Table of Content

10 November 2023, Volume 31 Issue 6

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Identification of gardenia yellow plant dyes and their dyed silk fabrics

GUI Zuwena, b, XU Haoninga, b, CHEN Haixiangb, YU Zhichenga, b, WANG Leia, b

2023, 31(6):  1-8. 

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In recent years, with the improvement of people's awareness of environmental protection, ecological textiles have been increasingly favored by people. Because of their non-toxic, biodegradable and other characteristics, plant dyes are widely used to study the dyeing and printing of textiles. Dyeing and printing with plant dyes can not only reduce the harm of dyes to the human body and make full use of natural renewable resources, but also greatly reduce the toxicity of printing and dyeing wastewater, playing a role in protecting the environment indirectly. At present, the development and utilization of plant dyes is under the active exploration and research, and the plant dye demonstration system engineering has been launched officially. In order to fill the deficiency of the world plant dye standard system, and lay a solid foundation for China to lead the development of the global plant dye industry, it is necessary to establish the identification methods and standards of plant dye series of products. In order to ensure the quality of plant dyeing products on the market, crack down on fake and shoddy products, and standardize market operation, so that consumers can rest assured and buy satisfactory plant dyeing products, it is very important to identify the corresponding vegetable dyes and dyeing textiles.
In order to identify plant dyes and their dyed textiles, this paper takes gardenia yellow plant dyes and dyed silk fabrics as the research objects. Firstly, the gardenia yellow plant dyes were tested by ultraviolet spectrophotometer, and the markers of gardenia yellow plant dyes were indentified by combining with the descriptions in the literature. Then the markers, gardenia yellow plant dyes and their dyed silk fabric extract were detected by using liquid mass combination instrument under negative ion mode. By comparing the retention time and mass spectrometry of the dyes, dyed silk fabric extract and the dyed silk fabric, whether the dye and fabric were gardenia yellow plant dye and its dyed silk fabric was determined.
The results showed that crocin Ⅰ and crocin acid could be used as markers to distinguish gardenia yellow plant dyes and their dyed silk fabrics. The molecular ion peaks m/z=975.3472 and m/z=327.1553 were detected in the mass spectrum of gardenia yellow plant dyes, and the retention times were 0.61 min and 1.38 min, respectively. The molecular ion peaks m/z=975.396 and m/z=327.1489 were detected in the mass spectrum of dyed silk fabric extract, and the retention times were 0.61 min and 1.38 min, respectively. The retention times were similar to the peak time of the crocin Ⅰ standard substance (0.61 min) and crocin acid standard substance (1.36 min), and the deviations were within the allowable deviation range of ±2.5%. Therefore, it was determined that the dye and the dyed silk fabric are respectively the gardenia yellow plant dye and its dyed silk fabric.
At present, many textile colleges and universities have established relatively complete database of vegetable dyes and comprehensive vegetable dye color cards. However, there are certain deficiencies in the relevant standards of plant dyeing in every link in the current market, and consumers have insufficient awareness of them and cannot verify the conformity of products. Therefore, identifying the corresponding plant dyes and their dyed fabrics is a priority in the development of plant dyeing.


Continuous salt-free pad dyeing process to improve the fibrillation of Lyocell fibers

TANG Qi, HE Yi, ZHENG Jinhuan, WANG Chenglong, WANG Zhicheng, CHAI Liqin

2023, 31(6):  9-16. 

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Lyocell fibers are regenerated cellulose fibers. In addition to the advantages of hygroscopic property, good luster and comfortable wearing, Lyocell fibers also have better wet and dry strength than other regenerated cellulose fibers. However, Lyocell fibers are prone to fibrination, which limits their application in textile applications. The reactive dye is one of the most commonly used dyes for cellulose fiber dyeing, with advantages of simple application, cheap price and bright color, but in the process of immersion dyeing, to promote reactive dye dyeing, a large number of inorganic salts are often added in the dyeing solution. Therefore, there are high energy consumption, complex and variable dyeing wastewater composition, deep color, alkaline and expensive treatment costs and many other drawbacks. In this paper, the continuous salt-free rolling dyeing process of Lyocell fiber fabrics with reactive dyes was systematically studied, which not only improved the dyeing property and reduced the emission of inorganic salts, but also improved the fibrillation degree of Lyocell fibers and effectively improved the quality of Tencel fabrics.
The effects of dyeing and fixing process and formula (baking temperature, baking time, dipping times, dosage of alkali and urea) on dyeing properties (K/S value and fixing rate) of fabrics were discussed. The dyeing properties and fibrination degree of fabrics were compared with those of traditional dyeing process. The results show that the optimized rolling, baking and dyeing formula and process of the Lyocell fabric require alkali of 25 g/L, urea of 60 g/L, and a baking time of 2 min at 160℃ after twice dipping and twice padding. The three dyes of Br Red CA, Br Yellow CA and Blue CA have good dyeing effect, and the color fixing rates are 76.98%, 67.48%, 77.15%, and K/S values are 21.87, 10.87, 15.85, respectively. Compared with the traditional immersion dyeing process, the continuous salt-free rolling dyeing can obtain higher dyeing depth , and the K/S values of the three dyes are increased by 28.10%, 5.23% and 6.20%, respectively. The maximum absorption wavelength of the same dye is the same under rolling, baking and immersion dyeing, indicating that pad dyeing does not change the color light of the fabric. The L* value of the pad dyeing fabric is generally lower than that of the immersion dyeing fabric, indicating that the color of the Lyocell fabric dyed by the former will be darker under the condition of the same amount of dyes. The dry rubbing fastness of the three dyes is higher than that of the wet rubbing fastness, reaching grade 5, while the wet rubbing fastness is one or two grades lower. Both of them have good soap color fastness, generally at grade 4-5 or above. The surface fibril of Lyocell fibers after continuous salt-free rolling dyeing is less than that of immersion dyed fabrics, and the fibrillarization degree of the fabric is weaker and the surface is smoother.
Continuous salt-free rolling dyeing of Lyocell fibers can obtain good dyeing effect, reduce energy consumption and pollutant emission in the dyeing process, which will be conducive to clean dyeing of cellulose textiles, and promote the sustainable development of the whole dyeing process.


Silk fabric modified by quaternary ammonium salt/amphoteric chitosan and its synergistic effect

YANG Sheng, XU Zhaomei, MA Tingfang, FU Feiya, LIU Xiangdong, YAO Juming

2023, 31(6):  17-27. 

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With excellent wearability, biocompatibility and biodegradability, silk is widely used in textile, biomedicine, food and other fields. Chemical modification is an important technical means to further expand the use of silk. However, the protein properties of silk have high requirements on chemical raw materials and reaction paths, so it is difficult for traditional single substance modification methods to achieve green and efficient modification at the same time. In this paper, a new method of tandem chemical modification of real silk fabric (SF) using water-soluble carboxylated chitosan (CMC) and 2,3-epoxy-propyl trimethyl ammonium chloride (GTA) is proposed for the first time. The morphology, structure and physicochemical properties of SF, SF/CMC, SF/GTA and SF/CMC/GTA samples were compared and analyzed by means of scanning electron microscopy, fourier transform infrared, X-ray diffraction, X-ray photoelectron spectroscopy, tensile test and thermogravimetric analysis. The results show that although the amide bond formed by CMC reaction in infrared spectroscopy coincides with SF characteristic peak, the shift of carbonyl C binding energy and the increase of C-N peak area in X-ray photoelectron spectroscopy prove that the tandem chemical modification can be successfully implemented at 80 ℃ in aqueous solvent. The introduction of CMC provides more reaction sites for GTA, and a large number of hydroxyl groups forming after the reaction of GTA can form rich hydrogen bonds with CMC to help it stabilize. With the chemical modification in tandem, a small amount of fiber appeared on the surface of the fabric fiber. X-ray diffraction spectra also showed that the modification reaction was mainly in the amorphous region of the surface, and had little effect on the SF crystal structure. Compared with SF, the tensile strength (62.7 MPa) and thermal decomposition temperature (327 ℃) of SF/CMC/GTA have no obvious changes, which shows that the series modification method used in this work is mild and effective, and the modified fabric still maintains good mechanical properties and thermal stability. The difference is that compared with SF, the permeability and water absorption of SF/CMC/GTA increased significantly, reaching 272 g·m-2·d-1 and 326%, respectively, which should be related to the strong hydrophilic groups introduced by CMC and GTA. In addition, the Zeta potential of SF/CMC/GTA (1.5 mV) was significantly increased compared with that of SF (-26.3 mV), proving the high efficiency of tandem modification. Compared with the single modified sample SF/CMC and SF/GTA, the tandem-modified sample SF/CMC/GTA had a quite high antibacterial rate (above 99.9%) both against S. aureus and E. coli. The dyeing experiment showed that the dyeing rate of SF/CMC/GTA was 55 times higher than that of SF, which is expected to be applied in the field of non-washing printing and dyeing. This paper provides scientific data for the application of tandem reaction in functional modification of real silk fabrics and a new technical path for green silk dyeing and finishing.

To optimize the preparation process of cotton-shaped hemp fabrics with the RSM method and orthogonal tests 

KONG Lingping , WANG Dawei , SUN Dan , KANG Fuhang

2023, 31(6):  28-35. 

