new peak was present in the wavenumber of 1730 cm-1, which corresponded to the stretching vibration of ester carbonyl group, revealing the successful introduction of propionate substituents in the starch molecules. The element analysis proved that in addition to C and O elements, there were N and Cl elements in the starch sample. The results from the two analyses demonstrated the successful preparation of PTAS. SEM technique revealed that PTAS sample was still in particle state, but some partide surfaces were damaged, which was mainly attributed to the facts that the modifications were occurred under alkaline condition and at the free hydroxyls on the particle surfaces. By using the previous preparation method, PTAS samples with propionylation level of 0.030 and tertiary amination level range of 0.010-0.035 could be prepared, by fixing the 4.63% in the mass ratio of PA to AHS and altering the amounts of DMC-HCl in the range of 10-40 g. The adhesion of PTAS to polyester, polyester/cotton and cotton roving was obviously higher than that of AHS, but the surface tension was significantly lower than that of the latter. The introduction of propionate and 2-dimethylammonium chloride ethyl substituents on the starch chains not only significantly reduced the surface tension and heterogeneous state of the starch paste, improved wetting and spreading of the paste on the fiber surface, but also played an internal plasticization on the starch adhesive layers, which is conducive to reducing the internal stresses within the adhesive layer and at the interface between the adhesive layer and fibers, hence promoting the bonding forces to three roving. With the increase in the total degrees of substitution, the surface tension was gradually decreased, and the bonding force was gradually increased. In addition, the bonding of PTAS to cotton roving was better than that to polyester roving. One main reason is that the positively charged 2-dimethylammonium chloride ethyl substituents can induce the electrostatic attraction between PTAS and cotton fiber, thereby promoting the adhesion of starch to cotton fiber.

      Conclusion The propionylation-tertiary amination could improve the adhesion of starch, and this in turn promotes its sizing quality to warp yarns. This study proposed a new starch derivative (PTAS) for the warp sizing of polyester, polyester/cotton and cotton yarns and laid an important foundation for this application.

      Preparation of multi-component organic polysiloxane for flame retardancy of polyamide 6 fabrics with anti-dripping behavior
      FAN Shuo, YANG Peng, ZENG Jinhao, SONG Xiaodi, GONG Yudan, XIAO Yao
      Journal of Textile Research. 2024, 45(01):  152-160.  doi:10.13475/j.fzxb.20230101301
      Abstract ( 109 )   HTML ( 12 )   PDF (5539KB) ( 111 )   Save
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      Objective Polyamide 6 fabrics are widely used in the fields of textiles and garment, aerospace, construction, and other industries by virtue of its lightweight, softness, high-strength, and abrasion resistance. However, polyamide 6 fabric is a combustible material, which is easy to ignite with fast burning speed, high heat release, and serious melt-dripping behavior, which greatly limits the application of polyamide 6 fabrics in some special regions. Thus, developing the flame-retardant polyamide 6 fabrics with good anti-dripping behavior becomes an important and meaningful task.

      Method A multi-component synergistic flame retardant of organic polysiloxane containing phosphorus and Schiff base units was designed by hydrolysis-condensation reaction. Subsequently, flame-retardant polyamide 6 fabric was prepared by dipping method, and its chemical structure, thermal stability, combustion behavior, char residues, and pyrolysis volatiles were systematically investigated by fourier transform infrared spectro scop (FT-IR), thermo-gravimetric analysis (TGA), microscale combustion calorimetry (MCC), and Py-GC/MS test methods, respectively.

      Results FT-IR and XPS results showed that polyamide 6 fabric was finished by the synergistic flame retardant successfully. According to TGA results, the degradation behavior of the finished polyamide 6 fabric changed to a two-stage degradation mode under the assistance of flame retardant. The initial degradation temperature (T5%) and the temperature at maximum weight loss rate (Tmax) of the finished polyamide 6 fabric decreased distinctly. On the contrary, the carbon yield (Yc) of the finished fabric approached 33.9%, which was largely higher than that of polyamide 6 fabric (3.6%). The increased carbon residue as a physical barrier was conducive to protecting the underlying fabric from heat and combustible gases. Significant differences were also observed between polyamide 6 fabric and the finished fabric from real-time combustion images. The polyamide 6 fabric was ignited quickly with fast fire spreading speed and serious melt-dripping behavior after being heated, and the fabric kept burning until the whole fabric was burnt up. In contrast, the finished fabric was self-extinguished rapidly after the fire was removed, and no melt droplet was produced during combustion. Meanwhile, the peak of heat release rate (PHRR) and the total heat release rate (THR) values of the finished fabric decreased by 23.8% and 20.4%, respectively, compared with the polyamide 6 fabric. Moreover, the PHRR and THR values of the finished fabric after washing were still lower than that of polyamide 6 fabric. During combustion of flame-retardant polyamide 6 fabric, a compact and dense carbon layer containing large quantities of small-sized SiO2 particles was generated. This generated char layer with lower intensity D-peak/intensity G-peak (ID/IG) value exhibited higher graphitization degree than the char residues of polyamide 6 fabric. The higher graphitization degree represents higher thermal stability of char layer, which is more beneficial to improve the flame retardancy of fabric. Main pyrolysis volatiles of the finished fabric were common with polyamide 6 fabric, including carbon dioxide (CO2), caprolactam, nitriles, and carbonyl fragments. Besides, some phosphorus-containing volatiles were also produced, and the proportion of caprolactam, the major combustible pyrolysis volatiles, was reduced in the pyrolysis process of the finishing fabric, reflecting flame retardant helped to retard the chain degradation reaction of polyamide 6 backbone.

