Table of Content

15 November 2024, Volume 45 Issue 11

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Fiber Materials

Structure and properties of fibroin nanofibril reinforced regenerated silk protein/polyvinyl alcohol fiber

YANG Xin, ZHANG Xin, PAN Zhijuan

Journal of Textile Research. 2024, 45(11):  1-9.  doi:10.13475/j.fzxb.20230805601

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Objective Extracting silk fibroin protein from waste silk to prepare recycled fiber is one of the approaches to recycle waste silk, but the mechanical properties of recycled fiber are generally poor. Therefore, it is necessary to explore new methods to improve the mechanical properties of recycled silk fibroin fibers and achieve the high-value recovery and reuse of waste silk.

Method The silk fibroin nanofibrillar fiber (SFNF) and the recycled silk fibroin (RRSF) extracted from waste silk were blended with polyvinyl alcohol (PVA) to prepare the blending solution. The effect of SFNF on the properties of the blended solution was investigated, the RRSF/PVA/SFNF blended fibers were prepared by dry spray wet spinning process and the effects of SFNF on the microstructure and mechanical properties of the blended fibers were investigated.

Results The SFNF was obtained after mechanical grinding and filter screen filtration of degumming waste silk, with length distribution between 20 and 90 μm and diameter distribution between 30 and 100 nm. The SFNF crystal obtained by mechanical grinding is not damaged and still retains the original crystalline structure of silk fibroin. RRSF/PVA/SFNF blended solution were non-Newtonian fluids with obvious shear thinning properties. With the increase of SFNF addition, the shear viscosity and shear stress of the blended solution was increased, and the elastic and viscous characteristics of the solution were enhanced. When the amount of SFNF was greater than 0.3%, the viscosity of the solution was obvious and gelation was easy to occur. Besides, SFNF significantly improved the stability and uniformity of the blended membrane. After the addition of SFNF, the pore structure inside the blended fibers was changed and the number of pores were increased. A small amount of SFNF induced the molecular conformation change from α-helix structure to β-fold structure. When the addition amount was 0.2%, the α-helix content reached the minimum of 20.03%, and the β-fold content reached the maximum of 54.42%. The fiber crystallinity was increased first and then decreased with the increase of SFNF addition. The addition of SFNF effectively enhanced the tensile strength and toughness of the blend fibers. When the amount of addition was 0.2%, the RRSF/PVA/SFNF blended fiber demonstrated a breaking strength of 38.98 MPa, an elongation at break of 443.27%, a modulus of elasticity of 640.83 MPa, and a specific work of fracture of 133.50 N/mm².

Conclusion The preparation method of SFNF is environmentally friendly, simple and efficient, which makes it an ideal fiber reinforcement material for regenerative silk fibroin protein. The compatibility of RRSF and PVA was improved, and the uniformity and stability of the blends were enhanced when SFNF was added to the RRSF/PVA blended solution. The compatibility of RRSF and PVA was improved when SFNF was added to the RRSF/PVA blended solution as a reinforcing material. The addition of a small amount of SFNF to RRSF/PVA/SFNF blend fiber was found to have improve the crystallinity of the blend fiber, and significantly improving the tensile properties and toughness of the blend fiber. The SFNF reinforced RRSF/PVA/SFNF blend fiber has good mechanical properties and biocompatibility, which can be further explored in the field of biomedical materials.

Preparation and synergistic mechanism of reed-based cellulose acetate catalyzed by La³⁺

BAO Xinjun, WANG Xing, ZHANG Zhuo, JIANG Xinwei, XIE Kaifang, CHEN Qing, HE Bin, ZHOU Hengshu

Journal of Textile Research. 2024, 45(11):  10-20.  doi:10.13475/j.fzxb.20230804801

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Objective Aiming at the high value utilization of reed-based pulp, obtained from the rich reed resources in Dongting Lake area, this research explores the feasibility for the preparation of reed-based cellulose acetate under an efficient catalytic system and tests and analyzes the microstructure and performance of the thus-obtained reed-based cellulose acetate. Meanwhile, the co-catalytic mechanism of La³⁺ in the process of acetylation was studied in detail.

Method The reed-based cellulose acetate was prepared by low temperature acetylation., where acetic acid is used as solvent, acetic anhydride as acylating agent, concentrated sulfuric acid and La³⁺ as co-catalyst for the first time. The effects of acetic anhydride dosage, acetylation time, acetylation temperature and the addition amount of La³⁺ on the degree of substitution and crystallinity of the acetylation products were systematically studied. The whiteness and polymerization degree of the prepared reed-based cellulose acetate were evaluated. The degree of substitution, crystallization property, morphology and structure of the thus-obtained sample were scrutinized, measured and analyzed. The density functional theory was used to analyze the synergistic catalytic mechanism of La³⁺ during the acetylation of dissolved reed pulp.

Results Under the conditions that the reaction time was 2 h, the reaction temperature was 70 ℃, and the solid-liquid ratio of acetic anhydride to acetic anhydride was 2∶100∶18, the corresponding acetylation products showed obvious acetyl functional group characteristic absorption peaks around 1 750, 1 380 and 1 235 cm^-1, regardless of whether La³⁺ was added. However, it is worth noting that when the mass ratio of lanthanum nitrate to reed-based pulp was 22.5%, the acetyl functional group characteristics in the corresponding FT-IR spectrum illustrated obvious blue shift, which was due to the fact that the hydroxyl group in the dissolved pulp was replaced by a larger acetyl group during the acetylation reaction, resulting in breakage of the intermolecular and intramolecular hydrogen bond of the product. The maximum degree of substitution was 2.85, the whiteness of the thus-obtained cellulose acetate was 87.45 and the average degree of polymerization was 171. Scanning electron microscope images of the acetylation products under different conditions showed porous structures. The characteristic (210), (310), (021) and (012) crystal planes representing cellulose acetate showed diffraction peaks of acetylated products after the addition of different amounts of lanthanum nitrate. When the ratio of lanthanum nitrate to reed pulp was 22.5%, the characteristic diffraction peak was the strongest. In addition to the slight increase of grain size corresponding to (021) crystal plane, the grain size corresponding to other crystal planes was decreased significantly, indicating that under the synergistic catalysis of an appropriate amount of La³⁺, the acetylation reaction of dissolved reed pulp was easier to penetrate into the crystallization zone, so that the hydrogen bond in the fiber chain was continuously opened and then broken. The DFT calculation results supported and confirmed that with the addition of La³⁺, due to its unique electronic structure and coordination ability, La³⁺ and acetic anhydride molecules interact to form an intermediate complex [La(Ac₂O)₂]³⁺, and the electron density in the complex is redistributed. This greatly reduces the energy barrier for the ionized electron donor $\mathrm{HSO}_4^-$ of sulfuric acid to react with it to form acetyl sulfuric acid, which in turn acetylates with cellulose in the dissolved reed pulp.

Conclusion The reed-based cellulose acetate was successfully prepared by low temperature acetylation by using concentrated sulfuric acid and La³⁺ as co-catalyst. Density functional theory (DFT) analysis shows that the addition of La³⁺ can effectively improve the catalytic efficiency of acetylation. The successful preparation of reed-based cellulose acetate will provide a foundation for high-value utilization of natural renewable cellulose resources, which has important academic significance and obvious social and economic value.

Preparation of zein/ethylene-vinyl alcohol copolymer composite filter by electrostatic spinning and its air filtration performance

YUE Tiantian, ZHENG Shuai, HU Jing, LIU Yuqing, LIN Jinyou

Journal of Textile Research. 2024, 45(11):  21-28.  doi:10.13475/j.fzxb.20230903501

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Objective Particulate pollutants in the air are the main cause for air pollution, threatening public health and ecological environment. The requirements for air quality around the world are becoming more and more stringent. However, traditional petroleum-based synthetic polymer fiber filter materials may cause secondary pollution to the environment due to their non-degradable properties. Therefore, it is of great significance to study biodegradable air filtration materials. Due to the good membrane forming, biodegradability, biocompatibility and rich functional groups of zein, more and more research has been carried out in the field of air filtration in recent years.

Method Using ethylene-vinyl alcohol copolymer (EVOH) and zein as raw materials, the mixed fiber membranes of zein and EVOH were prepared by single-needle two-component and double-needle two-component electrospinning, respectively. The fiber morphology prepared by two different electrospinning methods was studied, and the filtration performance and mechanical properties were compared and analyzed by attaching the nanofiber membrane to the commercial cellulose paper towel to form a composite filtration.

Results The EVOH/zein composite filter prepared by two-needle two-component electrospinning showed better performance than the single-needle two-component electrospinning EVOH/zein-n filter. Under the condition of controlling the weight, the filtration efficiency of the single-needle two-component electrospinning EVOH/zein-n filter was 26.8%-50.7%, the pressure drop was 19.2-39.6 Pa, while the pressure drop of the pure EVOH filter was 45.2 Pa. The filtration efficiency of the two-needle two-component electrospinning EZr filter is 43.2%-93.0%, and the pressure drop was 10.1-74.6 Pa. Among them, the EZ20 filter has the best filtration performance, the filtration efficiency reached 94.5%, and the quality factor of the EZr composite filter was greater than that of the pure EVOH and zein filters. Under the condition of controlling the flow rate, when the zein concentration was 20%, the air filtration stability of the EVOH / zein mixed filter was the best, the filtration efficiency increased from 92.45% to 98.19%. With the increase of flow rate, the pressure drop of the filter also increased, from 34.9 Pa to 184.5 Pa. When the particle size was 3-5 μm, the over-rate efficiency of the pure EVOH filter was 96.13%, while the EZr filter achieved 100% filtration efficiency, and EZ20 achieved about 100% filtration efficiency for PM_0.5-PM₃ including PM_2.5. In addition, the breaking strength of EZr fiber membrane was between that of pure zein fiber membrane and pure EVOH fiber membrane, and the breaking strength of EZ20 fiber membrane was 72.87 cN, which is 7 times that of pure zein fiber membrane.

Conclusion An environmentally friendly EVOH/zein filter was prepared by electrospinning EVOH/zein nanofibers on cellulose paper towels. By studying the single-needle two-component and double-needle two-component electrospinning, it is found that the EVOH/zein composite fiber prepared by single-needle two-component electrospinning is a circular structure with smooth surface, which is different from the flat ribbon zein fiber. It is not conducive to capturing particulate pollutants and shows poor air filtration performance. In the EVOH/zein composite filter prepared by double-needle opposite electrospinning, circular EVOH fibers and flat ribbon zein fibers are interlaced, and have the same filtration efficiency and lower pressure drop as the pure zein filter. In the study of mechanical properties, the mechanical properties of the prepared filter were significantly improved by mixing EVOH fiber with zein fiber, leading to good stress and strain. The mechanical properties also show more obvious advantages. This study will provide ideas for the further development of air filters.

Preparation of gradient-structured nanofibrous membranes for sterilization and filtration properties required for beer production

WANG Ziao, HUANG Peng, CHENG Pan, LIU Ke, XIANG Yang, ZHOU Feng, GAO Fei, WANG Dong

Journal of Textile Research. 2024, 45(11):  29-36.  doi:10.13475/j.fzxb.20230901101

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Objective With the growing fierce competition in the beer market and the increasing demand for high beer quality, the breweries try to reduce the cost and improve the quality of beer via optimizing their manufacturing process and raw materials, among which the filtration of beer is one of the main important steps. However, the flux instability of beer often occurs in the membrane filtration process. Therefore, it is of practical significance to develop a membrane material which can reduce the turbidity of beer while ensuring high throughput.

Method In this research, polyvinyl alcohol-ethylene copolymer (PVA-co-PE) nanofibers were prepared by melt blending phase separation method. Nanofibrous membranes with gradient porous structure were further fabricated by coating nanofibers with different diameters in different coverage density sequentially, crosslinked by glutaraldehyde (GA). The gradient bactericidal membrane was characterized by scanning electron microscopy, aperture distribution and flux analyzer. The filtration performances including permeability, turbidity and bacteria removal ability, antifouling and flux stability of the as-prepared membranes were investigated compared with that of Pall^® commercial nylon microporous membrane.

Results The experimental results showed that the morphology of sterilized membranes were similar to that of the nascent one without GA crosslinking modification, indicating an effective strategy for the preparation of high-performance sterile membrane. After modification and high temperature sterilization, the average pore size of the membranes were slightly reduced because of the increased the fiber diameter and partial filling of the pores associated with GA crosslinking. The decreased pore size of crosslinked membrane should be beneficial to the sterilizing filtration application. During the long-term water flow test, GSM-3 with additional 6 g/m² and 750 nm nanofiber layer always showed the highest pure water flux within 60 min even after it became stable. The cyclic filtration flux chart of membrane materials towards BSA solution was presented, and GSM-3, in comparison to other sterilization membranes, exhibited a remarkably high flux recovery rate, reaching 80% of its initial flux. Furthermore, sterile filtration performance tests revealed that all sterilization membranes effectively block the passage of Serratia bacteria which completely covered the membrane surface, obstructing the membrane channels and significantly reducing filtration efficiency. However, when filtering bacterial suspensions using the gradient sterilization membrane GSM-3, filtration proceeded smoothly with lower resistance and higher efficiency. Additionally, GSM-3 gradient sterilization membrane maintained a stable flux of approximately 750 L/(h·m²), with a 95% reduction in turbidity of the filtrate. These results indicate that the GSM-3 with a three-layer gradient structure possesses the most excellent filtration performance.The outer 750 nm fiber layer presented a loose structure primarily responsible for trapping larger particles and preventing them from clogging the inner pores, while the inner 450 nm fiber layer featuring dense pores increased the effective surface area of the membrane, resulting in improved membrane permeability and better control of membrane fouling.