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The single fiber length of hemp is short, and the content of hemicellulose and lignin is higher than that of other hemp fibers. There are problems such as difficulty in degumming and poor fiber quality after degumming. The produced hemp yarn has a low count, and the hemp fabric has a rough and hard feel. Due to the rich resources of hemp in Northeast China, the single fiber length and fineness of hemp are similar to those of cotton, and there is no itching sensation compared to other hemp types. In order to make full use of hemp, improve the softness of hemp fabrics, and increase product added value, we conducted optimization research on the processing conditions of cotton shaped hemp fabric.
Firstly, single factor experiment was conducted to investigate the effects of the sodium periodate dosage, oxidation time, and oxidation temperature on fabric softness. Based on this investigation, representative sodium periodate dosage, oxidation time, and oxidation temperature experimental conditions were selected from comprehensive experiments according to orthogonality (evenly dispersed, and comparable in integrity) for orthogonal test analysis at three factors and one level. Because response surface methodology is an optimization method that integrates experimental design and mathematical modeling, it can provide intuitive contour maps and three-dimensional stereograms, and can examine the interaction between influencing factors. This method not only establishes a prediction model, but also tests the adaptability of the model, the significance of the model and coefficients, and the mismatched terms. We further performed analysis of variance and model diagnosis. However, the premise of response surface optimization requires that the experimental points designed should contain the optimal experimental conditions. In order to obtain the optimal results and compensate for this limitation of response surface optimization, we adopted the experimental analysis method of response surface design and orthogonal experimental design using the activity rate as the response value, verifing that the selected experimental conditions are the parameters containing the optimal experimental points orthogonal experimental optimization. Additionally, we used response surface optimization to screen the optimal process parameters for sodium periodate dosage, oxidation time, and oxidation temperature, improving the reliability of the experimental optimization results.
Through comprehensive consideration of the results of single factor tests on fabric softness at three factors: sodium periodate dosage, oxidation time, and oxidation temperature, and three levels of optimal design for orthogonal tests: a sodium periodate dosage of 6 g/L, 13 g/L, and 20 g/L were selected; oxidation time: 0.5 h, 1.5 h, 2.5 h; oxidation temperature: 40 ℃, 50 ℃, 60 ℃. Using the L9 (34) orthogonal table and the activity rate as the response index, it can be seen that the order of influence of various factors is sodium periodate dosage>oxidation temperature>oxidation time. The optimal level requires a sodium periodate dosage of 13 g/L, oxidation temperature of 50 ℃, and a oxidation time of 1.5 h. A response surface design experiment was conducted on the basis of orthogonal experiments. With Design Expert 11 software, response surface analysis was conducted on the experimental results and variance analysis was conducted on the levels of various influencing factors. It can be seen that the model is significant; the significant degree of influence of various factors on the activity rate is sodium periodate dosage>oxidation temperature>oxidation time, which is consistent with the results of orthogonal experiments. The probability value P of the mismatch test is between 0.05-0.10, being 0.0537, and the mismatch analysis result is not significant. Therefore, the quadratic model can accurately describe the actual activity rate. Analysis of factor contour plots and response surface plots showes that the amount of sodium periodate and oxidation time has a strong interaction on the reactivity of response values; there is a certain interaction between the amount of sodium periodate and oxidation temperature on the response value activity, but the interaction between oxidation time and temperature is not obvious. Through comparison, it is found that the analysis results are consistent with the optimal prediction chart. On this basis, it is found by comparing the reactivity, strength retention, and wicking height of hemp fabrics before and after process optimization that except for slightly lower strength, both the feel and water absorption of the fabrics are improved. The design optimization model has certain significance for improving the added value of hemp fabrics.


Construction of efficient cleaning properties of microfiber synthetic leather surfaces based on micro-nano structures and photocatalysis 

ZHAO Qi, FANG Zheng

2023, 31(6):  36-42. 

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Because of its natural leather-like structure, microfibre synthetic leather has excellent resistance to wear, ageing, as well as cold and breathability, and is widely used in furniture and leather goods. However, microfibre synthetic leather is prone to contamination by various types of stains in use, and due to the special characteristics of furniture, etc., stain removal cannot be achieved by simple washing, so new strategies are needed to achieve easy cleaning of microfibre synthetic leather. In previous studies, temperature-sensitive hydrogel coatings were cross-linked to the surface of microfibre synthetic leather to enhance the removal of oleophilic stains by exploiting the transformation of hydrophilic and hydrophobic properties at different temperature zones, but this method was limited in its effectiveness in removing hydrophilic stains. In this study, g-C3N4 with photocatalytic properties was introduced into the hydrogel coating to effectively decompose organic compounds by using the free radicals generated during the photocatalytic process, and to enhance the roughness of the surface of microfibre synthetic leather by constructing a micro-nano structure on the surface of microfibre synthetic leather with the help of g-C3N4, so as to improve the removal efficiency of hydrophilic stains from two aspects. The experiments were carried out by using ammonium persulphate (APS) and N,N,N',N'-tetramethylethylenediamine (TMEDA) as redox initiators to completely cross-link the composite hydrogel coating containing g-C3N4 with microfibre synthetic leather. The effect of the hydrophilic treatment on the removal rate of both oleophilic and hydrophilic stains was compared. The experimental results show that the surface hydrophilic treatment of g-C3N4 can effectively enhance the removal ability of oleophilic stains, while due to the spontaneous aggregation behaviour of g-C3N4 nanoparticles, protrusions with micro-nano structures are constructed on the surface of the composite hydrogel coating, which enhances the specific surface area and enhances the g-C3N4 photocatalytic degradation effect, optimizing the removal ability of aqueous stains.
The microfibre synthetic fabrics developed are easy to clean in everyday use: oleophilic stains (e.g. cooking oil) can be removed simply by scrubbing with water. If hydrophilic stains (e.g. red wine) are present, they can be effectively degraded by photocatalytic action. As a functional fabric, it can be widely used in the design of automobiles, furniture and bags to enhance the customer experience and increase product sales, which has promising market potential. The research can provide reference for further improvement of the easy cleaning performance of microfibre synthetic leather fabrics.


Preparation of Bifunctional Au@Cu2O binary heterojunctions with photothermal effect and photocatalysis for clean water generation

WANG Cheng, DONG Xinxin, ZHANG Hua, ZHENG Min

2023, 31(6):  43-50. 

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The scarcity of fresh water resources has become a major threat to human survival and development. It is critical to maintain social stability and development by addressing the scarcity of fresh water resources. Solar-driven interfacial evaporation technology can use solar energy directly to purify wastewater and produce clean water without relying on fossil fuels. It has received widespread attention due to its low cost, sustainability, and environmental friendliness. However, when solar steam is generated during the purification process, non-volatile impurities may remain and accumulate, causing more serious pollution. Pollutants can be effectively degraded by incorporating a photocatalytic system. The bifunctional fabric was combined with the photo-thermal photocatalytic bifunctional cuprous oxide (Cu2O)-based heterojunction material in this paper to produce clean water.
At the moment, research on the production of clean water via interfacial evaporation is focused on how to improve the evaporation rate and the water transport rate. There hasn't been much research into how to remove pollutants while evaporating water. The majority of related research focuses solely on stacking two distinct materials, photothermal and photocatalytic, on the same substrate to achieve dual functions. Because it can be excited by visible light, Cu2O is widely used in photocatalysis. Nevertheless, photo-corrosion affects the photoactivity of Cu2O, limiting its exclusive use. To improve its photocatalytic activity, Cu2O is usually combined with metal. Au is a precious metal that is frequently used to improve the catalytic activity of Cu2O, but its photothermal properties are rarely used. The Au@Cu2O heterostructure was created in the experiment by using gold rods (Au NRs) with near infrared absorption as the core. The thickness of the Cu2O shell was changed by adjusting the Au/Cu ratio, resulting in a successful Au@Cu2O near infrared response. A bifunctional material with photothermal and photocatalytic properties was designed and prepared successfully, and its application in water purification was investigated by combining it with cotton fabrics. Under the irradiation of a simulated solar source with a power density of 0.1 W/cm2, the evaporation rate of the Au@Cu2O-modified cotton fabric is 1.25 kg/(m2·h), the conversion efficiency of sunlight to steam is 77.4%. After 180 minutes of visible light irradiation, the degradation rate of methyl orange reaches 89.2%.
Water scarcity has sparked widespread concern as a global issue. Using solar-driven interfacial evaporation to produce clean water not only corresponds to the current state of water scarcity, but also makes use of solar energy, an inexhaustible source of energy. Photothermal photocatalytic bifunctional materials can decompose pollutants in water while allowing for water evaporation, which is a gap in current research but has significant application potential.


Degradation of organic pollutants by carbon black metal phthalocyanine in situ producing high valent iron

XIA Yun, XU Jinlong, CHEN Long

2023, 31(6):  51-60. 

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The rapid development of industry, the intensification of urbanization and the growth of population make human's increath demand for clean freshwater resources year by year, but at the same time, human production and domestic wastewater was discharged into the environment, resulting in the scarce freshwater resources. Organic pollutants such as drugs, personal care products, are present at extremely low concentrations from ng/L to μg/L in water, but they can cause immeasurable damage to the environment and living organisms, it causes harm to the human body ultimately. So more and more researchers pay attention to the recycling of wastewater which comes from daily life, agricultural or industrial production.
In order to respond to the “dual carbon”strategic objectives, it is necessary to efficiently degrade and remove organic pollutants in water to achieve sustainable development. Biological enzymes have high catalytic activity and strong selectivity to substrates, we can use them to catalyze degradation of organic pollutants. However, the direct extraction of enzymes from organisms will bring high extraction cost, the change of the application environment of enzymes will significantly reduce their catalytic activity. So we designed an environmentally friendly bionic catalyst called peroxide mimicking enzyme which can catalyze the degradation of organic pollutants in water efficiently. In peroxide mimicking enzyme, iron hexadecachlorophthalocyanine (FePcCl16) worked as the active site, pyridine group (Py) acted as the fifth ligand, carbon black (CB) served as a protein skeleton. Inspired by the principle of peroxidase metabolizing drugs, we constructed the environmentally-friendly bionic catalytic system which used peroxide simulation enzyme as catalys, hydrogen peroxide as oxidant to catalyze the oxidative degradation of dexamethasone (DXMS). The results showed that the bionic catalytic system maintained high efficiency and stable degradation rate of DXMS in the range of temperature from 25℃ to 65℃，it showed that the simulated enzyme catalyst was not sensitive to temperature. The degradation rate of DXMS was 100% in 60 min in acid or neutral conditions. It can be seen that the catalytic system was better than that of Fenton system. At the same time, the catalytic system did not change the degradation rate of organic pollutants in the presence of inorganic salts, and the degradation rate of DXMS still reached 100%, indicated that the catalytic system still had a good catalytic oxidation degradation efficiency in complex water environment. However, the degradation rate of DXMS was reduced by 28% due to the rapid decomposition of H2O2 under alkaline conditions. Surprisingly, we found that the catalytic system had excellent recycling performance, the degradation rate of DXMS was still 95% after 6 cycles of use. By adding isopropyl alcohol (IPA) and p-benzoquinone (p-BQ) into the system as trapping agents of hydroxyl radical(·OH) and superoxide radical (O2▪-) respectively, electron spin resonance (EPR) detection of ⸱OH and O2▪- captured by 5,5-Dimethyl-1-pyrroline N-oxide (DMPO), gas chromatography-mass spectrometry (GC-MS) for the detection of dimethyl sulfone (DMSO) oxidation product confirmed that the main active species of DXMS in the catalytic system were high-valent iron oxo (Fe (IV)=O) active sites, followed by ⸱OH.
Degradation path analysis showed that the first path of DXMS degradation began with the dehydrogenation of C8 and C14, then hydroxylation, the second path of DXMS degradation started with the removal of HF at C8 and C9, then hydroxylation or demethylation at C19. After 60min, all the intermediate products generated small molecule organic acid (succinic acid) or mineralization. The construction of the bionic catalytic system provided a new perspective for sewage treatment.


