Table of Content

10 February 2024, Volume 32 Issue 2

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Development of traditional Chinese medicine pulse diagnosis information collection gloves based on flexible sensing technology

WANG Lüfeia, ZHU Weigangb, LUO Jianyib, HUANG Aipingb, XIE Yonga

2024, 32(2):  1-8. 

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With the increasing demand of people for health and medical services, auxiliary pulse diagnostic equipment has the advantages of remote diagnosis, real-time monitoring, convenient self-help, high efficiency and so on, and is increasingly favored by consumers. Currently, pulse diagnostic equipment, such as intelligent pulse monitoring system and dynamic pulse waveform analyzer, has high requirements for environmental conditions, low sensitivity and slightly cumbersome operation. Therefore, the equipment with smaller volume, more convenience, stable performance, simple operation and data visualization has attracted the attention of a wide range of researchers. Our team has developed gloves for collecting pulse information of traditional Chinese medicine. The device can fit perfectly with the skin and has good collection performance.
This paper discusses the functional structure design and implementation of pulse collection gloves, including device preparation, structure design, system construction, operation test and so on. The carbon fiber dimension material independently developed by our team is used in the sensing material in the pulse collection gloves. Two carbon fibers are used as a cross structure and are fixed on the flexible printed board through copper holes, which is used as a single sensing unit. The flexible sensor is placed at the fingertips of the index finger, middle finger and ring finger of the glove. It can not only read the key pulse information of the human body such as Cun, Guan and Chi, but also accurately identify the pulse information of the wrist and neck. The copper wire in the mezzanine channel is used as the transmission line to connect with the sensing unit, and the pulse information is transmitted to the circuit acquisition module on the back of the hand. The pulse information data are processed here and sent to mobile phones, computer terminals and uploaded to the cloud database.
The structural highlight of the pulse collection glove is the sandwich design on the back. When the glove works, with the bending and straightening of the fingers, the transmission line carried by the glove is frequently in a tight and relaxed state. The design of the glove mezzanine channel can realize the relatively loose state of the transmission line all the time, avoid the phenomenon that the transmission line is easy to be stretched and broken during use, and it fits well with the skin, ensuring the stable transmission of pulse diagnosis data.
The pulse diagnosis collection gloves can assist users to digitize and standardize pulse information, provide more stable and rich data tips and references for clinical diagnosis of traditional Chinese medicine, and provide more possibilities for home self-help pulse diagnosis and cloud diagnosis.


Construction and testing of laminated fabric pressure distribution sensing system

CHEN Junpeng, WANG Xiaodong, ZHANG Jikang, LV Peng, PEI Zeguang

2024, 32(2):  9-17. 

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With the development of the Internet of Things and sensing technology, people have designed a pressure distribution sensing system based on the fabric pressure sensing array, realized human-machine intelligent interaction, completed the measurement and analysis of the pressure distribution data of the human body or object, and applied it to the fields of attitude monitoring, classification and recognition. At present, the pressure distribution sensing system can be divided into wearable and non-wearable. Among them, the non-wearable pressure distribution sensing system does not need to be worn during use. It is convenient to integrate with other technologies and has high scalability. It is favored by many researchers and shows broad application prospects in intelligent medical treatment, rehabilitation nursing, and motion detection. However, the pressure distribution sensing system still faces many challenges in preparation and use, such as complex manufacturing process, difficult to achieve large-scale production, can only be used in fixed workplaces, and crosstalk effects.In order to facilitate the application of the pressure distribution sensing system to various occasions and reduce the crosstalk effect, a two-layer laminated fabric pressure sensing array is prepared in this paper. A laminated fabric pressure distribution sensing system is constructed by combining the fabric packaging layer and the data acquisition module. The fabric pressure sensing array is composed of two layers of substrate fabric, silver-plated conductive yarn and sensing unit. The upper layer of the substrate fabric is stitched with silver-plated conductive yarn at equal intervals in the weft direction and the lower layer of the substrate fabric in the warp direction, and the pressure-sensitive material is printed. The two layers of fabrics are stacked orthogonally with conductive yarns to form a sensing unit at the intersection of warp and weft conductive yarns. In order to facilitate the application of the fabric pressure sensing array to various occasions, it is encapsulated with a stacked fabric packaging layer to provide mechanical protection. The data acquisition module of the pressure distribution sensor array is designed to complete the data acquisition and upload, and a reasonable flexible circuit board is designed for the connection between the conductive yarn on the substrate fabric and the data acquisition module. The electrical and mechanical properties of the sensing unit of the fabric pressure distribution sensing system were experimentally studied, and the constructed fabric pressure distribution sensing system was tested. It is found that the reciprocal of the resistance value of the sensing unit is approximately linear with the pressure, and the piezoresistive response characteristics are good. After 500 cycles of pressure tests, the sensing unit can respond stably to external signals. Based on the collected data, the pressure distribution cloud map is drawn. Under four different conditions, the fabric pressure distribution sensing system can better present the distribution of the pressure applied by the measured object. The pressure sensing array with double-layer superimposed structure makes the initial state of each sensing unit in the system more consistent, which can effectively reduce the noise interference introduced by the series-parallel path between the sensing units. The system shows good application prospects in the fields of disease prevention, motion monitoring, fall detection and so on.