Conclusion In this study, GA in situ cross-linked EVOH nanofibers was used to improve the sterile filtration properties of beer, where a nanofibrous membrane with fine nanofibers (average diameter of 450 nm) as the substrate membrane, and it was further coated with a coarse nanofiber layer (average diameter of 750 nm) on its surface. It was found that the nanofibrous membrane presented transmembrane gradient pore structure, which is beneficial to the improvement of water permeability with a high interception of particular contaminants especially bacterial in beer brewing. The superiority of the structure is attributed to the combination of inner fiber layer consisted of nanofibers with diameter of 450 nm and skin fiber layer made up of nanofibers with diameter of 750 nm fibers. The skin fiber layer has a loose structure, which not only intercepts larger particles to prevent them from clogging the smaller pores inside, but also provides the channels for interflow. The inner fiber layer provides a dense pore structure, the smaller pore size provides a prerequisite for intercepting bacteria, ensuring the bacterium removal performance of the membrane. They jointly contribute to the stepwise interception.

Preparation and thermal management performance of thermoregulated fabric based on polyvinyl butyral/polyethylene glycol coaxial nanofiber membrane

LI Han, WANG Haixia, ZHANG Xu, LIU Liping, LIU Xiaokun

Journal of Textile Research. 2024, 45(11):  37-45.  doi:10.13475/j.fzxb.20240101001

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Objective In order to enhance the thermal comfort properties of textiles, this study employs the coaxial electrospinning method to fabricate a composite nanofibrous membrane with polyvinyl alcohol formaldehyde (PVB) as the skin layer and PEG2000 as the core layer (PVB/PEG). Simultaneously, a sandwiched phase change heat storage composite fabric is designed using the as-prepared PVB/PEG nanofibrous membranes. The fabric exhibits excellent heat storage and release properties and offers an effective thermoregulated effect.

Method Coaxial electrospinning technology was employed to fabricate PVB/PEG nanofibrous membranes with various fiber skin/core ratios. Using nanofibers with fiber skin/core (2∶1) ratio as the sandwiched layers, single-layer (T1), double-layer (T2), and triple-layer (T3) PVB/PEG composite fabrics were prepared. Phase change enthalpy, thermal storage performance, and fabric's thermal management ability were tested by SEM, TEM, DSC, thermal infrared imaging, and thermocouples.

Results The PVB/PEG nanofibers had a continuous core-shell structure with diameters ranging from 244 to 372 nm, and phase change enthalpy is between 27-47 J/g. The phase change enthalpy of T1, T2, and T3 fabrics ranged from 6-14 J/g and were closely related to the PEG contents in the nanofibers. The fabrics maintained good shape stability at 65 ℃ and thermal energy storage and temperature regulation capabilities keep stable after 100 thermal cycles, demonstrating the composite fabric's repeatability. The 50 ℃ thermal buffering platform demonstrated the fabric's good temperature-regulating effect, and the thermal buffering time depends on the amount of nanofiber membrane layers.

Conclusion The composite fabrics ensure good thermal buffering effects, and they reduce the fabric's breathability and moisture permeability at loading triple-layered nanofibrous membranes. Achieving balance of thermal comfort and fabric properties is of importance in obtaining the satisfied nanofiber diameter, phase change material content, and fabric thickness. This opens a promising application in personal thermal management textiles.

Preparation and properties of carbon nanotube modified three-dimensional fiber-mesh nonwoven sensors

ZHANG Rui, YING Di, CHEN Bingbing, TIAN Xin, ZHENG Yingying, WANG Jian, ZOU Zhuanyong

Journal of Textile Research. 2024, 45(11):  46-54.  doi:10.13475/j.fzxb.20230804201

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Objective Flexible sensors, as core components of flexible smart wearable devices, have a promising future in many fields. However, a common problem is that lower sensitivity and poor durability affect the performance of flexible sensors. In order to improve the problems of low sensitivity, poor durability, and lack of flexibility and comfort in the use of flexible wearable pressure sensors, a highly sensitive and more wear-resistant piezoresistive sensor based on a three-dimensional (3-D) fiber mesh nonwovens prepared from polyethylene/polypropylene hot-melt fibers with polyester fibers was proposed.

Method Firstly, three-dimensional fiber mesh nonwovens were prepared by blending polyethylene/polypropylene hot-melt fibers with polyester fibers, which were pre-strengthened and heated to shape. Then, using piezoresistive sensing as its basic principle, carbon nanotube/nonwoven (CNN) sensors were prepared by immersing 3-D fiber mesh nonwovens into CNT suspension for surface treatment through ultrasonic-assisted modification and impregnation-drying method. Scanning electron microscopy, DM6500 series digital multimeter, and homemade tensile tester were used to characterise and analyse the CNT-modified CNN sensors.

Results Nonwovens with four different hot-melt fiber proportions (5%, 10%, 20% and 25% by mass), denoted as CNN₅, CNN₁₀, CNN₂₀ and CNN₂₅, were prepared, and four different proportions of CNT-modified nonwovens sensors were compared for sensitivity and sensing performance. The results showed that the sensitivity would decrease with increasing hot-melt fiber proportion and pressure, attributing to the increase in fiber density leading to higher compression modulus. The polyester hot-melt nonwoven fabric with a base of CNN₅ has the highest sensitivity up to 0.91 kPa^-1 in the range of 0-0.17 kPa, 3.5×10^-3 kPa^-1 in the range of 0.17-53.65 kPa and 4.8×10^-4 kPa^-1 in the range of 53.65-166 kPa. Sensing performance studies of the CNN sensors showed that the sensor exhibited a stable dynamic signal response when pressure was continuously applied and released using weights with different forces, demonstrating that the sensor is able to accurately discriminate between different pressures and has a fast response and recovery time (73/122 ms). In addition to high durability (>2 000 cycles), the CNN sensors can also be applied to information encryption, monitoring of human physiological signals, speech monitoring and handwriting monitoring, and multi-site sensing arrays.

Conclusion The above characterization shows that the sensing performance of CNN sensors prepared from 3-D fiber mesh nonwovens modified by CNT is significantly improved. The experimental results show that the CNN sensors have higher sensitivity, faster response time and more stable durability due to the unique 3-D structure of the fiber mesh nonwovens. It can be used to monitor human physiological signals, voice signals as well as handwriting signals. In the future, by collecting a large number of data signals and using machine learning to train and predict their signals, it will pave the way for health monitoring, speech recognition, handwriting recognition and other fields.

Composite fiber felts based on photothermal modification and their application in high viscosity oil adsorption

LIU Yanbo, GAO Xinyu, HAO Ming, HU Xiaodong, YANG Bo

Journal of Textile Research. 2024, 45(11):  55-64.  doi:10.13475/j.fzxb.20230804401

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Objective Due to the gradual depletion of petroleum energy and the increasingly serious oil pollution, efficient cleaning and recovery of crude oil become an important issue. However, due to the high viscosity and poor fluidity of crude oil, it is difficult for traditional oil-absorbing materials to deal with crude oil spills quickly and effectively. Therefore, it is necessary to develop fiber felts with the ability to absorb high-viscosity oil.

Method Three-dimensional porous fiber felt (PET/PVDF) was prepared from polyethylene terephthalate (PET) and polyvinylidene fluoride (PVDF), reduced graphene oxide fiber felt (rGO-PET/PVDF) was prepared by in-situ reduction method, and carbon black fiber felt (CB-PET/PVDF) was prepared by hot bonding. The morphology, mechanical properties, photo-assisted heating and oil absorption properties of the three fiber felts were systematically analyzed and compared to explore the feasibility of viscous oil treatment.

Results The experimental results showed that the rGO-PET/PVDF and CB-PET/PVDF were three-dimensional porous structures, in which the holes and fiber surfaces of the rGO-PET/PVDF fiber felt were scattered with reduced graphene oxide particles, while the CB-PET/PVDF fiber felt was attached to the fiber surface under the action of PVDF hot melt adhesive. Due to the different preparation process and modified material characteristics, both the two fiber felts demionstrated thermal stability, favorable hydrophobicity and oleophilicity, mechanical properties, adsorption properties, but showed different photothermal properties. The porosities of the rGO-PET/PVDF and CB-PET/PVDF fiber felts were 82.46% and 96.47%, respectively, and the thermal stability of the CB-PET/PVDF fiber felt was better. The water contact angles of the two were 154.5° and 125.9°, respectively, and the oil contact angle is 0°, showing strong hydrophobic and oleophilic properties. For the rGO-PET/PVDF filter, the maximum compressive stress corresponding to a single compression cycle was 119.20 kPa, while that for the CB-PET/PVDF fiter is 34.20 kPa, and the compressive stress of the rGO-PET/PVDF was higher. Moreover, the maximum compressive stress of the two did not decrease significantly after 100 compressions, and both showed good compression fatigue resistance. The adsorption rates of the rGO-PET/PVDF and CB-PET/PVDF filters on organic solvents and oils (acetone, n-hexane, chloroform, dichloromethane, toluene, petroleum ether, corn oil, crude oil, and silicone oil) were 3.79-21.42 g/g and 13.48-40.37 g/g, respectively, showing strong adsorption capacity. The rGO-PET/PVDF and CB-PET/PVDF fiber felts demonstrated strong photothermal conversion ability, and the temperature was increased from room temperature to 107 ℃ and 122 ℃, respectively in three minutes. After heating silicone oil, the adsorption time of a drop of silicone oil with a room temperature viscosity of 9 000 mPa.s of the rGO-PET/PVDF and CB-PET/PVDF filters decreased from 5 min and 10 min to less than 1min, and the adsorption rate of silicone oil was increased from 3.79 and 13.48 g/g to the presently 7.85 and 21.91 g/g at room temperature.

Conclusion Two photothermal modified fiber felts, rGO-PET/PVDF and CB-PET/PVDF, were prepared by in-situ reduction method and hot melt adhesive method. The rGO-PET/PVDF has better water repellency and better pressure resistance than the CB-PET/PVDF, and the CB-PET/PVDF has better thermal stability, photothermal heating performance and adsorption performance than the rGO-PET/PVDF. The difference in the properties of the two fiber felts is mainly caused by the differences in the preparation process and in the modified material characteristics. The in-situ reduction method used in the preparation of the rGO-PET/PVDF makes part of the pores of fiber felt occupied by reduced graphene oxide, which is the main reason for its lower porosity and worse adsorption performance. The CB-PET/PVDF was prepared by thermal adhesion, and the hydrophilic carbon black was attached to the fiber felt, occupying the binder between the fibers, which caused the reduction in the compressive stress and water contact angle. The two photothermal modified fiber felts have their own advantages and disadvantages in performance, which provides two feasible methods for viscous oil adsorption and cleaning with different requirements in different scenarios.

Textile Engineering

Finite element modeling and simulation of cotton fiber assembly carding process based on 3-D braided and fractal theory

ZHU Lei, LI Yong, CHEN Xiaochuan, WANG Jun

Journal of Textile Research. 2024, 45(11):  65-72.  doi:10.13475/j.fzxb.20230301101

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Objective Carding is the core step of cotton carding process. Its principle is to separate the fiber bundles in cotton roll into a single fiber by means of needle surface movement. In order to achieve the carding effect and prevent cotton fiber from being damaged due to excessive force at the same time, it is essential to control the carding force of cotton fiber within a reasonable range. To study the stress of cotton fiber assembly in carding process and improve the quality of cotton sliver, a new model of cotton fiber assembly was built.

Method The cotton fiber units were established based on the fractal theory, combined with the modeling idea of three-dimensional braided composite materials. The fractal cotton fiber units were arranged according to the fiber distribution in the internal single unicellular structure of three-dimensional four-way braided composite. The model was applied to simulate the carding process of cotton fiber assembly. The stress and strain variation of cotton fiber was studied by finite element method, the change of carding force over time was analyzed.