      Conclusion A multi-component organic polysiloxane flame retardant is synthesized and adopted to finish a polyamide 6 fabric. With the assistance of flame retardant, the carbonization capacity and fire safety, especially the anti-dripping behavior, of polyamide 6 fabric are improved significantly. In detail, a satisfactory reduction of 23.8% in PHRR value is achieved for the finished polyamide 6 fabric, and the melt-dripping behavior of the finished polyamide 6 fabric is suppressed effectively. This significantly improved flame retardancy of polyamide 6 fabric can be attributed to synergistic effects of the formation of stable carbon layer and the release of incombustible pyrolysis volatiles, which are originated from the cooperation of polysiloxane, phosphorus group, and Schiff base structure. Moreover, the finished fabric after washing still remains good carbonization capacity and fire safety, which is crucial to post-processing and application of fabric. The reported multi-component organic polysiloxane for preparing flame-retardant polyamide 6 fabric results in good anti-dripping behavior, which will help the formation of a versatile strategy for further developing functional polyamide 6 fabric and organic polysiloxane-based flame retardants for various applications.

      Apparel Engineering
      Quantitative relationship between fabric elasticity and shock absorption performance of sports bras
      SHENG Xinyang, CHEN Xiaona, LU Yaya, LI Yanmei, SUN Guangwu
      Journal of Textile Research. 2024, 45(01):  161-167.  doi:10.13475/j.fzxb.20221102701
      Abstract ( 137 )   HTML ( 13 )   PDF (5917KB) ( 61 )   Save
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      Objective Anti-shock performance of sports bras is closely related to the tensile properties of fabrics adopted to produce the sports bras, but seldom research was published on the qualitative and quantitative relationship between the two aspects. The aim of this study is to explore the quantitative relationship between the tensile properties of cup fabrics and the shock-absorbing performance of sports bras, and to provide data support for the optimization design of sports bras in the future. The study also aims to investigate the fabric stretching condition of sports bra during exercise.

      Method Three coordinates of seven markers representing the trunk and breast movement were recorded with no bra and with six sports bras used. A dynamic mannequin with 75C-cup breasts was adopted to simulate the vertical breast movement at the running speed of 10 km/h. Six sports bras were produced with exactly the same structure, and the same materials except for the cup materials which were with different elasticity modulus in vertical direction. The quantitative relationship between elasticity modulus of cup materials and vertical breast displacement relative to trunk was fitted by ten curve-fit models. The static and dynamic stretch of cup materials were measured and calculated.

      Results The mean maximum dynamic stretch of the six cup fabrics was (53.44±2.75) mm (rangeing from 50.63-58.55 mm). The mean maximum dynamic elongation of the six cup materials was 30.02% (ranging from 19.52% to 42.80%), implying that it is reasonable to select the elasticity modulus of 30% elongation as the index of cup fabrics. The vertical breast displacement under the no-bra condition was 21.84 mm, and the vertical breast displacement under the six bra conditions ranges from 9.69 mm to 19.76 mm. Pearson test result shows significant negative correlation (r=-0.886, P=0.019<0.05) between the elasticity modulus of cup materials and vertical breast displacement relative to trunk. Using vertical breast displacement under no-bra condition as the reference, less vertical breast displacement represents better shock absorption performance of a sports bra. The findings indicate that greater elastic modulus of cup fabrics induces better shock absorption performance of the bra, which may be resulted from greater stiffness of bra-breast unity relating to greater pressure at the interface of cup and breast exerted by cup fabrics. It was noted that the negative correlation between elastic modulus of cup fabrics and vertical breast displacement was nonlinear, and the vertical breast displacement decreased less as the elasticity modulus of cup materials increases. Eight of the ten curve fit models were screened by the significance of regression equations (P<0.05). The fitting degree (R2=0.891) of power function model was higher than that of other seven curve fit models, suggesting that power function can be adopted to predict the shock absorption performance of sports bras through the elasticity of cup materials. The quantitative relationship between the elasticity modulus of cup materials and vertical breast displacement can be expressed by the fitting equation lnB=-0.248lnE+ln64.289, where E represents the elasticity property modulus of cup fabrics and B represents vertical breast displacement of sports bra. The findings of this study also implied that it is feasible to employ the dynamic mannequin to evaluate performance and factors of the sports bras.

      Conclusion The research showed that that 30% is a reasonable elongation to calculate the cup elasticity modulus when exploring the relationship between cup fabric and the performance of sports bra for women with 75C breasts when running at 10 km/h. The support performance of sports bras increases significantly as the elasticity modulus of cup fabrics increases. Power function can be adopted to predict the support performance of sports bras through cup elasticity modulus. For future research, the impacting mechanism of cup elastic properties on breast movement reduction should be explored by measuring the pressure exerted on the cup-breast interface and the stiffness of breast-cup unity.