Research progress on alkali deweighting promoter for polyester fabrics

CHEN Linguoa, b, ZHANG Hongjuana, b, DING Leia, b, PEI Liujuna, b, WANG Jipinga, b

2023, 31(6):  61-71. 

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Polyester fiber is currently the most widely used synthetic fiber. However, its poor moisture absorption, susceptibility to static electricity, and other issues have hindered its market prospects as a high-end textile material. Alkali reduction treatment can improve the inherent defects of polyester fiber, resulting in a soft and smooth texture, a pleasant sheen, good drapability, water retention, and other advantages. Meanwhile, this treatment makes it has the characteristics of imitated silk. Nevertheless, the traditional alkali reduction process for polyester involves excessive use of alkali, making it difficult to process. Finally, it requires a large amount of acid to neutralize. As a result, there are many problems, such as high energy consumption, serious environmental pollution, and serious damage to the fabric. Additionally, the liquid alkali is also a dangerous chemical, so safety problems should be considered. All these problems seriously restrict the sustainable development of the polyester textile industry. Therefore, reducing the amount of liquid alkali with promoters is currently the most convenient, environmentally friendly, and easily implementable improvement method in the alkali reduction technology.
Currently, promoters are widely used to improve alkali utilization, reduce the environmental hazards of excessive alkali, and impart exceptional performance to fabrics. Promoters can be roughly categorized into quaternary ammonium salts, gelatin protein promoters, cationic polymers, ionic liquids, amines, alcohols, and others. Among them, quaternary ammonium salts are widely used. In terms of effectiveness, most promoters can accelerate the hydrolysis of polyester and reduce the amount of alkali required. And different promoters have different promotion mechanisms. Quaternary ammonium cationic surfactants mainly utilize positively charged quaternary ammonium ions to attack the carbonyl carbon atoms by carrying the hydroxide ions, further promoting the rapid hydrolysis of ester bonds in polyester macromolecules. Gelatin has certain surface activity, infiltration, and colloidal protection. In the process of alkali reduction, gelatin can play a role in swelling fiber and reducing surface tension. Some new alkali reduction promoters are mainly cationic polymers. They mainly adsorb more hydroxide ions through water-soluble quaternary ammonium cation groups, so as to achieve the purpose of promoting the hydrolysis of polyester. Ionic liquid is a kind of compound ionic surfactant and it can completely ionize in water. The cationic part of the ionic liquid has a long carbon chain and strong adsorption capacity for polyester. Its mechanism is similar with quaternary ammonium salts. There are some other additives that can also promote polyester hydrolysis. For example, ammonia mainly generates an amide group at one end and a hydroxyl group at the other end to destroy the polymer chain through the diffusion of amine molecules in the polymer. Alcohol can realize the purpose of surface functionalization of polyester through the exchange reaction of ester and amine. 
The traditional alkali reduction treatment of polyester fiber has the following problems, such as high concentration of liquid alkali, great difficulty in processing, serious environmental pollution, and high energy consumption. All these problems seriously restrict the sustainable development of the polyester textile industry. The addition of promoters is an effective way to improve the utilization rate of alkali. The promoter can transfer and enrich the OH- in the solution on the fiber surface, and OH- is more likely to attack the carbon atoms in the carbonyl group with partial positive charge in the polyester molecule. As a result, the hydrolysis reaction of the polyester molecule becomes easy. Therefore, how to effectively use promoters to reduce the amount of liquid alkali has become a research hotspot to promote the sustainable development of polyester textiles.
The development of alkali reduction promoters can be started from the following perspectives: first of all, the new promoter is synthesized to increase the function of the fabric while effectively reducing the amount of liquid alkali and retaining the advantages of liquid alkali treatment. For example, the use of gelatin protein reagents can also play a certain role in fiber repair while improving the performance of fibers. By increasing the study of the combination of accelerators to explore the mechanism, the cost saving treatment formula with the best effect was obtained. The development of alkali reduction technology can also be applied to the alkali reduction dyeing one-bath system of polyester fabrics, which can reduce energy consumption and be more environmentally friendly and efficient. The use of promoters to reduce the alkali concentration provides more possibilities for the pH application range of some alkali-resistant disperse dyes, and development space for alkaline dyeing technology. This provides reference for promoting the industrialization development of polyester fabric alkali reduction technology and realizing the sustainable development of the textile printing and dyeing industry.


Preparation and water-induced power generation performance of flexible macroporous SiO2 nanofibers

LIU Shu, DING Xinbo, LIN Wanli, QIU Qiaohua, LI Ya,

2023, 31(6):  72-79. 

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 Nowadays, the development and utilization of clean and renewable energy has received tremendous attention due to the growing demand with the continuous improvement of social living standards. There are a lot of untapped energy sources, and water can be seen everywhere; therefore, the rational use and development of water resource has become an important issue that needs to be addressed. Converting water in the environment into electrical energy is a hot research direction today. SiO2 is one of the extremely important inorganic new materials, especially nanoscale SiO2 has been widely used in many disciplines and fields owing to its small particle size, abundant micropores, large specific surface area, strong surface adsorption, large surface energy, high chemical purity, good dispersion performance, superior stability and other specific performance.
In this experiment, a flexible macroporous SiO2 nanofiber membrane with mesoporous structures was prepared by sol-gel electrospinning to explore its performance in water-induced power generation. Firstly, TEOS was hydrolyzed, then mixed with PVA solution, and PS was added as a pore making agent to prepare a precursor solution. Composite precursor nanofibers were prepared by electrospinning, and afterwards, flexible macroporous SiO2 nanofibers were obtained through calcination. By controlling the proportions of pore-forming agents, PS microspheres, and the adjustment of calcination temperatures, the influence of PS proportion on the microscopic and macroscopic morphology, mesopore and macropore contents of SiO2 nanofibers was explored. Then the charge property analysis of SiO2 nanofibers was conducted through the adsorption comparison of anion MB and cationic CR dyes. Half of the obtained SiO2 nanofiber membrane was placed in NaCl aqueous solution, the other half was exposed to air, and its output voltage was measured at both ends, and then its performance of water-induced power generation was tested. 
It is found that the addition of PS nanospheres could contribute to the preparation of flexible macroporous SiO2 nanofibers with mesoporous structures. The adsorption properties of SiO2 nanofibers to anionic MB and cationic CR dyes were very different. It showed that the adsorption rate of MB was about 77%–78%, and the adsorption rate of CR was only 16%–20%, which indicated that the SiO2 nanofibers were negatively charged. Therefore, SiO2 nanofibers can be applied to water-induced power generation. The composite nanofiber membranes without calcination did not have the performance of water-induced power generation. After calcination, the water-induced power generation performance of SiO2 nanofiber membrane was improved. When the temperature was 500 °C, the output voltage was the highest, up to 0.46 V. It is speculated that the water-induced power generation voltage of SiO2 nanofibers with negative charges is related to the contents of pore structures, and too much or too little will both lead to the decrease in the output voltage, illustrating that the flexible macroporous SiO2 nanofibers can be applied in water energy conversion to electrical energy.


Effect of spinneret structure on flow characteristics of polymer melt in melt spinning extrusion process

SHEN Zekun, WANG Hui, YING Qifan

2023, 31(6):  80-91. 

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At present, the preparation of highly homogeneous polyester fibers is still a great challenge. The stability of melt flow in melt spinning process and the degree of non-uniformity of radial velocity distribution before extrusion affect the quality of subsequent spinning. In this paper, the flow process of polyester melt in microporous flow channel was studied by numerical simulation. The melt flow characteristics under different microporous structure of spinneret and different inlet velocity were analyzed. The non-uniformity coefficient related to melt velocity was proposed, and the influence mechanism of microporous flow channel structure parameters on the stability and uniformity of melt flow was further clarified. The spinneret structure corresponding to the optimum non-uniformity coefficient of melt flow is pointed out.
With the increase of inlet velocity, the variation degree of melt average velocity before and after extrusion first decreases and then increases, and the flow is the most stable at 1 m/s. The time pressure drop is more stable when the inlet velocity ranges from 0.5 m/s to 1 m/s, and is more conducive to the internal stress of the primary fiber. The increase of flow velocity increases the average shear rate in the free section and strengthens the melt orientation. However, when the inlet flow velocity is 2 m/s and 3 m/s, the maximum shear rate in the flow passage reaches 105 orders of magnitude, and the possibility of melt fracture is higher, which is not conducive to the flow stability. The inlet velocity has little effect on the non-uniformity coefficient of melt flow when the spinneret geometry is unchanged. The study shows that the inlet velocity of 1m/s should be selected.
When the die length-diameter ratio is 2 and 3, the average velocity before and after extrusion changes less, and the flow is more stable. When the length-diameter ratio is 2 and 3, the pressure drop is more conducive to the internal stress of the primary fiber. When the aspect to diameter ratio is 2,3,4, the average shear rate in the free section is high, that is, the melt orientation degree is high. However, when the aspect to diameter ratio is 2 and 4, there is still a maximum shear rate in the free section, which is easy to lead to melt fracture and is not conducive to flow stability. At the same time, as the melt is always in the fully developed section when the length-diameter ratio is increased, the thicker the boundary layer is, the more uniform the flow will be, and the non-uniformity coefficient will decrease. The results show that 3 spinneret is the best.
When the convergence Angle is 54° and 74°, the average velocity before and after extrusion changes less, and the flow is more stable. When the convergence Angle is from 54° to 96°, the pressure drop changes stably with the maximum difference of 14.29%, which is within the reasonable range. The average melt shear rate in the free section decreases with the increase of convergence Angle, and the degree of melt orientation decreases. However, when the convergence Angle is 54° and 74°, the maximum melt shear rate in the center of the flow channel is small, and the melt is not easy to break, and the flow stability is better. At the same time, because the convergence Angle changes the radial velocity component at the entrance of the die, the influence on the flow uniformity is obvious. The results show that the spinneret with convergence Angle of 74° is the best.


Effect of coordination environment on polycondensation of polyester catalyzed by organic titanium compounds

SU Ya, WANG Yongjun, CHEN Wenxing, LÜ Wangyang,

2023, 31(6):  92-99. 