Results The carding process of cotton fiber under the fixed moisture regain was simulated by using finite element software. The cotton fiber was in the working area between cylinder and plate of the carding machine. In this process, cotton fiber was held by the needle teeth of cylinder and sorted by the needle of plate. The carding force of cotton fiber assembly, the stress and strain variation of cotton fiber over time were studied. Stress relaxation parameters shows that the stress and strain of cotton fiber first increases and then decreases as time goes on. It can be seen from assembly diagram that the stress of cotton fiber mostly occurs in the part directly in contact with the needle of plate and the part held by the needle teeth of cylinder. The effect of cotton fiber moisture regain on carding process was analyzed. The simulation parameters of cotton fiber under different moisture regain conditions were determined. The change of moisture regain will cause the change of friction coefficient of cotton fiber surface, and then affect the carding force. On the basis of the existing friction coefficient values of cotton fiber surface, the interpolation polynomial of friction coefficient and moisture regain was determined by method of undetermined coefficients. The friction coefficient values of cotton fiber under different moisture regain conditions were obtained. With the rise of moisture regain, static friction coefficient between cotton fiber and metal decreases, while dynamic friction coefficient increases. Both static friction coefficient and dynamic friction coefficient between cotton fibers increase. The stress of cotton fiber and the carding force on cotton fiber assembly increase first and then decrease with the rise of moisture regain.

Conclusion The simulation results of carding force are in agreement with the experimental results, indicating that the model of cotton fiber assembly is reasonable. As moisture regain increases, both the stress of cotton fiber and the carding force of cotton fiber assembly generally increases first and then decreases. According to the stress cotton fiber assembly under different moisture regain conditions, when the moisture regain is 6.5% and 8.5%, the stresses in both conditions are not very different and are relatively large. But the carding force is greater when the moisture regain is 6.5%, in this condition the carding effect is the best. The finite element method can better analyze the process of cotton carding, provide reference for the parameter setting of each part of the carding machine, and improve the carding efficiency and quality.

Effect of heat treatment on mechanical property of core-spun yarn from low melting point polyester filament made by air-jet vortex spinning

MIAO Lulu, MENG Xiaoyi, DONG Zhengmei, PENG Qian, HE Linwei, ZOU Zhuanyong

Journal of Textile Research. 2024, 45(11):  73-79.  doi:10.13475/j.fzxb.20230903201

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Objective Low melting point polyester fiber can be used as a hot-melt adhesive material. The strength of air-jet vortex spinning core-spun yarn is closely related to the mechanical properties of core-filament. We replace the core-filament of the air-jet vortex spinning core-spun yarn with a low melting point filament. By studying the appropriate heat treatment process, it can not only help the core-filament to maintain a certain mechanical properties, but also use the effect of thermal bonding enhancement of low melting point fibers to further improve the strength of air-jet vortex spinning core-spun yarn.

Method The core-spun yarn with low melting point polyester filament wrapped by polyester staple fiber was produced on MVS No.870 spinning machine, and the yarn was subjected to non-contact heat treatment on the XPLORE flat traction heating device. The heat treatment process was designed based on Box-Behnken Design (BBD) response surface. The effects of heat treatment temperature, heat treatment speed and draft multiple on the breaking strength, breaking elongation and breaking work of core-spun yarn were investigated by statistical analysis method. At the same time, the response value was optimized to obtain the best heat treatment scheme for the preparation of high strength core-spun yarn.

Results The breaking strength of the core-spun yarn was significantly affected by heat treatment temperature, heat treatment speed, draft multiple, as well as the interaction term of heat treatment temperature and heat treatment speed. The breaking elongation was significantly affected by heat treatment temperature, heat treatment speed, draft multiple, draft multiple secondary term, heat treatment temperature and heat treatment speed interaction term, and heat treatment speed and draft multiple interaction term. The breaking work was significantly affected by heat treatment temperature, heat treatment speed, draft multiple, heat treatment temperature secondary term, and heat treatment temperature and heat treatment speed interaction term. By analyzing contour plots of the relationship between response value and heat treatment process, it was found that under the same draft multiple, the breaking strength of the core-spun yarn showed an monotonous increase with the heat treatment speed increasing and the heat treatment temperature decreasing. The higher heat treatment temperature led to greater increase in the breaking strength of the core-spun yarn. In addition, at a stable draft multiple, when the heat treatment temperature was lower and the heat treatment speed was higher, the core-spun yarn breaking elongation was higher, and breaking work was higher. When the heat treatment temperature was constant, the breaking strength of the core-spun yarn would increase and the breaking elongation and the breaking work would decrease with the increase of the draft multiple. Combining the results of contour plots and response optimizer processing, the optimal heat treatment process parameters were obtained, with heat treatment temperature being 130 ℃, draft multiple 1.00, and heat treatment speed is 9 000 mm/min. After the heat treatment of the raw yarns, the yarn properties were improved, the longitudinal morphology of the core yarns became more compact, and some of the single fibers were bonded to each other in the cross-section. After the optimal heat treatment process, the yarn properties were improved, the longitudinal morphology of the core-spun yarn became more compact, and there was adhesion between some single fibers in the cross section.

Conclusion Air-jet vortex spinning was to prepare low melting point filament core-spun yarn. Through heat treatment process, the core-filament was partially melted, effectively limiting the slip of fibers in air-jet vortex spinning, and the cohesion between fibers can be improved. The breaking strength, breaking elongation and breaking work of the yarn are closely related to the setting of heat treatment temperature, heat treatment speed and draft multiple. In general, with the decrease of heat treatment temperature and draft multiple, and the increase of heat treatment speed, the breaking strength and breaking elongation of core-spun yarn increase, so the breaking work also increases. Using the optimized heat treatment process, the core-spun yarn breaking strength is increased by 7.64%, the breaking elongation is increased by 9.34%, and the breaking work is increased by 13.78%.

Three-dimensional parametric modeling of yarn based on point clouds

LI Wenya, LIANG Jianhang, XUE Tao, DONG Zhenzhen

Journal of Textile Research. 2024, 45(11):  80-87.  doi:10.13475/j.fzxb.20230806801

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Objective The three-dimensional yarn simulation is an important part for yarn design and fabric development. The use of computer simulation technology to simulate and visualize the yarn appearance is the key part of the current research. At present, most yarn simulations are carried out in two-dimensional or three-dimensional space, so that the appearance and shape of the yarn are limited. Therefore, it is necessary to design a fast and real three -dimensional yarn modeling method.

Method Circle stack diagram is first established based on the space circle and the Circle library, and then the spatial spline curve is established by combining the spiral twist equations of the circle stack diagram in different quadrants. According to the twisting characteristics of the fibers in the yarn, the curve is divided into multiple equidistant line segments, the spatial circle represented by the 3-D point cloud is established with the line segments as the normal vector, and the point cloud meshing algorithm is used to construct the point cloud as the initial triangular mesh model. The Loop subdivision algorithm is used to subdivide the mesh model.

Results The effectiveness of the 3-D yarn model based on point cloud method is verified and analyzed, and the 3-D yarn model established by different methods was compared and demonstrated. According to the effect of the 3-D yarn model established in literature, the geometric tube is modeled according to the input yarn parameters to match these fibers, and several single yarns with different structures are simulated, which shows that this is an effective yarn modeling and rendering method. In the three-dimensional yarn model based on the point cloud method, the distribution of fibers in the yarn cross-section is uneven, therefore it is necessary to deal with the regular circle pile diagram established by the regular yarn cross-section. Through the randomness of the starting point of fiber generation and the twisting state of the fiber, combined with the spiral twisting formula of different quadrants, the three-dimensional spatial spline without splicing state can be continuously generated. According to the twisting characteristics of the fibers in the yarn, the curve is divided into multiple equidistant segments, and the spatial circle represented by the 3-D point cloud is established with the line segments as the normal vector. Then, the point cloud grid algorithm is used to construct the point cloud as an initial triangular mesh model. Finally, the Loop subdivision algorithm is used to subdivide the surface of the mesh model, and the number of subdivisions is set according to the required model accuracy to improve the overall smoothness of the 3-D yarn model. In addition, the hairiness on the 3-D yarn model is formed by one end of the fiber protruding from the surface of the yarn body, which is consistent with the generation state of the actual yarn hairiness. Experiments show that the method can quickly generate a real 3-D yarn model, and the model contains multiple feature points such as number of fibers, fiber diameter, yarn twist direction, hairiness, and so on, which further illustrates the effectiveness of the method.

Conclusion Based on the importance of 3-D yarn simulation in yarn design and fabric development, a method for parametric modelling of 3-D yarn based on point cloud is proposed. The starting point of 3-D yarn model establishment is the circle stack diagram, the spatial spline curve composed of multiple equidistant line segments is created according to the custom conditions, and the spatial scattering circle expressed by 3-D point cloud is generated with the line segments as the center of the circle, and then the 3-D point cloud reconstruction algorithm is used to construct the point cloud between multiple spatial scattering circles into a triangular mesh model, and finally the surface subdivision of the initial 3-D yarn model is carried out to obtain the 3-D yarn model with high accuracy. The experimental results show that the 3-D visual effect of the yarn model is more obvious based on the number of constructed point clouds and the optimization of subdivision. At the same time, the algorithm realistically expresses the geometric characteristics of the simulated object, such as yarn thickness, hairiness, twist direction and fiber diameter, and so on, and can be adjusted according to the actual situation. The simulation is easy to operate and runs fast, which can better assist yarn design and development for practice.

Construction of jacquard structure model with full gamut color spaces based on bidirectional multi-primary color

LU Shuangyi, ZHOU Jiu

Journal of Textile Research. 2024, 45(11):  88-98.  doi:10.13475/j.fzxb.20231100301

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Objective Referring to the issue of gamut color spaces for structural coloring caused by the restricted primary color configuration and selection of warp and weft for digital jacquard structure, jacquard structure with bidirectional multi-primary color was proposed under layered-combination design mode, the way how three factors namely weave repeat R, the quantity of face weft group(s) N and the transition speed M determine the quantity of warp and weft configuration, face and back layer relationship, coloring compound weave-databases and representative weaves and compound weaves for coloring of jacquard structure basic and derived model were revealed, providing theoretical reference to the construction of jacquard structure model with a finite group of primary color threads and the expansion of its structural gamut color spaces.

Method First, the construction of jacquard structure model with full gamut color spaces based on bidirectional multi-primary color referred to the structural characteristic of double-layer structure, with only face warp and face weft(s) used for coloring. Besides, the basic model with double warps and quadruple wefts and the derived model with double warps and sextuple wefts were established, 4 chromatic colors as well as 2 achromatic colors, namely red, yellow, green, blue, black, and white, were applied to the configuration of thread color, in this case, 4 groups of chromatic threads configurated weft-wised only, 2 groups of achromatic threads were arranged warp-wisely and bi-directionally, with warp threads configurated with 1∶1 ratio, while weft threads allocated under 1∶1∶1∶1 and 1∶1∶1∶1∶1∶1 ratio respectively. What's more, the quantity of coloring compound weave-databases and the quantity of representative weaves and compound weaves for coloring of jacquard structure basic and derived model were calculated and analyzed. Last but not least, the applicability of the two structure models were verified through the comparison of fabric simulation.

Results Jacquard structure model with full gamut color spaces based on bidirectional multi-primary color were illustrated, including jacquard structure basic model with double warps and quadruple wefts and jacquard structure derived model with double warps and sextuple wefts. According to the arrangement sequence of primary color threads, the warp and weft configurations were 48 and 1 440 correspondingly, based on the assignment of the quantity of face weft group(s) N , the face layer and back layer relationships were 28 and 124 respectively without stitching. To stabilize structural coloring characteristics, it is essential to avoid the juxtaposed non-backed effect generated by adjacent face wefts inserted into the same shed when full gamut shaded weaves are combined in succession to form compound weaves for coloring with the quantity of face weft group(s) N equaling or exceeding 2, then the quantity of valid coloring compound weave-databases and the quantity of representative weaves and compound weaves for coloring were obtained according to weave repeat R and the quantity of face weft group(s) N, further, the maximum quantity for total weaves and compound weaves for coloring were 3 605 139 and 84 392 722 413 respectively with 40-threads satin weave and 153 levels of gamut weaves applied for the two structure models, and the characteristics of 6 structural coloring points on fabric simulation revealed that the jacquard structure model proposed is able to adjust chromatic, purity and brightness to enlarge the gamut color spaces of structural coloring.

Conclusion The results demonstrated that achromatic threads configurated codirectionally and bidirectionally conduct to the brightness adjustment of structural coloring in jacquard structure model with bidirectional multi-primary color, besides, with chromatic threads configurated codirectionally and interlaced with achromatic threads according to gamut weaves, the quantity of structural color reaches to the level of {10}^6 and {10}^{11} theoretically for two structure models respectively. Thus, this study contributes to the development and intelligent design research of digital jacquard fabric with full gamut color spaces.

Design and performance evaluation of knitted soft mat fabric

ZHAO Yajie, CONG Honglian, SUN Jianglong

Journal of Textile Research. 2024, 45(11):  99-105.  doi:10.13475/j.fzxb.20230601501

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Objective As the greenhouse effect intensifies, the ambient temperature in summer becomes hotter. This research aims to alleviate that influence of the hot environment in summer on the sleep comfort of the human body, and solve the problems of hard texture, poor moisture absorption and air permeability, and poor heat dissipation of the traditionally made cool mat. From the perspectives of yarn selection and structure design, the soft mat fabric with soft hand feel, good air permeability, moisture absorption, moisture permeability, heat permeability and cooling properties was designed.

