Table of Content

15 September 2023, Volume 44 Issue 09

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Fiber Materials

Fabrication and oil absorbency of superhydrophobic and elastic silk fibroin fibrils aerogel

YANG Qiliang, YANG Haiwei, WANG Dengfeng, LI Changlong, ZHANG Lele, WANG Zongqian

Journal of Textile Research. 2023, 44(09):  1-10.  doi:10.13475/j.fzxb.20220408901

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Objective Silk fibroin (SF) aerogels prepared by conventional regeneration-dissolution process generally suffer from poor mechanical elasticity, resulting in weak oil absorption performance of the hydrophobically modified SF aerogels. This research aims to prepare highly elastic SF-based aerogels with excellent oil absorption properties for practical applications by using SF micro-nanofibrils (SMNF) aerogels as carriers, following the hydrophobic modification.

Method The SMNF aerogels were fabricated by a freeze-induced assembly process using low-melting solvent liquid-phase exfoliated SMNF as precursors. Subsequently, the SMNF aerogel was hydrophobically modified by a methyltrimethoxysilane (MTMS) chemical vapor deposition strategy. The microstructure, element distribution and mechanical properties of MTMS modified SMNF (MS) aerogel were characterized by scanning electron microscopy, energy dispersive spectroscopy, infrared spectroscopy and universal material testing machine. Meanwhile, the oil absorbency of MS aerogel was systematically studied.

Results The urea/guanidine hydrochloride deep eutectic solvent liquid-phase exfoliated SMNF retained the micro-nanoscale fibril structures of natural silk fibers (Fig.1), facilitating the construction of highly elastic SF aerogels. The resulting MS aerogel was characterized by hierarchical cellular architectures (Fig. 2), which endowed it with low density (5.36 mg/cm³) and high porosity (99.63%). The MS aerogel exhibited high compressi-bility (15.72 kPa at a strain of 80%) and superior fatigue resilience (over 81% relative height retention after 100 cycles) (Fig. 4). The results of energy dispersive spectroscopy and infrared spectroscopy confirmed that the siloxane network structures were formed on the aerogel surface after MTMS modification (Fig. 3), endowing SMNF aerogel with superhydrophobicity (water contact angle of 150.9°) (Fig. 5). Consequently, MS aerogels demonstrated strong absorption capacity for various oil agents with the oil absorption capacity of 84.48-188.75 g/g (Fig. 7). More importantly, owing to the high elasticity and stable skeleton structure, MS aerogel displayed excellent repeatable oil absorption performance (Fig. 8, Fig. 9).

Conclusion Highly elastic and superhydrophobic MS aerogels were fabricated by urea/guanidine hydrochloride low eutectic solvent liquid phase exfoliation, freeze-induced assembly, and MTMS chemical vapor deposition modification. The assembled MS aerogels were characterized by hierarchical fibril networks and hierarchical cellular structures, which endowed MS aerogels with exceptional properties, including low density, high porosity and superelastic performance. Benefiting from the above features, the superelastic and superhydrophobic MS aerogel not only showed strong absorb ability to various oil agents, but also had excellent repeated oil absorption performance. This work provides a reliable approach for the fabrication of highly elastic and superhydrophobic SF aerogels and endows application prospects in oil absorption opportunities.

Preparation and properties of regenerated silk fibroin/polyvinyl alcohol blended nanofiber membranes with predesigned orientation

YAO Shuangshuang, FU Shaoju, ZHANG Peihua, SUN Xiuli

Journal of Textile Research. 2023, 44(09):  11-19.  doi:10.13475/j.fzxb.20220309601

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Objective Non-oriented nanofiber membranes are usually obtained on the receiving device due to instable movement of polymer jet in electrospinning. Oriented nanofiber membranes are obtained by changing the receiving device and other methods.Compared with non-oriented nanofiber membranes,oriented nanofiber membranes have the advantages of regular fiber arrangement and good mechanical properties. The paper proposes the preparation of oriented nanofiber membranes by electrospinning with regenerated silk fibroin (RSF) and polyvinyl alcohol (PVA) as raw materials,and potential applications of oriented nanofiber membranes in the field of textile biomedicine.

Method The optimal spinning parameters were determined by single factor experiment and orthogonal experiment,and the morphology,chemical structure,mechanical properties,thermal stability,pore size distribution of oriented nanofiber membranes were studied with the assistance of scanning electron microscopes,Fourier transform infrared spectrometer,medical multi-function strength tester,synchronous thermal analyzer,and porous material pore size analyzer.

Results Based on the nanofiber membrane morphology obtained from single factor experiment and orthogonal experiment (Fig. 1,Tab. 2 and Fig. 2),it was evident that the optimal electrospinning parameters for preparing RSF/PVA blended oriented nanofiber membranes were as follows, formic acid as the solvent,roller speed of 2 400 r/min,spinning fluid concentration of 0.16 g/mL,spinning voltage of 23 kV,outflow velocity of 0.6 mL/h,and receiving distance of 17 cm.Under these parameters,the oriented nanofiber membranes demonstrated regular morphology and high orientation (Fig. 3 and Tab. 3). It can be seen from the infrared spectra of RSF power,PVA grain and RSF/PVA oriented fiber membranes (Fig. 4) that compared with RSF powder,part of amorphous structure in the oriented nanofiber membranes was transformed into the ɑ helix structure. The stretching effect of the high-speed roller on the fiber was conductive to improving the degree of orientation and crystallinity of nanofiber membranes,thus the breaking strength of the oriented nanofiber membranes obtained under the same spinning time was more than two times that of the non-oriented nanofiber membranes, but the elongation rate at break was lower than that of the latter (Tab. 4).The oriented and non-oriented nanofiber membranes almost coincide,and both begin to decompose at 284 ℃ with their thermal decomposition rates fastest at 312 ℃ (Fig.7),indicating that the thermal stability of the oriented and non-oriented nanofiber membranes was similar,and the stretching and alignment of fibers by the high-speed roller had substantially no effect on the thermal stability of RSF/PVA nanofiber membranes.The pore sizes of oriented and non-oriented nanofiber membranes were distributed in 0.46-1.50 μm and 0.08-0.48 μm, respectively,and were concentrated near 0.5 μm and 0.1 μm, respectively,indicating that oriented nanofiber membranes had larger pore sizes and were expected to be used in the field of textile biomedicines.

Conclusion RSF and PVA were electrospinned into oriented nanofiber membranes.The optimal spinning parameters were determined by single-factor experiment and orthogonal experiment,and the morphology,chemical structure, mechanical properties and thermal stability of nanofiber membranes were studied. The experimental results showed that part of the amorphous structure in the oriented nanofiber membranes was transformed into the ɑ helix structure; and the oriented nanofiber membranes had higher strength than the non-oriented nanofiber membranes,but had lower elongation at break under the same spinning time. And the pore sizes in the oriented nanofiber membranes were larger than that of the non-oriented ones and the oriented structure has substantially no effect on the thermal stability of the nanofiber membranes. The experimental results provided a theoretical basis for further enhancing the application potential of oriented nanofiber membranes in the field of textile biomedicine.

In-situ electrospun membranes from recycled polyethylene terephthalate for conservation of paper documents

MENG Xin, ZHU Shufang, XU Yingjun, YAN Xu

Journal of Textile Research. 2023, 44(09):  20-26.  doi:10.13475/j.fzxb.20220405301

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Objective Paper documents, such as old books, archives, and paper-based commemorative items are a rich source of human knowledge and passion. It is challengeable to protect paper documents from moisture, tear and aging. This paper proposes a straightforward and cost-effective approach for paper documents protection by in-situ electrospinning, which directly deposited as-spun nanofibrous membranes onto the paper documents surface.

Method Used mineral water bottles which are transparent and hydrophobic were selected as the raw material (mainly polyethylene terephthalate, rPET) and were dissolved to form solutions with different concentrations. The rPET solution was electrospun into fibers under different spinning parameters, which were directly deposited onto the paper document surface to form a transparent protective membrane using a portable electrospinning device (Fig. 1). The morphology, surface wettability, mechanical properties and UV resistance of the paper documents before and after in-situ electrospinning were analyzed to evaluate the protective effect of the membranes.

Results The optimized spinning parameters were the rPET mass fraction of 8%, spinning distance of 15 cm, spinning time of 10 min, spinning voltage of 15 kV, and solution feeding rate of 10 μL/min. Under these parameters, the prepared rPET fiber membrane was almost transparent without covering the prints on paper (Fig. 2) but would block common dust and mold effectively due to the small membrane pore diameters of about (5.53±0.38) μm (Fig. 3). The as-spun rPET nanofibrous membranes under optimal conditions made the paper's surface hydrophobic with the water contact angle about 135.1° (Fig. 4) to avoid water immersion. It was also found that the deposited rPET fibers could form an interlocking grid structure, increasing the tensile strength in the horizontal and vertical directions by 129.1% and 16.1%. Tear resistance was also improved in both transverse (86%) and longitudinal (161.1%) directions, respectively (Fig. 6). The study also revealed that the as-spun rPET nanofibrous membrane also increased the UV protection factor (UPF) of the paper documents from 16.2 to 71.4 (Fig. 7), reducing UV induced aging.

Conclusion In-situ electrospinning rPET membrane onto paper documents is easy to operate and could achieve a good protection effect. The prepared rPET fiber membrane is transparent, and has small pore size, which could prevent dust while not affecting the appearance of the paper documents. The as-spun rPET membrane could also obviously enhance the mechanical and UV protect properties of the paper documents. These results suggested that in-situ electrospinning rPET onto the paper document forms an useful way for both protection of paper documents and the recycling of water bottles.

Preparation and properties of modified polyester fiber for super softness and high hygroscopy

QI Xiaojie, SUN Li'na, LIAO Haiyang, MA Bomou, YU Jianyong, WANG Xueli, LIU Xiucai

Journal of Textile Research. 2023, 44(09):  27-34.  doi:10.13475/j.fzxb.20220408201

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Objective Polyethylene terephthalate (PET) fibers have excellent mechanical properties, stable thermal and chemical properties, and are widely used in industrial, home textile, and apparel fields. However, because of its regular macromolecular chain structure and the lack of hydrophilic groups, the softness and moisture absorption of the fibre and fabrics made from it are poor, leading to low wearing comfort. This research aims to improve the softness and high moisture absorption of PET fiber.

Method Two series of modified PET fibers containing different molar fractions (3%, 6%, 9% and 12%) of modified monomers and different drafting multipliers were prepared by melt spinning ethylene terephthalate (BHET) copolymerized with glutaramide adipate (PA56 salt) and its derivative p-adipic acid diamide (APA56), respectively, combined with the two-step method of spinning undrafted yarn followed by progressive drafting. The properties of modified PET fibers were tested and analyzed with the aid of an acoustic velocity orientation meter, an X-ray diffractometer, and a yarn tensiometer.

Results The orientation and crystallinity of modified PET fibers were found lower than those of PET fibers, and the orientation and crystallinity decreased gradually with the increase of the molar fraction of modified monomers, but increased with the increase of the draft multiple (Fig. 1 and Fig. 3). The modified PET fiber was still trigonal as PET and the crystal shape does not change, but the diffraction peak was gradually weakened and the peak broadened as the molar fraction of the modified monomer was increased (Fig. 2). The breaking strength and initial modulus of modified PET fibers also decreased with the increase of the molar fraction of modified monomer, and the strength of fibers decreased while the softness increased. When the molar fraction was below 6%, the breaking strength of fibers could reach more than 2.0 cN/dtex, illustrating better mechanical properties (Fig. 4 and Fig. 5). For the same molar fraction of PA56 salt and APA56 modified PET fiber, the former showed higher breaking strength and initial modulus than the latter at the same drafting times, so the APA56 modified PET fiber became more flexible. The relative bending stiffness test results further showed improved softness of the modified PET fibers, with relative bending stiffness reduced by 18% to 71% and 40% to 88%, respectively(Fig. 6). APA56 show better softness than PA56 salt modified PET fibers, and the softness basically reached the level of fine wool when the molar fraction of modified monomers reached 6% and above. The moisture regain of PA56 salt and APA56 modified PET fibers increased by 39% to 200% and 53% to 213%, respectively, compared with PET fibers when the molar fraction of modified monomers was 3% to 12%. The modification of PA56 salt and APA56 significantly improved the moisture absorption of PET fibers, and the moisture absorption of APA56 modified PET fibers was better (Fig. 7).