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Polyethylene terephthalate (PET) has excellent physical and chemical properties and is the most commonly used polyester material. The polycondensation stage of polyester synthesis requires the participation of catalysts. At present, antimony catalyst is widely used in industrial production. Antimony catalyst is a kind of heavy metal compound, which has biological toxicity and will cause harm to human health and ecological environment. With the increasing awareness of healthy, the design and development of non-toxic and non-hazardous polyester catalysts has become an important hotspot in the field of polyester research. The titanium-based catalysts are expected to replace the antimony-based catalysts due to the advantages of environmental protection, strong catalytic activity and abundant resources. The high activity of titanium catalysts increases the reaction rate of the PET polycondensation process, but also promotes side reactions such as thermal degradation and thermo-oxidative degradation, which is one of the most prominent problems limiting the application of titanium catalysts in polyester synthesis. The regulation of the catalytic activity of titanium catalysts is therefore crucial. In order to investigate the catalytic performance of organotitanium compounds in the condensation synthesis of polyesters under different coordination environments, firstly, density functional theory (DFT) quantum chemistry method was used to study tetramethylphenol titanium(Ti·[C7H7O]4，Cat1), acetyl acetone titanium oxide(TiO·[C5H7O2]2，Cat2), isopropyl tri (dioctylpyrophosphoxy) titanate(C51H112O22P6Ti，Cat3), and the coupling mechanism of electronic effects and steric hindrance of coordination groups on catalytic activity of organotitanium was analyzed theoretically. The Gaussian software was used to carry out structural optimization and energy calculations for the three organotitanium compounds, and the wave functions were extracted from the calculation results. The wave function analysis was carried out using the Multiwfn software package to obtain the Hirshfeld charge values of the titanium metal centres and the surface distance projection maps used to assess the effect of steric hindrance. Theoretical calculations show that Cat1 is more capable of forming titanium alcohol salt active species than Cat2 and Cat3; the Hirshfeld charge values for the central titanium atoms of the three active species are: 0.661, 0.524 and 0.600, respectively, and the Hirshfeld charge is strongly correlated with the electrophilic ability of the atoms, the higher the charge value, the stronger the electrophilic ability.By analyzed the distance between ligands in the surface distance projection，, respectively, and the size of the coordination space is Cat2、Cat1、Cat3. The catalytic reaction kinetics experiments results show that the reaction activation energies of Cat1, Cat2 and Cat3 catalyzed the synthesis of polyesters from BHET(Dihydroxyethyl terephthalate) were 72.41, 80.16 and 102.47 kJ/mol, respectively, and the highest catalytic activity was obtained for tetramethylphenolato-titanium (Ti·[C7H7O]4，Cat1), indicating that the electronic effect of the ligand group and the spatial site resistance jointly affect the catalytic activity of the titanium catalysts, with the electronic effect being more influential than the spatial site resistance. This work is a guide to the screening of ligands when adjusting the activity of titanium catalysts in the future.

Effect of sodium hydroxide treatment on the interface and mechanical properties of GF/VER composites

MING Lin , FENG Xuhuang, SHAO Lingda, DING Hao, SUN Zeyu, MA Leilei, TIAN We, ZHU Chengyan,

2023, 31(6):  100-109. 

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Fiber-reinforced composites have many advantages, such as good mechanical properties, corrosion resistance, high-temperature resistance, and high moldability. It is the fastest-developing and most widely used class of composite material. The technology of fiber-reinforced composites has gradually matured in all aspects since the 1960s and is one of the new materials focused on research and development worldwide. Fiber-reinforced composites continue to develop toward high performance, multifunctionality, and complexity. To meet this demand for the materials, academics at home and abroad have investigated fiber-reinforced composites in greater depth, and current research primarily focuses on modifying the interfaces of composites. The small size region of the composite interface makes it more difficult for researchers to characterize its chemical structure, physical properties, and mechanical properties. Characterization of interfacial properties is thus also one of the hot spots in academic research. There is still a need to explore and refine the relationship between the microscopic interfacial and macroscopic mechanical properties of composites.
We aimed to modify the glass fiber (GF) surface with a sodium hydroxide solution to improve the interfacial properties between GF and vinyl ester resin (VER). Glass fibers were soaked in sodium hydroxide solutions at concentrations of 1 mol/L, 2 mol/L, and 3 mol/L for 24 h, 48 h, 72 h, and 96 h. Glass fiber reinforced vinyl ester resin (GF/VER) composites were made by using vacuum-assisted resin infusion molding technique. The interfacial shear strength between the fibers and the resin matrix was investigated by using the characterization method for the interfacial property of fiber extraction. We aim to examine the effect of the modification treatment on the surface morphology and the chemical interaction of the GF by using scanning electron microscopy and infrared spectroscopy. Before and after modification, the GF/VER composites were tested for interfacial shear strength, flexural strength, and impact strength by using a single fiber strength machine, a universal material testing machine, and a pendulum impact testing machine. The effects of sodium hydroxide treatment on the interfacial and mechanical properties of GF/VER composites were investigated. It was found that after modification with a solution of sodium hydroxide (concentration of 2 mol/L, and treatment time of 48 h), the wettability of GF was improved, the surface became roughened, and the reactive groups on the surface increased. After the modification treatment, the interfacial properties of GF/VER composites were improved. The monofilament interfacial shear strength reached 5.00 MPa, and the fiber bundle interfacial shear strength reached 29.04 MPa, 25.31%, and 27.48% higher than the original samples before modification, respectively. The mechanical properties of the composites were improved, with the bending strength reaching 346.72 MPa and impact strength reaching 158 kJ/m2, which increased by 20.96% and 25.40%, respectively, compared with the initial samples before modification. Thus, it was shown that sodium hydroxide treatment positively improved the bonding strength between the fiber and the resin. These research findings provide a benchmark for modification processing methods for fiber-reinforced composites and ideas for enhancing composites' interfacial and mechanical properties.


Thought and practice on the high-quality development of the modern textile industry in Zhejiang province lad by group standards

YE Xiangyu, LIU Furong, CONG Mingfang, LIANG Huifang, YUAN Haomin, LOU Caiying

2023, 31(6):  110-116. 

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Group standards refer to the voluntary adoption of social organizations established by law to meet the needs of market and innovation. The problems of single supply system, formulation cycle and slow update of national and industry standards in the textile industry cannot meet the rapid development of the industry and market. Group standards have become an important starting point for promoting standardization reform and innovation in China. The textile industry is one of the pillar industries in Zhejiang province and the "block regional economy" has significant characteristics and comprehensive advantages of the industrial chain, while the textile industry is large but not strong. In particular, there is a problem that the standardized discourse power does not match the industry status. Promoting the brand building and industry voice of Zhejiang textile industry with high-quality group standards is of great significance for Zhejiang to build an advanced textile manufacturing base, promote regional economic development and achieve common prosperity.
The representative standardized social groups in the textile field in Zhejiang province are mainly Zhejiang Brand Construction Federation and Zhejiang Textile Engineering Society. Until early 2023, more than 200 standards had been developed for textile "Defined Quality Zhejiang Made", involving the whole industrial chain of chemical fiber, yarn, clothing and production equipment. Zhejiang Textile Standard (ZFB) has released items. During the epidemic period, it took the lead in the national release of T/ZFB 0004－2020 "Children's Mask" standard. On the night of the release, it ranked the top three in Sina Weibo trending topics, with more than 170 million people reading it. Shanghai, Shandong, Guangdong, Jiangsu and other testing institutions have expanded their items and it has great influence.
Through the examples and analysis of group standards to promote the high-quality development of the industry, this study systematically expounds the thinking and practical results of standards supporting and leading the modern textile industry chain "functional fashion, green ecology and intelligent manufacturing". First, at the beginning of its establishment, the group standard organization clarified the field and direction of standard formulation, positioned social groups with high-quality requirements, and tailored the standardization development path for first-class enterprises and first-class products. Second, using the advantages of regional aggregation and integrating resources to build an industrial chain and regional standard cooperation network are conducive to the growth of group standard participants and the formation of brand effect. Third, the organizational structure of group standards with inherent flexibility and flexibility can make it constantly fine-tune the field and direction of standard formulation according to technological development and external environment, accurately grasp the development trend of new technologies, and lead the development of group standards in this field. Fourth, culture is the activity mode and product of human transformation of society. Standardization, as a kind of human practice, is an integral part of culture. The two influence and support each other. Introducing culture into standardization is an important way to explore and develop group standards. By focusing on the active planning and layout of Zhejiang's high-quality textile quality standard chain, we will form a "three-step" systematic improvement of the industry with standards, brand quality, and quality promotion. With the breakthrough of advanced standards at each point of the system framework, a modern textile standard system with Zhejiang characteristics will be constructed to help Zhejiang build a national and even international modern textile industry benchmark.
The combination of high-quality products and group standards will lead the modern textile industry in Zhejiang to achieve high-quality development. It is suggested to improve the level of standardization from the aspects of introducing support policies, strengthening team building, and integrating multi-sectoral collaboration, so as to better play the role of textile standardization, and at the same time promote the improvement of the group management system, and jointly promote the high-quality development of modern textile group standards in Zhejiang province.


Construction of a full color gamut mixing model based on four primary colors and color yarn spinning

LI Juanjuan, XUE Yuan, XU Zhiwu, YU Jian, ZENG Dejun

2023, 31(6):  117-129. 

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Color spinning yarn, as a kind of yarn formed by opening, carding, drawing, roving and spinning process of various colored fibers, has a production history of over 30 years in China. At present, the domestic color spinning yarn has more than 10 million spindles. With the progress of new spinning technologies and the gradual accumulation of production experience, the quality level and technological content of color spinning yarn are also gradually improved. Color spinning technology is a technique of spinning two or more colored fibers into a certain hue, lightness, and saturation according to a certain mixing ratio. The color spinning technology using fiber dyeing before spinning process not only greatly reduces pollution in the production process, which is in line with the green and environmental protection production concept, but also each fiber is dyed separately, reducing problems such as staining that may occur in the subsequent process. Nevertheless, as the yarn color cannot be intelligently controlled at the spinning stage, and its actual product application has great limitations, how to achieve innovation in color spinning technology and products has become a challenge for the color spinning industry.
To achieve key technologies such as precise control of yarn color during the development and production of color spinning yarn products, we, based on the double coupling color mixing model, constructed a full color gamut color mixing model by using a 12.5% discrete gradient grid based on four primary colors, constructed the three-element regulation mechanism of “three-channel draft ratio, color fiber mixing ratio, and yarn color value” based on three-channel digital spinning combined with the full color gamut color mixing model and digital three-channel spinning technology, proposed the process method for regulating the hue, lightness, and saturation of formed yarns, selected a number of grid points in the full color gamut blending chromatography and designed the spinning process for full color gamut blended yarns. To achieve online regulation of the blending ratio of colored fibers in the blended yarn by using a multi-channel digital ring spinning machine for three different color roving asynchronous drafting, gradient color matching, and convergence twisting, we spun three series of colored yarns with different hues of equal lightness, different lightnesses of equal hue, and different saturations of equal hue, and tested the evenness, hairiness, and strength of the colored yarn. The test data were compared and analyzed with the performance indicators of the natural color yarn. The results show that the combination of the full color gamut blending model and digital three-channel spinning technology can spin three series of color yarns of equal saturation and different hues, equal hue and different lightnesses,  equal hue and different saturations. Under the same color fiber mixing ratio, the actual spun color yarn is basically consistent with the color comparison in the full color gamut model. The various performance indicators of the actual spun color yarn can meet the first-class requirements of ordinary natural color yarn, proving the feasibility of spinning colored yarn based on the full color gamut mixing model and three-channel digital spinning technology further.
Nowadays, people's requirements for textiles are no longer limited to comfort and durability. Textile products with unique styles and appearance effects are increasingly favored by consumers. As a diverse form of fancy yarn, blended yarn has been a hot spot of many scholars. On the one hand, color is an important appearance indicator, and the construction of full color gamut chromatography further expands the production range of blended yarn. On the other hand, different styles of fancy yarns can also be developed by integrating other spinning technologies, combining different raw materials and optimizing the process, and promoting the development of textiles in the direction of diversification of raw materials, color enrichment and more optimal production.