Method Three types of yarn with ultrahigh molecular weight polyethylene (UHMWPE) of 1.85 dtex, nylon with 1.62 dtex and polyester of 2.31 dtex and polyester with superfine polyester draw texturing yarn (DTY) of 0.24 dtex were combined into three groups of yarn. Using the knitted composite structure, three types of knitted soft mat fabrics were produced on KSC-132 domestic Longxing computerized flat knitting machine. The three types of woven fabrics are numbered as 1^#, 2^# and 3^# in turn. The two types of straw mats and rattan mats on the market selected in this paper were numbered 4^# and 5^# respectively. The softness, air permeability, moisture permeability, moisture absorption and moisture conductivity and cool sensibility of the fabric were tested, and were compared with the two types of mats on the market.

Results Fabric softness are shown that the longitudinal and transverse bending stiffness of 1^# to 3^# soft mat fabrics is less than 5.000 mN·cm, far less than 4^# straw mat and 5^# rattan mat, indicating that the softness of the 3 soft mat fabrics is better than the straw mat and the rattan mat. The air permeability test results of fabrics are shown that the air permeability of all 5 fabrics is 658.19, 303.79, 427.56, 59.82 and 961.74 mm/s, indicating that the air permeability of 5^# rattan mat is the best, 4^# straw mat is the worst, and the air permeability of 1^# soft mat fabric is better than that of 2^# and 3^#. The moisture permeability test results of fabrics shows that the moisture permeability of 1^#-3^# soft mat fabrics is 7 615.55, 7 539.22 and 6 801.41 g/(m²·24 h), while the moisture permeability of 4^# straw mat and 5^# rattan mat is much less than that of the three soft mat fabrics, indicating that the moisture permeability of 1^# soft mat fabric is the best. The results of the moisture absorption rating of the 5 fabrics demonstrates that 1^#-3^# soft mat fabrics soaking time and water absorption rate are rated at grade 3, suggesting that the 3 designed soft mat fabrics have good moisture absorption, and 4^# straw mat and 5^# rattan mat have lower water absorption rate which is less than grade 3, and they failed to meet the requirement, indicating that poor moisture absorption. The one-way transfer index for 1^# and 3^# fabrics are rated at level 3, indicating that only 1^# and 3^# fabrics have good wet conductivity. The test results of the cool sensitivity of fabrics show that the heat transfer coefficient of 1^# soft mat fabric is 54.05 W/(m²·℃), which is the largest among the 5 types of fabrics and has the best cool sensitivity. The performance evaluation of the 5 types of fabrics was conducted, and the result shows that the comprehensive rating value of 3 soft mat fabrics is greater than the 2 commercial mats, and the comprehensive evaluation value of 1^# fabric is 0.769 4, which is the largest among all 5 fabrics, indicating that its comprehensive performance is the best.

Conclusion Based on three combinations of fiber materials and one knitted double-sided stitch, three knitted soft mat fabrics were produced. A series of hot and wet comfort performance tests were conducted on these 3 soft mat fabrics, and the results show that the soft mat fabric with UHMWPE is better than the fabrics containing nylon and polyester in related performance. The 3 soft mat fabrics were compared to 2 commercial mats made from straw and rattan respectively, and the results show that the 3 soft mat fabrics are superior in softness, moisture permeability, and moisture absorption over the straw mat and rattan mat, and UHMWPE soft mat fabric introduced cool sensation which is better than the straw mat and rattan mat. For comprehensive evaluation and analysis of the hot and wet comfort performance of all 5 fabrics, the result is that the comprehensive performance of 1^# soft mat fabric is the best, and the comprehensive performance of straw mat and rattan mat is worse than that of the 3 soft mat fabrics, so the soft mat fabrics designed in this research can replace the straw mat or rattan mat as a good bed to deal with the hot sleep environment in summer.

Digital design method for multi-needle bed weft-knitted fabric

MU Xiuping, JIANG Gaoming, CHEN Yushan, LI Bingxian

Journal of Textile Research. 2024, 45(11):  106-113.  doi:10.13475/j.fzxb.20231004201

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Objective In order to shorten the product development cycle, improve the design efficiency of multi-needle bed weft-knitted fabrics, and address the inconvenience caused by the coexistence of multiple code systems (loop codes and cam codes) in current weft-knitting computer aided design (CAD) systems, this paper digitizes the working state of multi-needle bed weft-knitted fabrics based on their knitting principles and structural characteristics. By using matrix operations, a rapid design method for multi-needle bed weft-knitted fabrics is achieved.

Method Based on the digitalization of the working states of knitting needles and cams in multi-needle bed weft-knitted fabrics, a weft-knitting color code system is created, establishing the relationship between loop shapes, knitting needle, and cam configurations. The mathematical relationships among the knitting process matrix, cam configuration matrix, and knitting needle arrangement matrix are constructed. The algorithm is incorporated into the weft-knitting CAD system with an added automatic error correction feature for ease of application.

Results In the design of multi-needle bed weft-knitted fabrics, there are three main needle arrangement methods: single-side needle arrangement, double-side aligned needle arrangement, and double-side staggered needle arrangement. Based on the triangular working states of the knitting needles in different knitting conditions, nine loop code systems were constructed, and matrices for knitting needle arrangement, triangular cam configuration, and knitting process were created. The three matrices were mathematically expressed to derive the conversion relationships between them. After establishing the transformation relationships of the fabric matrices, an intelligent error correction design was implemented to address potential issues in different types of fabric designs. The algorithm developed in this study can be applied to the weft-knitting CAD system. The algorithm's correctness was verified through specific product designs, such as the successful transformation between the triangular cam configuration, knitting needle arrangement, and knitting process diagrams for the Dutch double pearl fabric using matrix operations. Finally, the algorithm was implemented into the weft-knitting CAD system using programming tools such as C# and Visual Studio, enabling automatic error correction and achieving fast, accurate, and intelligent product design and production on the machine.

Conclusion This paper primarily investigates the digital design method for multi-needle bed weft-knitted fabrics. Based on the knitting principles of multi-needle bed weft-knitted fabrics, a digital loop system was established. By utilizing matrix operations, a new method was provided for the rapid, convenient, and intelligent processing in weft-knitting CAD design.

Preparation of weaving edge structure flexible sensor woven webbing and analysis of influencing factors on sensing performance

SHI Ya'nan, MA Yanxue, FAN Ping, XUE Wenliang, LI Yuling

Journal of Textile Research. 2024, 45(11):  114-120.  doi:10.13475/j.fzxb.20230206501

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Objective Current research mainly focuses on monitoring human physiological signals or fingers movements that can cause a certain strain under low stress. However, shoulder and neck movement require high stress to cause small strain, which is difficult to be monitored using knitted sensing fabrics. Therefore, the study aimed to develop elastic sensing woven webbing, to investigate its design and fabrication method, and to explore the sensing properties and the application feasibility through corresponding human wearing test.

Method The conductive yarns were used as selvage yarns in elastic web weaving process. Effects of on-machine weft density, elastic yarn fineness and the number of conductive yarns on sensing properties were explored. Three levels of each factor created 27 treatment combinations, leading to 27 elastic woven webbing samples with different tensile properties. The resistances in a certain length of the webbing samples were measured when the elastic webbings were stretched to the same strain. The resistance-strain curve was developed, presenting the sensing curve. Linearity and reproducibility of the sensing property were analyzed after repeated tests. Also, the corresponding equivalent resistance calculation formula was obtained so that to examine the selvedge structure and the sensing mechanism caused by conductive yarns. Finally, the elastic webbing with the best performance was applied in a wearing experiment of human postural hunchback angle monitoring to verify the stability and application possibility of the sensing webbing.

Results The sensing curves of elastic sensing woven webbing demonstrated an increasing trend with ideal linear feature, with high corresponding sensitivity and stable repeatability. The special selvage structure of the elastic woven webbing was found to play an important role in sensing properties. Increasing the on-machine weft density, fineness of elastic yarn, or the number of elastic yarns in the locked selvage enhanced the sensitivity of the sensing elastic webbing. In addition, the human wearing test further verified that the sensing performance of this elastic sensing woven webbing was stable and applicable to monitor human shoulder and neck motion.

Conclusion The study was undertaken to analyze the sensing property and sensing mechanism of the elastic webbing with conductive selvage yarns. The weft density, the fineness and the number of elastic yarns have significant effects on the sensing performance. The corresponding equivalent resistance calculation formula obtained is helpful to analyze the corresponding varying trend of each equivalent resistance unit under the strain. Findings in the study provide an ideal way to monitor human movements with high stress and small strain.

Damage crack repair and performance evaluation of glass fiber reinforced composites

YU Xiaopei, SHEN Wei, CHEN Lifeng, ZHU Lütao

Journal of Textile Research. 2024, 45(11):  121-127.  doi:10.13475/j.fzxb.20230506301

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Objective Due to impact damage, fatigue, aging, and other factors, composite parts may inevitably experience damage. Interface cracking between the layers of glass fiber reinforced composites (GFRP) can significantly reduce mechanical properties, such as stiffness and compressive strength. To prevent resource wastage and economic loss caused by replacing damaged components, this research focuses on developing cost-effective and simple maintenance procedures for repairing defects.

Method We investigated a simple and convenient GFRP repair technique for the repair of sharp-edge delamination cracks. Pressure was not required, as the resin solution containing acetone penetrated the delamination crack through capillary action. The acetone solution effectively covered and wetted the micro-cracks in the composite laminates during service, allowing the resin to fill the cracks. The prepared resin pre-coating solution was applied to the damaged laminates, followed by the conventional repair solution. Over time, the resin filled the cracks, and the repair effect was evaluated using scanning electron microscopy (SEM) and mechanical property testing.

Results Glass fiber composite laminates were prepared using a hot-press pot forming process, and impact damage was induced by the drop hammer method. Five different mass fractions of pre-coat (RPC) solutions were used for the repair: 10% RPC, 20% RPC, 25% RPC, 35% RPC, and 45% RPC. The repair effects were compared with the method without RPC and evaluated at room temperature and 60 ℃. The curing effect of the repair solution was analyzed using Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). CT scanning revealed effective repair of the damaged parts, with filling and recombination of the layered damage under the action of resin. The results of FT-IR and DSC showed high conversion of epoxy groups and low curing temperature, indicating good curing performance of the repair liquid. Increasing the temperature was found to enhance the curing of the repair solution, with better repair effects observed at 60 ℃ compared to room temperature, as shown in Tables 2 and 3. The repair rates for the five RPC solutions with different mass fractions at room temperature were 8%, 10%, 17%, 13%, and 12%, respectively. It was found that normal temperature was not conducive to resin permeation, resulting in lower repair rates. At 60 ℃, the repair rates were 11%, 17%, 26%, 20%, and 16%, respectively, which were significantly higher than at room temperature. Among the different concentrations, 25% RPC demonstrated the best performance. After curing at room temperature for 7 days, the compressibility of the repaired specimens recovered by 17%, and this recovery was more pronounced at 60 ℃, reaching 26%. Compressive load-displacement curves were obtained for the specimens cured at 60 ℃ for seven days. After repair with a 25% RPC solution, the composite exhibited significant fluctuations in compressive load with displacement, reaching a maximum of 11 664.57 N, while the compressive load after repair with a 10% RPC solution was relatively low, possibly due to interlaminar fiber fracture. At the point of maximum load, the curve dropped abruptly, indicating complete damage of the specimen under compression. The strain energy was rapidly released, and the composite specimen was no longer subjected to compression load, resulting in a rapid drop in load.

Conclusion Using NPEL-128 epoxy as a component of the repair solution, combined with D230 curing agent, the repair solution demonstrated effective repair, with the resin showing resistance to hydrolysis and strong adhesion to the material. The six repair methods ranked as follows: 25% RPC > 35% RPC > 45% RPC > 20% RPC > 10% RPC > routine repair (without RPC).

Original article

Synthesis of polyethylene glycol citrate ester smoothing agent and performance of compound formulation design for spinning oil agents

CHEN Shichang, YANG Dongdong, CHEN Wenxing

Journal of Textile Research. 2024, 45(11):  128-135.  doi:10.13475/j.fzxb.20231203101

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Objective Chemical fibers need to undergo high-temperature thermal drawing and treating during post-processing, which can easily cause scattering and breakage. Oil agents can adjust friction characteristics and give fibers high-temperature smoothness during spinning processing to run smoothly and steadily for the fiber production. However, with domestically produced oil agents used at high temperatures, abnormal phenomenon such as serious coking of hot rollers and tangled (remnant) fibers would still occur. As a result, the spinning oil agents for PET industrial fibers in domestic large-scale production are independent of imports.

Method In view of the problems of poor heat resistance and poor high-temperature smoothness of domestic chemical fiber oils, compound design of oil components was carried out on the basis of successful synthesis of excellent smoothing agents, which was prepared from polyethylene glycol and citric acid as monomers. The smoothing agent synthesis conditions was optimized, then a heat-resistant spinning oil could be achieved with the presence of self-prepared smoothing agent, selected polyether emulsifiers and other components. The chemical structure, thermal properties and viscosity of the smoothing agent, and the smoothness, interface properties, antistatic properties and thermal stability of the oil agent were also characterized and compared with the current products.