Progress in wearable products to improve animal welfare

SHA Shaa, b, LIU Mengjiea, b, CHI Chengb, LIU Yatingc

2024, 32(2):  18-26. 

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To improve the level of animal welfare and reduce the risk of animal diseases, this paper presents wearable animal products from the perspective of animal emotional needs, physiological needs and intelligent disease diagnosis.
The first is the analysis of pet clothing based on the pets' emotional needs. The design takes into account the needs of owners and pets, such as easiness to wear and take off, dirty and wear resistance, easiness to store, etc. At the same time, it should also reflect the practicality and convenience of clothes, pay attention to science, rationality and humanization, so that the owners can experience the sense of care and participation in the process of wearing for pets, so as to get a kind of emotional satisfaction. The emotional needs of pets are mainly reflected in "separation anxiety". To address such problems, it is necessary to explore feasible treatment methods in terms of materials, structure, color, etc. of animal clothing. Second, animal clothing is based on physiological needs. At present, the main objects of animal clothing design are pet cats and dogs, and different varieties have great differences in body shape, which makes it necessary to produce various sizes of clothing in production, and is easy to cause economic losses and bring difficulties to production and sales. In addition, the animal clothing materials used are generally the same as those of the staff, but due to the great differences in the physiological characteristics of humans and animals, the existing animal clothing materials can not fully adapt to the functional requirements of animals in different specific environments. Finally, smart wearable devices are used to diagnose animal diseases of animal behavior and vital signs. With the gradual expansion of the smart wearable field in the market of pet products, smart wearable products have an important application value in monitoring physical and mental health and vital signs. In terms of wearable products that monitor animal behavior, most wearable clothing include sound sensors and acceleration sensors. This kind of monitoring method has high monitoring accuracy, but the equipment generally has low battery life and needs to be replaced frequently. And there is a large number of animals in the farm, so the frequent replacement of products brings great inconvenience to the staff. In addition, in the aspect of wearable products for monitoring animal vital signs, wearable sensors are usually used to measure animal body temperature, which can achieve high accuracy. However, the stress reaction of animals may lead to the displacement of the sensor, which in turn affects the measurement accuracy. At the same time, the high cost and endurance of the products are also one of the main reasons that affect its application.
The research shows that the development trend of wearable products for animal welfare can be summarized into three aspects. First, animal clothing should better meet the spiritual needs of animals, so as to alleviate the common psychological problems of pets. On this basis, a method of combining flexible garment materials and adjustable garment structure is proposed to solve the problem of multitype production. Second, based on the needs of animal living environment and physiological characteristics, the functional clothing fabrics are developed, so as to improve the welfare level of animals and better protect and help them. Third, the use of energy conversion technology to achieve wearability can reduce the number of wearable clothing changes for animals. At the same time, we will also explore the use of functional materials to replace the sensors in biological wearable devices, such as thermochromic materials, to realize the temperature detection of biological wearable devices, so as to solve the problems of expensive and frequent replacement of biological wearable devices.


Research progress on wearable flexible sensors with one-dimensional structure

YUE Xinyana, HONG Jianhana, b

2024, 32(2):  27-39. 