      Analysis of influence of lower limb movement characteristics on hip circumference of pants
      WU Dongxue, LIU Rangtong, YU Yuanyuan, LI Shujing, HAN Yun
      Journal of Textile Research. 2024, 45(01):  168-175.  doi:10.13475/j.fzxb.20221107801
      Abstract ( 117 )   HTML ( 14 )   PDF (2679KB) ( 57 )   Save
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      Objective It may be uncomfortable for human being to wear clothing that conforms to the static state during certain motion states. Since the hip of human body are complex curved bodies, pantsuits should not only fit the lower limbs under static state, but also meet the needs of dynamic deformation caused by motion. Therefore, it is necessary to explore the hip circumference requirements of trouser suit in different motion states so as to achieve the goal of fitting without binding.

      Method The constraint relationship between human body characteristics and dynamic parameters of lower limbs was comprehensively analyzed, and the morphological variation rule of hip circumference section was discussed based on single leg and double leg lifting. The mathematical model between hip circumference and human characteristics, dynamic parameters of lower limbs was constructed, and the trend analysis and model modification were carried out.

      Results In exploring the relationship between hip circumference and state parameters, the analysis was performed using the control variable method. The hip circumference size increased with the increase of lifting angle β in both unilateral and bilateral leg lifts, and the change rate increased continuously, and the slope of their curve increased sharply and changed more obviously after 80°, in which the hip circumference in the bilateral leg lift state was more sensitive to the lifting angle. The variation curve of Pants hip circumference with direction angle α was shown, in which β=45°. When the lifting angle of the single leg is 45°, the hip circumference of trouser suit will first decrease and then increase with the increase of the direction angle α. When the legs were raised 45°, the hip circumference of trouser suit gradually decreased with the increase of α, and rapidly decreased after 60°. In the application of the model, based on the basic leg range of motion of human body, 60°was used as the cut-off point and divided into two cases for discussion. When β≤60°, the walking state hip circumference was calculated and the results are shown in, where data show that the Pants hip circumference is closely related to human characteristics and the lower limb motion state parameters. In addition, the same subjects did different stride tests (samples 2 and 6) and it is clear that the increase in stride length increased their lifting angle by nearly 9°, which increased the value of Pants hip circumference by nearly 3 cm. For the situation where β > 60°, the sitting hip circumference and hip circumference increase were calculated and the results are shown. Among them, samples 2 and 4 were the same person at different fat and thin times, and it was found that the different sitting width parameters at their sitting posture led to larger differences in the increase of hip circumference. Even for the same person, the human body data at different time will alter, and it is necessary to measure in real time when making clothing customization.

      Conclusion The relationship between hip circumference and the changes of human cross section is studied. Through the construction of mathematical model of hip circumference, the relationship between hip circumference, human characteristics and lower extremity state parameters is discussed, and a hip circumference model considering dynamic parameters of the lower extremity is established. When the leg lifting angle β≤60°, hip circumference line is parallel to waist circumference, pants do not bind the human body, hip circumference line does not produce fold accumulation phenomenon, and pants appear more elegant. All these can be calculated according to the angle range of individual movement needs hip circumference value. When β>60°, the hip circumference is inclined with the body. The pants do not bind the human body but will produce wrinkles which accumulates near the hip circumference. The seated width parameter is adopted to replace the hip circumference width. The maximum hip circumference after the change is selected as the minimum hip circumference of trouser suit without binding the human body under multiple lower limb movements. The model solves the influence of lower extremity motion state on hip circumference of pants, and can provide theoretical basis and reference for pants hip circumference plate making and clothing customization.

      Novel method for determining water vapor permeability of bra cups
      WANG Zhaofang, ZHANG Hui, DING Bo, ZHANG Miao
      Journal of Textile Research. 2024, 45(01):  176-184.  doi:10.13475/j.fzxb.20221104001
      Abstract ( 101 )   HTML ( 9 )   PDF (8835KB) ( 88 )   Save
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      Objective The current testing standards and methods for fabric water vapor permeability are only applicable to sheet fabrics withuniform thickness and flatness, and cannot measure fabrics with curved surfaces and fabrics with uneven thickness, which leads to the lack of systematic water vapor permeability measurement methods for bra products.

      Method This paper proposes a method for measuring the water vapor permeability of bra cups to solve the above problems. The main body of the equipment adopts the idea of "differential method", and consists of multiple slender water vapor permeable columns with a ground area of 1 cm×1 cm that continuously change in inclination angles to form a breast model with an arc-shaped evaporation surface. The innovations of the equipment are as follows: 1. the evaporation surface is designed to fit the cup radian more closely; 2. the sodium polyacrylate solution with a mass ratio of mPNNamH2O=1∶500 is used instead of the pure water, which approximately eliminates the water vapor resistance of the air layer above the evaporating liquid surface. According to the relationship between the evaporation rate of pure water and the thickness of the air layer, the relationship between the evaporation rate of pure water and the type of medium, the relationship between different concentrations of sodium polyacrylate solution and the obtained the corresponding curve fitting equations were adopted to calculate the corresponding evaporation coefficients Kair, Kangle and KPNNNa. Then algorithm and program design were carried out and the Visual Basic programming language was adopted to write the model method cup water vapor permeability calculation program. The program realizes the selection of water vapor permeability area, the input of independent variables such as mass and time, and the calculation of water vapor permeability. During the measurement, under the environmental conditions of temperature of 25 ℃, humidity of 30%, and wind speed of 0.4 m/s, the water vapor permeable column covered by the cup sample with approximately mPNNNamH2O=1∶500 sodium polyacrylate aqueous solution (keep the air layer height above the liquid level at 2 mm), the cup sample was fixed on the model with gauze to evaporate 6 h, mass the initial mass G0, evaporation end mass G1, evaporation time and evaporation area distribution were reoorded, and then input them into the user interface, and the permeability was calculate of by the program. The water vapor permeability of 4 cup samples with different air-ventilation hole areas was and compared the waster vapor permeability of fabrics measured by the upright cup method.