Conclusion Two series of modified PET fibers were prepared by melt spinning using PA56 salt and APA56 as the modifying monomer, respectively, for copolymerization modification of PET. Compared with PET fibers, the orientation, crystallinity, and fracture strength of the modified PET fibers were reduced by the introduction of the modified monomers, and the molar fraction of the modified monomers increased, but the presence of flexible methylene chain segments and amide groups in the modified monomers significantly improved the softness and moisture absorption of the fibers, and the softness and moisture absorption of APA56 were better than those of PA56 salt. When the molar fraction of the modified monomer reaches 6% and above, the softness can reach the level of fine wool, and the mechanical property test shows that the fiber with a 6% molar fraction of modified monomer can reach the breaking strength of 2.0 cN/dtex and above, which retains good mechanical properties and can meet the requirements of the service performance, and will provide the possibility of replacing cotton and other natural fibers in the field of clothing in the future. It will provide the possibility of replacing cotton and other natural fibers in the apparel field in the future.

Degradation properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) modified polyester composite filament

NIE Wenqi, XU Shuai, GAO Junshuai, FANG Bing, SUN Jiangdong

Journal of Textile Research. 2023, 44(09):  35-42.  doi:10.13475/j.fzxb.20220404301

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Objective Polyester (PET) filament has made remarkable contributions to the development of textiles and is widely applied in various fields because of its high strength, superior durability, and good dimensional stability. At present, the annual production of polyester filament is as high as 43.26 million tons/year, however it is more difficult to degrade under natural conditions, causing environmental concerns. Therefore, it is a critical challenge to improve the degradation properties of PET filament without changing its other performance.

Method A novel composite filament was rationally fabricated via poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) modified PET, called PHBV/PET filament. The degradation performance of PHBV/PET filament was investigated by thermal degradation and soil degradation. The influences of temperature and soil filling time on the molecular structure of filaments were studied in depth. Scanning electron microscope, thermogravimetric analyzer (TG), differential scanning calorimeter, and Fourier transform infrared spectroscopy were adopeed to analyze the mechanical properties, crystallinity, structure and surface morphology of the PHBV/PET filaments after degradation.

Results The addition of PHBV slightly was found to reduce the strength of the PET fibers with a breaking strength of 1.69 cN/dtex for 1% PHBV/PET filament. However, the elongation of break was increased significantly, indicating that the introduction of PHBV would not limit the processing applications of the composite yarn (Fig.1). Apart from its fine mechanical properties, PHBV/PET also exhibited better thermal degradation performance. The 5% mass loss temperature of the 1% PHBV/PET filament was 364 ℃, lower than 386 ℃ for PET filament. The PHBV cansed the crystallization of the filament more difficult during pyrolysis process, and the filament seemed to be more likely to degrade at low temperatures (Fig. 2). The mass loss of the PHBV/PET filament was only 88.42%, while the mass loss of the non-thermally degraded filament was as high as 94.90% in TG curves (Fig. 4), indicating the PHBV/PET filament macromolecular chains easier to break at high temperatures degradation condition. It was also found that 3% PHBV/PET filament after thermal degradation occurred an apparent absorption peak at 110 ℃ (Fig. 5), implying the high temperatures would promote recrystallization of composite filament and that PHBV can promote the degradation of PET filament. Furthermore, 1% PHBV/PET filament lacked an exothermic peak at 2 959.25 cm^-1 after thermal degradation, confirming that 1% PHBV/PET filaments can be degraded (Fig. 6). After 60 d buried in soil environment, grooves distinctly appeared in the surface of the 1% PHBV/PET filament (Fig. 7), suggesting that the 1% PHBV/PET filament was eroded by soil microorganisms, leading a change to the internal structure of the fiber, which caused the breakage and decomposition of the macromolecular chains. The results showed a significant increase in the absorption enthalpy of 1% PHBV/PET filaments (Fig. 8).

Conclusion 1% PHBV/PET filament was found to have excellent mechanical properties and can be degraded both thermal and soil embedding. When increasing PHBV content, the side groups and branched chains of PET filaments are more easily moved, and the degradation is much more easily. Therefore, the PHBV/PET filament can be used as a new environment-friendly material to replace part of PET filament in related application fields, contributing to green production of textiles.

Influence of heat-setting process on structure and properties of high-tenacity polyester industrial yarns

ZHANG Ying, SONG Minggen, JI Hong, CHEN Kang, ZHANG Xianming

Journal of Textile Research. 2023, 44(09):  43-51.  doi:10.13475/j.fzxb.20220400401

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Objective The continuous expansion of the application field of polyester industrial fiber puts forward more detailed requirements for its performance, and the relationship between process-structure-performance needs to be further clarified. In order to explore the intrinsic structural factors of the differences in the application fields of high-tenacity polyester industrial yarns obtained at different heat-setting temperatures, the structure and properties of three high-tenacity polyester industrial yarns were compared.

Method Synchrotron radiation small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) were adopted to study its multi-scale microstructure. Establish a multi-level structure analysis method from macro to micro was established, and the influences of different heat-setting processes on the structure and properties of high-tenacity industrial yarns were clarified.

Results The fiber spinning process differences between the three high-tenacity polyester industrial yarns were reflected in the difference of heat-setting temperatures (Tab. 1). Compared with high-tenacity medium-shrinkage (HTMS) and high-tenacity (HT) polyester industrial yarns, high-tenacity low-elongation (HTLE) was shown to have lower heat-setting temperature, resulting in higher amorphous orientation, lower crystallinity, smaller crystallite size, smaller long period and larger tilting angle of crystalline lamellae (Tab. 4 and Tab. 5). Because the microstructures with high crystallinity and high orientation are formed under the condition of high drafting ratio, the breaking strength of the three industrial yarns are relatively high, and the differences are not obvious(Tab. 2). The mechanical properties are different in elongation at break, initial modulus, elongation at a specific tenacity of 4.0 cN/dtex (Easl-4) and tenacity at a specific elongation of 5% (Lase-5). HTLE polyester has the smallest elongation at break, the largest initial modulus, the largest thermal shrinkage, the worst dimensional stability, and the highest α transition temperature. HTLE has the highest sound velocity orientation and small deformation during stretching, and thus has the lowest elongation at break. The amorphous orientation of the fibers is the key structural factor determining the elongation at break due to the small difference in the crystallite orientation of the three industrial yarns. The initial modulus appears in the first stage of the stretching process, which is mainly related to the amorphous region. With the increase of the amorphous orientation, the initial modulus also increases. Therefore, the amorphous orientation of HTLE is the largest, and its initial modulus is the largest. The heat-setting temperature of HTLE is low, the fiber shrinkage is small, the molecular orientation is large, and the thermal shrinkage is maximum (Tab. 3). In addition, crystallization will form a cross-linking effect, limiting the movement of molecular chains, and also has an impact on the thermal shrinkage performance of the fiber, therefore, crystallinity of HTLE is low, the crystallite size is small, and the thermal shrinkage is the largest. The dimensional stability refers to the sum of the Easl-4 and thermal shrinkage rate, and the smaller the sum is, the better the dimensional stability is. In addition, the tilting angle of crystalline lamellae also has a certain influence. When angle is small, it can be considered that the fiber has a regular structure and good dimensional stability. HTMS has a smaller thermal shrinkage rate and a smaller tilting angle of crystalline lamellae, and thus has good dimensional stability (Tab. 3). The higher the glass transition temperature is, the higher the temperature at which the molecular chains in the amorphous region begin to have thermal motion, the larger the chain binding, the smaller the activity capacity. HTLE has the highest amorphous orientation, which limits the movement of molecular chain, resulting in the highest T_g (Fig. 3).

Conclusion The heat-setting temperature mainly affects the amorphous orientation and the lamellar structure of polyester industrial yarns. Compared with HTMS and HT, HTLE has the lowest heat-setting temperature, and the stretched amorphous molecular chains produced by high draw ratio didn't enter the crystal lattice to form crystallization, and occurred a small recovery at low heat-setting temperatures, which causes HTLE industrial yarns to show the structural characteristics of high amorphous orientation, low crystallinity, small crystallite size and large tilting angle of crystalline lamellae, resulting in the lowest ultimate elongation, the highest initial modulus, the worst dimensional stability.

Preparation and characterization of acetate grade reed pulp

WANG Xiaokang, XIE Kaifang, ZHOU Hengshu, BAO Xinjun, XU Yingsheng

Journal of Textile Research. 2023, 44(09):  52-59.  doi:10.13475/j.fzxb.20230101201

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Objective Based on the research on using biomass materials (such as bamboo, straw, sorghum straw, mulberry straw, hemp, bagasse, olive, tobacco stem and so on) to prepare acetate grade dissolving pulp and downstream products, this paper proposes the use of rich reed resources in Dongting Lake area to explore the feasibility of preparing acetate reed pulp, and test and analyze the performance of the prepared pulp so as to establish understanding on the preparation of cellulose acetate and acetate fiber.

Method The typical sulfate method was adopted to prepare the Triarrhena lutarioriparia dissolving pulp. Firstly, the water pre-hydrolysis of Triarrhena lutarioriparia slices was carried out in an electrothermal high-pressure boiling pot (Fig. 2) with a liquor ratio of 1∶4. Then, the equipment was used for sulfate boiling (Fig. 3), where the main components of the boiling solution were NaOH and Na₂S. Crude pulp was cleaned with a 45 μm polyester mesh bag and sieved with a sieve machine with a sieve gap of 0.25 mm. Finally, the D₀E_pD₁ three-stage bleaching process (Tab. 2) was used for bleaching, and the bleaching agents were ClO₂ and H₂O₂. The cellulose I content, whiteness, polymerization degree, pentosan content, ash content and iron content of the prepared triarrhena lutarioriparia dissolving pulp were tested, and the apparent morphology, infrared spectroscopy, Raman spectroscopy and X-ray diffraction were employed for analysis.

Results The yield of crude pulp after boiling was 46.31%. The three-stage bleaching process significantly improved the main performance indexes of Triarrhena lutarioriparia pulp. The content of cellulose I increased by 1.24% to 97.70%, the whiteness doubled to 91.42%, and the intrinsic viscosity decreased by 38.01%, which made the average degree of polymerization of pulp reach 1 413. In addition, the pentosan content, ash content and iron content of the pulp after bleaching were 5.76%, 0.004% and 0.000 562%, respectively. The cellulose fibers prepared from Triarrhena lutarioriparia dissolving pulp were long cylindrical with rough surface showing a large number of grooves, cracks, pores and filaments. In the infrared spectra (Fig. 5), the Triarrhena lutarioriparia dissolving pulp showed a typical cellulose characteristic peak, and the intensity of the absorption peak was enhanced compared with that of Triarrhena lutarioriparia. The characteristic peaks of lignin at 1 254 cm^-1 and 1 511 cm^-1 and the characteristic peaks of hemicellulose at 1 726 cm^-1 disappeared, indicating that the pulping process removed the lignin and hemicellulose in Triarrhena lutarioriparia. The characteristic peaks at 1 169 cm^-1 and 1 607 cm^-1 relating to lignin disappeared, and the intensity of the characteristic peak at 2 896 cm^-1 decreased indicating that non-cellulose substances such as lignin in Triarrhena lutarioriparia were removed during pulping (Fig. 6). The Triarrhena lutarioriparia dissolving pulp showed a typical diffraction curve of cellulose I. The small peak at 26.4°disappeared and no peak appeared at 29.4°(Fig. 7), suggesting that the inorganic components such as SiO₂ in Triarrhena lutarioriparia were effectively removed after the pulping process.

Conclusion The acetate grade Triarrhena lutarioriparia dissolving pulp was prepared by water pre-hydrolysis-sulfate cooking-D₀E_pD₁ three-stage bleaching process. The combined action of high temperature and chemical agents during the pulping process effectively removed the lignin, hemicellulose and ash in Triarrhena lutarioriparia, formed irregular microfibril structure on the surface of cellulose fiber, and presented a rough surface full of grooves. The successful preparation of acetate grade Triarrhena lutarioriparia dissolving pulp not only lays a foundation for the preparation of cellulose acetate and acetate fiber, but also helps open up a new way for high-value and efficient utilization of reed resources.

Textile Engineering

Full color phase mixing model constructed by blending of six primary colored fibers and colored yarn production

SUN Xianqiang, XUE Yuan, LIU Yuexing, ZHANG Guoqing, LIU Lixia

Journal of Textile Research. 2023, 44(09):  60-67.  doi:10.13475/j.fzxb.20220507401

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Objective In conventional spinning process, colored yarns are prepared by blending different colored fibers through the process of fiber blending, grabbing, and drawing, but the process does not support online regulation, real-time control, and accurate digital adjustment of the yarn color. Inspired by color inkjet printing, the purpose of the paper is to investigate how to build a multi-channel computer numerical control (CNC) spinning system for making colored yarns of a full color phase. To this end, using the Newton's three primary-color principle and through digital blending of the six primary colored fibers of red (R), yellow (Y), green (G), cyan (C), blue (B), and magenta (M), the color hue of the forming yarn can be changed from 0 to 360°, enabling the spinning of colored yarns of full color phase.