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With the advancement of technology and the growth of market demand, smart wearable technology is developing rapidly. Smart wearable electronic devices are becoming more and more popular in people's daily life including electronic skin, sports wristbands, smart watches, etc. At present, smart wearable devices are gradually developing towards flexibility, light weight and portability, and they need to meet the characteristics of softness and comfort, flexibility and lightness, and fit the human body well.
Textile materials are found everywhere in people's daily life and can be classified according to their form into fibers, yarns and fabrics, subsequently utilized in various textile processing techniques to manufacture various garments and textile products. At different stages of the manufacturing of processing textiles, fibers and yarns have been defined as one-dimensional horizontal structures and fabrics as two-dimensional or three-dimensional horizontal structures. Now various methods have been proposed to endow them with conductive sensing properties to build wearable and flexible sensor devices to play an important role in fields such as sports, health care, and human-computer interaction. One-dimensional structured flexible sensors have the advantages of less integration difficulty, more excellent conformability, flexibility stretchability, and greater malleability compared to non-one-dimensional sensors, allowing for low-cost processing and continuous production. At present, the research on one-dimensional structured flexible sensors has made significant progress, including the perception of temperature, pressure, stretching and optical changes, and the monitoring of object shape, human movement posture, health status and other functions of the sensor. Some researchers have produced electronic skin, smart clothing and smart textile products by processing them with existing knitting and weaving technologies, which has shown great development potential in developing different smart products. Therefore, one-dimensional structured wearable flexible sensors need to be further studied in depth and a series of smart products such as smart textiles, smart clothing and smart wearable devices can be developed through continuous production with existing mature processing technologies. In addition, the possibility of use of one-dimensional structured flexible sensors to build functions including sensing, actuation, and communication has been proven by researchers. In the future, it will promote the advancement of scientific research in the direction of flexible circuits, fabric antennas, multifunctional sensors, etc., and it has become a research hotspot to research and develop flexible one-dimensional structured sensors and to expand the scope of their comprehensive applications.
In summary, as an important branch of flexible sensor devices, wearable flexible sensors with one-dimensional structure have been favored in the fields of wearable technology, health monitoring, and smart electronic skin, and have also gradually integrated into people's daily life to provide convenience. There is no uniform testing standard for the performance of flexible electronics products, which is still a challenge for researchers in their research work. At present, it is necessary to continuously enhance and improve the functionality and practicality of the products to promote the development of wearable flexible sensors with one-dimensional structure in the field of smart wearables. The future endeavor to design one-dimensional structured sensors with high sensing efficiency, multi-modal functionality, and stable performance requires mutual cooperation among researchers in various fields of textile engineering, electronic information, and materials science to promote scientific and technological innovations, and to bring more convenience to people's life and work.


Composition control and performance of silk/wool/cotton colored spun yarn

WANG Dengfeng, LUO Xiaolei, CHEN Wenhao, LIU Lin

2024, 32(2):  50-56. 

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Silk, due to its soft and smooth texture and comfortable touch, has been widely used in fields such as clothing and home textiles, and the silk industry is one of China's important textile industries. However, there are still some challenges in the production and performance of silk fabrics. In terms of production, the silk industry is an energy-intensive and relatively high-emission industry, and the waste water produced during its production process causes certain pollution to the environment, so environmental protection measures need to be strengthened. In terms of products, silk fabrics are prone to damage and deformation when exposed to water, making it difficult to meet the high-quality and diverse competition requirements of the international market. In terms of color spinning technology, the technique of dyeing before spinning is adopted, which blends differently colored fibers or fibers of different colors and types into yarn. This not only greatly reduces the discharge of dyeing wastewater but also enables precise control of yarn color and diverse combinations, thereby producing textiles with unique colors and effects. Therefore, herein, cotton, cashmere, and wool fibers were selected as raw materials and combined with color spinning technology to address the high pollution and inadequate product performance issues in the silk industry.
We designed a series of color spinning yarns with unique luster and performance by adjusting the fiber composition and ratio in the color spinning process. We investigated the influence of different fiber compositions on the performance of color spinning yarns through the observation of the microstructure of fibers in the yarn and the analysis of mechanical properties. Color spinning technology not only achieves complementary advantages between fiber components, but also overcomes the dyeing differences caused by different raw material structures, thereby improving product quality and added value. It provides a new approach for the development of the traditional silk spinning industry, promoting the development of silk products towards serialization, diversification, high quality, and environmental friendliness. Firstly, through SEM analysis of the distribution and composition of the yarn, the fiber distribution in the silk-colored yarn is basically consistent with the preset blending situation, and the resulting mixed color yarn has a uniform color distribution. Then, through the analysis of yarn hairiness and unevenness of the dryness, the influence of fiber composition and forming process on the appearance and style of the yarn was studied. It is found that the addition of short fibers such as cotton and wool will increase the yarn hairiness and unevenness of the dryness, but the phenomenon of hairiness and unevenness of the dryness can be reduced by increasing the twisting degree. Through mechanical performance analysis, it is found that blending cotton fibers with excellent mechanical strength in silk contributes to enhancing the mechanical strength of dyed spinning, while adding wool fibers helps improve the cohesion between fibers, thereby promoting the elongation at break of dyed spinning. In addition, the twisting process can effectively improve the overall mechanical performance of dyed spinning. In terms of color fastness, silk, cashmere, and wool are all protein fibers, which are less prone to dyeing and prone to fading compared to plant fibers. Therefore, the color fastness under different environmental conditions was studied and analyzed. From the environmental conditions, light radiation has the greatest impact on the color fastness of yarns; from the composition, the presence of cotton fibers helps to improve the color retention ability of yarns, while the presence of cashmere may slightly decrease the color retention ability of fibers.
This study provides a new approach for the development of the traditional silk spinning industry, which can achieve the direction of serialization, diversification, and high quality of silk products. At the same time, colored spun yarn is a blended yarn among different types of dyed fibers, which can improve the performance deficiencies of silk products and achieve diversification of silk series products. Furthermore, its productive process has significant energy-saving and emission-reducing advantages.