Results The optimized conditions for the synthesis of polyethylene glycol citrate as smoothing agent are considered as: the acid-to-alcohol molar ratio of 1∶2, 0.02% of catalyst, the temperature of 170 ℃ with reaction time of 1.5 h in N₂ atmosphere, and the esterification rate reaches 97%. The acid value, hydroxyl value and saponification value of the synthetic smoothing agent are 0.62 mgKOH/g, 8 mgKOH/g and 182 mgKOH/g, respectively. The high temperature viscosity and heat resistance are higher than that of common smoothing agents. The vital performance parameters of the well-designed oil agent are excellent, as the surface tension is 31.05 mN/m, the wear scar diameter is 0.538 mm, the friction coefficient is 0.043, the specific resistance is 1.63 MΩ/cm, and the conductivity reaches 6.13 μS/cm, and the friction and antistatic properties exceed the imported oils. Even more importantly, the oil smokes well and has excellent thermal stability. The respective volatilization loss rate in 2 h at 140 ℃ and 250 ℃ are only 1.4% and 12%.

Conclusion The excellent physical and chemical properties of polyethylene glycol citrate were synthesized as a smoothing agent, whose viscosity and interfacial properties were equivalent to those of imported oils. With a careful selection of emulsifier, antistatic agent and other components, the formulation of the oil agent was configured to meet the high requirements of PET industrial fiber, the friction and antistatic properties exceed the imported oil. In terms of thermal properties, the three self-prepared oil agents could be completely comparable to the same type imported oil.

Preparation and properties of disperse dye nanocapsule inkjet printing ink

GUAN Yu, ZHANG Hengwei, FU Zheng, FU Shaohai

Journal of Textile Research. 2024, 45(11):  136-144.  doi:10.13475/j.fzxb.20240305401

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Objective In order to improve the stability and inkjet fluency of disperse dye inkjet ink, core-shell disperse dye nanocapsules (DDNC) were prepared, and the influences of glass transition temperature and thickness of disperse dye nanocapsules shell on the stability, filtration and ink-jet printing performance of the ink were studied.

Method The DDNC were prepared via emulsion polymerization by using copolymer (P(MMA-co-BA)) of methyl methacrylate and butyl acrylate as shell and C.I. Disperse Purple 93 as core. Then the DDNC were configured as ink-jet printing ink, and thermal stability, storage stability, centrifugal stability and filtration performance of the DDNC ink were tested. DDNC ink was used for polyester fabrics. Scanning electron microscope (SEM), spectrophotometric color meter, fabric style testing instrument and fastness meter were adopted to characterize the morphology, color performance, hand feeling and color fastness of the printed fabric.

Results The results show that core-shell DDNC were successfully prepared and the glass transition temperature and thickness of P(MMA-co-BA) shell could be controlled by adjusting the proportion and amount of comonomers. the DDNC ink demonstrated significant improvement in thermal stability, storage stability and centrifugal stability compared with C.I. Disperse Purple 93 ink, which is attributed to the shield of the P(MMA-co-BA) shell. The stability of the DDNC ink could be improved by increasing the glass transition temperature of the shell and adopting reasonable shell thickness. When the glass transition temperature of the P(MMA-co-BA) shell was 67.6 ℃ and the thickness of the shell was 87.5 nm, the thermal stability, storage stability and centrifugal stability of DDNC ink reached 81.6%, 96.6% and 80.5%, respectively. The P(MMA-co-BA) shell with high glass transition temperature avoided film forming during the filtration process, thus reducing plugging of PVDF filter membrane pores. However, the particle size of the DDNC demonstrated a remarkably increase when the P(MMA-co-BA) shell became sufficiently thick, resulting in the reduction of filtration flow rate. DDNC ink showed a better filtration performance with a high flow rate of 5 mL/s to penetrate through PVDF filter membrane when the glass transition temperature of the P(MMA-co-BA) shell was 67.6 ℃ and shell thickness was 87.5 nm. Optical images of the DDNC ink inkjet printing polyester fabrics displayed a bright color and clear pattern while C.I. Disperse Purple 93 ink failed to penetate properly, indicating that DDNC ink has good ink-jet performance and the P(MMA-co-BA) shell on the surface of the disperse dye could effectively improve the ink-jet performance without affecting color brightness. SEM shows a thin film formed on the surface of the printed polyester fabrics due to the P(MMA-co-BA) shell of the DDNC, which is conducive to improving the color fastness of the printed fabric. The rubbing and washing fastness of the printed fabrics reached grade 5.

Conclusion The glass transition temperature and thickness of P(MMA-co-BA) shell can be controlled by adjusting the proportion and amount of comonomers, and the stability of the ink can be improved by increasing the glass transition temperature of the shell and adopting reasonable sbell thickness. When the glass transition temperature of P(MMA-co-BA) shell is 67.6 ℃ and the thickness of the shell is 87.5 nm, the thermal stability, storage stability and centrifugal stability of DDNC ink can reach 81.6%, 96.6% and 80.5%, respectively. The DDNC ink shows a better filtration performance with a high flow rate of 5 mL/s to penetrate through PVDF filter membrane. The fastness of printed fabrics can reach grade 5 with a soft hand feeling. This study offers an effective approach to improve the ink-jet performance of disperse dyes, with good application prospects in inkjet printing.

Preparation of foam printing paste for polyamide fabrics and its influence on printing performance

ZHENG Xiaojia

Journal of Textile Research. 2024, 45(11):  145-152.  doi:10.13475/j.fzxb.20231104501

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Objective Conventional printing methods are characterized by high water consumption and high energy consumption. In order to promote green and low-carbon development and reduce pollution, new printing technologies that save water and energy should be developed. Foam printing is a low-liquor ratio dyeing through the air instead of water as the dye solution, and the foam produced by the combination of these two elements is utilized for printing, so as to achieve water-saving, energy-saving, paste saving, and soft fabric hand. This research aims to prepare foam printing paste and to evaluate its printing performance.

Method By observing and analyzing the foam morphology and combining it with the corresponding printed fabrics, the influences of paste concentration and foam placement time on printing performance were analyzed with using indicators such as the uniformity of foam diameter and the K/S value of the printed fabrics. Factory paste was used as the experimental raw material, and high-definition microscope and X Rite color tester were adopted to observe the foam diameter and the K/S value of the fabrics respectively.

Results The results showed that at the same stirring speed, the foam volume decreased with higher paste concentrations. Observation under a high-definition microscope revealed that the average diameter of the foam bubbles became larger and the degree of homogeneity decreased as the paste concentration increased. At a certain paste concentration, the diameter of the foam bubbles gradually increased and the volume slowly decreased with the increase of the placement time. The higher the paste concentration, the slower the increase rate in diameter and decrease in quantity of foam bubbles. In terms of printing performance, with the increase of paste concentration, the K/S value of the printed fabric showed a tendency to increase initially and then decrease. The color paste residue on the upper edge of the printing screen increased with increasing paste concentration, and the printing pattern became better defined. In the study of the influence of foam placement time on K/S values, the K/S and color difference values of 4% paste concentration were found the most stable, which represents minimal changes in placement time. When the mass fraction of paste is 4%, the foam size distribution is relatively uniform, the fluidity of the printing paste is good, the outline of the printed fabric is clear after printing, and the screen residue is less. When the prepared foam color paste is placed for shorter than 20 min, the degree of foam rupture is smaller, and the K/S value of printed fabric is stable, as well as the color difference is smaller. The wash fastness, rubbing fastness, perspiration fastness, and soaping fastness of the foam printed fabrics could all reach above grade 4, meeting the requirements of use.

Conclusion In this study, foamed color pastes with different mass fractions were prepared, and the characteristics of foams prepared under different conditions were observed by means of microscope. Meanwhile, the printing fabric's K/S value and color fastness were tested and analyzed at different time, which effectively solved the problem that the printing pattern quality would be affected by more foam breakage in foam printing, and reducing the influence caused by more foam bursting. This observation has a strong guiding significance for the implementation of polyamide fabric foam printing process.

Polypyrrole functionalized waste fabrics and their applicaiton in to enhancing desalination performance

ZHOU Fengkai, LI Yimeng, PENG Jiamin, MAO Jifu, WANG Lu

Journal of Textile Research. 2024, 45(11):  153-161.  doi:10.13475/j.fzxb.20230805801

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Objective Waste fabrics (WF) cause serious environmental pollution and waste of resources, while conventional recycling methods are known to be cumbersome, difficult for mass processing, and of low value, which is against the carbon neutrality goals and limits the sustainability of the textile industry. On the other hand, the capacitive deionization (CDI) desalination capacity is too low due to the simultaneous existence of co-ions adsorption and counterions adsorption on the surface of the electrode materials. Therefore, this paper proposes a simple and easy large-scale processing method for high-value recycling of waste fabrics aiming for efficient desalination.

Method Waste fabrics are soft and porous, with a high specific surface area and excellent mechanical properties, providing ideal mechanical support for the CDI electrode material. Under the oxidation of ferric chloride hexahydrate, pyrrole easily polymerized on the surface of waste fabrics (plain cotton fabrics) to form a polypyrrole coating (PPy/WF). Through different electrode assembly modes, PPy/WF was selected as the cathode electrode of CDI to selectively adsorb Cl^-, and MnO₂ as the anode electrode of CDI to selectively adsorb Na⁺, reducing the influence of co-ions adsorption to improve the desalination capacity and stability.

Results The results of SEM, FT-IR, and EDS proved that polypyrrole was successfully in-situ polymerized on the surface of waste fabrics. When the polypyrrole coating was polymerized on the surface of the waste fabric, the polypyrrole coating had low surface energy and showed hydrophobic properties, but PPy/WF could still be infiltrated in a very short time (150 ms) due to the large pore structure between the waste fabric fibers and the yarns. The CV curves of the MnO₂ and PPy/WF electrodes were approximately rectangular and leaf-shaped, respectively, indicating that no redox reaction occurred. This proved that the ions were adsorbed on the surface of the electrode to form an electric double-layer (EDL). The galvanostatic charge/discharge curves of MnO₂ and PPy/WF electrodes were approximately symmetric, further confirming their EDL behavior. The specific capacitance of the MnO₂ and PPy/WF electrodes decreased gradually as the current density increased from 0.1 A/g to 1.0 A/g and reached a maximum of 6.41 F/g and 80.81 F/g (at 0.1 A/g), respectively. EIS results showed that PPy/WF and MnO₂ electrodes approximated straight lines at low frequencies and semicircle curves at high frequencies, which were beneficial to the diffusion and transfer of ions. The concentration of NaCl solution declined the most when PPy/WF as the anode was coupled with MnO₂, which was possibly attributable to the asymmetric configuration of the electrode to avoid the adsorption of co-ions. The desalination capacity of the PPy/WF-MnO₂ assembled form (39.89 mg/g) was much greater than that of the symmetrically arranged CDI electrode form. The CDI Ragone plotted by the desalination rate versus desalination capacity showed that the desalination rate was higher at higher operating voltages and up to 8.42 mg/(g·min). The initial and maximum desalination capacity during the repetitive cycles reached 40.52 mg/g and 44.97 mg/g, respectively, and the desalination capacity still reached 36.18 mg/g after 30 desalination cycles with only a 10.71% reduction, showing excellent cycle stability in desalination.

Conclusion The influences of different CDI electrode assemblies on the desalination performance were investigated, and the results showed that when the PPy/WF was assembled into CDI with the cathode material MnO₂ as an anode material, excellent desalination capacity (44.46 mg/g) and desalination rate (9.81 mg/(g·min)) were guaranteed. The stable pore structure formed between the fibers and yarns in the fabric ensures excellent desalination stability (only 10.71% reduction after 30 cycles). This simple and cost-effective recycling strategy for used fabrics helps reuse resources and alleviates water scarcity. PPy/WF exhibited excellent desalination capacity, and it has attractive economic benefits by virtue of simple synthesis, large batch preparation, and low cost. It is worth noting that the overall structure of the PPy/WF has not been significantly damaged after 30 cycles, and can be repolymerized with PPy to prolong the service life of waste fabrics.

Preparation and properties of halogen-free and phosphorus-free environment-friendly flame-retardant system for polyamide microfiber synthetic leather

DU Lei, WANG Shijie, JIANG Zhiming, ZHU Ping

Journal of Textile Research. 2024, 45(11):  162-169.  doi:10.13475/j.fzxb.20240100901

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Objective As an excellent substitute for natural leather, microfiber synthetic leather (MSL) is widely used in aerospace, high-speed rail, domestic decoration and other fields because of its excellent performance such as air permeability and wear resistance. However, MSL is composed of flammable polymers like polyamide, polyester, and polyurethane. When it burns, serious droplet melting occurs, endangering personal safety. As a result, it is critical to endow MSL with flame-retardant properties.