Method The mechanism of controlling the mixing ratios of colored fibers by CNC spinning was combined with the full color phase mixing model of with six primary colored fibers, and the "multi-channel drafting ratios - colored fiber mixing ratios-colors of yarns" synergistic regulation mechanism was established. Based on the six primary colored fibers of red, yellow, green, blue, cyan and magenta, a full color phase mixing model with 60 grid points and a hue control of 0-360° was built. The spinning process parameters were designed based on the grid point number and a total of 60 different colored yarns and their fabrics in six color systems, consisting of R-Y, Y-G, G-C, C-B, B-M, and M-R, were fabricated.

Results According to the fiber mixing ratio in the above model, 60 colored fabrics were obtained (Fig. 6). The color variation regularity was consistent with the regularity of mixing ratios of the six primary colored fibers, and also has consistency with the color distribution regularity of the full color phase grid mixing model. The colored yarns were measured and analyzed for appearance and mechanical properties such as yarn unevenness, surface hairiness and tensile strength. In terms of evenness, the coefficient of variation (CV) varied with the mixing ratios, with a minimum of 12.40%, a maximum of 16.50%, and an average of 14.15% (Tab. 4). Its corresponding unevenness (U) also varied with the mixing ratios, with a minimum of 9.23%, a maximum of 12.73% and an average of 10.68%. Among them, the number of thick parts and thin parts was less than 220, and the number of neps varied from 50 to 95, with a mean value of 72. Regarding the surface hairiness, the number of 3 mm hairiness ranged from 46 to 64 (Tab. 5). Among the hairiness of 1-3 mm, the samples with mixing ratios of 10∶0 and 5∶5 had relatively small numbers of hairiness, while those with mixing ratios of 9∶1 and 1∶9 had more hairiness. With respect to the tensile strength, the minimum breaking strength was 442.70 cN and the maximum was 527.70 cN, and the minimum elongation was 5.72% and the maximum was 6.58% (Tab. 6). Among them, the strength CV value ranged from 1.75% to 3.74%, with an average of 2.91%, and the elongation CV value ranged from 1.46% to 6.13%, with an average of 3.78%.

Conclusion The research results proved that the mixing ratios of colored fibers in the forming yarns can be adjusted based on the regulation of the multi-channel drafting ratios by using the multi-channel CNC spinning platform, and furthermore, the color of the forming yarns can be controlled. By building a full color phase gridded mixing model through the six primary colors of R, Y, G, C, B and M, the color mixing of full color phase can be realized in the range of 0°-360° according to the six color system gridded color mixing of R-Y, Y-G, G-C, C-B, B-M and M-R. by combining the regulation mechanism of multi-channel CNC spinning with the full color phase mixing model, 60 different colors of yarns distributed in six color systems of R-Y, Y-G, G-C, C-B, B-M and M-R were prepared, which realized the spinning of colored yarns of full color phase. It is proved that the process of the spinning of colored yarn of full color phase is feasible by testing the color, appearance and mechanical properties of the forming yarn, and the indexes of the yarns are substantially in line with the second level of the standard GB/T 398—2018 "cotton gray yarn".

Jacquard fabric design of special-structure dot patterns and its grayscale simulation characteristics

ZHANG Aidan, GUO Zhenni

Journal of Textile Research. 2023, 44(09):  68-74.  doi:10.13475/j.fzxb.20220604801

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Objective Aiming at the situation that the dot shapes applied to the grayscale simulation jacquard fabric are limited to simple geometry, a special-shaped dot database design method was proposed, and the reproduction performances of the created special-shaped dot databases in the design of jacquard fabric were compared and investigated, attempting to provide a new method for promoting the color simulation of jacquard fabric design technology.

Method Four specially-shaped dot databases were designed by graphic generation technology. One group of fabric color cards showing grayscale from black to white gradient changed and four jacquard fabric samples representing an image were woven by applying the special-shape dot databases. All fabric samples were interwoven from one set of white warp and black weft yarns. The materials of warp and weft threads were both 23.3 dtex×2 silk, and the warp and weft filling density were both 1 100 threads/(10 cm). By comparatively analyzing the average lightness differences between the values of the fabric color cards and the original grayscale color, and between the value of the jacquard fabric samples and that of the original image, the grayscale simulation feature of the special-shape dot databases in the color simulation design of jacquard fabric were explained.

Results The mean value of the fabric color cards woven using the tree-shaped dot database and the original grayscale from the black to the white were calculated, respectively, and the difference between them was only 1, which indicated that the grayscale simulation performance of the tree-shaped dot database was excellent compared with the another six group of fabric color cards applying frequently-used shaded weave databases in total (Tab. 1). In order to further analyze the color simulation capability of the special-shape dot databases for rending complex image, six jacquard fabric samples were produced by using the four special-shape dot databases and two shaded weave databases, respectively. All figured jacquard fabric samples are scanned to become digital images, and then each digital jacquard fabric image was divided into nine pieces one by one (Fig. 4). The average lightness values of the nine pieces in one fabric image were calculated in sequence (Fig. 6), and the average lightness differences between the each fabric image pieces with that of the original image pieces were counted accordingly (Tab. 3). From the data of the six groups and their average lightness differences with the original image, it was shown that the four jacquard fabrics using special-shape dot databases had slight deviation value in grayscale simulation performance, but the average value difference between the two groups of jacquard fabrics with shaded weave databases was obvious. In addition, the heart-shape dot database had the best performance among the four special-shape dot databases, the ingot-shape was the second, the third was the tree-shape and the last was the leaf-shape. In view of the comparative analysis of the average lightness difference between the jacquard fabric images expressed by special-shape dot databases and by shaded weave databases, it was proved that the special-shaped dot databases have better and more stable grayscale simulation performances than that of the shaded weave databases that are widely used for the design of the color simulation jacquard fabrics in present.

Conclusion Special-shape dot structure fabrics have more stable grayscale simulation performance than the shaded weave structure fabrics, and the fullness of the dot shape is found to be the main factor affecting the grayscale simulation effect in the experiment. The design and application of the special-shaped dot database, on the one hand, is a breakthrough in the conventional dot shape and develops new design paths to the production of color simulation jacquard fabrics with graphic generation technology. The application research of special-shaped dot database in grayscale simulation of jacquard fabrics provides a new idea and design references for the development of creative jacquard fabrics.

Development and performance of dragonfly wing structure like winter knitted fabrics

DING Xueting, WANG Jianping, PAN Ting, YAO Xiaofeng, YUAN Luning

Journal of Textile Research. 2023, 44(09):  75-83.  doi:10.13475/j.fzxb.20220704401

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Objective Warm retention knitted sports underwear has always been a hot winter product, but different from other daily clothing, knitted sports underwear is more likely to accumulate sweat in the process of strenuous exercise, leading to discomfort and negatively affecting athletes' performance. Many knitted fabrics are difficult to ensure the effective export of sweat on the basis of ensuring warmth, so it is necessary to design and develop knitted fabrics to improve the hot and wet comfort of knitted sports underwear.

Method Using graphene yarn of 150 dtex (144 f) as surface yarn, Dryarn^® polypropylene yarn/spandex covered yarn (30 dtex/30 dtex ) as inside yarn, 4 knitted fabrics with imitated structural features were developed following the study of macrostructure and microstructure of dragonfly wings, and 1+2 false rib weave knitted fabric was set as control group. Each knitted fabric designed 3 densities with P10, 0 and N10, corresponding to step motor value of 90,100 and 110,respectively. Warmth retention property, air permeability, moisture permeability and liquid water management ability of knitted fabrics were analyzed, and then comprehensively analyzed hot and wet comfort combined with concentrated mapping method and functional value evaluation.

Results All 4 types of bionic knitted fabrics were evaluated for hot and wet performance. Under the same fabric density, the warmth retention of papillary structure fabric was the best (Tab. 2), and under the same bionic structure, the warmth retention property of bionic knitted fabrics was increased with the decrease of density. Under the density 0 and N10, the air permeability of papillary structure fabric performed better (Tab. 3), and under the density P10, the air permeability of quadrilateral structure fabric is the best. Under the same bionic structure, the air permeability of bionic knitted fabrics was improved with the decrease of density. Under the same fabric density, the moisture permeability of hexagonal structure fabric stoodout (Tab. 4), whilst under the same bionic structure, the moisture permeability of bionic knitted fabrics was enhanced with the decrease of density. Under the N10 density, the liquid water management ability of hexagonal structure fabric was the best (Tab. 5), and under the same bionic structure, the liquid water management cap ability of bionic knitted fabrics increased with the decrease of density. The evaluation of the hot and wet comfort of knitted fabrics by a single index was not comprehensive enough, so combining concentrated mapping method and functional evaluation value made a comprehensive evaluation of many related factors, and analysis of the hot and wet comfort performance of knitted fabrics were conducted comprehensively. Under the same bionic structure, the smaller the density of bionic fabrics, the better the comprehensive performance have. At the same density of bionic fabrics, the comprehensive performance of bionic fabrics was better than twill tissue fabric, and at any density, except that the hexagonal structure fabric at P10 density was seen to be inferior to the twill fabric at N10 density, the comprehensive performance of other bionic fabrics was better than twill fabric at any density. For all fabrics, the comprehensive performance of papillary structure was the best with N10 density.

Conclusion By imitating the non-smooth surface texture of dragonfly wings, 4 bionic knitted fabrics are designed with concave and convex texture, which increases the thickness of fabrics and thus improves their warmth preservation, bionic knitted fabrics contact with the human skin to form a microclimate regulation space, the space can store hot air flow emitted by human body to achieve the thermal effect, and the space can improve the fluidity of gas to achieve the effect of rapid perspiration. The 4 types of bionic knitted fabrics demonstrate excellent hot and wet performance, and are suitable for winter knitted sports underwear, providing direction and fabric options for winter knitted sports underwear development.

Embroidery style transfer modeling based on multi-scale texture synthesis

YAO Linhan, ZHANG Ying, YAO Lan, ZHENG Xiaoping, WEI Wenda, LIU Chengxia

Journal of Textile Research. 2023, 44(09):  84-90.  doi:10.13475/j.fzxb.20220504801

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Objective There are still many problems in the existing embroidery image generation algorithms, such as singular style of the generated image, rough features, and many artifacts. Aiming at this situation, embroidery style transfer modeling based on multi-scale texture synthesis is proposed. By improving the existing style transfer algorithm, embroidery-style images with higher perceptual quality are expected to be created.

Method Multi-stylized loss function was adopted to extract the edge information and detailed structure of the content image and the style image, and the results were compared with the effect of the transfer image generated by only using the content loss and the style loss.

Results Experiments presults showed that the multi-stylizd loss function could generate embroidery migration images with clear texture. Gatys' model was shown to have more artifacts and deformations in the conversion process of the image with dense lines, and Johnson's model also had artifacts and conversion errors in the conversion of feather details. Li and Wand's model lacks embroidery details such as stitching and texture variations (Fig. 6). The multi-scale texture synthesis embroidery style transfer model (MTE-NST) proposed in this research transfered the detailed structure of the style map well, which was closer to the real embroidery work, and was better than the first three models in terms of style and details. MTE-NST had the smallest MSE (the smallest style loss) and the smallest LPIPS (the highest image perceptual similarity), and the image quality and transfer effect were better. The test time and occupied memory were second only to Johnson, which are 0.58 s, 3 900 MB, respectively which are quite close, further verifying that MTE-NST can generate more realistic embroidery style image (Tab. 2).

Conclusion This paper proposes a MTE-NST, which learns hierarchically the multi-scale embroidery art styles. MTE-NST can not only restore the style image color but also preserve the texture structure and fine details of the image edge, which solves the problem of texture conversion mismatch and can generate embroidery style transfer pictures with better visual effects.

Influence of needling reinforcement frequency on properties of jute/polylactic acid fiber composite sheets

SUN Mingtao, CHEN Chengyu, YAN Weixia, CAO Shanshan, HAN Keqing

Journal of Textile Research. 2023, 44(09):  91-98.  doi:10.13475/j.fzxb.20220309501

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Objective In order to use biomass degradable composite materials to replace conventional petroleum-based materials in the field of automotive interiors, jute fiber reinforced polylactic acid (JF/PLA) composite sheets were prepared by web molding technique, where needling reinforcement was believed beneficial to the infiltration and encapsulation of PLA matrix on jute fiber during the web forming process. The needling frequency has a certain influence on the structure and properties of the final obtained JF/PLA composite sheets, which has rarely been reported. This paper explores the influence of needling frequency on the structure and performance of composite sheets.

Method PLA short fiber of 60% mass fraction and jute fiber of 40% mass fraction were used for preparing JF/PLA composite sheets by web forming technique, where the needling frequency was selected at 280, 300 and 320 times/min. The volume densities of the JF/PLA composite sheets were 2.50, 2.81, and 2.92 g/cm³ corresponding to the 280, 300, and 320 times/min needling frequencies, respectively. Scanning electron microscope, universal testing machine, impact testing machine, water-absorbency tests, combustibility tests and biodegradability tests were used for exploring the influence of the needling reinforcement frequency on properties of PLA/JF composite sheets.