Preparation of basalt-based composite yarns and their flame retardant fabric properties

LUO Chunxu, LI Hui, WU Minyong, XIONG Xiaoman, LIU Keshuai

2024, 32(2):  57-62. 

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The Basalt fiber is an inorganic fiber, with high-temperature resistance and high strength, but its shear and abrasive properties are poor, and the surface is particularly prone to burr after being subjected to external forces. When the fiber is damaged, it can cause painful damage to human skin. It is significant for making inorganic fiber yarns flexible to make up for the shortage of materials by spinning technology and to strengthen its multi-functions at the same time. In this paper, the basalt fiber was used as the matrix material, and the properties of composite yarn and fabric formed by aramid fiber, ultra-high molecular weight polyethylene and flame retardant viscose were discussed. Basalt inorganic fiber covering mainly contains two layers, with the first layer being the bi-directional covering of filament and the second layer being the covering of staple fibers. By combining the spinning methods and parameters under the two processes, the development of basalt composite yarns was realized, which is expected to provide ideas for research institutes and enterprises.
Basalt core yarn of 10 tex, 44 tex of UHMWPE, and aramid were selected as the outer covering yarn. Firstly, the core yarn was wrapped with different twist directions by using hollow spindle wrapping technology, and secondly, the soft flame-retardant viscose staple fiber was wrapped in the outermost layer by friction spinning technology. By observing the apparent shape of the yarn, and testing the tensile breaking strength, hooking strength, thermal stability, and other quality indexes, we investigated the yarn formation performance and the flame-retardant and anti-cutting performance of the fabric. The surface of the yarn covered by the first layer is smooth and straight, and the surface of the yarn covered by the second layer is given a layer of short fibers, which makes the hand feel softer. The aramid/aramid/viscose yarn has a strength of 197.66 N, a hooking strength of 37.3 cN/tex, and a hooking displacement of 3.8 mm, while the UHMWPE/aramid/viscose yarn has a strength of 175.5 N, a hooking strength of 45.4 cN/tex and a hooking displacement of 6.3 mm. In other words, the aramid/aramid/viscose yarn has high strength and the UHMWPE/aramid/viscose yarn has high tenacity. The thermal stability of the two yarns is excellent, and the core yarn basalt is inorganic fiber, so theoretically there is no loss of mass, and the residual mass of aramid/aramid/viscose yarn and UHMWPE/aramid/viscose yarn at 800 ℃ is 59.2% and 53.8g%, respectively. There is no flowing or dripping burning material during the combustion process, and there will be brittle debris on the surface of the fabric after the combustion, which is the residue of combustion. Some of the basalt is exposed on the surface, but it still acts as a skeleton, and the white material can be revealed from the ultra-high strength molecular weight polyethylene portion of the UHMWPE/aramid/viscose yarn after melting. The limit oxygen index value of the aramid/aramid/viscose fabric and the UHMWPE/aramid/viscose fabric is 35.45% and 28.55%, respectively, indicating evident flame-retardant effect of the two fabrics. The anti-cutting performance of fabrics mainly depends on the external cutting force borne by the surface energy of fabric, and the cutting performance of polyarylene viscose fabric is better than that of aramid/aramid/viscose fabrics, that is, the anti-cutting index of blended fabric prepared in this paper is higher than that of pure fabrics.


Automatic identification of woven fabric weave points based on Gaussian Mixture Model-EM (GMM-EM) algorithm

LIU Wei, YU Ling, WANG Changwei, DENG Wentao, DENG Zhongmin

2024, 32(2):  63-69. 