Method In order to solve the flammability of polyamide microfiber synthetic leather (PA/MSL), layer by layer self-assembly technique was applied using biological polysaccharide carrageenan (KC) as anion component, and polyethylenimine (PEI), (3-aminopropyl)triethoxysilane polymer (APTES) and their mixtures as cationic components. The influence of different components on the flame retardation of PA/MSL was investigated.

Results Compared with the control sample, the modified MSL presented some additional characteristic peaks responding to KC, PEI and APTES in the infrared spectra. In addition, the surface of the modified MSL was covered by the flame-retardant coating. Meanwhile, S and Si elements with uniform distribution were detected in the modified MSL, which were from the KC and APTES, respectively. The results indicated that the flame-retardant coating was successfully assembled on the surface of MSL. The flame-retardant performance of the modified MSL were analyzed by vertical flammability test (VFT) and limited oxygen index (LOI). KC/PEI and KC/APTES were found to improve the flame retardant performance of MSL with LOI values of 24% and 26%. Furthermore, the modified MSL by ternary self-assembly systems (KC/APTES/PEI) presented perfect flame retardancy with LOI value of 37%, and self-extinguishing behavior could be achieved without melt-dropping in VFT. The thermal stability of the modified MSL was analyzed through thermal degradation. Compared with control sample, the carbon residue of the modified MSL was increased to 14.2% at 800 ℃ in nitrogen gas atmosphere. The carbon residue of modified MSL by KC/APTES and KC/APTES/PEI showed characteristic peaks belonging to Si-O-Si bonds, indicating the formation of silicon-carbon chemical compounds. Meanwhile, silicon or sulfur elements were maintained in the char residues. The combustion behavior of control sample and modified MSL were studied by cone calorimetry test. The total heat release and total smoke release of modified MSL did not decrease as compared to the control sample. Still, the increased TTI demonstrated that the assembled coating had some effect on increasing the flame-retardant performance of the MSL.

Conclusion The influences of different cationic and anionic components on the flame retardant and anti-dripping properties of PA/MSL were investigated using layer by layer self-assembly technology. The flame-retardant performance and thermal stability properties of modified MSL were analyzed. The results showed that all flame-retardant coatings significantly improve its carbon formation capacity. Meanwhile, the ternary self-assembly systems (KC/APTES/PEI) greatly improved the flame-retardant performance of PA/MSL and the LOI values increased to 37% with self-extinguishing behavior and anti-drip phenomenon. This study presented a facile method to prepare flame-retardant MSL with non-phosphorous flame-retardant coating, which promotes the green development of flame-retardant materials.

Preparation and performance analysis of durable antimicrobial and superhydrophobic cotton fabrics

WANG Xinyu, GUO Mingming, ZHANG Lele, ZHENG Weijie, AMJAD Farooq, WANG Zongqian

Journal of Textile Research. 2024, 45(11):  170-177.  doi:10.13475/j.fzxb.20231102201

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Objective As a natural polymer of high molecular weight, cotton fiber has advantages in wide availability, rich reactive chemical sites, good natural non-toxic properties, softness, and high comfort. It is widely used in the development of superhydrophobic and other composite functional textiles. Currently, the prepared superhydrophobic and other composite functional cotton fabrics demonstrate the disadvantages in low chemical durability of cotton fabrics, large impact on the wearability of cotton fabrics during the modification process, and failure to meet the wear requirements. This research aims to improve the durability of antibacterial superhydrophobic cotton fabrics while maintaining their wearability, which is a research challenge.

Method This study works on the modification of cotton fiber by using L-cysteine (L-Cys) as crosslinking agent. The carboxyl groups of L-Cys molecules underwent esterification with the hydroxyl groups of cotton fibers, resulting in the grafting of L-cysteine onto the surface of cotton fabrics. This provides thiol groups for the subsequent introduction of silver nano particles. At the same time, the thiol group of L-Cys molecules chelated silver nano particles (AgNPs) through coordination bonds, enhancing the binding force between AgNPs and cotton fibers, which further increases the surface roughness of cotton fibers, laying the foundation for the preparation of superhydrophobic cotton fabrics. After this step, the surface energy of cotton fabrics is further reduced by a polydimethylsiloxane polymer coating (PDMS), resulting in the preparation of cotton fabrics with antibacterial superhydrophobic multifunctional properties. In order to further explore the potential mechanism of this synergistic effect existing between cotton, AgNPs and PDMS, the modified cotton fabrics for chemical structure, microstructure, superhydrophobic, antibacterial properties, and durability were tested. In the practical application of antibacterial super-repellent cotton fabrics, apart from the keen consideration and assessment of the durability property of the fabric, it is also necessary to consider the wearing performance of the antibacterial superhydrophobic cotton fabrics. Therefore, the influences of these finishing processes on the pemeability and softness of the fabric were evaluated, aiming at maintaining the comfort of the fabric while enhancing antibacterial superhydrophobic properties.

Results Experimental results showed that untreated cotton fabric (OCF) fibers were flat and smooth with no attachments. The modified cotton fibers were covered with granular-shaped AgNPs. However, after PDMS coating, a dense film was formed on the surface of the fibers covered with AgNPs. This led to the reduction in the surface energy of the cotton fabrics which further improved the load retention of AgNPs. The antibacterial superhydrophobic cotton fabric (P-AgCF) prepared by grafting AgNPs and PDMS coating met the standard of superhydrophobic. The static contact angle of the antibacterial superhydrophobic cotton fabric surface reached 154.6°, demonstrating excellent self-cleaning functionality. It effectively removed different solution stains due to liquids, such as orange juice, milk, cola, and dye commonly encountered in daily life. Additionally, the antibacterial rate of the antibacterial superhydrophobic cotton fabric (P-AgCF) against Escherichia coli and Staphylococcus aureus reached 98.67% and 97.44%, respectively, indicating excellent antibacterial performance. The durability of the samples was tested by gradually increasing the number of washing cycles. The static contact angle and antibacterial rate against both bacteria species showed slight decreases with increasing washing cycles. However, after 40 washing cycles, the static contact angle still exceeded 150.6°, and the antibacterial rate against both bacteria species was higher than 95.25%, indicating excellent durability. Additionally, this finishing process did not affect the pemeability and the softness of the cotton fabrics.

Conclusion A synergistic method of grafting and coating finishing is adopted to prepare cotton fabrics with both antibacterial and superhydrophobic functions. The static contact angle of the multifunctional cotton fabric surface reaches 154.6°, and it has excellent self-cleaning performance. It has excellent antibacterial properties against both Escherichia coli and Staphylococcus aureus. In addition, after 40 washing cycles, the static contact angle still exceeded 150.6°, and the antibacterial rate against both bacteria species was higher than 95.25%, indicating excellent durability, indicating excellent durability. Additionally, this finishing process did not affect the pemeability and the softness of the cotton fabrics. In summary, this study provides an effective method for preparing cotton fabrics with antibacterial, superhydrophobic, durable and other multifunctional properties. This fabric has broad application prospects in medical care, home furnishings, sports and other fields, and it is expected to bring more convenience and comfort to people's lives. Additionally, this preparation method also provides new ideas and references for functional modification of other fiber materials.

Apparel Engineering

Structure design and modeling of zero-cut warp knitted fully-formed lapel T-shirt

YAO Sihong, DONG Zhijia, JIANG Gaoming, WANG Ernan

Journal of Textile Research. 2024, 45(11):  178-184.  doi:10.13475/j.fzxb.20231009301

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Objective Warp-knitted fully-formed clothing has the problems in simple garment pattern, limited style change and cutting cost in production process. Due to its difference from conventional clothing production technology, the common methods to reduce cutting cost cannot be adopted. Therefore, using the characteristics of warp knitting forming technology, through the transformation of the structure of the T-shirt, it is possible to achieve a variety of patterns of the T-shirt production by taking zero cutting loss and diversification into account.

Method According to the dynamic characteristics of the upper limbs of the human body, the knitting sequence was changed from downward to upward, and the feasibility of the production of the zero-cut warp knitted shirt was analyzed. In order to eliminate the tension and lay down the sleeves, hollowing design was applied to the shoulder to meet the requirements arising from a range of activities. On the other hand, the collar, sleeve and body were partitioned and assigned with different pattern stitches, the prototype template was extracted from the parametric human model, and the loose and tight versions of the clothing were adjusted according to the style. As the last effort, the forming effect was virtual displayed and woven.

Results The upper limb was lifted from 180° to the natural droop state when the human body was moving, and the sleeve design was utilized to realize the angle rotation. However, the distance from the shoulder end to the neck socket point would become larger, and the shoulder of the garment would produce a large tensile force while the underarm would produce material accumulation. Therefore, the hollow design was applied to the shoulder. Through the structural design, the hollowing range was made equal to the depth of the sleeve cage, and the pattern structure of the contraction effect was added in the underarm. The underarm fabric was naturally folded and fitted to the underarm when the arm is naturally drooped without excessive accumulation. When the arm is raised, the underarm would be slowly unfolded while the shoulder hollowing is closed. As a result, the comfort level was improved. In addition, the structure of warp knitted fabric was stable, and the loop was not easy to be dispersed after breaking. Based on this feature, the mesh organization was adopted to mark the position. It was designed to make sure that the wearer would cut arbitrarily according to their own preferences without sewing. This feature was shown to improve the interest of consumers' independent design to achieve multi-purpose wear for one garment. It prolonged the service life of the garment, and reduced production loss and raw material waste. By observing the effect of the finished sample clothing, it was found that the effect of warp knitting forming loose T-shirt garments agreed with the expected effect. The fabric of tight T-shirt was stretched when wearing, the sample style was slightly deformed, and the sleeve hollow edge was changed from cone to arc. By comparing the number of grids in flow chart for the process template before and after optimization, it was found that the structure eliminates the raw material cutting cost of about 30%-40% of the reqion, facilitating zero cutting cost and zero sewing production with low-carbon.

Conclusion The structure optimization of the warp knitted fully formed T-shirt and the addition of the lapel structure is studied to achieve the low-carbon production of zero cutting and zero sewing of different patterns. However, the actual clothing effects of different versions of knitting need to be fully considered in production. Through three-dimensional modeling, garment parameters are visualized, which can help timely adjust the plate structure, reduce the cutting cost and time caused by repeated proofing, and shorten the production process flow.

Design method of sleeve cap structure based on enclosing armhole structure model

ZHANG Heng

Journal of Textile Research. 2024, 45(11):  185-192.  doi:10.13475/j.fzxb.20240201801

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Objective Precise matching of sleeve cap and armhole is the core technical issue in designing sleeve cap structure. In order to accurately match the sleeve cap and armhole, a design method for the sleeve cap structure based on the armhole closure structure model is proposed to address the issue of a lack of relevant design theory for sleeve cap structure design.

Method By creating a model of the armhole structure in the enclosed state of clothing, a formula for calculating the armhole depth in the enclosed state was derived based on the flat state armhole data. Using the trigonometric function formula and the variable relationship between the sleeve angle and the armhole height, the calculation method of the sleeve cap height was determined. The key structural turning points in the design of sleeve cap structure were determined through three groups of nine experiments with different sleeve pinch angles and sleeve hole depth states. Experimental data were analyzed by regression using SPSS software.

Results From the analysis of the virtual simulation structure model of the armhole, it was found that the sleeve angle and the armhole height are closely related. The variable relationship between the sleeve angle and the height of the sleeve cap can be accurately calculated by using the trigonometric formula. The armhole depth in the enclosed state has more practical significance for setting the sleeve height, and the data is more accurate. Based on the planar armhole data, virtual simulation experiments can verify that this method of using the semi-elliptic perimeter formula to calculate the depth calculation formula of the encirclement armhole is feasible. Therefore, the planar armhole data can be used as the basic data for building the sleeve cap structure model. The sleeve cap height can be accurately calculated by taking the armhole depth data in the enclosed state and the preset sleeve angle. From the analysis of the correlation between the armhole and the sleeve cap planar structure model, the accurate setting of points E and F in the structure based on the arc of the armhole becomes the key to achieve the accurate matching of the sleeve cap and the armhole. The experimental design of the fitted sleeve cap structure model was completed based on the basic type of garment body structure model, the focus of the experiment was to complete the initial determination of the key structural turning points in the design of the sleeve cap structure. From the comparative analysis of the experimental data of the sleeve cap arc length and the armhole arc length, the intersection point obtained by taking GB3/5 as the horizontal line intersecting the front and back armhole arcs can be used as the key structural turning point.Through the experiment on designing the sleeve cap structure based on different morphological armhole structure models and the comparison of sleeve cap arc length and armhole arc length data for three groups of nine different sleeve angle and armhole depth states, the SPSS software was utilized to complete the t-test for paired samples of anterior sleeve cap arc length and anterior armhole arc length, and the t-test for paired samples of posterior sleeve cap arc length and posterior armhole arc length, it is proved that the intersection point obtained by taking GB3/5 on the horizontal line intersecting the front and back armhole arcs can be used as the key structural turning point to complete the design of the sleeve cap structure based on the armhole.