Results The mechanical properties of JF/PLA composite sheets increased first and then decreased with the increase of needling frequency. When the needling frequency was 300 times/min, the mechanical properties of the JF/PLA composite sheets were optimal, and the vertical tensile strength, the flexural strength and notched impact strength were 14.54 MPa, 33.02 MPa and 9.54 kJ/m², respectively. However, the high needling frequency seemed to cause decline in the mechanical properties of JF/PLA composite sheets due to the fracture of part of the jute fibers. The water-absorbency of JF/PLA composite sheets gradually decreased with the increase of needling frequency (Fig. 6), because the increase of needling frequency caused the further entanglement between the jute fibers and PLA matrix, which made the internal structure of the composite sheets denser after hot-pressing. However, the microporous structure was uniformly distributed to a great extent, making the water absorption rate decrease. The horizontal burning test results of JF/PLA composite sheets with different needling frequencies showed a gradually decreasing as the needling frequency increases (Tab. 1). This may be because the higher needling frequency made the internal structure of the composite sheets more compact with reduced orifice size was, and the flame retardant effect was better. After 4 months of soil burying, the mass loss rate of PLA/JF composite sheets showed a gradual decrease with the increasing needling frequency. This was due to the tighter network structure of the jute fiber in the composite sheets caused by the high needling frequency and by the increased bonding ability between jute fiber and PLA matrix. The natural degradation process made the composite weaker and the mass loss rate reduced.

Conclusion The needling frequency, which is an important parameter in the preparation of composite materials by web forming technique, has not been much reported. In this work, three different needling frequencies of JF/PLA composite sheets were prepared. The results demonstrated that the mechanical properties were optimal at a needling frequency of 300 times/min, and the excessive needling frequency was not favorable to the mechanical properties of the composite sheets. Moreover, the increase of needling frequency facilitates reducing the water-absorbency and biodegradability and to improve the flame retardancy of the composite sheets. This study provides a theoretical basis and application guidance for controlling the mechanical properties, water-absorbency, biodegradability and flame retardancy of JF/PLA composite sheets by needling frequency, and expands the application possibilities of JF/PLA composite sheets used as automotive interior materials.

Deformation characteristics of jute fabric/polyethylene composite under different cyclic loading paths

WANG Zexing, ZHOU Hengshu, YANG Min, TAN Dongyi

Journal of Textile Research. 2023, 44(09):  99-107.  doi:10.13475/j.fzxb.20220305501

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Objective Owning to the advantages in terms of low-density, low-cost, recyclability, and excellent mechanical properties, the natural fiber reinforced thermoplastic composites have broad application prospects in fields such as transportation and construction. However, natural fiber reinforced thermoplastic composites are still limited in engineering design and application, partly due to a lack of in-depth and comprehensive understanding of its mechanical properties and failure mechanisms under complex loading conditions. Therefore, the paper proposed to investigate the influence of cyclic loading paths on the deformation characteristics and mechanism of jute fabric/polyethylene composites.

Method Jute fabric/polyethylene composite prepared by hot press method based on jute woven fabric as reinforcement and polyethylene film as matrix, the mechanical properties of the composite were tested under cyclic loading paths of constant-amplitude cyclic loading, stepwise increasing cyclic loading and decreasing cyclic loading. The accumulated strain, strain of each cycle and strain recovery factor were analyzed, and the deformation mechanism was also discussed.

Results The jute fabric/polyethylene composite exhibited cyclic softening characteristic at all loading stages under constant-amplitude cyclic loading, and stepwise increasing cyclic loading and in first loading stage under stepwise decreasing cyclic loading led to cyclic hardening in the subsequent loading stages under stepwise decreasing cyclic loading (Fig. 3). Under constant-amplitude cyclic loading and stepwise increasing cyclic loading, the jute fabric/polyethylene composite demonstrated similar deformation mechanism; and with the increase of cyclic peak stress and cycle number, the accumulative strain (accumulative maximum and residual strain) of each loading stage was increase (Fig. 5), and the loading strain, elastic strain and residual strain of each loading stage were decrease (Fig. 6). Under stepwise decreasing cyclic loading, the variation of accumulative strain, loading strain, elastic strain and residual strain with cycle number in the first loading stage was similar to that under constant-amplitude cyclic loading and stepwise increasing cyclic loading, and was opposite in the subsequent loading stages (Fig. 5, Fig. 6). Meanwhile, the strain recovery coefficient gradually approached 100% with increase with cycle number under different cyclic loading paths, and the strain recovery coefficient gradually increase close to 100% in all loading stages under constant-amplitude and stepwise increasing cyclic loading and in first loading stage under stepwise decreasing cyclic loading, however, decreased close to 100% in the subsequent loading stages under stepwise decreasing cyclic loading (Fig. 7).

Conclusion The results show that deformation characteristics and mechanism of jute fabric/polyethylene composite are affected by cyclic peak stress, which is also closely related to cyclic loading paths. Hence, the influence of cyclic loading path was investigated on the deformation characteristics of the natural fiber reinforced thermoplastic composites, which better reflect the long-term mechanical performance under actual use conditions, and thus make more practical conclusions. In order to comprehensively study the mechanical behavior of these materials under complex loading histories, in-depth investigation on deformation and energy dissipation under different cyclic loading rates, random cyclic peak stresses was proposed for future research.

Unit modeling and pore analysis of C/C soft-hard blended preform based on multi-dimensional modeling

MEI Baolong, DONG Jiuzhi, REN Hongqing, JIANG Xiuming

Journal of Textile Research. 2023, 44(09):  108-115.  doi:10.13475/j.fzxb.20220600301

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Objective In order to explore the pore distribution and change of the C/C soft-hard blended preform in the initial and final stages of the compaction process, the problem that the porosity can not be predicted at the completion of the preform was set and research focus.

Method A 3-D four-direction pore model was established based on the C/C soft-hard weaving preform process. The pores from the xoy plane and xoz plane of the unit model in two dimensions and four directions were studied with and without compression load. The influences of fiber shape and cross section shape of the pore of the unit under the load were studied from mesoscopic and microscopic scales. The mapping relationship between the change of fiber size and porosity was solved by using the geometric model and the size coefficient affecting the porosity was proposed.

Results The minimum porosity of the unit preform in the final compaction stage was found to be 26.1% by using the 3-D four-direction preform unit pore model and parameters (Tab. 1). A universal tensile testing machine was used to perform compaction and densification experiments on the preforms of different sizes. Resin curing was performed on the preform under different compression loads, before the pore morphologies were observed. The results show that the compaction process of the preform consists of three stages, i.e. initial linear, nonlinear and final linear. In the initial linear stage, the height of the preform was compressed rapidly by small pressure, the load increases and the height decreases slowly in the nonlinear stage, and in the final linear stage, the load was increased while the height of the preform does not change. The porosity in the compaction process was obtained using the weighing method, and the mapping relationship between the height and porosity of the preform was obtained. The compression load and height variation curve of the three groups of preform with different bottom areas and the same height was showed, and the compression load of the three groups of experiments approximately increased by multiple times (Fig. 10(a)). The porosity decreased with the decrease of the height of the preform (Fig. 10(b)). When the height was kept constant, the porosity of the preform reached the minimum value of 27.4%. The compression load and height variation curve of three groups of preform with different heights and the same base area was reveal, and the compression load of the three groups of experiments was approximately equal (Fig. 11(a)). The minimum porosity of the preform at the compaction and densification stage was 27.9%, 28.4% and 28.7%, respectively (Fig. 11(b)). The experimental results show that the maximum error between the theoretical model and the actual minimum porosity was 2.6%.

Conclusion The experimental results verify the feasibility and correctness of the 3-D four-direction C/C soft-hard blended preform unit pores, which were observed and virtually constructed in two dimensions and four directions of xoy plane and xoz plane. At mesoscopic and microscopic scales, the influences of fiber shape and cross section shape on the porosity of the preform under load were studied. The mapping relationship between fiber size change and porosity was established by geometric modeling, and the size coefficient affecting the porosity was proposed to make the final porosity of the preform designable. At the same time, the compaction and densification process law of the 3-D four-direction preform was revealed, The results show that the final linear stage determines the porosity of the preform. The modeling method can also be applied to the pore model of the preform fabric of the integrated piercing fabric and the 3-D orthogonal fabric, providing theoretical guidance for the regulation and prediction of the final porosity of the preform fabric.

Dyeing and Finishing & Chemicals

Recycling treatment of dyeing wastewater by metal organic framework/graphene composite membrane based on photothermal utilization

LI Jingzi, LOU Mengmeng, HUANG Shiyan, LI Fang

Journal of Textile Research. 2023, 44(09):  116-123.  doi:10.13475/j.fzxb.20220800301

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Objective With the goal of reducing pollution and carbon, efficient and low-cost photothermal wastewater recycling technology has attracted more attention. Solar interfacial evaporation is considered a green and sustainable water treatment technology for treating wastewater by absorbing solar energy to convert light energy into heat energy. However, the photothermal efficiencies of most photothermal carbon materials are dissatisfactory. Therefore, in order to improve the photo-thermal utilization rate, a metal organic framework(MOF)/graphene photothermal composite material with good photothermal performance was prepared by a vacuum filtration method. The prepared material was used to treat dyeing wastewater and recycled pure water by interfacial evaporation.

Method The graphene-based MOF material was prepared by in-situ growth method and deposited on a hydrophilic polyvinylidene difluoride (PVDF) based membrane surface as a photothermal layer to facilitate the evaporation of fresh water and rejection of pollutants. Because of the selectivity of the prepared G-ZIF membrane, only allowed water vapor was to pass through the membrane pores, and non-volatile organic matters were thus rejected. In addition, the microstructure and optical properties of the membrane materials were characterized, and the photothermal properties and wastewater evaporation performance were studied.

Results The results showed that the graphene surface changed from a two-dimensional layer-layered structure to a three-dimensional regular polyhedral crystal structure after in-situ growth of ZIF-8, which nucleated uniformly on the graphene surface and tightly encapsulated flake graphene (Fig. 1). According to the results of X-ray diffraction and Raman spectroscopy, ZIF-8 has been successfully loaded on the surface of graphene and has similar characteristic peaks to ZIF-8 (Fig. 2). The loading of ZIF-8 greatly increases the specific surface area of graphene up to 1 096.50 m²/g, thus providing more evaporation interfaces (Fig. 4). Furthermore, the optical performance analysis showed that the PVDF membrane had poor light absorption capacity, while the G-ZIF absorbance was about 2 times higher than that of the original graphene membrane, indicating the good optical property. Under the light radiation of 1.0 kW/m², the G-ZIF membrane surface temperature rose to 97.6 ℃ that is far higher than that of the PVDF membrane, demonstrating its excellent photothermal conversion property (Fig. 5). The test of pure water evaporation performance showed that the pure water evaporation rate of G-ZIF membrane reached 1.34 kg/(m²·h) under one sun illumination, and the photothermal efficiency was 91.2% (Fig. 6). The recycling treatment of printing and dyeing wastewater showed that each square meter of G-ZIF membrane could recover 3.19, 3.37 and 2.99 kg of pure water from the three types of printing and dyeing wastewater, respectively, with photothermal utilization rates of 83.3%, 87.9% and 78.4% (Fig. 7). After photothermal treatment, almost all dyes were removed, the color retention reached 99.9%, and the COD removal rate of wastewater was over 99.6%. After evaporation, the concentration of salt ions in distilled water was reduced to 0.01-0.84 mg/L, which is far lower than the concentration of ions in drinking water set by the World Health Organization. Meanwhile, the salt rejection reached 99.9% (Fig. 8). In addition, the photothermal performance of the G-ZIF composite membrane was stable, and the flux did not decrease significantly after 7 times consecutive operations (Fig. 9).

Conclusion A graphene/MOF-based photothermal material (G-ZIF) was prepared, which can efficiently produce pure water from synthetic dyeing wastewater. The porous microstructure of the G-ZIF membrane not only provides more surface area for water vapor but also improves light absorption. In the process of dyeing wastewater treatment, the concentrations of organic-inorganic pollutants and salt decreased significantly after treatment. The results showed that the G-ZIF membrane has the advantages of high evaporation rate, high photothermal conversion efficiency, and good performance stability. By simply modifying graphene materials with MOF, the photothermal properties of two-dimensional carbon-based materials are significantly improved, implying potential application values for textile wastewater purification.