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The structural parameters of woven fabrics mainly include warp and weft densities and fabric weave. The identification and analysis of these structural parameters is an important prerequisite for textile enterprises to conduct sample design, large-scale production, and quality control. At present, the traditional texture analysis of textile manufacturing mainly relies on external tools and artificial vision, which has strong subjective factors and low efficiency. With the continuous development of digital image processing technology, the traditional textile industry is gradually transitioning towards intelligence and automation. Research on detecting woven fabric weave parameters is more inclined towards automatic recognition. As for automatic recognition, cameras and machine vision are used to replace artificial vision for parameter detection of woven fabric images, which has good objectivity and improves the recognition efficiency, and woven fabric tissue information is quickly obtained. Therefore, automated identification of woven fabric parameters has become a research hotspot. There has been a lot of research on automatic recognition of woven fabric weaves nowadays, but there are still shortcomings in the segmentation and recognition of weave points. The segmentation of weave points only has high accuracy for the segmentation of ideal fabric images, while the recognition of weave points fluctuates greatly for different fabrics and different fabric images, indicating that the adaptability is not ideal.
In order to improve the accuracy and stability of recognition, the effect of Gaussian Mixture Model-EM (GMM-EM) algorithm on woven fabric weave recognition was studied. First, different fabric images were preprocessed and skew correctly to improve the subsequent segmentation of the weave points. Then, the grayscale projection method was used to locate the fabric weave points, and the grayscale co-occurrence moments of the tissue points were extracted as texture features. The texture feature data were dimensionally reduced by using principal component analysis. Finally, two kinds of common unsupervised learning were compared with the EM algorithm for Gaussian Mixture Models (EM-GMM), and four evaluation indicators of unsupervised learning were used for evaluation.
On this basis, for fabric images with warp and weft yarns not perpendicular to each other, the improved grayscale projection method in this paper was used to achieve fabric weave point positioning. The identification algorithm used in this paper was based on the Gaussian Mixture Model-EM (GMM-EM) algorithm to identify the weave chart.
The results of the four evaluation criteria indicate that the recognition algorithm proposed in this paper has high recognition accuracy and good adaptability, achieving automatic recognition of organizational points and outputting organizational charts. Compared with that of the other two clustering algorithms, the recognition performance of this algorithm has been effectively improved.


The structural characteristics and evolution of China′s textile patent technology transfer network

WANG Pengfei, CHENG Hua

2024, 32(2):  70-82. 

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A new round of scientific and technological innovation will help promote the high-quality development of the textile industry and is the key to enhancing the international competitiveness of Chinese textile enterprises. Based on the textile patent technology transfer data as the research object, this paper adopts patent econometric analysis and complex social network analysis methods to comprehensively analyze the evolution process, structural characteristics and development trend of domestic textile patent technology transfer network. The results show that: Since the 21st century, the overall trend of textile patent technology transfer in China has experienced three stages: embryonic period, steady development period and rapid growth period. Under the state's adherence to the strategy of independent innovation and sustainable development of science and technology, domestic technology transfer activities in this field have shown an upward trend year by year, becoming an important link to help scientific and technological resources be transformed into productivity and economic advantages. In terms of the structural characteristics of the overall transfer network, the technology transfer network in this field has changed from nodes, edges and network connections are relatively loose, to the network map showing the network state of dense radiation of nodes and edges, and the technology transfer institutions and frequency have also increased significantly; The main subjects of transfer have gradually become the backbone of technology transfer activities from domestic leading enterprises and multinational companies in the early stage, to textile enterprises such as garments, fiber materials and chemical fibers in coastal areas such as Guangdong, Jiangsu and Zhejiang. In terms of the structural characteristics of individual networks, by establishing a two-dimensional matrix of "breadth-depth", D06 and D01 patented technologies such as textile treatment, fiber, spinning or spinning are located in the "high breadth-high strength" quadrant, which have long been favored by the market. The technology transfer of A41, B65 and D04 patents has also developed rapidly and obtained a wide range of market application prospects. With the help of the activity evolution map of patented technology subcategories, it is found that the scale of textile patent technology transfer in China has expanded rapidly after 2011, and the trend of node increase has shown a relatively significant trend, indicating that the transformation and upgrading of China's textile industry is closely related to the innovation of enterprises in different technical fields. The washing treatment of textiles, the production of artificial filament, thread, fiber and equipment dedicated to the production of carbon fiber, as well as the liquid, gas or steam treatment of textile materials, and other technology transfer activities are more prominent, becoming an important part of the domestic textile technology transfer network. With the influence of the concept of sustainable development and the "low-carbon" policy, the rapid integration and development of technologies in different fields, and the growth rate of patent transfer technologies such as A61 medical textiles and H01 electronic components has increased significantly. Especially the global new crown epidemic at the end of 2019, the technological innovation and transfer represented by medical textiles have a positive role in promoting the needs of society to resist the epidemic and improve the competitiveness of enterprise products, and have become an important part of the technology transfer market attention in recent years．

Stiffness prediction of 3D five-directional circular braided composites with radial yarns based on microstructure

CHEN Bo, ZHANG Shengyu, YANG Xinglin, ZHANG Junmiao

2024, 32(2):  83-95. 