Innovative design of triple-weft overlapping color flashing digital jacquard fabrics

ZHANG Xin, ZHOU Jiu

2023, 31(6):  130-137. 

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Color flashing fabrics are generally produced with plain weave or plain weave change structure configuration of contrasting color silk lines. The flashing effect of the fabric surface is single, and cannot show the pattern flashing effect. The research and application of digital jacquard technology, especially the proposal of layered combination design pattern of digital jacquard fabrics and the invention of the combined full color structure design method, provide technical support for realizing jacquard fabrics with pattern flashing effect. The triple-weft overlapping flash digital jacquard fabric is a kind of jacquard fabric developed on the basis of the layered combination design mode. It adopts digital design technology for design and production. The surface of the fabric has the special effect of overlapping and flash color. However, we have not found related research literature of triple-weft pile on color flashing fabric color mechanism and the design practice.
We presented the design principle and method of triple-weft overlapping color flashing digital jacquard fabrics, and proved the effectiveness and application value of the design principle and method through the design practice. To address the limited expression and color variation of general color flashing fabrics and to solve the key technical problems of the overlapping effect of triple-weft complex weave patterns and rich flashing effect displayed on the fabric surface, we, according to the basic principle of the layered combination design pattern of digital jacquard fabrics and the design method of total color combination structure, started from the interweaving layer of different colors, explored the design principle of overlapping patterns and the basic principle of color flashing, put forward the design principle and method of triple-weft overlapping patterns and color flashing digital jacquard fabric, and focused on the analysis of the color principle and structure principle of triple-weft overlapping patterns and color flashing digital jacquard fabric design and development. Based on the developed triple-weft overlay and flash fabric, we designed experiments to compare and analyze the effects of observing the fabric from the three different angles of 45 degrees, 90 degrees and 135 degrees. The results show that: (a) when the observation angle is 45 degrees, the fabric has the best overlay and flashing effect, the contrast of color between red and green is obvious, and the weave is exquisite; (b) when the observation angle is 90 degrees, the color expression is not clear, and the flashing effect is poor; (c) when the observation angle is 135 degrees, the weave pattern of the fabric is not clear, the red is obvious, and the flashing effect is satisfactory. Under the condition of 90 degrees, the warp and weft yarns do not cover each other, and the mixed color of the warp and weft yarns is of a certain equal proportion. Under the condition of 45 degrees and 135 degrees, the yarns have different absorption and reflection degrees of light, and the mixing ratios of color are different.
According to the design practice and experiment, the surface of the triple-weft overlapping color flashing digital jacquard fabric will show a special pattern color flashing effect when observed from different angles. It can meet the technical requirements of stable structure and interleaved balance, and realize the digital innovative design of triple-weft overlapping color flashing digital jacquard fabrics on the level of color and technology.


Analysis of volatile gas composition of cotton towels after UVB irradiation

LI Kexin, MENG Fenye, LUO Guohe, YANG Xudong, HU Jiyong

2023, 31(6):  138-144. 

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The current studies on the effects of UV light on cotton towels mainly focus on the changes of their surface morphology and physicochemical properties, and there are fewer studies on the volatile gases of cotton towels under the irradiation of UV light source. To study the gas composition of cotton towels after UVB-313 irradiation, the volatile gases of cotton towels were extracted and detected by headspace solid-phase microextraction coupled with HS-SPME-GCMS.
Pre-treatment with solid-phase microextraction is required to enrich and concentrate the gases to be measured before gas detection, and the extraction conditions largely affect the extraction effect of the gases. To improve the extraction efficiency of the sample, the parameters of extraction time and extraction temperature of the pretreatment were optimized in this experiment before the gas test, and the pretreatment time of 60 min and the pretreatment temperature of 50 ℃ were determined.
The volatile gases of cotton towels after UVB-313 irradiation for different irradiance levels and irradiation times were tested by HS-SPME-GCMS, respectively, and the total ion chromatograph of the samples was obtained by choosing the SCAN full scan format for the test. The GCMS solution workstation was used to process the sample data, and the mass spectra of the tested samples were compared with the standard mass spectra in the NIST library, and the substances with a match of 75% and above were selected as their qualitative results.
The results showed that the gas composition produced at different irradiance levels varied for the same irradiation time. Six volatile gas substances including two aldehydes, one alcohol and three alkanes were produced at 7 W/m2 irradiance, two aldehydes at 5 W/m2 irradiance and only nonanal at 3 W/m2 irradiance.
The odor activity value (ROAV) method was used to evaluate the contribution of the gas to the overall flavor of the samples by combining the relative percentages of gas components and odor threshold values. The two substances that mainly contributed to the aroma of the samples were analyzed to be nonanal with fat and rose fragrance and decanal with strong sweet and fruity fragrance of all the volatile gas components produced by cotton towels after 3 h irradiation by UVB-313 ultraviolet light source with 7 W/m2 irradiance.
Finally, irradiance and irradiation duration were used as independent variables and the relative percentage content of nonanal as dependent variables, which were modeled by a binary linear regression model, and the analysis of the model parameters showed that there was a significant linear relationship between the relative percentage content of nonanal and irradiance and irradiation duration, and the influence of irradiance on the content of nonanal was greater as shown by the standardized coefficients.


Water vapor transfer performance of a fabric system with an underwear air layer

WU Xiangxiang a, WANG Gehui a, b, SHAO Xuening a, ZHAO Tao c, d

2023, 31(6):  145-151. 

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The human body transfers water vapor to the outside environment by sweating. If water vapor fails to be transferred to the outside environment effectively, it will accumulate in the underwear air layer, resulting in increased humidity and human discomfort. The underwear air layer is affected by the skin surface curvature, fabric quality and clothing profile of various parts of the human body. The influence of its existence and thickness on water vapor transmission is relatively complicated. The research on the influence of underwear air layer on wet comfort is also relatively complicated. With the development of related instruments such as perspiration hot plate instrument and water vapor transmission tester, more and more studies have been done on heat transfer of fabric underwear air layer and water vapor transmission of enclosed air layer around. However, the opening air layer around the fabric also has a significant influence on the water vapor transfer performance of the fabric system, which is different from that of the closed air layer. At the same time, there is no corresponding instrument to detect the water vapor transfer performance of the fabric under the open state.
To study the water vapor transfer performance of fabric under the open state of the air layer around, we developed an instrument for measuring water vapor transmission of the fabric system with an open underwear air layer through the design and construction of auxiliary devices on the basis of M 261 fabric moisture permeability tester, and simulated the water vapor transmission rate of the fabric under different air layer thicknesses. On this basis, the corresponding analysis method was used to study the influence of the existence and thickness of the underwear air layer on the water vapor transmission rate of the fabric system. Specifically, under the condition of wind speed of 0.03 m/s, when the thickness of the underwear air layer is 4 mm, the water vapor transmission rate of the fabric system is lower than the water vapor transmission rate of the fabric. Under the condition of wind speed of 0.03 m/s, the water vapor transmission rate of the fabric system increases with the increase of underwear air layer thickness within a certain range. For ordinary clothing fabrics, the water vapor transmission rate of the fabric system reaches the maximum value when the thickness of the underwear air layer is 16 mm, which increases by 29.3% compared with the water vapor transmission rate of the fabric. For the waterproof permeable fabric with a low water vapor transmission rate, the water vapor transmission rate of the fabric system reaches the maximum when the underwear air layer thickness is 20 mm, and there is almost no difference with the water vapor transmission rate of the fabric system for ordinary fabric.
The simulated measurement of the water vapor transmission rate in the underwear air layer is closer to the actual wearing state. The water vapor transmission testing device and experimental method of the fabric system designed can provide reference for further research on the water vapor transmission testing in the underwear air layer.


Calibration methods of a respirator particle leakage rate tester for masks

LIU Sumei, QI Haiyang, PAN Sunqiang, HU Penbing, YE Xiangyu

2023, 31(6):  152-159. 

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Masks are an important defense line to prevent respiratory infectious diseases. The mask respirator particle leakage rate tester is used to measure the ratio of the particle matter concentration that leaks into the mask from all other parts except the filter element of the mask to ambient particle matter concentration outside the mask during inhalation. At present, there are many domestic manufacturers of mask respirator particle leakage rate testers, but there are some common problems such as inconsistent technical parameters and obvious differences performance of different instruments. However, the existing standards do not make requirements for the performance detection. In other words, under the current circumstances, the accuracy of mask particle leakage rate tests cannot be guaranteed. Thus, it is of great significance to ensure the measurement accuracy of particle leakage rate testers for controlling the protective performance of masks. 
The mask respirator particle leakage rate tester generally consists of an aerosol generator, aerosol concentration monitoring devices and a test chamber. The test chamber is airtight in which human subjects can complete the required motions. The aerosol generator generates aerosol particles with the specific concentration and size distribution. The generated aerosol particles are imported into the test chamber through the top interface. After active mixing, it is discharged from the exhaust port at the bottom of the test chamber. Human subjects perform multiple required actions. During each action, the particle matter concentration in the test chamber and the mask was monitored simultaneously. Thus, the leakage rate of masks can be calculated. 
As there is no standard test equipment or standard filtration membrane with metrological traceability for the leakage rate at present, the conditions for comparative evaluation are not available. According to the working principle of the tester, the performance of each key component of the tester needs to be measured and verified by the partial method to ensure the accuracy and consistency of the measurement, including aerosol generation performance, aerosol mixing performance and aerosol collection and detection performance.
In this paper, according to the technical route of aerosol generation-aerosol mixing-aerosol collection and detection, the metrological calibration method of the mask particulate leakage rate tester is studied. Specifically, it involves six items, namely flow rate of aerosol generation, test concentration of aerosol, particle size distribution and median diameter of tested aerosol, aerosol particle space uniformity in the test chamber, flow rate of aerosol collection, and indication error of aerosol mass concentration. These calibration items ensure the accuracy of aerosol generation, mixing and detection, respectively. Thus, the accuracy of mask particle leakage rate tests is guaranteed. 
In this study, the selection of calibration equipment and calibration methods are described in detail. The feasibility and effectiveness of the proposed calibration methods are verified by the analysis of the calibration results of the particulate matter leakage tester of different application institutions.