      Results The results show that a strong correlation (R>0.6) exists between the water vapor permeability values of different cups measured by the model method and the value of the hole quantity (R>0.6), indicating that the measurement results of the model method proposed can characterize the differences in the water vapor permeability of cups with different hole areas. On the one hand, the cups of each type were measured three times, and the CV values obtained were all less than 6%. It can be seen that the coefficient of variation of the data measured by the model method is small, and the stability of the equipment is high. And the water vapor permeability of cups made of five kinds of fabrics plain cotton, flax, silk, wool and canvas cotton obtained by this method has a high consistency with the water vapor permeability of the corresponding five fabrics measured by the upright cup method (R>0.6).

      Conclusion The water vapor permeability measured by the model method can be adopted to characterize the water vapor permeability of bra cups and fabrics. This test method solves the problem that the water vapor permeability of bra products cannot be measured and characterized at present, and can provide method support for the evaluation of the water vapor permeability of bra products for underwear companies, facilitating companies research on the heat and humidity comfort of bras. Enterprises can find out the problems and deficiencies of research and development products through measurement, and reduce the flow of bras that do not meet the water vapor permeability requirements into the market. For consumers,by marking the water vapor permeability performance data of bra products on product details, consumers can be provided with more convincing and objective consumption guidance.

      Mediating role of emotions between pleated costume elements and semantic evaluations
      HAN Yanna, JIANG Yicheng, ZHENG Xia, YANG Zitian
      Journal of Textile Research. 2024, 45(01):  185-193.  doi:10.13475/j.fzxb.20221200101
      Abstract ( 138 )   HTML ( 12 )   PDF (4489KB) ( 70 )   Save
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      Objective Chinese opera costumes play a vital role in the opera performance. To ensure the social preservation of traditional opera culture, it requires understanding how young audiences perceive and evaluate costumes emotionally and semantically. However, limited research has been done on the quantitative relationship among costume design elements, aesthetic emotions, and semantic evaluations. Therefore, using Leder's aesthetic cognitive processing model and the emotional Pleasure-Arousal-Dominance (PAD) model, this study investigated how emotions are involved in the semantic evaluations of clothing. The Xiaosheng pleated garment of Yue Opera served as the specific research object.

      Method Using two types of materials, pure polyester and pure silk, with 15 colors (top five colors, bottom five colors, middle five colors) and 4 patterns (no pattern, flower decorated border, flower broken in branch, flower medallion) for combination design, 120 pictures were built by CLO3D 6.0. Through corpus search, group classification, and expert consultation, we screened five groups of semantic differential pairs used to describe the Xiaosheng pleated garments: low level-high level, refined-rough, fresh-gaudy, brave-gentle, and stiff-drape. University students were invited to randomly score all the samples on the liking, PAD emotions, and semantic evaluations on PsychoPy 2022.2.4, and data from 35 validated subjects was analyzed via SPSS 25 and Amos 26.

      Results The relevance of pleated garment design elements, emotions, and semantic evaluations was first examined. The results showed that only the material had a significant correlation with the semantic "stiff-drape". The color was strongly correlated with liking, pleasure, dominance, arousal, "low level-high level", and "refined-rough". The pattern was also significantly correlated with the last three. Moreover, pleasure had a significant correlation with all semantics except for "fresh-gaudy", while arousal was significantly correlated with "fresh-gaudy" and "brave-gentle". Finally, dominance had a significant correlation with all semantics. We further leveraged one-way ANOVA to test the effects of design elements on emotions and semantics, respectively. Material did not affect emotions, and showed significance only in semantics "stiff-drape". The arousal of flower medallion was significantly higher than that of no pattern, and those with flower medallion were voted to be more high-class. Color had a significant effect on all emotions and semantics. According to the emotional impact, the color of Xiaosheng pleated clothes can be clustered into 3 categories: the first category is high pleasure, low arousal, high dominance colors, containing Aiqing, white, light pink, light blue, and black. The second category is high pleasure, high arousal, low dominance colors, containing bright red, goose yellow, pink, and bright yellow. The third category is low pleasure, low arousal, low dominance colors, containing treasure blue, lake, old green, medium green, and purple. Finally, the study constructed the mediating model of emotions on partial design elements and semantic evaluations. The analysis shows that arousal and dominance played a mediating role in clustered color type, pattern and "low level - high level". Pleasure, arousal, and dominance mediated the "refined-rough" in the clustered color and pattern. In the clustered color and semantic judgment of "fresh-gaudy", PAD played the mediation roles. "Brave-gentle" evaluation was mediated by the pleasure and arousal of the color. In addition, the dominance of color positively predicted the semantics "stiff-drape".

      Conclusion The combinations of materials, colors and patterns of pleated garments have effects on both aesthetic judgments and aesthetic emotions. Pleated garments with the feeling of high-level, refined, drape, fresh, and gentle were more likely to be preferred by the youngsters, and the design of patterns was significantly associated with the semantics "low level-high level", "refined-rough", and emotional arousal. The study also found that color can significantly affect aesthetic emotions. Based on the PAD emotion model, the traditional opera costume color scheme was reclassified into three major categories: high pleasure, high arousal, and low dominance; high pleasure, low arousal, and high dominance; and low pleasure, low arousal, and low dominance. It was also explored that emotions played an important mediating role in the pleated garment design elements and semantic evaluations. Therefore, this study provides an empirical reference for the aesthetic process of opera costumes and their innovative design.