Preparation of three-dimensional ping-pong chrysanthemum-like CdS/BiOBr composite and its application on photocatalytic degradation of Rhodamine B

LI Hongying, XU Yi, YANG Fan, REN Ruipeng, ZHOU Quan, WU Lijie, LÜ Yongkang

Journal of Textile Research. 2023, 44(09):  124-133.  doi:10.13475/j.fzxb.20220811701

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Objective The energy crisis and environmental pollution are the two major tests facing mankind. Nitrogen-containing dyes with chromophores have stable chemical properties, which can darken the color of water bodies and affect the light transmission and are hazardous in causing genetic mutations. BiOBr has a good visible light response, but its forbidden band width is slightly larger, the visible light utilization is low, and the photogenerated carriers are prone to compounding. The combination of CdS and BiOBr is believed to have the capacity for the effective separation of electrons and holes to increase the visible light utilization to improve the photocatalytic performance.

Method BiOBr nanosheets were prepared by the solvothermal method, followed by the preparation of the CdS/BiOBr composites by growing CdS particles directly on the layered BiOBr surface by the hydrothermal method, where the morphology of the composite catalysts was adjusted by adjusting the molar ratio of the two. The prepared photocatalysts were characterized by transmission electron microscope(TEM), X-ray diffraction(XRD), UV-Vis DRS, etc., and the degradation effect and stability of the catalysts on Rhodamine B (RhB) were investigated by visible light catalysis experiments. The main active substances in the degradation process were identified by active species capture experiments.

Results When the molar ratio of CdS to BiOBr was 1∶3, the catalyst CdS/BiOBr (1∶3) morphology showed a three-dimensional ping-pong chrysanthemum-like hierarchical structure, and the CdS nanoparticles were uniformly distributed on the surface of BiOBr petal-like flakes (Fig. 2(e) and (f)). Peaks associated with Bi, Br, O, Cd and S were observed in the EDS spectrum, confirming the presence of these six elements in the composite (Fig. 3(a)), the successful formation of heterojunction between CdS and BiOBr was confirmed by the analysis of TEM (Fig. 3(b) and (c)), and the XRD spectrum indicated that the CdS/BiOBr composite was successfully prepared with high purity (Fig. 4). The catalyst CdS/BiOBr(1∶3) showed a significant red shift compared with both pure BiOBr and pure CdS, and in addition, the absorption intensity of the catalyst was significantly enhanced at 550-800 nm (Fig. 5(a)). The forbidden band widths of BiOBr and CdS were 2.70 eV and 2.28 eV (Fig. 5(b) and (c)), respectively, and the CB and VB positions of 0.33 eV and 3.03 eV for BiOBr and -0.59 eV and 1.69 eV for CdS were calculated according to equations. The fluorescence spectrum intensity of the catalyst CdS/BiOBr (1∶3) was significantly weaker compared to that of the pure BiOBr (Fig. 6), and the specific surface area of the catalyst CdS/BiOBr (1∶3) was increased compared with that of the pure component BiOBr (Fig. 7). The results of the visible photocatalytic experiments demonstrated that the light degraded 99.5% of RhB for 120 min with a primary kinetic constant of 0.044, which was 3.67 times the rate constant of pure BiOBr (Fig. 8). After 7 cycles of photocatalytic degradation of RhB, the photocatalytic activity of the three-dimensional ping-pong chrysanthemum-like catalyst CdS/BiOBr(1∶3) still reached 90.1%, and no significant changes were found in the XRD diffraction peaks of the catalyst before and after the reaction (Fig. 9-11); and by adding EDTA and BQ to the photocatalytic system, the degradation activity of RhB was obviously inhibited and the degradation rate constant was significantly reduced (Fig. 12). The EPR results showed that a large number of h⁺ and ·O₂^- radicals were indeed generated in the photocatalytic degradation reaction, which confirmed the accuracy of the radical capture experiment (Fig. 13).

Conclusion In summary, a regularly combined three-dimensional ping-pong chrysanthemum-like CdS/BiOBr photocatalyst was synthesized for the first time, which exhibited excellent photocatalytic activity and cycling stability in the photocatalytic degradation of Rhodamine B. This was attributed to the fact that the prepared CdS/BiOBr catalyst showed higher visible light absorption efficiency, lower electron-hole pair complexation chance, and a larger specific surface area of the three-dimensional ping-pong chrysanthemum-like layered structure, which provided sufficient transport paths for reactant molecules and facilitates the transfer of interfacial photogenerated carriers, thus improving the catalytic efficiency of the photocatalyst.

Preparation of zirconium-based organic framework material/activated carbon fiber composites and their degradation properties

LIU Qixia, ZHANG Tianhao, JI Tao, GE Jianlong, SHAN Haoru

Journal of Textile Research. 2023, 44(09):  134-143.  doi:10.13475/j.fzxb.20220706001

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Objective Mustard gas, as a typical and widely-used chemical warfare agent, poses serious damage to human beings and ecosystem ascribing to their high toxicity and fast-diffusion. How to effectively protect against these hazards is the focus and challenge of the current research. Carbon-based materials, especially activated carbon fibers, have been applied for producing breathable chemical protective clothes, benefitting from their high adsorption capacity, fast adsorption rate, and extensive sources. However, the removal of toxic chemical agents by activated carbon fibers is mainly based on the physical-adsorption process, which is easy to reach adsorption saturation and cause secondary pollutions. Endowing the existing activated carbon fibers with high-efficient catalytic performance against chemical agents seems an effective route to tackle this problem.

Method The commercial activated carbon fibers were first cleaned and then deposited with zirconia sol through suction filtration at ambient temperature. Subsequently, the preprocessed activated carbon fibers (ACF) were sequentially immersed into ZrCl₄ and terephthalic acid solutions at 130 ℃for 15 min to enable the layer-by-layer growth of zirconia-based metal-organic frameworks(Zr-MOF)on the fiber surface. Different consecutive cycles(3, 6, 9, 12, 15, 18 and 21) were performed to prepare various Zr-MOF/ACF composites using the similar procedure. The surface morphologies and micro-structures of the resultant fibrous composites were characterized using scanning electron microscopy(SEM), X-ray diffraction(XRD), and chemisorption-physisorption analysis. Moreover, the degradation and mechanical properties of the composites were tested.

Result It was found that a layer of microscopic zirconium nanoparticles was uniformly loaded on the surface of activated carbon fibers after pre-treated using zirconia sol. After the subsequent layer-by-layer assembly process, the synthesized Zr-MOF particles were loaded onto the fiber surface, and amount of loading was proportional with cyclic number (Fig. 3). By comparing with XRD standard spectrum, it was seen that the characteristic peaks appeared at 2θ= 7.03°, 25.78° were consistent with that of UiO-66, revealing the successful synthesis of Zr-MOF on the fibrous composites(Fig. 4). As presented in the XPS spectrum(Fig. 5), the contents of lattice oxygen, zirconium and C=O increased in line with the cyclic numbers, demonstrating the occurrence of coordination reaction during the layer-by-layer assembly process. The increase of Zr-MOF particles loaded on the fiber surface enabled an obvious decrease of surface area and total pore volume of the resultant fibrous composites(Fig. 6 and Tab. 1). 2-Chloroethyl ehtyl sulfide(CEES)was introduced as the simulator of mustard gas to detect the protective performance against chemical agents of the resultant activated fibrous composites. The in-situ growth of Zr-MOF on the surface of ACF significantly improved the removal performance of CEES, and the degradation of CEES was also significantly improved with the increase of the cyclic numbers(Fig. 7). After 18 cycles, the degradation rate of CEES reached 84.23% after 24 h. After 3 cycles, the removal rate of CEES still reached 60% after 12 h, revealing the favorable recyclability of the obtained Zr-MOF/ACF composites(Fig. 7). In comparison with original ACF, the mechanical strength of the resultant fibrous composites was obviously increased(e.g., 80.99 % for Zr-MOF/ACF15). However, the mechanical performance displayed a declined with the increase of cyclic numbers (Tab. 2).

Conclusion The commercial activated carbon fibers were robustly endowed with high-efficient catalytic performance against chemical agents by a layer-by-layer self-assembly method, and the loading contents could be regulated by increasing the cyclic numbers. The resultant Zr-MOF/ACF composites exhibited outstanding degradation performance against CEES, and the degradation rate could reach 86.02 % for 18 cycles. The removal of CEES by Zr-MOF/ACF composites was proved to be mainly through degradation process. After three times consecutive circulation, the degradation rate of CEES by Zr-MOF/ACF composites could still maintain 63.47 %, demonstrating the favorable recyclability of the resultant activated carbon fiber composites. After the comprehensive consideration of the degradation performance, tensile strength, and sample preparation efficiency, Zr-MOF/ACF-15 with a degradation rate of 83.08 % within 24 h and a tensile strength of 0.4 MPa was preferred. The integration of outstanding degradation performance, enhanced tensile strength, and easy preparation enabled the resultant Zr-MOF/ACF composites with broad application prospect.

Preparation and properties of flame retardant cotton fabrics by layer-by-layer assembly of polyvinylphosphonic acid and polyethylene polyamine

QIAN Yaowei, YIN Lianbo, LI Jiawei, YANG Xiaoming, LI Yaobang, QI Dongming

Journal of Textile Research. 2023, 44(09):  144-152.  doi:10.13475/j.fzxb.20220709101

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Objective Cotton fibers are ideal materials for clothing, furniture and bedding because of good hygroscopicity, wear comfort and biodegradabity. However, cotton fabrics are flammable and have been identified as one of the main sources of household fire. This research aims to enhance the flame retardance of cotton fabrics using a flame retardant system composed of polyvinylphosphonic acid (PVPA) and polyethylene polyamine (PEPA) to achieve environmental-friendly flame retardant cotton fabrics.

Method Vinylphosphonic acid (VPA) was used as a monomer to synthesize PVPA, and a flame retardant coating system on cotton fabrics with PVPA and PEPA was constructed via layer-by-layer assembly (LBL). The surface morphology, flame retardancy and physical properties of coated cotton fabrics were measured, and the flame-retardant mechanism of gas phase and condensed phase were explored.

Results In this study, the VPA was successfully prepared using 2,2'-azobis[2-methylpropionamidine] dihydrochloride (AIBA) as initiator, and its conversion rate reached 93.6% by means of ³¹P nuclear magnetic resonance (³¹P NMR) (Fig. 2). When the PVPA/PEPA flame-retardant system was prepared by the layer-by-layer assembly method, the flame retardant coating formed evenly on cotton fabric surfaces through the measurement of Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) (Fig. 3 and 5). When the number of finishing layers reached 12, the weight gain of the coated cotton fabric was 38.0%, and the limiting oxygen index (LOI) of flame retardant cotton fabric reached 29.8%. The research showed that the flame of the coated cotton fabric self-extinguished and the damaged length was 31 mm during the vertical burning test. After 10 standard washing cycles, the LOI value of the coated cotton fabric was 27.1% (Tab. 1). The cone calorimetric test showed that the peak heat release (PHRR) and total heat release (THR) of coated cotton fabrics decreased by 16.8% and 19.7%, respectively, lower than that of uncoated cotton fabrics (Fig. 7). The above results indicated that the coated cotton fabric had good flame retardant property. Accordingly, the volatile components of flame retardant coated cotton during thermal degradation were studied by the combination technology of thermogravimetric analyzer and infrared spectrometer (TG-IR) (Fig. 9), and the structure of residual carbon after vertical burning test was investigated by SEM and X-ray photoelectron spectroscopy (XPS) (Figs. 10 and 11). These results indicated that the flame-retardant coating played a key role in the cohesive phase flame retardant process, when cotton fabrics were burned, forming a stable carbon insulation layer, insulating the transfer of heat and gas, and inhibiting the occurrence of combustion reactions. Besides, it was found that from the test results of electronic fabric strength machines and whiteness meters, the tensile strength and whiteness values decreased from 730.7 N and 89.2 % to 512.6 N and 74.2%, respectively, after the flame retardant coating, which suggested the flame-retardant system had a small impact on the breaking strength and whiteness of the fabric (Tab. 4). It ascribed that the alkaline PEPA reduce the acid embrittlement caused by VPA on cotton fabrics in the flame-retardant coating system.

Conclusion A flame-retardant coating was prepared by the layer-by-layer assembly method, which was applied to flame retardant coated cotton fabrics, achieving good physical properties of cotton fabrics while flame retardant finishing, and meeting the requirements of household curtains, interior decoration, and industrial textile fabrics.

Water-repellent finishing of cotton fabrics with silica sol and short-chain fluorinated polyacrylic ester

DU Shan, WEI Yunhang, TAN Yuhao, WU Ting, LI Yong, YANG Hongying, WANG Ming, ZHOU Weitao

Journal of Textile Research. 2023, 44(09):  153-160.  doi:10.13475/j.fzxb.20220810601

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Objective Water-repellent cotton fabrics have attracted widespread attention because of their exceptional innovative functionality and promising applications. However, the poor adhesion of particles to construct roughness and the refractory fluorinated finishing agents with the carbon atom number greater than 8 lead to poor washing durability and environmental pollution. Therefore, a novel eco-friendly short-chain acrylate polymer-based coating with silica gel was developed to endow cotton fabrics with superior water-repellent performance, washing durability and acid-alkali resistance.