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As one of the main load-bearing components, 3D five-directional circular braided composites have great advantages in mechanical properties, economy and structure, and have been gradually applied in aerospace, maritime transportation and other fields. They are a typical 3D multi-directional circular braided composite material. But due to the high complexity of the internal structure, the research on the mechanical properties of the material is not sufficient, the theoretical prediction is difficult, and the relevant research literature is seriously insufficient, which greatly limits the application and development of 3D five-directional circular braided composites. Therefore, it is of great significance to improve the theoretical research of mechanical properties by studying the mechanical properties prediction and damage evolution law of 3D five-directional circular braided composites.
To effectively predict the mechanical properties of 3D five-directional circular braided composites, the topological structure of 3D five-directional circular braided composites with radial yarns was obtained based on the spatial structure of 3D five-directional circular braided yarns with radial yarns at the meso-scale, considering the cross-sectional shape of the yarns after squeezing each other. The periodic law of circular unit cell braiding was introduced, and the unit cell structure characteristics of 3D five-directional circular braided composites with radial yarns were obtained. The unit cell was divided into three seed cells including “the upper surface unit cell, the internal unit cell and the lower surface unit cell”. The unit cell geometric model and mesh model of 3D five-directional circular braided composites including upper and lower surface sub-unit cells and internal unit cells were established by ANSYS APDL. The appropriate periodic boundary conditions were applied to the geometric model. Starting from the unit cell model, based on the stiffness volume average method, the tensile stiffness prediction of 3D five-directional circular braided composites with pitch lengths of 0.6, 0.7 and 0.8 along the circular axis was carried out, and the results were compared with the results obtained by the theoretical calculation method of mechanical stiffness of composites. The results show that the fiber volume content of the three pitch lengths is 24.94%, 23.33% and 22.04%, respectively. The fiber volume content and braiding angle are inversely correlated with the pitch lengths. The elastic modulus prediction results of the unit cell model are 16.42 GPa, 15.63 GPa and 14.83 GPa, respectively. The theoretical results are 16.96 GPa, 16.25 GPa, and 15.34 GPa, and the longitudinal stiffness is inversely related to the pitch lengths. In the unit cell model, the mutual extrusion of fiber bundles is considered, which makes the fiber volume content in the unit cell model slightly smaller than the theoretical calculation method, resulting in the theoretical calculation results being slightly larger than the unit cell prediction results. The stress distribution of fibers and matrix in the composite is analyzed.
In this paper, the geometric model of the unit cell of the 3D five-directional circular braided composite material of the radial shaft yarn is established based on the microscopic scale. Based on the unit cell model, the stiffness of the 3D five-directional circular braided composite material of the radial shaft yarn is predicted by the stiffness volume average method, and the mechanical properties of the 3D five-directional circular braided composite material are improved.


Preparation and properties of CA/PVA nanofibrous membrane with high water resistance

ZHANG Jiapenga, WANG Yana, b, YAO Jumingb, c, JIRI Militky, DANA Kremenakova, ZHU Guochenga, b,

2024, 32(2):  96-104. 