Conclusion The results of the study indicate that the sleeve angle, sleeve cap height and the overall structure of the sleeve cap are closely related. Verified through structural design practice, the design method of sleeve cap structure based on the enclosed structure model can improve the precise matching between the sleeve cap and armhole,which has theoretical guidance and practical application value in practical work.

Comparative analysis of contact perception between dry and wet fabrics

ZHANG Zhaohua, YANG Yue, NI Jun, ZHANG Xu

Journal of Textile Research. 2024, 45(11):  193-198.  doi:10.13475/j.fzxb.20240104201

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Objective The production of skin moisture perception does not necessarily require water; however, contact with dry and cold fabrics can also induce a wet perception due to skin cooling. Nevertheless, no comparative analysis of the subjective feeling when using the same fabric with consistent skin cooling has been proposed. This research aims to explore the influence of dry and wet fabrics on subjective perception by controlling for an equal amount of skin temperature drop.

Method The pre-test determined the amount of water added to the wet fabric when the skin cooling was equivalent to that of the dry fabric. Three groups of controlled skin cooling experiments were designed, with skin cooling set at 0.9 ℃ (produced by contacting 18 ℃ dry fabric or wet fabric with 2 mL water added), 1.2 ℃ (produced by contacting 13 ℃ dry fabric or wet fabric with 12 mL water added) and 1.4 ℃ (produced by contacting 8 ℃ dry fabric or wet fabric with 16 mL water added), respectively. Sixteen subjects were invited to touch fabrics from each of the three different groups and report their subjective sensation scores for cold/warmth, dryness/wet ness and smooth ness/roughness.

Results The Wilcoxon non-parametric test results were conducted on the two associated samples. It was found that the cold sensation of dry fabric at 18 ℃ was significantly stronger than that of the wet fabric with 12 mL water (Z=-2.961, P=0.003). Additionally, the dry fabric at 13 ℃ had a significantly stronger cold sensation compared to the wet fabric with 12 mL (Z=-2.456, P=0.014), but no significant difference existed between the dry fabric at 8 ℃ and the wet fabric with 16 mL water (Z=-1.611, P=0.107). No significant difference existed in roughness sensation between the dry fabric at 18 ℃ and the wet fabric with 2 mL water (Z=-1.459, P=0.145), while roughness of the dry fabric at 13 ℃ was significantly lower than that of the wet fabric with 12 mL (Z=-2.645, P=0.008), and roughness of the dry fabric at 8 ℃ was significantly lower than that of the wet fabric with 16 mL water (Z=-2.646, P=0.008). The wet sensation scores showed no significant difference between the dry fabric at 18 ℃ and the wet fabric with 2 mL water (Z=-0.656, P=0.512), while the wet feeling of the wet fabric with 12 mL water was significantly stronger than that of the dry fabric at 13 ℃ (Z=-2.616, P=0.009), and the same was found between wet sensation of the wet fabric with 16 mL water and the dry fabric at 8 ℃(Z=-3.339, P=0.001). Specifically, when the skin temperature drop increased to approximately 1.2 ℃ and 1.4 ℃, the wetness of the wet fabric was significantly stronger. The Friedman test was adopted to further analyze changes in the wetness of both dry and wet fabrics with temperature and water addition. The perception of wetness in dry fabrics among the three groups showed significant differences (χ²=10.906, P=0.004), with a significantly stronger sensation of wetness in the dry fabric at 13 ℃ compared to that in the dry fabric at 18 ℃ (Sig.=1). Significant differences existed in perceived wetness among different groups for wet fabrics (χ²=24.875, P<0.001), where a lower sensation of wetness was observed for the wet fabric with 2 mL water compared to that for both the 12 mL and 16 mL soaked fabrics (Sig.=1).

Conclusion When the skin cooling is (0.965±0.015) ℃ and (1.165±0.015) ℃, the cold sensation of dry fabric is significantly stronger than that of wet fabric in the same group (P<0.05), indicating that a larger initial temperature difference makes it easier to experience a strong feeling of coldness. When the skin temperature consistently drops to(0.965±0.015) ℃, neither the dry nor wet state of the fabric significantly affects the perception of smoothness/roughness or dryness/wetness. In groups 2 and 3, wet fabrics feel rougher and wetter compared to dry fabrics, indicating that higher moisture content (12 mL, 16 mL) increases adhesion to the skin and enhances sensations of roughness and wetness. The comparative research of dry and water-containing fabrics enriches the theoretical basis of contact sensing characteristics. In the wetness reproduction device, the immersion feeling of wetness in the virtual world can be increased by reducing the contact temperature.

Machinery & Equipment

Design of cooked cocoon conveying device based on cocoon feeding trolley

LOU Hao, LÜ Wangyang, CHEN Wenxing, JIANG Wenbin

Journal of Textile Research. 2024, 45(11):  199-206.  doi:10.13475/j.fzxb.20231006101

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Objective In recent years, the development of China's cocoon and silk industry has stagnated due to the lack of production equipment. In the process of raw silk processing, some problems exists, such as low degree of automation, high labor cost, untimely delivery of cocoons and unbalanced distribution in the transportation of cooked cocoons. Therefore, it is important to develop a device that can replace manual labor to facilitate automatic conveying of cooked cocoons.

Method In order to solve the conveying problem of cooked cocoons and improve the production efficiency, an automatic conveying device for cooked cocoons was designed. By analyzing the convenional cocoon feeding method, the necessary conditions of the cocoon feeding process were obtained and analyzed. According to the theory of mechanical principles, the mechanism and device to replace the manual cocoon feeding action were designed. The feasibility and structural parameters of the device were determined by calculation and analysis.

Results The automatic conveying device of cooked cocoon was mainly composed of cocoon feeding trolleys, sliding contact line, a fixed track, columns and side frames. The communication between the components of the device and the operation of the control device were carried out by programmable logic controller (PLC) controller. A conveying device with a set of PLC controller, equipped with N cocoon cart, together for 6 groups of automatic silk reeling machine was responsible for supplying cooked cocoon. According to the production process of the silk reeling workshop and the structural characteristics of the automatic conveying device, the operation flow of the automatic conveying device was formulated, including the operation logic of the cocoon feeding trolley. By comparing different power supply modes and transmission modes, the sliding contact line was selected as the power supply mode of the cocoon feeding trolley, and a motor was used as the driving part of the cocoon feeding trolley. The cocoon feeding trolley was mainly composed of a positioning mechanism, a collector driving mechanism, a running mechanism, a tipping bucket mechanism and a single-chip microcomputer controller. The parameters of the running mechanism of the cocoon feeding trolley were determined by calculation, and the functions of independent on-orbit operation, automatic loading and unloading of cooked cocoons and communication of the cocoon feeding trolley were realized. Finite element analysis of the stiffness and strength of the fixed track was carried out using ANSYS, and the stiffness and strength of the track were verified to be within the safe range.

Conclusion The structure design of the automatic conveying device for cooked cocoon is proved reasonable. The design of the suspended track improves the utilization rate of the workshop space. The sliding contact line mobile power supply device can realize the whole process of continuous power supply for the cocoon cart. The design of the running mechanism of the polyamide fiber friction wheel improves the mobility of the cocoon cart. The structural design of the track reduces the length of the contact line between the polyamide fiber friction wheel and the track, and reduces the wear caused by the speed difference between the inside and outside of the polyamide fiber friction wheel during operation. The design of the positioning mechanism of the cocoon feeding trolley ensures the safety and stability of the cocoon feeding trolley running on the track. The cocoon feeding trolley can replace 6 cocoon feeding workers, thus improving production efficiency and reducing costs. Compared with the conventional way of sending cocoons, the automatic conveying device of cooked cocoons effectively solves the problems of untimely supply of cooked cocoons in the head position of automatic silk reeling machine and unbalanced distribution of cooked cocoons in different positions, and realizes the on-demand distribution and timely supply of cooked cocoons.

Detection method of position and posture of cheese yarn based on machine vision

REN Jiawei, ZHOU Qihong, CHEN Chang, HONG Wei, CEN Junhao

Journal of Textile Research. 2024, 45(11):  207-214.  doi:10.13475/j.fzxb.20230805201

Abstract ( 138 )   HTML ( 3 )   PDF (3377KB) ( 22 )   Save

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Objective Aiming at the detection of cheese yarn's posture and position of cheese packages in the process of cheese yarn handling, this research proposes a machine vision based method for detecting the position and posture of cheese packages to provide data support for robots to accurately grasp the cheese package in manufacturing.

Method An industrial camera was adopted to capture an image of the cheese yarn. Improved median filtering was adopted to preprocess the image, then Canny edge detection was adopted to acquire the contour curve of the cheese yarn, the discrete curve was smoothed using B-spline curve, the curvature distribution of the discrete curve was calculated and to determine the placement status, and finally the bobbin yarn center point was calculated. A curvature distribution based line detection algorithm was adopted to acquire the edges of the cheese yarn and calculate the pose angle of the cheese yarn axis.

Results Through experiments, it was found that improved median filtering can distinguish between texture and edge regions in images, and adaptively use windows of different sizes for filtering. This effectively filters texture signals while preserving edge signals. This research compares the accuracy and stability of several line detection algorithms in experiments. 250 images of the cheese yarn in a horizontal position were selected and their two edges are marked. Then, the line detection algorithm proposed, Hough transform, and EDLines were adopted to detect the images. The accuracy rate, missed detection rate, time consumption, angle error and position error of the algorithms were compared. The algorithm proposed has a detection accuracy of 100% for 250 images, without missed detections. The angle and position errors also reach the level of conventional line detection algorithms, ensuring the accuracy of the pose angle calculation of the cheese yarn, and the computational complexity is small, which can effectively save calculation time. Three different sizes of cheese yarns were selected for pose detection and conduct fetching experiments. The selected three types of cheese yarn have diameters of 160 mm, 200 mm, 250 mm, with cheese lengths of 180 mm. The cheese is FANUC M-20iA/35M. The cheese yarn was randomly placed on the device platform, then an industrial camera was adopted to take photos of the cheese yarn and the algorithm proposed was utilized to detect the position of the cheese yarn. The detected position results are sent to the robotic arm, guiding the robotic arm to fetch the cheese yarn and conducting 50 tests on each size of cheese yarn. From the experiment results, it can be seen that the algorithm proposed can accurately identify the position and pose of different sizes of cheese yarns, and has a small error. It can guide the robotic arm to accurately grasp the cheese yarn, with a success rate of 100%. The algorithm proposed also has real-time performance, and the average detection time for different sizes and placement states of cheese yarn is stable between 19 ms and 24 ms, with an overall average time of 21.61 ms.

Conclusion This research proposes a method for detecting the pose of cheese yarn based on machine vision. Firstly, based on the improved median filtering algorithm, the collected image of the bobbin yarn is preprocessed. Then, the Canny edge detection algorithm is adopted to extract the contour of the cheese yarn, and the contour curvature of the bobbin yarn is calculated. Finally, the contour curvature is adopted to calculate the pose information of the cheese yarn. Through experiments, it has been proven that the algorithm proposed can effectively detect the position and orientation of the cheese yarn, and has good accuracy and adaptability. It can accurately guide the robotic arm to grasp the cheese yarn, and the success rate for grasping light-colored cheese yarn of variable sizes is 100%, with an average time consumption of 21.61 ms.

Design and optimization of semi-enclosed free-surface electrospinning nozzle

LIU Jian, WANG Chenghao, DONG Shoujun, LIU Yongru

Journal of Textile Research. 2024, 45(11):  215-225.  doi:10.13475/j.fzxb.20230806101

Abstract ( 184 )   HTML ( 2 )   PDF (7935KB) ( 5 )   Save

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Objective In the process of electrospinning, the yield of capillary needle spinning is low and the free-surface electrospinning solution system is unstable. Therefore, it is necessary to design a new type of nozzle to ensure the stability, high efficiency and controllable preparation of electrospinning nanofibers. Aiming at the problems of multi-needle electrospinning and needle-free electrospinning, a multi-blade semi-enclosed free-surface electrospinning nozzle is proposed.

Method The multi-blade semi-enclosed free-surface nozzle was primarily divided into the straight pipe section and the blade section. The straight pipe section was first designed based on the uniformity of solution distribution. Next, the blade part was modeled according to the shape and distribution characteristics of a lotus petal, with the inner and outer layers of the blade clips determined using a neural network (BP) combined with a simulated annealing algorithm. The model was then set up to verify the accuracy of the algorithm, and theoretical calculations of droplet holding time were performed for the designed model. Finally, the model's validity was confirmed through experiments.