      Machinery & Equipment
      Model for empty bobbin recognition based on improved residual network
      LU Weijian, TU Jiajia, WANG Junru, HAN Sijie, SHI Weimin
      Journal of Textile Research. 2024, 45(01):  194-202.  doi:10.13475/j.fzxb.20220706101
      Abstract ( 90 )   HTML ( 10 )   PDF (12276KB) ( 25 )   Save
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      Objective In the automatic production line of circular weft knitting robot, the use of conventional machine vision to identify empty yarn cylinders has low accuracy and a large number of model parameters in the process of automatic empty cylinder changing of the bobbin changing robot, due to the complex background of the textile workshop and the many types of yarn cylinders. In order to ensure the accurate identification of empty bobbin by bobbin changing robots, it is necessary to design an empty bobbin identification model with high accuracy and light weight.

      Method Based on the ResNet-18 model, the convolution kernel was light weighted, the classical residual module was improved, the SENet attention mechanism was increased, and the detection accuracy of empty bobbin was improved. By simulating various interference factors at the production site, the training samples were increased, aiming to improve the robustness of the model and to make it more suitable for the actual production environment. The model before and after improvement was compared with other detection models.

      Results The original dataset was adopted to study the influence of convolutional kernel lightweight design, attention mechanism and improved residual module on the model. Ablation experiments showed that the application of small convolution helped reduce the model parameters to a certain extent, the addition of attention mechanism improved the recognition accuracy by 3.86%, and the addition of the optimized residual structure not only improved the recognition accuracy by 1.22%, but also reduced the amount of model parameters by 650%. Under the same experimental conditions, the detection results were compared among the improved model, ResNe-18, VGG-16, and AlexNet network model. The accuracy of the improved model in the verification set is 99.6%, which is 4.46% higher than that of the ResNet-18 model, and 7.05%-9.41% higher than that of VGG-16 and AlexNet. Under the experimental conditions of the same training parameters and network structure, the training on the data-enhanced dataset was verified. Because the data enhancement could improve the diversification of the spindle data and effectively avoid the phenomenon of overfitting, the accuracy of the original model and the improved model were improved. The accuracy of the improved model was 0.43%-0.72% higher than that of the ResNet-18 model, and the accuracy of the improved model was less affected by the dataset, indicating better robustness of the model against interference from the surrounding conditins. The convergence speed of the improved model was higher than that of other recognition models, the ascent speed was smoother, and the training accuracy was the highest. Tthe reliability and effectiveness of the improved model for identifying empty bobbins are illustrated. The improved model was found far superior to the original model in extracting shallow and deep network features, and it could effectively reduce the loss of yarn feature information during convolution kernel and effectively improve the ability to identify yarn. The number of parameters of the improved model was reduced to about 1/10 of the number of parameters of the original model hence reducing the storage space. The work provides an idea for the application of the empty yarn cylinder identification system based on the residual network model to the edge deployment in textile workshops.

      Conclusion On the basis of ResNet-18 network, the network is modified, combined with the lightweight of convolution kernel, the SENet attention mechanism and the improved residual module. The new model not only improves the result accuracy but also reduces the number of model parameters in identifying empty bobbins in complex environments. Compared with other recognition models, the improved model has better robustness against interference. The improved model has a small number of parameters, which provides an idea for deploying empty bobbin identification models for embedded devices.

      Dynamic compensation design for electronic shogging movement in warp knitting machines
      XIA Fenglin, ZHANG Hang, ZHANG Qi, ZHENG Baoping
      Journal of Textile Research. 2024, 45(01):  203-210.  doi:10.13475/j.fzxb.20221202301
      Abstract ( 84 )   HTML ( 7 )   PDF (2876KB) ( 82 )   Save
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      Objective When the electronic shogging system of a warp knitting machine is in operation, it needs a certain period to process and transmit the shogging control signal, resulting in the lag of the shogging of the guide bar, which makes the shogging and the swing of the guide bar not synchronized, affecting the high-speed operation of the warp knitting machine. If the shogging lag of the guide bar can be dynamically compensated, the lag of the electronic shogging system could be improved or even eliminated, thus improving the overall performance of the electronic shogging control high-speed warp knitting machine.

      Method The shogging command signal received by the servo driver and the actual running signal of the servo motor in the electronic shogging system were collected in real time by the monitoring software. Three types of AC servo systems commonly used in the electronic shogging system of the warp knitting machine, such as Yaskawa, Tamagawa and Inovance, at different speeds of 700 r/min, 1 100 r/min, 1 500 r/min and 1 900 r/min were involved in the research. The lag between the shogging command curve and the actual motion curve of the systems above was evaluatedin to understand the effect of different running speed of warp knitting machines.