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Heavy metal ions are widely present in the aquatic environment, not only damaging the aquatic ecosystem, but also accumulating in the human body, and posing a serious threat to health. Therefore, it is necessary to remove heavy metal ions from water. Compared to traditional methods, the membrane separation method has the characteristics of low energy consumption, high accuracy, simple equipment, simple operation, and wide application range, making it one of the most promising separation technologies at present. Among numerous separation membranes, nanofiber membranes have become one of the most widely used separation membrane materials due to their high specific surface area, easy modification, and high adsorption efficiency. Nanofiber membranes can be prepared through various methods, and electrospinning is currently one of the most commonly used preparation techniques. The preparation process is fast, efficient, and the equipment is simple and easy to operate. At present, the use of natural, environmentally friendly, economical, and efficient raw materials to develop water treatment membrane materials has become a research trend. Cellulose acetate (CA) is a derivative of cellulose, which has advantages such as wide source, low price, and biodegradability. Its molecules contain a large number of hydroxyl groups, making it a good natural adsorption material. However, there are also a large number of hydrogen bonds between and within CA molecules, which can cause tight intermolecular connections and make it difficult for molecular chains to move. There are also shortcomings in the mechanical properties of CA nanofiber membranes, such as low strength and poor toughness. Polyvinyl alcohol (PVA), as a good degradable material, not only has good fiber forming properties and excellent mechanical properties, but also has a large number of negatively charged hydroxyl groups on the molecular chain, which can adsorb a large number of heavy metal cations. Therefore, co-spinning CA and PVA can not only improve the performance of CA nanofiber membranes, but also avoid the problem of poor separation ability of nanofiber membranes prepared from a single polymer. However, PVA itself also has some shortcomings. The presence of a large number of hydroxyl groups in PVA molecules gives it good hydrophilicity, which leads to poor water resistance of the prepared nanofiber membrane. However, the water resistance of CA/PVA nanofiber membranes can be effectively improved through glutaraldehyde (GA) steam crosslinking method. Therefore, to prepare a naturally degradable and highly efficient adsorption membrane material, this article uses electrospinning technology to prepare CA/PVA composite nanofiber membranes, and uses the glutaraldehyde vapor crosslinking method to cross-link and modify the membranes. The water resistance and heavy metal ion adsorption performance of the modified membranes under different conditions are explored. The research in this article can provide a fast and efficient method for preparing adsorption membrane materials, and promote the application of CA in the field of heavy metal adsorption.
The results show that CA and PVA still have good spinnability after blending. Due to the acetal reaction between glutaraldehyde and a large amount of hydroxyl groups in the raw material, the surface of the nanofiber membrane gradually densifies. After 24 h in water, the mass loss rate of the modified membrane decreases from 70.76% before modification to 7.28%, effectively improving the water resistance of the CA/PVA nanofiber membrane. The mechanical properties of the modified CA/PVA nanofiber membrane have also been improved to a certain extent, with a fracture strength increased from 0.76 MPa to 1.51 MPa and a maximum elongation at break of 9.30%. It was found by exploring the ion adsorption performance of the membrane that the modified CA/PVA nanofiber membrane reached an adsorption equilibrium for Cu2+ at 2 h, with a maximum adsorption capacity of 89.52 mg/g. Exploration has shown that the modified CA/PVA nanofiber membrane has good water resistance and mechanical properties, and has good adsorption effect on heavy metal ions, providing an effective method for the treatment of heavy metal wastewater.


The rubbing fastness of cashmere fibers dyed with madder vegetable dyes

YU Jianweia, b, HOU Zhanchang, CHEN Chao, YU Zhichenga, b

2024, 32(2):  105-111. 

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As the most commonly used red natural dye, madder is widely used in the dyeing of silk and cellulose fibers. Nevertheless, it is found that the rubbing fastness of cashmere fibers dyed with madder vegetable dyes with alum as the mordant is very poor, with the dry rubbing fastness reaching grade 1, and the wet rubbing fastness reaching grade 2–3, respectively. In contrast, the dry and wet rubbing fastness of cashmere fibers dyed with madder vegetable dyes with ferrous sulfate as mordant can reach grade 3 and grade 4. To explore the reason why the rubbing fastness of the two is so different, scanning electron microscopy tests were carried out on the cashmere dyed by alum and ferrous sulfate, respectively. The results showed that there was a large amount of solid sediment on the surface of cashmere fibers dyed by alum, but no solid sediment was found on the surface of cashmere dyed by ferrous sulfate. This is because the pH value of the solution during alum dyeing is higher than the precipitation point of the aluminum ion, and a large amount of aluminum hydroxide is deposited on the surface of cashmere during the dyeing process. As a result, the madder dye will react with aluminum ions on the surface of cashmere during dyeing, and the madder dye attached to the surface of cashmere cannot be diffused into the interior of the cashmere fiber, resulting in poor rubbing fastness. Ferrous sulfate dyeing is carried out under weak acidic conditions, ferrous ions are slowly and uniformly absorbed and diffused into cashmere fibers to have coordination reaction with cashmere, and the madder dye can diffuse into cashmere fibers and combine with fibers and ferrous ions during dyeing, so both the dry rubbing fastness and wet rubbing fastness are good. Previous studies have shown that the rubbing fastness of madder to silk and cellulose fibers is excellent, but that of cashmere is poor. In this regard, it is proposed to use hydrogen peroxide to moderate de-flake treatment of cashmere fibers. The results show that the hydrophobic scales on the surface of cashmere affect the rubbing fastness of alum dyeing and madder dyeing of cashmere. Moderate scale removal can effectively reduce the deposition on the surface of cashmere during alum dyeing, which has a certain effect on the improvement of the dry and wet rubbing fastness. The dry and wet rubbing fastness of unscaled cashmere can be improved to grade 2 and grade 3. The alum-organic acid system was used to dye the cashmere, and then madder dyeing was carried out. Consequently, the dry and wet rubbing fastness of the madder dyed cashmere was improved to grade 2 and grade 3–4. This is because acetic acid reduces the pH value of the dye solution and inhibits the hydrolysis of alum. However, due to the volatility of acetic acid, some acetic acid volatilized at 80℃, resulting in the rise of pH value of the dyeing solution, and the generation of a small amount of aluminum hydroxide. Further, the alum-acetic acid system is used to dye cashmere, and the dry and wet rubbing fastness of dyed cashmere fibers is increased to grade 4 and grade 5. This is because tartric acid effectively reduces the pH value of alum dye solution, and  Al3+ can be evenly diffused into the interior of cashmere fibers and have coordination reaction with cashmere. During dyeing, madder dye can fully combine with Al3+ and fiber. Moreover, infrared spectrum shows that tartric acid can form hydrogen bond with cashmere, which makes tartric acid, cashmere fiber and madder binding. The dry and wet rubbing fastness of dyed cashmere has been improved to grade 4 and 5, respectively, and the soap fastness and sun fastness are all above grade 4, which lays the foundation for industrial application.