Method In this coating system, silica gel and short-chain fluorinated polyacrylic acid were introduced into the cotton fabric through facile chemical reaction for achieving high water-repellent performance. The process to obtain hydrophobic cotton fabric was optimized. The obtained hydrophobic cotton fabric was next characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry (TG) for its surface morphology and structure. The application properties were investigated by surface contact angle, acid and alkali resistance and fabric style tests.

Results The critical process parameters, such as silica sol concentration, short-chain fluorinated polyacrylate concentration, pre-baking temperature and baking temperature, were investigated on the repellency of cotton fabrics. The optimal process conditions were determined as follows: 0.3% (o.w.f) of silica sol, 30 g/L of short chain fluorinated polyacrylic ester, 20 min of soaking time, 80 ℃ of pre-baking temperature and baking at 170 ℃ for 2 min (Fig. 1). With such optimal process, the cotton fabric exhibited hydrophobic character of the surface (water contact angle changed from 42° to 155.6°, Fig. 2). Surface morphology characterized by SEM indicated acrylate polymer possessing preferable film form ability, beneficial to reduce the surface tension and to improve water repellency (Fig. 3). With the presence of Si—O—Si group and C—F group (Fig. 4), the improved water repellency was verified to be due to the introduction of silica gel and short-chain fluorinated polyacrylic acid. Thermogravimetric analysis (Fig. 6 and Tab. 1) also confirmed the introduction of silica gel and short-chain fluorinated polyacrylic acid, which was consistent with the IR results. The obtained hydrophobic cotton fabric demonstrated superior water durability, with water contact angle greater than 90°, even after 50 washing cycles (Fig. 7). In neutral solutions, cotton fabric exhibited the best hydrophobic effect, with water contact angle of 155.6°. This hydrophobic performance appeared some diminution with acid/basic enhancement. With the action of strong acids (pH=3) and alkalis (pH=12), the finishing cotton fabric still exhibited hydrophobic property, with water contact angles at 100° and 93°, respectively. Although hydrophobic finishing of cotton fabric caused a slight decrease in drapability, elasticity and smoothness, the crease recovery rate of cotton fabric was greatly improved (Tab. 2). This greatly compensated for the deficiency of cotton fabric.

Conclusion Under neutral conditions, the contact angle of the water-repellent cotton fabric could reach 155.6° with superior thermal stability, softness and crease recovery. After 50 washing cycles and acid-alkali reaction, the water contact angles were still greater than 90°, indicating superior hydrophobicity. Meanwhile, the finishing process has little influence on the fabric style, apart from the improved crease recovery. This eco-friendly short-chain acrylate polymer-based coating with silica gel provides a new strategy for fabricating green water repellency systems without using scarcely degradable materials but with superior water repellency, washing durability and acid-alkali tolerance.

Preparation and properties of polyactic acid nonwoven substrate touch-sensing electronic textile

XU Ruidong, WANG Hang, QU Lijun, TIAN Mingwei

Journal of Textile Research. 2023, 44(09):  161-167.  doi:10.13475/j.fzxb.20220503701

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Objective Touch-sensing devices are the most promising technology for human-computer interaction. However, current touch-sensing devices still suffer from poor bending resistance and low comfort due to the use thin films or silicone as substrate. Herein, this work proposes a novel strategy to breakthrough above bottleneck. PLA nonwoven materials with skin-friendly is used as substrate and combined with intrinsically flexible ionic hydrogels to develop a touch-sensing electronic textile with wearable comfort and resistance to deformation interference.

Method The touch-sensing electronic textile is a typical sandwich structure, where the ionic hydrogel is encapsulated by the upper and lower polylactic acid nonwoven layers. The ionic hydrogel is polymerized by acrylamide and lithium chloride under a thermal environment. It is noteworthy that the upper PLA nonwoven layer possesses conductive properties, which is a result of the uniform deposition of graphene nanosheet layers on the PLA fiber surface using the core-absorption deposition effect. The touch-sensing electronic textile has precise touch localization capability, which stems from the construction of a uniform low-voltage AC electric field on the surface of the touch-sensing electronic textile. When the human body touches the surface of the electronic fabric, a coupling capacitance is formed, which trigger the flow of current from the electrodes to the touch point. Owing to the surface capacitive sensing mechanism and the selected intrinsically flexible material, the touch-sensing electronic textile is resistant to bending and comfortable to wear.

Results The results show that the touch-sensing electronic textile can recognize the locations of touch points, and an example test was designed for illustration. Five points were selected at equal intervals on the fabric named 1#—5#, respectively. When the points 1#—5# were touched on, the touch current monitored by the A1 ammeter showed a decreasing tendency (from 8.08 μA to 7.61 μA), while the A2 touch current demonstrated an increasing trend (from 7.68 μA to 8.05 μA). It is noteworthy that the touch currents monitored by the two ammeters at the midpoint are approximately equal in magnitude at 7.85 μA and 7.84 μA, respectively (Fig. 3). Response speed is a crucial parameter to wearable interaction devices. As excepted, the touch-sensing electronic textile demonstrated an excellent response speed. In particular, the touch-sensing electronic textile showed response time of about 25 ms. Besides, the touch-sensing electronic textile has brilliant release time of about 31 ms. This result illustrates that the touch-sensing electronic textile has great advantages in the wearable field (Fig. 4). At the same time, the touch-sensing electronic fabric showed stable touch performance. Three different sliding velocities (40, 100 and 200 mm/s) were selected to observe the change law of touch current. The results revealed that the maximum fluctuation of touch current at the same slip speed was only 5 % (Fig. 5). In addition, the touch sensing electronic fabric illustrated bending resistance. The touch-sensing electronic textile was subjected to 0, 50, 150, 300 and 500 bending cycles, respectively. The midpoint of the touch-sensing electronic textile was selected as the touch point to monitor its current changes. The touch current at the midpoint was 7.86 μA, when no bending deformation was applied. Then the touch currents at the midpoint were 7.97, 7.96, 7.95 and 7.98 μA when different cycles of bending deformation were applied sequentially. The above results suggested that the touch-sensing electronic textile had anti-deformation characteristics (Fig. 6). Further, thermal and humid comfort is an important characteristic of wearable devices and a key index to evaluate the microenvironment of the wearable interface. After the touch-sensing electronic textile was attached to the arm for a period of time, the skin surface morphology was observed (Fig. 7). After wearing the touch sensing electronic fabric for 48 h, the surface temperature of the covered skin does not change significantly, which proves that the nonwoven material-based touch sensing electronic fabric has excellent thermal and wet comfort.

Conclusion The touch-sensing electronic-textile can accuracy locate and recognize the touching points, attributing to the surface capacitive touch-sensing mechanism. Meanwhile, the touch-sensing electronic-textile exhibits excellent response speed (< 25 ms), mechanical stability and anti-interference properties. In addition, the touch-sensing electronic-textile exhibits excellent wearing comfort by virtue of the polyactic acid nonwoven substrate material. As a proof-of-concept, the touching controllers have been fabricated to achieve real-time game control function. Based on this, this work opens a new path for flexible touch sensing devices and has great potential in the field of wearable interaction.

Apparel Engineering

Parametric design modeling and implementation of patterns for knit sweaters

LI Yuxian, WU Xiaowen, WU Guangjun, CONG Honglian

Journal of Textile Research. 2023, 44(09):  168-174.  doi:10.13475/j.fzxb.20220703701

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Objective Parametric platemaking is widely used in the rapid construction of clothing patterns, and the rapid design process is becoming more and more mature, but the forming process of knitted sweater is complex, and the parametric platemaking methods of existing patterns are difficult to apply. Based on the principles and methods of conventional clothing pattern design, the design of the basic patterns of knit sweaters was carried out in combination with the forming process, and the parametric platemaking method in the design process was discussed for improvement of the digital design of knit sweaters.

Method The basic patterns of knit sweaters were made based on the clothing pattern design method, the relationship between the patterns and the human body parameters was discussed, and the key points of each part were determined. The fitting constraints of the neckline curve, armhole curve and sleeve mountain curve were then carried out, the mathematical relationship existing in the fitting process was discussed, and the key data in the curve fitting process were determined. The parametric design software was utilized to constrain the basic patterns and to determine the constraint data and user parameters of the fit sweater. The feasibility of the parametric design method was verified by making the finished product on the computerized flat knitting machine.

Results Based on the principle of woven garment plate making, the data of length, bust, sleeve length and sleeve width were used as the basis to construct the basic plate of knitted sweater, taking into consideration of the sweater forming process. The curve part of the sweater needed to be set flat and retracted needle segment, and the correction factor was adopted to finely adjust the local size (Fig. 1). In the process of parametric design, the sweater curve was further decomposed by arc, and in order to match the shape of the neckline and the change trend of curvature, the curve mostly adopted a three-stage retracting needle process. For the neckline and the armhole, the curves were divided into three segments, and the formula was converted after setting the key point data of each part, and the complex spline curve was converted into a multi-terminal single arc. The arc length of the front neckline curve was related to x₁, y₁ and the angle θ₁ (Fig. 4). The arc length of the front armhole curve was related to y₂, x₂ and the angle δ₁ (Fig. 6(a)), and the arc length of the rear armhole curve is related to y₃, x₃ and the angle φ₁ (Fig. 6(b)). For the sleeve top curve, the Bezier curve model was used for parametric design, generating the required curve according to the specification of the control point coordinates (Fig. 8). Using the parametric platemaking software, the geometric constraints and annotation constraints of the basic plates of sweaters were carried out, and the expressions of each constraint object were obtained according to the platemaking principle (Tab. 2), and then the user parameters were generated according to the variable parameters, and finally the complex plate change principle was converted into simple user language. An example fitted sweater using the parametric platemaking method of sweater was used, and the size specifications of the knit sweater was shown to meet the design requirements and the loop has no bad stretching state (Fig. 13).

Conclusion In the design process of knit sweater, the arc fitting model is proved useful to constrain the neckline curve and the armhole curve, and the Bezier curve model can be adopted to constrain the sleeve curve. Based on the mathematical and position relationship between parts, the parametric variant design of knitted sweaters is carried out, and then the machine process is quickly generated in combination with dimensional data. After data processing and transformation, the size specifications of each part of the knitted sweater plate meet the requirements, and it is feasible to be produced on the computerized flat knitting machine, which can reduce repeated calculation and proofing time, and improve the digital design level of sweaters.

Detection of human shoulder feature points based on image analysis

DENG Zhongmin, WANG Jiankai, JIN Xiaoning, WEI Wantong, YU Dongyang, KE Wei

Journal of Textile Research. 2023, 44(09):  175-179.  doi:10.13475/j.fzxb.20220707001

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Objective Human body size data plays an important reference role in measuring human body type. Along with the continuous development of computer technology, non-contact anthropocentric methods based on two-dimensional images were reported to obtain human body size data, the accuracy of which depends largely on accuracy of the feature points of each part detected using these methods. For the shoulder, which is a feature part with fewer obvious feature point characteristics, the existing two-dimensional detection methods leads to large errors in the feature points, calling for further improvement.

Method In order to address the problems of false detection, missed detection, and large detection errors of the existing detection algorithms for shoulder feature points, an improved detection method for shoulder feature points based on human contour coding was proposed. The method was capable of determining the length of the feature chain code string by the size of the image occupied by the human body and selecting the feature points of the shoulder by a search method of feature partitioning, feature region traversal, and dynamic screening of the chain code string with geometric features. After acquiring the shoulder feature points, the shoulder width values were calculated based on the location of the feature points and compared with the actual manually measured shoulder width values to analyze the experimental results.

Results In this research, a total of 100 young testers of different body types (50 males/50 females) were selected to test the feasibility of the method under the same shooting environment. The experimental study showed that the method can quickly and accurately identify the shoulder feature points of the human body, and the locations of the selected feature points exist and are single, reducing the occurrence of false detection and omission (Tab. 1). The average error derived was only about 3%, which verifies the feasibility of the method.

Conclusion While maintaining the advantage of the low cost of the 2-D measurement method, it also greatly improves the efficiency of 2-D human shoulder width size detection, enabling it to provide more accurate data support in the subsequent human body shape research, clothing matching and professionalization, and other related fields.