Research on fabric draping anisotropy

SONG Weinaa, LIU Chengxiaa, b

2023, 31(6):  160-168. 

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The draping of fabrics is mostly tested without distinguishing between directions, generally, it is to research the overall draping. However, the same fabric has significant differences in draping due to different warp and weft yarn densities or distinct fabric structures. Therefore, researching the draping of different directions is necessary. This topic provides an evaluation method for the investigate of multi-directional draping performance of fabrics. In this paper, the traditional method of umbrella-shaped measurement is improved. First,15 common fabrics were chosen and marked in the 0°, 90 °, 45 °, and 135 ° thread directions to test, then use XDP-1 fabric draper to test the fabric's draping and obtain a drape projection image, process and analyze the image to obtain the maximum widening, projection area and drape coefficient in four directions. Finally, the bending length and bending stiffness of the fabric are tested, and the relationship between drape and bending length and bending stiffness in various directions of the fabric is analyzed. 
The maximum widening, projected area and drape coefficient are compared with the bending length and bending stiffness in four directions. Results show that the new indicators have high correlation with both bending length and bending stiffness, with a high correlation at a significance level of 0.01, and the three new indicators are positively correlated with the bending length and bending stiffness. The harder the fabric, the greater its maximum widening and projection area. In other words, the poorer the drape of the fabric, the less prone it is to bending, and the greater its ability to resist bending deformation. The equation between projected area and bending length is a linear function: Y=0.482X1+2.759, R2=0.71, where Y represents the bending length (mm) and X1 represents the projected area (cm2). And the equation between drape coefficient and bending length is a cubic function: Y=0.180X2+10.272, R2=0.70, where Y is the bending length (mm) and X2 is the drape coefficient (%). Then, based on the umbrella method, the anisotropy of fabric drape is analyzed and two indicators are extracted: the maximum widening ratio A1 of warp and weft and the maximum widening ratio A2 of oblique direction. Anisotropy analysis is conducted by combining the drape projection shapes of different fabrics.
The results show that all three new indicators have good correlation with bending length and bending stiffness. The direction of fabric stiffness is prone to wave peaks, while the direction of softness is prone to wave valleys. The better the drape of the fabric in a certain direction, the easier it is to bend, and the smaller the bending resistance in that direction. Therefore, the drape projection of a circular sample can be used to estimate the bending performance of the fabric in a certain direction. It is feasible to measure the drape anisotropy of the fabric using the umbrella method.


Preparation and technology of PLA double-side shearing plush knitted fabric

PENG Li-ping, ZHOU Ke-hua, SHEN Yua

2023, 31(6):  167-173. 

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PLA fiber is a natural recyclable polymer material in the 21st century, and the development and utilization of its products meet the current requirements of green, environmental protection and renewable. It has good social and economic value, which is conducive to the high-quality development of green textile technology in China. Using PLA fiber as raw material, based on weft woven towel tissue, a double-sided shearing plush knitted fabric was developed by weaving on a large circular knitting machine using a small ingots knitting structure.
PLA double-sided shearing plush fabric has the advantages of fluffiness, warmth, breathability, softness, skin-friendly, bacteriostatic, mildew-proof, and no irritation to human skin. It is an ideal fiber fabric for clothing. In order to ensure that the fabric surface is smooth and without creases, and save water, dyeing materials, additives and energy, and truly achieve energy saving, emission reduction, green and environmental protection, this variety should use airflow dyeing machine for printing and dyeing processing. PLA double-sided shearing plush fabric cannot use strong alkali in the process of washing and degreasing and dyeing, reduction and cleaning, otherwise serious hydrolysis of PLA fiber and strong damage of PLA fiber will occur, resulting in short hair, hair loss and other phenomena. In order to overcome the influence of reduction cleaning on PLA fiber damage and its color depth under strong alkali conditions, it is advisable to use the process of low temperature reduction cleaning of soda ash/fuse powder twice, and the ideal color fastness can be obtained. PLA double-sided shearing plush should be dried directly with hot air from the needle board of the stenter machine, which can prevent local high temperature during contact drying, resulting in local hardening of the fabric, hardening of the hand and other phenomena. PLA double-sided shearing plush fabric needs to reasonably adjust the process parameters according to the effect of the cloth in the process of brushing, combing and shearing; In order to prevent "choking" the hair and make the front and back sides of the hair consistent, it is necessary to reverse the cloth; Shearing requires the use of reverse upward machine shearing, which can achieve a uniform, fluffy, dense and plump suede on both sides of the fabric to achieve the desired effect. When PLA double-sided shearing plush fabric is pulled, it is necessary to reasonably adjust the upper and lower air volume and the overfeeding volume of needle board overfeeding; In order to avoid the creasing caused by hardening of the hand feeling, poor bulking sensation and high drop cloth temperature, the hot air temperature must be less than 120 ℃, the action time less than 30 seconds, and the drop cloth surface temperature less than 40 ℃; The finished stenter should not pass through the roll to avoid the effect on the fluffy feeling of double-sided shear.
This paper focuses on the characteristics of PLA fiber, the characteristics of PLA double-sided shearing plush fabric, and elaborates the production process and technical key of PLA double-sided shearing plush products such as weaving, dyeing, reduction cleaning, brushing, combing, shearing and shaping, so as to provide reference for the development of similar products.


Extraction and characterization of cellulose from ramie bone

2023, 31(6):  174-180. 

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Lignocellulosic biomass is a green and degradable carbon neutral resource that contains components such as cellulose to provide sustainable raw materials for the production of biofuels and chemicals. Ramie bone is a cellulose-rich agricultural waste mainly composed of cellulose, lignin and hemicellulose. Cellulose, hemicellulose and lignin are physically and chemically cross-linked and entangled with each other to form a dense supramolecular complex structure that resists damage from the outside world. The complex structure of biomass dictates that it needs to be treated to break the barrier of biomass against depolymerization and to achieve separation of cellulose and other components. The p-toluenesulfonic acid is an acid hydrotropes solvent that forms a colloid with lignin at its hydrophobic end to dissolve lignin, and dissociates hydrogen ions from the hydrophilic end to attack hemicellulose, leaving the cellulose as a solid residue. However, previous studies have tended to focus on the extraction and characterization of lignin using p-toluenesulfonic acid, with less attention being paid to the solid fraction of cellulose. In this study, we used p-toluenesulfonic acid combined with hydrogen peroxide in a one-step treatment of ramie bone to investigate the effects of p-toluenesulfonic acid concentration, hydrogen peroxide concentration, temperature and time on the degumming effect. The results showed that 95.90% of the lignin in ramie bone was dissolved and the cellulose content increased to 80.79% with 75% mass concentration of p-toluenesulfonic acid and 3% volume fraction of H2O2 at 75°C for 80 min, which was 37.61% higher than the original sample. Due to the removal of non-fibrous components, the thermal stability of ramie bone was improved and the surface changed from smooth to rough. Meanwhile, the results of infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis indicated that the combination of p-toluenesulfonic acid and hydrogen peroxide disrupted the structure of ramie bone and promoted the dissolution of lignin. This provides a simple and effective way for the utilization of ramie bone.

Preparation and application properties of silicon oil emulsion stabilized with nanoparticles

XIONG Chun Xian, ZHANG Yun Ju, WENG Yan Fang, Yu Jian Hua, Liu Zuo Ping, Zhang Jian She

2023, 31(6):  181-187. 

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Silicone oil is widely used in textile, leather, paint and other industries. In the textile industry, silicone oil is mainly used in the finishing of textiles, giving fabrics soft, smooth, fluffy and other feel. In printing and dyeing processing, it is often necessary to use silicone oil in the form of emulsion. Taking the common amino silicone oil as an example, on the one hand, soft finishing will bring smooth and soft feel to the fabric, but also make the fabric appear serious slipping, affecting the service life of the fabric; On the other hand, due to its high relative molecular weight and high viscosity characteristics, the dispersion stability of the emulsion is poor. In this paper, the copolymer emulsion particles of isooctyl acrylate (EHA) and methyl methacrylate (MMA) were prepared by semi-continuous seed emulsion polymerization and used as Pickering particles. Pickering silicone oil emulsion stabilized with nanoparticles and emulsifier was prepared to improve the stability of the emulsion and reduce the amount of emulsifier. The resulting emulsion was used in fabric finishing. The effects of Pickering silicone oil emulsion and emulsifier stabilized silicone oil emulsion on the chemical oxygen demand (COD) and the properties (feel, stitch, etc.) of finished fabrics were investigated.
Firstly, the hydrophilicity of Pickering granule latex was evaluated by testing the water contact Angle of the film. The results are shown in the bar chart. The contact Angle test shows that the water contact angles of PEHA, P(EHA-MMA) and PMMA are 88.1°, 88.5° and 89.6° respectively, which are all close to 90°. According to the free energy formula of all three kinds of spherical particles on the "oil/water" interface, they can be adsorbed on the "silicone oil/water" interface to form a stable adsorption layer. Gives Pickering silicone oil emulsion high dispersion stability. In order to obtain a stable emulsion, when the emulsifier is stabilized alone, the amount of emulsifier is as high as 24% of the mass of silicone oil (Table 2). It can be seen from Table 2 that the silicone oil emulsion can be stabilized when only 8% emulsifier and 6% nanoparticles are used in the cooperative stabilization system, indicating that the Pickering emulsion system has a high stabilization efficiency
The emulsification system also has significant influence on the COD value of the working liquid before and after finishing and the feel and stitch property of the finished fabric. When emulsifier is used alone to stabilize the emulsion, the COD value in the finished residue increases sharply with the increase of the emulsifier dosage. Studies have shown that the method of increasing the amount of emulsifier to improve the dispersion stability of the emulsion will lead to a large amount of silicone oil remaining in the residual liquid, which will not only cause the waste of additives and the burden of sewage treatment, but also lead to the deterioration of the feel of the finished fabric (Table 3). By replacing the emulsifier stabilization system with the Pickering emulsion system, the surface friction coefficient of the fabric is lower, the feel rating is 4-5, and the COD value in the finished residue is lower. P (EHA-MMA) nanoparticles not only guarantee the feel of the finished fabric (Table 3), but also make the fabric have good skid resistance.