Results A multi-blade semi-enclosed free surface nozzle was designed. The straight pipe part of the nozzle adopted the method of multi-channel uniform distribution. The blade section was simulated by the lotus petal section curve. The angle between the inner and outer layers of the blade layer was calculated by combining BP and simulated annealing algorithm, and the angle between the inner and outer layers was determined to be 27° and 50°, respectively. Fluent software was adopted to simulate the final model of the above design. At this time, the pressure ratio between the inner wall and the outlet of the inner and outer layer solution in the process of electrostatic spinning was 0.45, which was close to the theoretical calculation and verified the accuracy of the theoretical model. On the basis of calculating the tension coefficient, a formula for calculating the droplet retention time of the nozzle blade was derived, and the nozzle parameters involved were included in the calculation. The results showed that the droplet holding time of the inner and outer blades was 21.89 s and 17.80 s, respectively, which is sufficient for the droplet to complete the electrospinning process and stabilize the electrospinning solution system. The identified model was 3D printed with stainless steel and electrospinning experiment was carried out. In the experiment, it was found that 12 blade tips would form a stable jet, and the efficiency was about 12 times higher than that of a single needle jet. In addition, because of the angle between the inner and outer layers in the nozzle blade, the angle between the inner and outer layers of the nozzle blades ensures that the pressure of the solution on the inner wall is the same for both layers, resulting in equal outflow speeds. The spinning area was large, and the measured fiber membrane area in this experiment was in the range of 1 140-1 440 cm². Because the liquid supply rate was higher than the spinning rate during electrostatic spinning, the liquid droplets would not overflow on the nozzle surface or drop on the nozzle surface, and would not affect the quality of the fiber membrane. Finally, the film generated by the semi-closed free-surface nozzle with 10 mL/h supply rate and 15 min spinning time was observed by electron microscopy. The average fiber diameter was 275 nm and the CV value was 17.49%.

Conclusion Combining the advantages of single-needle and free-surface nozzle in electrospinning, a semi-enclosed free-surface nozzle with multiple blades is proposed and designed. It has the advantages of multi-jet formation, long droplet holding time and no solution volatization. Compared with conventional single needle electrospinning, the efficiency is improved and the spinning area is enlarged. Compared with electrospinning without needles, the solution utilization rate and stability of electrospinning solution are improved. Through the electrospinning experiment and the electron microscopy of the fiber membrane, the average diameter of the fiber film produced by the nozzle is 275 nm, with a diameter coefficient of variation (CV) of 17.49%, indicating excellent fiber characteristics, and this study has certain reference significance for the development of stable, efficient and controllable electrospinning nanofibers preparation method.

Comprehensive Review

Progress in preparation methods and applications of electrospun three-dimensional nanofiber materials

LIU Yunpu, LIU Wei, WANG Liming, QIN Xiaohong

Journal of Textile Research. 2024, 45(11):  226-234.  doi:10.13475/j.fzxb.20231100902

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Significance Nanofiber membrane materials are widely used in energy, environment, medical treatment, and health fields because of their unique characteristics such as light weight, small pore size, high porosity, and high specific surface area. Electrospinning uses high-voltage static electricity to make the viscous fluid of polymer overcome the surface tension, form a jet in the electric field, and produce continuous nanofibers easily and quickly through the process of drafting and curing. The product prepared directly by electrospinning is usually a nanofiber membrane with a thickness of micrometers, and the layers of stacked fibers are tightly connected. The two-dimensional nanofiber membrane materials are found to have shortcomings in mechanical properties, thickness regulation, and applications. In recent years, the preparation of electrospun three-dimensional nanofiber materials has become an emerging research focus. Compared with two-dimensional nanofiber materials, nanofiber materials with three-dimensional structures have higher porosity, higher specific surface area, better connectivity, better resilience, and thickness control, which widen nanofiber applications. Therefore, the development of novel nanofiber materials with three-dimensional structures has attracted more and more attention from researchers.

Progress According to the molding steps, the current preparation methods of three-dimensional nanofiber materials constructed by electrospinning can be divided into two categories, i.e., the re-forming method (fiber membrane reconstruction method) and the direct electrospinning method. The re-forming method is the most commonly used at present. Firstly, the nanofiber membrane is prepared by electrospinning, and then the porous three-dimensional nanofiber material is obtained by crosslinking, heat treatment, solvent displacement, and freeze-drying a new re-forming method was proposed, which used electrospinning together with freeze-drying technology to prepare three-dimensional nanofiber materials. In this study, three-dimensional porous nanofiber aerogels were reconstructed using fragmented nanofibers. In addition, using the method of adjusting ambient humidity, the researchers also prepared three-dimensional nanofiber materials by direct electrospinning. These three-dimensional materials prepared by electrospinning perform well in functional tests such as thermal insulation, separation, and filtration with attractive characteristics such as ultra-high porosity and excellent mechanical resilience. In the field of tissue engineering, three-dimensional scaffolds constructed by electrospinning have also played an important role in tissue culture repair. In short, three-dimensional nanofiber materials prepared by electrospinning show great application potential.

Conclusion and Prospect Summarizing the research findings described above, the following prospects for preparing and applying electrospun three-dimensional nanofiber materials can be drawn. (1) The preparation process should be simplified. At present, the main preparation method is the secondary forming method and the complicated process seriously restricts the development of three-dimensional nanofiber materials. Therefore, shortening the preparation process is the direction that needs further breakthroughs. (2) The preparation method should be universal. Many methods can only make three-dimensional materials from specific polymer systems, and the scope of application is too narrow. It is an urgent problem to improve and put forward appropriate methods to make them universally adaptable. (3) Size should be controllable. Because of the limitations of most preparation methods, many materials cannot be freely controlled in shape, size, especially thickness, but practical applications require three-dimensional nanofiber materials with unique shapes, so the realization of size controllability is still a problem that researchers need to optimize. (4) The construction of pore structure should be controllable. The unique pore structure advantage is an important reason for the wide application of three-dimensional nanofiber materials. The pore structure of controllable construction materials can further expand its deep application in filtration, medical treatment, and other fields. (5) Multi-function aggregation should be achieved. At present, functional 3-D materials are faced with the problem of single function. The development of 3-D materials integrating multiple functions is an important direction for the development of nanofiber materials.

Research progress in electrospinning technology for nanofiber yarns

WANG Yuhang, TAN Jing, LI Haoyi, XU Jinlong, YANG Weimin

Journal of Textile Research. 2024, 45(11):  235-243.  doi:10.13475/j.fzxb.20230902402

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Significance The development of high-performance yarn materials is a focal point of research in textile engineering and materials science. Electrospun nanofibers possess high specific surface area, porosity, unique interfacial properties, and rich physicochemical properties, and the aggregation of these fibers into yarns is an important approach to developing high-performance yarn materials. In addition, the yarns with anisotropic structural properties allow them to be made into 2-D or 3-D products using weaving or knitting technology. The versatile product structure and ease of functionalization make electrospun nanofiber yarns exhibit excellent properties in fields such as tissue engineering, moisture and heat management, energy sensing, and defense industry applications. However, current electrospinning techniques face challenges in low preparation efficiency and weak mechanical properties, which require further breakthroughs.

Progress In this paper, the forming methods of electrospun yarns from the principle of fiber aggregation and twisting are firstly reviewed, and the representative techniques are summarized. These yarn forming methods can be divided into manual twisting, electricity inducement, water bathing, high speed rotation and airflow coordination. At present, the fiber collector rotary twisting is the most commonly used method for electrospun yarn preparation, which has the advantages of good fiber orientation, yarn uniformity and stable yarn formation process. Subsequently, the influence factors affecting the yield of electrospun nanofiber yarns are discussed and summarized. The yarn yield is affected by the fiber yield, molding method, and material properties and other aspects. As the fiber yield increases, the yarn yield also increases significantly. The combination of four-nozzle needleless electrospun technology and yarn forming technology increases the yarn yield by 5 m/min, but it is still much smaller than that of the conventional spinning method. Finally, the effects of process, device and material on the mechanical properties of yarns were investigated from the perspective of yarn microstructure and fiber properties and are summarized. Moderate twist, high fiber orientation and high fiber crystallinity are all conducive to the yarn strength. At present, the polyacrylonitrile (PAN) electrospun yarns treated by hot drafting and bifunctional poly (ethylene glycol) bisazide (PEG-BA) modification are shown to have the most attractive mechanical properties. The yarn strength reached 1 236 MPa with the tenacity of 118 J/cm³, which initially reached the level of spider silk.

Conclusion and prospect The paper systematically reviews the preparation method, influencing factors influencing yield and strength of electrospun yarns. In order to address the issues of inadequate mechanical properties electrospun nanofiber film, electrospun nanofiber yarns have been prepared using various techniques such as manual twisting, electricity inducement, water bathing, high speed rotation and airflow coordination. The current technology for preparing electrospun nanofiber yarn is primarily based on a solution electrospinning system with single/double needles, resulting in low fiber yield and subsequently low yarn yield. Enhancing the yield of yarn can be achieved by combining needle-free electrospinning systems with spinning technologies, for which it is necessary to investigate the motion patterns of needle-free multi-jet electrospinning and orientation deposition twist methods. Simultaneously, developing an environmentally friendly spinning liquid system is crucial to mitigate risks posed by common organic solvents and achieve a sustainable preparation process. Melt electrospinning technology offers advantages such as complete conversion of raw materials into fibers, minimal jet whipping effects, and solvent-free preparation processes. Exploring novel approaches for enhancing the yield of melt electrospinning fiber thinning and controlling jet aggregation into yarn represents a pivotal avenue towards the sustainable production of electrospun nanofiber yarns. The reinforcement of electrostatically spun nanofiber yarns necessitates a harmonious integration of material system, device design, process control, and post-processing techniques to optimize yarn orientation and mechanical properties at the single fiber level. Investigating the spatial dynamics of electrospun fibers and evolving characteristics of the spinning jet during the fabrication process emerges as an indispensable means to enhance both yarn alignment and tensile strength. Furthermore, implementing post-treatments effectively enhances yarn structure and individual fiber strength, thereby significantly improving overall mechanical performance.

Research progress in geographic origin traceability technology for cotton fibers

WANG Bo, JIANG Zhiqing, BAO Junfang, LIU Jinwei

Journal of Textile Research. 2024, 45(11):  244-250.  doi:10.13475/j.fzxb.20231103002

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Significance The quality of cotton fibers is closely related to the quality of downstream textiles. At present, Problems exist in the cotton market such as shoddy goods and confusion of production areas, which infringe on the legitimate rights and interests of consumers and undermine the fairness and justice of national cotton storage. Therefore, research on the geographic origin traceability of cotton fibers is an important issue. The conventional methods for identifying the geographic origin of cotton fibers are based on manual experience identification and by reviewing cotton import documents. The manual experience appraisal method is easily influenced by human subjective consciousness and cannot fully and accurately distinguish the geographic origin and quality of cotton fibers, and cotton import documents are easy to forge. Therefore, it is necessary to develop a scientific and accurate method for tracing the geographic origin of cotton fibers, which will not rely on product packaging and product documents but rather on testing the cotton fibers, in order to quickly determine the geographic origin of cotton fibers, standardize the order of cotton trading markets, and ensure the quality of downstream textiles.

Progress In recent years, some emerging technologies have developed in the field of biological origin traceability, such as near infrared spectroscopy, DNA molecular markers technology, and stable isotope technology. The determination of the origin and traceability of cotton fibers using near-infrared spectroscopy technology is based on the slight differences in the absorption intensity of hydrogen containing chemical functional groups of cotton fibers from different origins in the near-infrared region, which can be combined with other analysis methods to detect and trace cotton fibers from unknown origins. The DNA molecular marker technology is adopted to identify the origin of cotton fibers by analyzing genetic markers between individual cotton fibers to determine biological differences. DNA molecular markers of cotton fibers are detected using DNA detection techniques such as polymerase chain reaction to obtain their DNA fingerprints, thereby achieving variety identification and origin traceability. Cotton usually grows in fixed areas, and the isotope "fingerprints" of cotton fibers in the same area are extremely similar, which can fully reflect the growth environment of cotton and its interaction with environmental changes. Therefore, the source of cotton fibers can be distinguished by common stable isotope ratios. These technologies have been preliminarily studied in the field of cotton fiber origin traceability, and have more advantages than other traditional identification methods.

Conclusion and Prospect The near infrared spectroscopy technology can utilize appropriate mathematical models for large-scale detection of cotton samples, but further exploration is needed in terms of modeling accuracy and automation. In the future, computer simulation technology can be combined to achieve real-time monitoring of cotton quality and production areas. The DNA molecular marker technology can directly detect differences on molecular chains of cotton fibers, without being limited by cotton fiber maturity, growth environment, and gene expression, and has extremely high accuracy. However, it is difficult to extract complete DNA molecular chains from mature cotton fibers, and no complete gene database can be provided yet. In the future, it is necessary to improve cotton fiber DNA purification technology and improve purification efficiency. The detection results of stable isotope technology are not affected by human and environmental factors, but many factors that affect the abundance of various isotopes in cotton fibers exist, such as latitude and longitude, climate, and human intervention. In future research, more factors that affect cotton growth should be considered, and research on other stable isotopes should be added, not limited to elements C, H, O, and N. Next, based on existing detection methods, multiple technology fusion traceability methods can be developed to overcome the drawbacks of a single technology, achieving complementary advantages, and increasing the applicability of detection. By collecting a large number of samples and expanding the sample range, the cotton fiber origin database will be enriched, and the efficiency and accuracy of cotton fiber origin traceability will be improved.