Finite element analysis of supportive performance and dynamic comfort of sports bra

SUN Yue, ZHOU Lingfang, ZHOU Qixuan, ZHANG Shichen, YICK Kit-lun

Journal of Textile Research. 2023, 44(09):  180-187.  doi:10.13475/j.fzxb.20220706601

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Objective Without the adequate support and protection, females' breasts would suffer from troubles such as ligament rupture and mastitis during physical activities. Wearing sports bra could limit the movement of breasts, thus reducing the pain or discomfort during exercises. In order to predict and evaluate the function and comfort of sports bra, as well as to reduce the process of product design and development for intimate apparel industry, a dynamic contact finite element (FE) modeling system for human body and sports bra was constructed to evaluate the performance of sports bra with different design features from the aspects of control level and contact pressure.

Method The data of female chest was obtained by 3-D body scanner to obtain the geometric model of breasts, body torso and sports bra. The method of interference fit was adopted to simulate the pre-tension of the breasts and sports bra after wearing. The displacement of the torso obtained from the motion capture system was used as the boundary condition to drive the finite element model under the gravity field. The motion of the breasts after wearing sports bra was simulated by this FE model and a parametric study was also conducted for different material parameters of the sports bra.

Results The simulated results from the constructed FE contact model between human body and sports bra was validated with the motion capture experiment in terms of the nipple displacement. The calculated relative average absolute error was 4.13% (braless condition) and 5.15% (wearing sports bra) which denoted the accuracy of the FE method. Based on the numerical model, a parametric study was conducted to investigate different fabric materials on the control performance and wearing comfort. A virtual sports bra (SPB2) with higher Young's modulus, which was 5 times than the original tested sample SPB1, was introduced into the FE contact model. The maximum motion displacement of nipple when wearing SPB1 was 235.043 mm, while that was 228.861 mm for SPB2. The control effect of breast movement by SPB2 was increased by only 2.6% when comparing with SPB1. With regards to the contact pressure, it was revealed that in a static state, the shoulder strap has the highest contact pressure, followed by the lower under-band and the bottom of breasts (Tab. 3). It is mainly because the effects of gravity lead to the sagging of the breasts, thus the shoulder strap produces a corresponding force to support the breasts. The dynamic contact pressure extracted from different positions of human body showed that large fluctuations were detected at the bottom breasts for both SPB1 and SPB2, appearing periodically. The dynamic pressure in the position of shoulder straps, under-band and bottom breasts of SPB2 (0.30-1.19 kPa) was all higher than SPB1 (1.56-4.65 kPa) (Fig. 10), which was out the range of comfort pressure of human body (1.96-3.92 kPa). The results showed that although the higher Young's modulus of sports bra could strengthen the control performance slightly, the corresponding increase of contact pressure was higher than the comfortable clothing pressure range of the human body, which could easily cause the human body feel discomfort.

Conclusion The breast displacement and the dynamic contact pressure between breasts and bra were evaluated quantitively by the proposed numerical simulation method. The supportive performance and wearing comfort by sports bra with different material properties were compared. This model can be utilized to investigate the complicated contact mechanism between the breasts and sports bra during physical activities, thus comprehensively guiding the fabric selection of sports bra from the perspective of functionality and comfort. The intimated apparel industry will be benefited by the proposed method in terms of optimizing the design for sports bra and shortening the development duration.

VR-oriented personalized head and face texture generation technology of dressed human body

CHEN Jinwen, WANG Xin, LUO Weihao, MEI Chennan, WEI Jingyan, ZHONG Yueqi

Journal of Textile Research. 2023, 44(09):  188-196.  doi:10.13475/j.fzxb.20220706301

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Objective In recent years, the meta-universe concept based on virtual reality (VR) augmented reality and mixed reality technology has developed vigorously. Especially, virtual avatars based on users' personalized customization are widely used in virtual reality. From the perspective of technical composition, the realization of three-dimensional dressing of the human body has become more common. However, it is still a proposition worthy of further exploration to endow the user's head and facial features to the dressed human body and apply them in virtual reality and even metauniverse scenes.

Method By inputting the user's single frontal face image, detailed expression capture and animation (DECA) neural network was adopted to generate the corresponding 3-D head model with initial texture. The initial texture was then corrected by illumination, and the skin color of the main area and edge of the face was extracted by a given mask. The facial texture was in-painted twice to obtain a complete face texture. Using the face texture as a style image and using the original body texture of the dressed human body as a content image, style transfer was carried out by progressive attentional manifold alignment (PAMA) neural network.

Results In the analysis of the influencing factors of facial texture illumination correction, when the convolution kernel was 5×5, the difference of local brightness V₁ between the two sides was decreased by 23.1% (Fig. 2), which shows that illumination correction can reduce the brightness difference of the user's facial texture and improve the illumination uniformity of the face with the best scale factor being 5. In the analysis of automatic facial texture restoration, when the weight coefficient was 0.4, the head and neck texture was closest to the facial skin color. When repairing, the combination of two methods was shown to be the best (Fig. 12(c)). The results of texture restoration for different users using the method were presented (Fig. 13), where it can be seen that after the original texture was restored and completed, the texture of the user's head and face model was similar to the neck skin color in the original three-dimensional dressed mannequin with natural boundary fusion, and the original facial information of the user was retained. The comparison between the results of this method and other head and face texture restoration methods based on a single image was shown (Fig. 14). It can be seen that the generated results of this method have the highest similarity with users, and it took the shortest time (8 s per person) under the same configuration. In the analysis of style transfer of body texture, using the PAMA style transfer network could make the skin texture of the body texture in virtual reality similar to that of the user's face texture (Fig. 15). In the application of VR, the rendering result of the user's dressed human body was displayed in various virtual scenes (Fig. 17). It can be seen that the model can present real light and shade effects in different indoor and outdoor lighting environments, demonstrating the practicability of this method in VR scenes.

Conclusion Based on the application of virtual reality, this paper presented a study on the generation of personalized head and face textures of dressed human body with a proposed technique of head and face texture fusion and restoration. By inputting a single frontal face image, a complete head and face texture and corresponding body texture can be generated, which solves the problem of natural fusion of head and face texture and body texture skin color from different sources and can meet the virtual fitting applications in various VR environments.

Machinery & Accessories

Dynamic simulation and finite element analysis of detaching roller linkage drive mechanism for cotton comber machines

FENG Qingguo, WU Aofei, REN Jiazhi, CHEN Yuheng

Journal of Textile Research. 2023, 44(09):  197-204.  doi:10.13475/j.fzxb.20230101101

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Objective This research aims to improve the long-lasting service and the reliability of the comber machine in cotton spinning. The mechanism of each part of the detaching roller at different velocities was analyzed to solve the problems caused by the fracture of the linkage parts of the detaching roller when working at a high velocity.

Method The first part of the research was focused on the dynamic simulations of the linkage gear of detaching roller based on the JSFA588 comber machine using a finite element (FE) analysis method. The three-dimensional (3-D) model of the linkage gear was established using SolidWorks software and then imported into Adams software. The curves of the force distribution of the linkage points at different velocities in a motion cycle were studied. The second part of this research concentrated on the FE analysis of the stress of each part of the linkage gear using Ansys Workbench software. The material properties of 45-carbon steel were assigned to the FE models and the maximum stress of each part at different velocities in a motion cycle was analyzed.

Results The change tendency of force in each part is the same in a motion cycle, but due to the existence of inertial force, the magnitude of force at the same index is different (Tab. 1). The peak force on each part increases with the speed of the comber machine (Tab. 2). The maximum stress of the eccentric sleeve was 66.565 MPa at 500 nippers/min (Fig. 4(a)); the maximum stress of the eccentric seat was 2.599 2 MPa ( Fig.4(b)); the maximum stress of the timing adjustment disc was 295.96 MPa (Fig. 4(c)); the maximum stress of the swing arm was 102.68 MPa, which is located at its lower end face (Fig. 4(d)); the maximum stress of linkage 2 was 38.667 MPa (Fig. 4(e)); the maximum stress of linkage 1 was 24.187 MPa (Fig. 4(f)); the maximum stress of the lower rocker, located at the round hole articulated with the linkage 1 was 4.718 7 MPa (Fig. 4(g)); and the maximum stress of the rocker was 101.62 MPa (Fig. 4(h)). All of the maximum stresses of the eccentric sleeve, eccentric seat, timing adjustment disc, swing arm, linkage gear 1, linkage gear 2, lower joystick and rocker were less than the allowable stress (400 MPa) in a motion cycle when the velocity of the comber was smaller than 500 nippers/min. The material strength of each part of the linkage gear of detaching roller was suitable for work. The maximum stress of the timing adjustment disc which was 415.98 MPa increased by 40.55% and 79.1%, respectively when the velocity of the comber was set to 600 nippers/min and 700 nippers/min compared to 500 nippers/min. The results showed that it has exceeded the allowable stress (400 MPa), which would lead to the fracture of each part of the linkage gear. Consequently, the comber machine was prone to be shut down. The tests were carried out according to the parametric requirements of the FE analysis on the JSFA588 comber machine, and the feasibility of the parameters was further verified (Tab. 6, Fig. 5 and Fig. 6).

Conclusion The influence of the device strength must be taken into account when the material property was confirmed. Conversely, in order to continue to increase the velocity of the comber machine, it is necessary to balance the influence of the material properties of each part and the cost.

Yarn state detection based on lightweight network and knowledge distillation

REN Guodong, TU Jiajia, LI Yang, QIU Zian, SHI Weiming

Journal of Textile Research. 2023, 44(09):  205-212.  doi:10.13475/j.fzxb.20220508801

Abstract ( 94 )   HTML ( 5 )   PDF (7047KB) ( 42 )   Save

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Objective The knotting machine in the circular weft knitting production line absorbs the yarn at the end of different yarn cylinders through the yarn guide tube, and sends the absorbed yarn to the knotting device to complete the knotting process. Aiming at the problem that it is difficult to detect the multi-state and multi-type yarn absorption in the yarn guide tube of the splitter, a detection scheme based on machine vision was proposed to realize the real-time monitoring of yarn number and color in the yarn guide tube of the knot machine to ensure the reliability of the joint.

Method In order to overcome the limitation of convenional yarn detection, an image classification method based on deep learning was proposed. 3 500 collected images were divided into 2 800 training sets and 700 test sets, and 560 images were separated from the training set as the verification set. Following that, a lightweight self-built student network was constructed by using superposition depth separable convolution. In order to overcome the defects of low accuracy and weak generalization performance of students' network, the combination training method of transfer learning and knowledge distillation was utilized to train the self-built network, and the final trained student network weight was deployed on the mobile terminal.

Results Experimental results showed that the teacher network using transfer learning had a verification set accuracy of more than 92% after the first round, and the convergence speed of the loss curve was also significantly accelerated (Fig. 9). When the student network was trained by knowledge distillation, the setting of loss weight α and distillation temperature T had no rule on the verification accuracy of the network. Compared with the student network verification accuracy of 95.7% before distillation, it was improved in general (Tab. 3). When the loss weight α was set to 0.2 and the distillation temperature T was set to 3, the best effect was achieved, and the top-1 accuracy on the verification set reached 99.57%. Comparative experiments of model reasoning were conducted on student network, teacher network and typical lightweight network before and after distillation (Tab. 4). The accuracy of the student network, which was originally 96.00% accurate on the test set, was improved to 99.28% after distillation. In addition, compared with the current typical lightweight model, the self-built lightweight student network had fewer parameters and less computation, which indirectly improved the forward reasoning time of the model. When the trained self-built network was deployed on the embedded terminal for actual test, the probability of a single yarn was higher than 70% (Fig. 11), while the probability of a double yarn was higher than 80%. The actual yarn detection accuracy rate was 98.86% after repeated experimental test on the yarn (Tab. 5). The difference in test accuracy between PC and embedded terminal was observed. The analysis showed that the PC side test was in the form of pictures taken before, while the embedded side test was in the form of actual video stream. On the other hand, the precision of weight parameters may be lost during the process of model quantization acceleration and deployment.

Conclusion The analysis result shows that, on the one hand, the PC side test is in the form of pictures taken before, while the embedded side test is in the form of actual video stream. On the other hand, the precision of weight parameters may be lost during the process of model quantization acceleration and deployment. It can be seen from the above yarn testing results that it meets the practical application needs and lays a solid foundation for promoting the application and popularization of the later knotting machine. In addition, the current yarn detection device is suitable for the knotting machine, but only it is necessary to optimize and upgrade the hardware and algorithm, useful in many occasions relating to yarn detection. Its lightweight size and low cost are undoubtedly progressed with commercial promotion value and significance.