Preparation of maleic anhydride modified polyvinyl butyral and its application in blue light curing coatings

WANG Guohui, HOU Dongliang, ZHANG Shujuan, CHAI Liqin, WANG Chenglong, ZHENG Jinhuan

2023, 31(6):  188-198. 

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PVB is a polymer material that contains hydroxyl, ester, and acetal groups in macromolecules. The presence of hydroxyl groups makes PVB resin soluble in polar or strongly polar solvents, and can undergo cross-linking reactions with phenolic, urea formaldehyde, epoxy resins, etc., providing strong tear resistance and good bonding performance. The six membered ring structure of the acetal group affects the hardness, toughness, and crystallinity of PVB molecular chains. In addition, PVB resin also has excellent light resistance, water resistance, film forming ability, and impact resistance. The unique structural characteristics enable PVB to be applied in fields such as ceramic printing paper, adhesives, coatings, aluminum foil paper, artificial sponges, etc. However, the most important application field is the production of automotive safety glass sandwich membrane materials. In the event of glass being impacted and broken, the PVB sandwich acts as an energy absorber. This PVB is a high viscosity resin with a molecular weight between 100000 and 250000. Due to the rapid development of the automotive and construction industries, the demand for safety glass has been increasing year by year, which has also led to the accumulation of discarded PVB. Improper treatment can cause environmental pollution and waste of resources. At the same time, due to the pollution of the environment and the harm to health caused by organic solvents, non-toxic, harmless, and environmentally friendly water is used as a solvent to replace the organic solvent system in its application process. In its preparation process, low-cost modifiers and reaction systems should be used as much as possible to reduce reaction steps, increase product yield, and prepare low-cost and high-performance PVB modified products. This has important research significance and can achieve the green application of PVB. Due to the poor hydrophilicity of PVB resin, it can be improved through grafting modification. Maleic anhydride has excellent hydrophilicity and contains carbon carbon double bonds within the molecule, making it suitable for use in the field of blue light curing. Its reaction with PVB is mainly realized by esterification with hydroxyl in PVB after C−O−C bond breaks. Blue light curing technology is that excited state molecules absorb photothermal energy and then undergo chemical reaction to realize the curing of polymerization system. This technology is efficient, low consumption and environmental protection. In order to recover and reuse rPVB, PVB-M was obtained by modifying and grafting pure PVB with maleic anhydride and introducing double bonds. The coated fabric was prepared by UV curing coating technology. The structural characterization of PVB-M showed that the grafting reaction was successful. The polymerization performance of PVB modified by maleic anhydride was the best when the temperature was 70 ℃, the time was 6 h, the amount of maleic anhydride was 3 g, the mass fraction of photoinitiator system was 1%, and the mass ratio of PVB-M to HEA was 1:2. The polymerization performance and membrane mechanical properties of modified PVB were improved. The addition of kaolin promotes the mechanical properties of the light cured film, and the surface structure of the coating slurry applied to the fabric is uniform. On this basis, rPVB was modified to prepare rPVB-M, and the feasibility of its application on coated fabrics was explored. The results showed that there was no significant difference in their performance compared to PVB-M coated fabrics. Therefore, rPVB can be applied in the field of textile coating for recycling and reuse.

Dyeing properties and theoretical study of anionic waterborne polyurethane microfiber leather

HAN Yulan, DU Yuanyuan, SONG Bing, LI Chunlin, NIU Jiarong

2023, 31(6):  199-206. 

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With the shortage of natural leather resources and the enhancement of people's awareness of environmental protection, the development of artificial leather products that can replace natural leather has become a trend of the industry. In recent years, synthetic leather products have been widely used in household, automobile and other industries. As the artificial leather products are most like natural leather at present, microfiber synthetic leather is often dyed to further expand its application range. In the dyeing process of microfiber synthetic leather, the dyeing properties of microfiber and polyurethane were not consistent, and the problems of levelness and poor color fastness often arise in the dyeing process. For the solvent based polyurethane microfiber leather, the current dyeing methods and technologies can meet the market demand. For the waterborne polyurethane microfiber leather, influenced by hydrophilic monomers, the internal structure of the polyurethane is changed, and the adsorption and diffusion behavior of dyes on waterborne polyurethane microfiber leather are also changed correspondingly. At present, the dyeing mechanism and dyeing properties of waterborne polyurethane microfiber leather are rarely studied. In order to improve the dyeing technology of waterborne polyurethane microfiber leather, it is necessary to study the dyeing behavior theoretically.
In this paper, the adsorption kinetics and dyeing thermodynamics of waterborne polyurethane microfiber leather dyed by weak acid dye blue MD-R and neutral dye isolan grey respectively were studied. The uptake of both kinds of dyes on waterborne polyurethane microfiber leather were improved with the increase of dyeing temperature. The blue MD-R was easily to desorpt from waterborne polyurethane microfiber leather, and the equilibrium dye rate decreased. While the neutral dye was easily to congregate, high dyeing temperature was helpful for dispersion and diffusion, so at 90 ℃ the equilibrium dye rate was increased significantly. During the dyeing process, the adsorption of the two dyes conformed to the quasi-second-order kinetic model. There were many micro interstice between the waterborne polyurethane and polyamide microfibers in the leather. During the dyeing process, the dyes were adsorbed on the surface of the microfiber leather and gradually penetrated into the interstice. The isothermal adsorption of the two dyes on the waterborne polyurethane microfiber leather was consistent with Freunlich adsorption model. The thermodynamic calculation results showed that the dyeing affinity of the two dyes were increased with the increasement of temperature. The dyeing of waterborne polyurethane microfiber leather with the weak acid dye was an exothermic process, while with the neutral dye was an endothermic process.


Tension control of rolling and dyeing machines based on chaotic particle swarm auto disturbance rejection control#br#

LI Xingfang, ZHAO Shihai

2023, 31(6):  207-215. 

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Continuous pad dyeing machine is a typical multi-unit joint equipment. According to its pad dyeing process, the continuous pad dyeing machine is divided into unwinding, pad dyeing, drying and winding units. The continuous pad dyeing machine needs to be controlled by constant tension during operation to ensure uniform dyeing of the fabric. If the fabric is subjected to excessive tension, it will produce warp and weft contraction and even fracture, which will affect the quality of pad dyeing. If the fabric tension is too small, it will produce wrinkles or fabric deviation, which seriously affects the economic benefits of enterprises. The pad dyeing unit is the most critical unit of the continuous pad dyeing machine, and its tension control effect will directly affect the printing and dyeing quality of the fabric. Therefore, it is very important to ensure the constant tension of the fabric during the operation of the continuous pad dyeing machine. In this paper, the tension control system of the pad dyeing unit of the continuous pad dyeing machine is taken as the research object. In view of the difficulty of tension control such as tension coupling, the nonlinear coupling mathematical model of the tension system of the rolling mill is established, the static decoupling model is obtained, the control algorithm is designed and verified by simulation experiments.
Firstly, according to the operation mechanism of pad dyeing unit and its structure diagram, the parameters such as moment of inertia in pad dyeing process are analyzed, and the dynamic model of pad dyeing unit is established according to the law of mass conservation and Hooke 's law. By observing the tension mathematical model of pad dyeing unit, it is concluded that there are tension coupling and tension speed coupling between adjacent two rollers, and the system has the characteristics of nonlinear, time-varying, multi-interference and strong coupling. It is difficult to achieve the ideal control effect for the conventional PID controller of this kind of system. In this paper, the tension controller of adjacent rolling workshop is designed by using the combination of chaotic particle swarm optimization ( CPSO ) and active disturbance rejection control ( ADRC ). The dynamic coupling part of the tension system is estimated and compensated by the active disturbance rejection algorithm to realize the complete decoupling of the system, and the chaotic particle swarm optimization algorithm is used to adjust the main parameters of the active disturbance rejection controller online. The tension system of pad dyeing unit is simulated by MATLAB / Simulink, and the control effect of chaotic particle swarm auto disturbance rejection controller and conventional PID controller is observed. The experimental results show that the chaotic particle swarm active disturbance rejection controller is insensitive to the change of internal parameters and has good anti-interference. The control accuracy and stability are better than the conventional PID controller, and it can effectively suppress the tension fluctuation caused by coupling and interference. It is of great significance to improve the overall operation performance of the continuous pad dyeing machine.


Research status and progress of textile materials with sound-absorbing and sound insulation functions

PAN Leilei, FAN Shuo, WANG Yuxuan, ZHANG Hongxia

2023, 31(6):  216-225. 

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As a global environmental problem, noise pollution seriously endangers people's physical health and quality of life, affecting sleep, damaging the hearing system, damaging cardiovascular system, causing mental system dysfunction, reducing work efficiency, and affecting children's intellectual development. Therefore, it is crucial to develop materials with sound absorption and sound insulation functions. The porous structure of textile materials endows them with sound absorption performance, making them widely used in the field of noise reduction.
Textile materials, as porous materials, are based on a combination of sound absorption and sound insulation mechanisms. The sound absorption and sound insulation of textile materials includes three parts. The first part is that the incident sound wave is reflected. The second part is that sound waves enter the pores in the fiber material, causing air vibration and causing sound energy loss. The third part is the multiple reflections of sound waves in the material pores. The biggest advantage of textile materials compared to other flexible materials lies in their processing performance, which can be processed into various shapes, arranged regularly, and distributed evenly. Based on this advantage, textile materials can be combined with other materials to prepare composite noise reduction materials. Materials with sound absorption and sound insulation functions include porous materials, resonant materials, and damping materials. To improve the noise reduction performance of porous textile materials, textile materials are combined with resonance materials and damping materials. Three types of textile composite noise reduction materials can be generated through different construction methods: porous composite noise reduction materials, porous and resonant composite noise reduction materials, and porous and damping composite noise reduction materials. These three composite noise reduction materials can effectively improve the noise reduction performance in the mid to low frequency range and broaden the range of sound absorption frequency bands.
Porous composite noise reduction materials can form three types of materials: multi-layer structure, sandwich structure, and gradient structure by laminating different materials. Porous and resonant composite materials are composites of fibrous porous materials and resonant materials, including thin plates, perforated plates, and microperforated plates. Among them, perforated plate resonance and microperforated plate resonance are the most commonly used resonant sound absorption methods today. In addition, noise reduction functional fillers are also widely used in textile materials, forming porous and damping composite noise reduction materials.
The preparation of composite noise reduction materials by combining textile porous materials with other materials is still the research focus of current sound-absorbing and sound insulation functional textile materials. In addition, with the rapid development of technology and the requirements of sustainable green development, the recycling and reuse of waste fibers and the application of new technologies will be the main development trends in the future. The future sound-absorbing and sound insulation textile materials should develop towards the direction of structural diversification, material composites, intelligent methods, and green environmental protection.