      Results Through testing the shogging command curve and the actual motion curve of the electronic shogging system using three kinds of AC servo systems at different speeds of 700 r/min, 1 100 r/min, 1 500 r/min and 1 900 r/min of warp knitting machines, it was found that the actual motion curve of the servo motor lagged behind the command curve of the servo driver in the electronic shogging systems with all three different shogging servo systems. The lag time of the electronic shogging system of the same servo system did not change with the running speed of warp knitting machine, that is, the lag time of the system was constant when the configuration of the electronic shogging system are fixed. The lag time of the electronic shogging servo system with different servo systems was found different, which was related to the performance and internal parameter setting of the shogging servo system itself. On this basis, the shogging lag was pre-compensated by modifying the corresponding control program in the electronic shogging system. During the operation of the warp knitting machines, the running speed of the machine main shaft was detected in real time, and the current shogging angle compensation value caused by the lag was calculated, which was then used for the shogging command control of the next knitting cycle. Through the test of the command curve of the shogging servo driver and the actual motion curve of the servo motor under the conditions of no compensation and compensation, the following synchronization of the actual motion curve of the servo motor and the command curve of the servo driver after compensation was improved, and the running speed of the warp knitting machine of the electronic shogging system was improved, from the original 1 780 r/min to more than 2 100 r/min, and the running performance and working efficiency of the high-speed warp knitting machine were improved effectively.

      Conclusion The shogging data in the electronic shogging system of the warp knitting machine needs to be calculated and transmitted, and the motion response of the servo system is delayed, which makes the actual motion of the shogging servo motor lag. When the system configuration is fixed, the shogging lag time is constant regardless of the running speed of warp knitting machine. The actual shogging lag of the guide bar of the electronic shogging system of the warp knitting machine affect the synchronization between the swing and the shogging of the guide bar, especially with the improvement of the running speed of the machine, making the warp knitting machine unable to run well. By presetting a forward of the guide-bar shogging angle, the lag compensation of the electronic shogging system has been achieved, and the running characteristics of the electronic shogging system of the warp knitting machine are effectively improved. The practice shows that the running speed of the warp knitting machine can be increased by 18%, which greatly improves the running speed of high-speed warp knitting machine with electronic shogging system.

      Design of constant yarn feeding tension control system for circular knitting machines based on active disturbance rejection control
      PENG Laihu, XIE Guowang, DAI Ning
      Journal of Textile Research. 2024, 45(01):  211-219.  doi:10.13475/j.fzxb.20220803701
      Abstract ( 89 )   HTML ( 3 )   PDF (3479KB) ( 57 )   Save
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      Objective Yarn tension is a critical parameter in the textile process, and its fluctuation directly affects the fabric quality. Aiming at the problems existing in the yarn feeding mode of circular knitting machines, such as large fluctuation of yarn tension, unadjustable yarn tension and feeding speed, a new yarn feeding control system based on active disturbance rejection control is proposed.

      Method Through the mathematical modeling of yarn tension, its formation mechanism and influencing factors were clarified. Based on this, a series of design schemes were proposed, such as the control strategy of feeding with constant tension, the main hardware structure of the system, and the closed-loop control algorithm of yarn tension. The system used PID controller to control the speed loop of the brushless direct-current (DC) motor in the inner closed loop and and active disturbance rejection controller to control the tension loop of yarn in the outer closed loop. Both of them constituted the inner and outer double closed loop control system of constant tension yarn feeding on circular knitting machine. Among them, active disturbance rejection control technology was adopted to obtain real-time yarn dynamic index, and to combine each yarn dynamic index through a nonlinear combination method to obtain the corrected reference speed of the brushless DC motor. The reference speed was finally applied to the brushless DC motor through the field oriented control technology. It was adopted to adjust the yarn feeding speed and ensure that the yarn tension is maintained near the set value.

      Results The yarn feeding test showed that the system achieved better results in controlling yarn tension fluctuation and overshoot. Taking the first group of experiments as an example, the yarn tension overshoot decreased by 50% and 54%, respectively, and the standard deviation of tension fluctuation decreased by 15% and 25%, respectively. The second group of experiments also reflected this rule, and it also showed that the fluctuation of yarn tension increased significantly with the increase of yarn feeding speed. When the target yarn tension increased by 52% instantaneously, the actual yarn tension reached the target yarn tension without obvious overshoot within 70ms. At the same time, the tension showed good real-time and following performance during continuous changes. In case of sudden change of yarn feeding speed, the yarn feeder reacted quickly to ensure that the yarn tension was still maintained close to the set value, and the yarn tension overshoot during the speed change process was controlled within 20%. In addition, the feeder also demionstrated good performance of constant tension control for elastic and non-elastic yarn. The test results suggested the suitability for the constant tension yarn feeding control system to be used for feeding yarns with small tension fluctuation and readjustable yarn feeding speed and yarn tension, which meets the process requirements for the circular knitting under different working conditions.

      Conclusion The new constant tension yarn feeding control system plays an important role in improving the intelligence of circular knitting machine, reducing the surface defects of fabrics, improving the elastic evenness of fabrics, and reducing the yarn breaking rate. The yarn feeder has the characteristics of programmability and wide range of yarn applications. It can also be conveniently applied to automatic winding machine, hosiery machine, seamless underwear machine and other textile equipments. Considering the large fluctuation of yarn tension under high-speed feeding conditions, a series of optimizations should be made in future research for the wire storage disk of the yarn feeder for yarns with small diameter and weak strength, such as the winding path, the number of winding turns, and the roughness of the contact surface of the wire storage disk.