Comprehensive Review

Application of silk fibroin-based biomaterials for drug delivery

LUO Yuanze, DAI Mengnan, LI Meng, YU Yangxiao, WANG Jiannan

Journal of Textile Research. 2023, 44(09):  213-222.  doi:10.13475/j.fzxb.20220500202

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Significance With the increasing incidence of chronic noncommunicable diseases (e.g. cancer), inflammation and diabetes, drug delivery systems with controlled release are developed and applied in clinical practice. Silk fibroin was studied widely for applications in the fields of tissue engineering and medicine because of its good biocompatibility and biodegradability. The research on the application of silk fibroin as drug carriers attracted much global attention. In order to expand and promote the clinical applications of silk fibroin materials in pharmaceutical field, this paper reviews the latest research progress of silk fibroin in drug delivery systems, with highlights on carrier types, preparation methods, drug loading types and application properties of silk fibroin drug delivery systems.

Progress As a controlled drug carrier, silk fibroin is an ideal candidate because of its unique chemical structure and aggregated structure, and its excellent biocompatibility and controllable degradation. Silk fibroin materials can be prepared into various forms, among which silk fibroin materials in the form of microspheres, hydrogels and microneedles exhibit efficient drug loading capacity and controllable release rate when used as drug carriers, resulting in the decrease of dosing frequency and improvement of the therapeutic efficiency. Silk fibroin-based drug delivery system not only can stably encapsulate various small molecule compounds, but also deliver biological macromolecules such as proteins and nucleic acids. Composite drug carriers developed by combining other materials can reduce the degradation of silk fibroin drug carriers in vivo and improve the drug availability. Furthermore, the alternating arrangement of hydrophilic and hydrophobic chains of the silk fibroin macromolecule provides a structure basis for regulating the molecular conformation and aggregation structure of silk fibroin materials. The crystal form and crystallinity of silk fibroin can be regulated by physical or chemical modification to control drug release or endow targeting ability to diseased cells, which can effectively improve the therapeutic efficiency of serious diseases and reduce the damage to normal tissue cells.

Conclusion and Prospect With the continuous exploration of the biological function of silk fibroin, some progress in silk fibroin-based drug release materials has been made in association with drug delivery forms, targeted therapy and drug availability. Silk fibroin as a drug carrier has been found to prolong the circulation time of drugs in the blood, reduce the frequency of drug use and alleviate adverse drug reactions of patients. These advantages provide important guidance for in-depth and sustainable development of silk fibroin in drug delivery application. However, there are still problems in the stability of the preparation of silk fibroin drug carriers and their drug loading capacity. The quality of silk fibroin varies greatly due to the different sources, such as varieties, seasons and regions. It is necessary to standardize the characteristics and extraction method of silk fibroin. Although silk fibroin drug carriers can be endowed with the capability of targeted drug delivery by physical or chemical modification, it may be attacked by the immune system at the initial stage of entering the body, leading to failure of targeted release. The accuracy and effectiveness of silk fibroin used as drug carriers still need long-term exploration and clinical trials. With the development of material science, chemical science and pharmacy, the research and application of silk fibroin-based drug delivery systems will be further continued.

Progress in preparation and application of graphene modified silk

HE Kaijun, SHEN Jiajia, LIU Guojin

Journal of Textile Research. 2023, 44(09):  223-231.  doi:10.13475/j.fzxb.20220401302

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Significance Fibers and fabrics are the main components of conventional wearable products because of its good flexibility, air permeability and mechanical properties. However, with the rapid development of science and technology and the improvement of people's living standards, the future textiles need to retain the advantages of conventional fibers and fabrics while providing them multi-functional and intelligent characteristics. Compared with other man-made chemical polymer materials, natural biomaterials have the advantages of being environmentally friendly, biodegradable, and sustainable among many others. Natural silk from silkworms has been used in clothing for thousands of years and can be continuously obtained and used in large quantities. Silk is a natural protein fiber with excellent mechanical properties, good flexibility, biocompatibility and biodegradability. Two-dimensional nano-graphene and its derivative materials with excellent thermal conductivity, biocompatibility and mechanical properties were synergistically combined with silk. By optimizing the interaction between silk and graphene materials, the properties and functions of silk can be further enhanced and enriched, and its applications in the field of textile and biomedical flexible wearables can be expanded. This paper reviews the latest research progress in graphene modified silk materials to identify research gaps for research.

Progress Because of the unique natural layered structure of silk and the excellent functionality of graphene material, graphene modified silk materials have been widely favored in the field of intelligent textiles. This paper firstly introduced the preparation methods of graphene modified silk. While retaining the natural structure and properties of silk, it can also endow silk with new functions. There are mainly two methods for attaching graphene and its derivatives uniformly and stably on silk, that is, internal modification and external modification. The internal modification mainly refers to the in vivo uptake of graphene materials by silkworms during their growth, including feeding method and in vivo injection method, and the external modification, also known as surface finishing method, includes dip-rolling coating method, dip coating method, spraying method, dry coating method and layer self-assembly method. The preparation methods of graphene modified silk materials were compared (Tab. 1), and the improvement of silk properties by graphene materials, including mechanical properties, electrical conductivity and multi-functional wearability, was reviewed. In addition, the applications of graphene modified silk in sensors, including respiratory sensor, gas sensor and infrared sensor, were scrutinized and summarized. It is believed that silk materials have great potential in multi-functional and intelligent textiles.

Conclusion and Prospect Graphene modified silk materials have laid a foundation for the development of flexible electronic wearable field in the fields of mechanical properties, electrical conductivity and biological adaptability. However, the low loading of graphene and the weak interfacial bonding force on silk are still yet satisfy the special required functions in some respects, which is the key and difficult point to be solved. The interfacial forces between graphene materials and silk, such as hydrogen bond, Van Der Waals force, and covalent bond, determine the loading capacity and durability of graphene on silk, and then affect the performance of modified silk. The reviewed researches include the assembly method of graphene on silk, the reduction method of graphene oxide, the pH value of solution, the screening of additives and other processes to obtain graphene modified silk materials with stable structure, excellent performance and complete functions. The preparation method of graphene functionalized silk with low cost, high efficiency and environment friendliness, the interface bonding force and working mechanism between graphene materials and silk, and the changes of secondary structure of modified silk are the main perspectives that has drawn research attention, which also determine the application of graphene modified silk materials in various fields. Researches also shows that single functionalization does not satisfy the application of silk in textile and biomedicine, hence it becomes imperative to develop multi-functionalization of graphene silk materials. For example, it is necessary to build a ternary or multivariate functional modification system, introduce environmentally friendly cross-linking additives, biomolecules and other modified materials with different sizes and functions in the process of modification of silk with graphene, increase the load of graphene on modified silk materials and endow it with multi-function, so as to expand its application in the textile and biomedical fields.

Research progress on high temperature resistant modified reinforcing fiber sizing agents

QIAN Chen, HUANG Boxiang, LI Yongqiang, WAN Junmin, FU Yaqin

Journal of Textile Research. 2023, 44(09):  232-242.  doi:10.13475/j.fzxb.20220708302

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Significance Fiber sizing agent is one of the core technologies in the production of reinforcing fiber (carbon fiber, aramid fiber, glass fiber, etc.) and its composites. The sizing agent coated on the surface of reinforcing fibers facilitates the bundling of filaments, remedies the surface defects of the fibers, and improves the processing property of corresponding fabrics. Moreover, the sizing agent promotes the infiltration and tight binding of the matrix resin on the fibers through physical and chemical effects such as increased compatibility in similar structure, induced crystallization, and crosslinking/reaction. Nevertheless, the stability of the general fiber sizing agents at high temperatures is insufficient to meet the needs for the development and advanced applications of high-performance thermoplastic resin-based composites. Therefore, the development of fiber sizing agents with high temperature resistance has attracted extensive attention. Based on the basic composition of sizing agents, this review reports research and development progress in fiber sizing agents with high temperature resistance, which focuses on the selection and modification of film former of the sizing agents and introduces the effect of the inorganic hybridization on the heat resistance of sizing agents and interfacial properties of composites. The importance and property of coupling agents in the formulations are also discussed.

Progress Fiber sizing agent is a mixed liquor composed of a variety of functional components, including film former, coupling agent, lubricant, antifoaming agent, antistatic agent, pH regulator, and other functional additives. Film former accounts for 70%-90% of the total solid mass of sizing agent which directly affects the wetting ability and compatibility of fiber in resin matrix. To meet both requirements of high temperature resistance and compatibility with the matrix, most research focuses on the development of novel film former based on polyimide and polyarylether, which show high thermal stability and the same or similar chemical structure with the high-performance thermoplastic matrix in composites. However, these sizing agents still have defects in applications, for example, the use of organic solvent, which causes health and environmental risk. Hybrid modification by nano-silica, carbon nanotubes, graphene, and other nanocomponents has become another common strategy to improve the thermal stability and properties of fiber sizing agents. In the high temperature resistant fiber sizing agent system, the nanocomponents show a significant effect on improving the heat resistance and functionalizing the interface of composite. The introduction of nanocomponents inhibits the thermal decomposition of film former and increases the surface roughness of fibers, resulting in improved interface bonding between reinforcing fibers and matrix. Moreover, in consideration of the necessity of adding a coupling agent in the sizing agent for glass fiber and basalt fiber, the thermal decomposition temperature of various silane coupling agents has been systematically studied and summarized with their chemical structure. Despite the complex chemical process, the macromolecular coupling agent that contains both high temperature resistant imide groups and functional siloxane groups holds great potential for the applications of high temperature and high performance.

Conclusion and Prospect The future development of high temperature resistant fiber sizing agents is expected. In view of practical applications, there are still great challenges for novel fiber sizing agents in industrial production, and future breakthroughs are still needed. First of all, an in-depth study on the green synthesis of novel water-soluble/water dispersible film former with high thermal stability is required. The green and environmentally friendly sizing agent with no organic solvent use and satisfactory property will be highly desired in applications. Secondly, it is necessary to develop corresponding high temperature resistant sizing agents that are suitable for each kind of reinforced fiber. Finally, a systematic study is needed to reveal the complex effects of the addition of other functional additives on the stability and properties of the sizing agent in future research.

Review on optimal design of personal cooling garments on cooling effect

ZHAO Chen, WANG Min, LI Jun

Journal of Textile Research. 2023, 44(09):  243-250.  doi:10.13475/j.fzxb.20220308702

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Significance Heat stress is one of the main health and safety threats for occupational workers when they engage in high-intensity physical labor in hot work scenes, and personal cooling garments (PCG) have been developed to reduce the risk of heat stress and heat-related injuries in hot environments. The cooling effect of PCG is chiefly evaluated by indicators such as cooling duration, cooling rate and human thermal and wet comfort, which are comprehensively affected by factors such as cooling media, basic garments, environment and human activities, reflecting the complexity of the functional design. However, previous studies focused on the cooling mechanism of the cooling media, ignoring supercooling caused by excessive cooling. In addition, basic garments carrying the cooling system for improving cooling effect and human thermal and wet comfort have not been fully considered. This has affected the establishment of the functional design method and system of PCG. Therefore, it is necessary to refine the design essentials for different media to meet different cooling needs, so as to establish a more accurate procedure for the functional PCG design.

Progress Researchers have conducted in-depth research on the factors that affect the cooling effect of PCG and human thermal and wet comfort, from the perspectives including environment, cooling media, basic garments and human activity. The functional design of PCG are considered from two aspects, i.e. the cooling media and the basic garments attached to them. Comparative studies on the characteristics of different types of cooling media, including the cooling methods, advantages and disadvantages of ventilation, liquid and phase change materials. The amount, temperature, humidity and mixed use of the cooling media have a great impact on the cooling effect of PCG and the thermal and wet comfort of the human body. However, insufficient attention was paid to the supercooling of the human body caused by excessive cooling, in contrast to the much increased attention to the cooling time of the cooling system. The auxiliary heat dissipation and moisture removal effect of basic garment fabric and structure design on PCG cannot be ignored as stressed by the researchers, were the fabric performance in heat insulation, air permeability, elasticity and moisture permeability, as well as the clothing structure design attributes such as clothing openings, styles and dimensions are all important. However, there is a lack of in-depth research on the configuration of fabrics and structures.

Conclusion and Prospect The functional design of personal cooling garments can be carried out from two aspects: cooling media and basic garments. The optimization cooling media design can be carried out in association of the media quantity, characteristic parameters, and mixed applications. The quantity and characteristic parameters of each cooling medium have primary and secondary effects on the cooling effect of PCG, and they can be adjusted according to the cooling demands. Under the premise of complementary advantages, the selection of hybrid cooling media should associated to appropriate application scenarios and appropriate cooling strategies. In the design of basic garments, the heat insulation performance, air permeability, elasticity, moisture permeability of fabrics, as well as the opening, style and size design of clothing should be considered separately, and the selection of fabrics and style structures should be adapted to the cooling media. In the future, the configuration design of basic clothing fabric performance and clothing structure under different cooling media can be deeply explored, and accurate design parameters for the configuration of cooling media and basic garments under different environments and different human activity levels can be provided through numerical parameterization research. At the same time, the improvement of cooling efficiency of system has also become the development focus of the PCG functional design.