Application and research progress of bionic design in smart textiles

ZHANG Rui, ZHENG Yingyinga, DONG Zhengmeia, ZHANG Ting, SHEN Liming, WANG Jian, ZOU Zhuanyong

2023, 31(6):  226-240. 

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The textile industry in China, where both the economy and technology are rising quickly, has a new market thanks to bionic technology. The fusion of fabric and bionic technology to create electronic fabrics with various functions, such as thermal insulation, structural color generation, and superhydrophobicity, is anticipated to play a significant role in the fields of health detection, intelligent medical care, motion monitoring, and human-computer interaction in a variety of smart wearable devices.
Bionic design of fiber materials is a key strategy for the textile industry to produce textiles with superior qualities. To acquire the excellent functions brought about by these unique structures for the prepared smart textiles, smart bionic textiles are primarily designed to respond to external environmental stimuli inspired by the structure and characteristics of live organisms in nature. Bionic technology has advanced significantly as a result of the ongoing advancements in intelligent technology and biological science, and it is increasingly being used in the textile sector.
The most typical representatives of insulation textiles based on bionic design are polar bears and penguins, whose internal structure is showing a hollow porous structure, and this porous structure enhances their thermal insulation performance. The hollow structure of fibers traps a large amount of air to increase thermal resistance or mimics the internal structure of polar bear hair or penguin feathers to develop heterogeneous fiber fabrics with special cross-sectional shapes. Next there are down of animals such as geese and ducks, whose internal structure shows a branching structure and whose thermal insulation properties are mainly attributed to their nano-scale and the trapped air in the branching structure. An environmentally friendly structured color-generating technology has been developed as a result of China's pressing need for the development of green textiles and eco-textiles. The idea that the shimmering butterfly's wings in the Amazon River Basin produce structural color has a significant impact on how color is generated.
The most typical superhydrophobic textile based on bionic design is a plant with self-cleaning function, which is represented by lotus leaf and water strider leg. There is a nanostructure on the micron structure mastoid on the surface of lotus leaf. This combination of micron structure and nanostructure is the fundamental reason for the self-cleaning function on the surface of lotus leaf. A number of researchers have produced excellent superhydrophobic fabrics mimicking the structure of lotus leaves and water strider legs. The fibers, fabrics, and textile sensors created through the fusion of bionic design and smart sensing textile materials, inspired by the structure of living organisms like spider hair, pale ears, and human skin, have great potential for advancement in the fields of protection, sports, medicine, and military.
The use of bionic techniques to create textiles with a variety of purposes has grown to be a crucial component of smart textile design. These techniques are inspired by the shapes and structures of living organisms found in nature. The use of bionic smart textiles is currently expanding into the medical, aeronautical, and military industries in addition to serving people's clothing requirements. The structure and application areas of multifunctional bionic smart textiles need to be further explored, notwithstanding the impressive achievements that have been obtained by smart textiles created by using bionic technology.


Application progress of conductive fibers in the application of new textiles

XIE Jinlin, ZHANG Jing, GUO Yuxing, ZHAO Zhihui, QIU Hua, GU Peng,

2023, 31(6):  241-254. 

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With the development of new science and technology, textiles are not limited to the applications of warm keeping and beauty. Extra functions such as sensing and indicating are the new trend of the 21st century and the concept of e-textiles and smart textiles emerges as the times require. Thus, conductive fibers have attracted extraordinary attention with the upsurge of interest in flexible and wearable health monitoring systems, energy storage devices and noninvasive human–machine interfaces. In the meantime, conductive fibers also show excellent antistatic and shielding electromagnetic radiation properties, which made conductive fibers the excellent candidate for wearable textile devices and industrial textile products. 
In the 1960s, people began to develop conductive fibers for antistatic purpose, and different types of conductive fibers were gradually developed. So far, conductive fibers can be divided into three main types. The first type is fibers made by inorganic materials such as metals and carbon, but these fibers exhibit poor wearability and conductive instability. The second type is polymer fibers such as PPy and PANI, which show a good conductivity up to 103 S/cm.  However, the preparation process of fiber formation is quite complex because of the high toxic monomer, high molecular weight and oxidation. The third type is composite conductive fibers made through coating or blending fabric technology. By blending or coating conductive polymers, metals or other conductive materials (such as MXene and Graphene), the composite fibers can always inherit the benefits from both conventional fibers and conductive materials.
Currently, the major researches of conductive fibers are focused on textile technology and materials science. Although there are some review articles on the similar topics, it is necessary to summarize the recent development of conductive fibers in the application of next generation textile products. In this study, we present a review of the classification and preparation techniques of conductive fibers, as well as the application and development of antistatic, electromagnetic shielding and flexible sensors in detail. Future perspective is given in the end, which could shed light in the conductive fiber research and industry, especially in the area of smart wearable devices. 


Progress on realistic modeling and simulation of weft knitted fabrics

2023, 31(6):  255-266. 

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Weft knitted fabrics, as an important type of textile, are widely applied in fashion garments, home textiles, automotive interiors, and other fields. However, traditional design and production methods suffer from inefficiency, resource waste, and discrepancies with the actual products. Conducting realistic modeling and simulation research on weft knitted fabrics not only helps accelerate product development speed but also reduces development costs and minimizes trial and error. Therefore, the development of realistic modeling and simulation techniques for weft knitted fabrics is of great significance.
The technology for simulating the visual realism of weft knitted fabrics encompasses two aspects: 2D and 3D. The 2D visual simulation technology primarily focuses on the simulation of surface texture and patterns of weft knitted fabrics, accurately representing their color, texture, and lighting effects. The 3D visual simulation technology further advances on the basis of 2D simulation, accurately simulating the three-dimensional effects of weft knitted fabrics. This technology can more realistically reproduce the details and structural characteristics of weft knitted fabrics, thereby enhancing the realism of visual simulation.
Another key research direction is the physical realism modeling and simulation technology of weft knitted fabrics. This technology simulates the physical characteristics of weft knitted fabrics, such as elasticity, deformation, and fluid behavior, by establishing models based on methods like spring-mass models, mesh models, yarn-level models, or finite element models. By simulating the interaction of weft yarns and the deformation of textile structures, the actual physical behavior of weft knitted fabrics can be predicted more accurately. 
Due to the nonlinear and complex nature of deformation in weft knitted fabrics, although physics-based simulation methods are capable of capturing the fabric's real behavior, there are still challenges of high computational complexity and low simulation efficiency in complex scenarios. Therefore, it is a key issue in improving simulation speed to optimize simulation algorithms to reduce computational complexity while maintaining accuracy to the greatest extent possible.
Currently, the development of weft knitted fabrics' realism modeling and simulation technology is progressing in several aspects. Firstly, the simulation effects will become more detailed to accurately reproduce the intricate features of weft knitted fabrics, such as textures, textile structures, and fabric shading effects. Secondly, the technology will focus more on real-time interactivity, enabling designers and users to quickly adjust and preview the visual effects of weft knitted fabrics, thus enhancing the flexibility of design and purchasing decisions. Thirdly, the simulation technology will emphasize the diversification of weft knitted fabric types, including the simulation of various materials, textures, and knitting methods. This will provide a broader range of choices and applications for different fields. Finally, the application scope of weft knitted fabrics' realism modeling and simulation technology will further diversify, providing support for innovation and development in various industries.


Research progress on fabric-based solar evaporators

HE Hongbei, ZHU Qingkai, REN Haitao

2023, 31(6):  267-276. 

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With the increasing shortage of freshwater resources, using seawater desalination to produce freshwater is a broaden incremental technology for achieving water resource utilization. The current main methods of seawater desalination include reverse osmosis membrane method and distillation method. Compared with traditional seawater desalination technology, solar-driven water evaporation is less costly and more environmentally friendly. In recent years, low-cost solar thermal desalination has been favored by many researchers.
According to the different placement methods of solar absorbers, they can be divided into two types: suspended solar absorbers and surface solar absorbers. The photothermal materials and principles of the two evaporators are not significantly different. They both absorb specific wavelengths of light and cause electromagnetic field changes through plasma resonance or electron transitions. The interaction between electromagnetic waves and substances at the water interface heats up nanoparticles. The suspended solar absorber heats the bulk water, while the surface solar absorber heats the water soaked in the evaporator. Compared with suspended solar absorbers, surface solar absorbers have more advantages.
The loose porous structure of fabrics can provide efficient water transportation, and the flexibility and elasticity of the fabric structure can provide better compatibility with surface solar absorbers. It can also modify the fabric's properties to better combine with photothermal materials. In current research on solar-driven water evaporation, cotton, linen, nylon, aramid, acrylic, and nonwovens are mainly used as substrate materials, and metal nanoparticles, metal oxides, and carbon-based materials as photothermal materials.
Improving the salt resistance of the evaporator can effectively maintain its evaporation rate and extend its service life. There are two ways to improve the salt resistance: increasing the hydrophilicity or hydrophobicity of the evaporator. In improving evaporation performance, it is necessary to balance heat loss, water supply, and salt crystallization. Excessive water can lead to more heat loss, and rapid water evaporation can cause salt to crystallize on the surface of the evaporator, thereby affecting photothermal performance. In order to achieve a balance between heat loss and water supply, there have been two main types of surface solar absorbers in recent years: hydrophilic bilayer structure and structure with dedicated water transport channels. The hydrophilic bilayer structure loses more heat due to wetting during use, and the water absorption rate of the water transport channels structure is higher than the evaporation rate, which does not limit evaporation and can effectively reduce heat loss.
At present, the solar-driven water evaporation with the highest evaporation rate is the surface solar absorber with a bridge structure composed of Janus hydrogel and cotton fabric. The evaporation efficiency of solar-driven water evaporation is relatively low, making it impractical to provide water for households. However, a solar evaporator with a solar thermal area of 1 square meter can meet the drinking water needs of households. With the continuous improvement of solar desalination technology, it will definitely be more widely used in remote and underdeveloped areas in the future.