      Comprehensive Review
      Research progress in performance regulation strategies of polybutylene succinate
      CHEN Yong, YE Mengting, WANG Chaosheng, WU Jing, WANG Huaping
      Journal of Textile Research. 2024, 45(01):  220-229.  doi:10.13475/j.fzxb.20221005502
      Abstract ( 89 )   HTML ( 9 )   PDF (3874KB) ( 83 )   Save
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      Significance While polymer materials bring convenience to people's lives, environmental pollution problems such as non-renewable resource consumption and microplastics caused by the manufacturing and disposal of non-degradable materials have received more attention. Poly (butylene succinate) (PBS) is a potential fully biodegradable aliphatic polyester. However, the long degradation cycle and relatively poor strength and toughness limited the actual processing and application process, and it is difficult to develop industrialization on a large scale. In order to seek new recycled degradable polymer materials as a way to improve and promote the performance optimization and industrialization progress of PBS materials, the performance regulation strategies and applications of PBS polymers were summarized. The latest research results of physical blending modification, molecular structure copolymerization modification and functional block modification of polymers were analyzed. Through the discussions of the influence of the modification control strategy on the chain structure and aggregation structure of the polymer, it is hoped to further promote the research of biodegradable polymer materials and the development of industrialization.

      Progress Through the analysis of PBS performance control strategy, the compatibility problem of physical blending is the key drawback and problem. In discussing the blending modification and the role of functional blending, chemical copolymerization modification strategy was found an effective approach to solve the problem of phase separation morphology. By sorting out the comonomers, the modified monomer structures were classified and summarized, and the role of flexible, rigid and functional structural monomers in the chain segment and the influence of structural units on the chain structure and aggregation structure of the polymer were analyzed. The influence of the structure and proportion of typical comonomers on the polymer glass transition temperature was analyzed to illustrate the relationship between the structure and the performance of the material. However, the problem of structural regularity destruction and PBS processing window narrowing caused by the chemical copolymerization strategy still needs to be solved. Then, the functional block modification strategy was described, and the performance of block copolymers was regulated by the introduction of molecular chains and chain structure. The block copolymerization modification strategy was described by the block copolymer reaction mechanism and typical chemical structure and preparation route. The regulation of the structure of polyester polyurethane copolymers was summarized. The influences of the introduction of flexible structure, rigid structure and amorphous structure on the polymerization products were discussed. Finally taking lactic acid as an example, the influences of different regulation strategies on polymers were discussed and analyzed. The advantages and disadvantages of physical and chemical modification strategies were analyzed and compared. The differences of different performance regulation strategies were described. The modification scheme with performance requirements as the starting point, product processing methods as the route, and application fields and final products as the goal was proposed.

      Conclusion and Prospect Through the analysis of the above modification strategy, the modification technology and method of polymer should be selected from the perspective of product demand and application environment and combined with the overall relationship of cost-efficiency-performance to realize the integrated development of product demand-production-application, and provide research and development preparation ideas for PBS-based modified product demand and industrial application. By summarizing the performance control strategies of PBS polymers, it is concluded that PBS can be applied to multiple fields such as intelligent medical treatment and degradable materials, rather than being limited to the development of new materials. It is also expected to achieve new breakthroughs in the substitution and performance of traditional polymer materials with its excellent performance and degradable advantages under the background of the times.

      Research progress in absorbable surgical sutures
      YANG Zhichao, LIU Shuqiang, WU Gaihong, JIA Lu, ZHANG Man, LI Fu, LI Huimin
      Journal of Textile Research. 2024, 45(01):  230-239.  doi:10.13475/j.fzxb.20221102502
      Abstract ( 315 )   HTML ( 26 )   PDF (3663KB) ( 198 )   Save
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      Significance Biomedical textiles are one of the most innovative and technologically advanced research fields in the textile industry today. Surgical sutures are one of the most used medical devices in clinical surgery, and research and development of sutures have been active worldwide. As a new generation of surgical sutures, absorbable surgical sutures are the ″darling″ of the medical community, with extremely important applications in obstetrics and gynecology, surgery, otolaryngology, ophthalmology, dentistry, and so on. Absorbable surgical sutures have become the first choice of surgeons in surgical procedures by virtue of their self-degrading, non-removable and less painful properties, and patients using absorbable surgical sutures are benefitted from having minimal visible scarring on the skin after healing, enhancing patient satisfaction. Although the development of absorbable surgical sutures is now at a relatively mature stage, many high value-added absorbable surgical sutures with excellent functionality are still in the laboratory stage and cannot be industrially produced and marketed for clinical applications. Therefore, this paper focuses on the analysis of various raw materials for preparation of absorbable surgical sutures based on the latest relevant research literature to systematically summarize the current research status of absorbable surgical sutures, promote the innovative development of absorbable surgical sutures and enhance the industrial production of absorbable surgical sutures.

      Progress The development of absorbable sutures and their performance requirements, the history of the development of absorbable surgical sutures from ancient times to the present day are introduced first. The development of the raw materials for their preparation from single to diversified are elaborated. The specific development history is shown, and the mainstream products on the market today are shown. In addition, the properties of absorbable surgical sutures, such as good biocompatibility and good knot strength, as well as the smoothness of the suture surface, are systematically reviewed. The four natural materials used for natural absorbable suture applications, namely catgut, collagen, chitin and alginate, are scutinised and the latest research in this area is summarized and analyzed. Four types of synthetic polymers, i.e., polylactic acid, polyglycolic acid, polycaprolactone and polyvinyl alcohol, are reviewed for making absorbable sutures and the latest research is summarized and analyzed. The advantages and disadvantages of developing absorbable surgical sutures from various materials are systematically studied and compared, and the analysis focused on three important indicators which are the mechanical properties, degradation properties and additional antibacterial properties of absorbable sutures. The overview of antimicrobial immune novel absorbable surgical sutures is also summarized the relevant mechanisms of action is described. Finally, the article concludes with an analysis and summary of the problems of today's absorbable surgical sutures and the trends of future development.

      Conclusion and Prospect The paper analyzes the current status of research on surgical sutures in recent years, starting from the materials used for the preparation of absorbable sutures. The technology for the development of absorbable surgical sutures is becoming more mature, but some problems still need research attention. 1) Relatively little research has been conducted on natural type of absorbable surgical sutures, and the initial catgut have disadvantages such as poor mechanical properties and tendency to trigger tissue reactions, which require further modification of the material. Chitin is commonly used as a functional coating finishing material to impart antimicrobial properties in recent years due to its excellent broad-spectrum antibacterial properties, but little research has been conducted on the preparation of sutures using chitin fibers for development. 2) The development of synthetic polymeric materials has provided more possibilities for the preparation of new absorbable surgical sutures. However, the degradation cycles of various materials are different, resulting in a mismatch between wound healing time and suture degradation time, which affects wound healing. Therefore, the controlled degradation of synthetic polymers is particularly important, so the research of absorbable sutures made of synthetic polymers should be enhanced in terms of the regulation of degradation properties. 3) Wound infection is a persistent problem in surgical procedures, and therefore the development of absorbable surgical sutures with excellent antimicrobial properties is the main theme in suture preparation. Tthe selection of suitable antimicrobial agents, the enhancement of antimicrobial agent loading fastness, and the long-lasting and stable action of antimicrobial agents are issues requiring future research attention.

      Advances in smart textiles oriented to personalized healthcare
      DONG Kai, LÜ Tianmei, SHENG Feifan, PENG Xiao
      Journal of Textile Research. 2024, 45(01):  240-249.  doi:10.13475/j.fzxb.20221106002
      Abstract ( 208 )   HTML ( 35 )   PDF (3892KB) ( 102 )   Save
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      Significance With the increasing prevalence of infectious diseases and the growing trend of population aging, the conventional hospital and the clinic-centered public health system lack the abilities for remote real-time monitoring, diagnosis and treatment, making it more difficult to achieve the monitoring of sustained vital signs and the implementation of long-term treatment programs. On the basis of the rapid development of wearable electronic devices, the Internet of Things, and artificial intelligence, the future healthcare model will transform from a therapeutic, centralized, passive, and even one-size-fits-all treatment to a new paradigm of proactive, preventive, personalized, customized and intelligent way. Therefore, various wearable signs and posture monitoring equipment, intelligent diagnostic and therapeutic tools, and highly integrated physiological health assessment systems are being developed, which will profoundly change the medical care and people's life in the future society.

      Progress As a combination product of advanced functional or intelligent attributes with conventional wearable textile materials, smart textiles are gradually emerging because of their abilities to collect, process, transmit, and display information, which can serve as a good medium for human being to interact with the outside world. In addition, smart textiles can be a powerful tool to generate and store energy, sense and respond to multiple external stimuli (such as mechanical, thermal, optical, chemical, radiant, magnetic or acoustic stimul, and even communicate with users, which will attract considerable research interest and enrich a wide range of application areas ranging from wearable power sources, luminescent visualization, athletic sports, to personal health management and information transmission and communication. In term of personized healthcare, smart textiles can provide insight into a person's physiological state, and directly conduct on-site disease monitoring and intervention, thus reducing the healthcare burden and improving treatment results. According to their basic working mechanisms or electrical response modes, smart textiles can be divided into seven categories, including piezoelectric effect, piezoresistive effect, capacitive effect, triboelectric effect, thermoelectric effect, optical fiber based effect, electrochemical effect, and etc. Each mode has its own advantages and disadvantages, which need to weighed based on the actual application scenarios and performance requirements. For example, based on the coupling effect of triboelectrification and electrostatic induction, a variety of smart textiles based on triboelectric effect are developed, which have two main functions of autonomous power supplying and active self-powered sensing. uwing to the outstanding advantages of simple structure design, wide range of material selection, and high energy conversion efficiency at low frequencies, the triboelectric-based smart textiles have attracted extensive attention both from academia and industry, which have been widely studied in the applications of emergency self-charging clothes, multifunctional flexible sensors, personalized healthcare devices, human-computer interaction interfaces and artificial intelligence.

      Conclusion and Prospect Aiming at the application of smart textiles in personalized healthcare, their recent research process in sleep respiration monitoring, electromyography monitoring, tactile sensing, personalized treatment, and intelligent diagnosis are mainly introduced. In each aspect, typical examples are given to illustrate the application of smart textiles in personalized healthcare. In the end, the future development trend and potential challenges of smart textiles in personalized healthcare are introduced. There is no doubt that with the integration of more intelligent technologies and the urgent needs of future medical market, smart textiles will be rapidly developed in personalized healthcare, and gradually form mature products. Meanwhile, it is also worth noting that the application of smart textiles in the field of personalized healthcare also faces many challenges, especially in the aspects of circuit connection reliability, long-time machine washability, affinity to human skin, large-scale fabrication and integration, and so on.