Preparation of durable superamphiphobic coatings on cotton fabric surfaces and their properties

SHAO Mingjun, JIAN Yulan, SAN Fuhua, CHAI Xijuan, XIE Linkun

2024, 32(2):  112-120. 

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With the development of economics and the improvement of living standards, people have more and more requirements for the functionality of cotton fabrics. The preparation of superamphiphobic cotton fabrics with self-cleaning, UV irradiation stability, and antifouling has attracted extensive attention in recent years. Currently, superhydrophobic/superoleophobic cotton fabrics are commonly prepared by pre-constructing micro/nano-rough structures on the surface of cotton fabrics and then modified with low surface energy by fluorinated compounds. However, the preparation methods for superamphiphobic cotton fabrics mostly have the shortcomings for complex processes and relatively long term. Therefore, it is of great significance to explore simple and efficient processes for preparing durable superamphiphobic cotton fabrics.
Cotton fabrics were finished by impregnation method by using the hydrolyzed solution of perfluorodecyltrimethoxysilane(PFDMS), ammonia water, and anhydrous ethanol at the volume ratio of 1:50:50, 1:25:25, 3:50:50. The effects of the PFDMS concentrations and their hydrolyzed time on the surface amphiphobic of the fabrics were investigated. The surface morphology, elemental composition, wettability and mechanical stabilities, and chemical durability of the cotton fabrics were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle tester, abrasion testing machine and UV aging tester. Meanwhile, the anti-fouling, and self-cleaning characteristics of the superamphiphobic cotton fabrics were tested and evaluated.
The results showed that the water/oil contact angle of PFDMS-coated cotton fabrics gradually increases with increasing concentration of the PFDMS solution. The cotton fabrics finished with the volume ratio of PFDMS to ammonia and anhydrous ethanol was 3:50:50 hydrolyzed for 10 min showed superamphiphobic with a water contact angle of 157.2°±0.3° and an oil contact angle of 150.0°±1.4°. SEM and EDX analyses showed that the surface of cotton fabrics finished with PFDMS has dense rough coatings, and two additional 0.66% of F and 3.37% Si elements were found on the surface. The XPS analysis showed obvious signal peaks of Si 2s, Si 2p and F1s, and −CF2 and −CF3 groups were found in the high-resolution of C 1s fit peaks. After 20 times of ultrasonic washing cycles (washing time was 600 min) for PFDMS-coated cotton fabrics, the water contact angle was 156.1°±1.3° and the oil contact angle was 147.7°±1.0°. After 10,000 times of abrasion for PFDMS-coated cotton fabrics, the water contact angle was 154.3°±0.9° and the oil contact angle was 138.4°±1.2°. After 24 h of UV aging, and 24 h of acid-base solution or organic solvent immersion, the contact angle of the surface of the superamphiphobic cotton fabric changed compared with that before the test, but the changes did not exceed 3.0°. The cotton fabric finished with PFDMS shows better self-cleaning properties and excellent anti-fouling to milk, coffee, orange juice, cola and soy sauce liquids. This process is efficient, the prepared cotton fabric has better mechanical stability and chemical durability. The prepared durable superamphiphobic cotton fabric has the potential applications in the field of anti-fouling and self-cleaning.


Adsorption of migratory components from polyethylene film by nylon polyurethane coating

ZHANG Chaoyu, HU Zhubing, ZHENG Siting, ZHU Bo, LIU Jianli

2024, 32(2):  121-129. 

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Polyethylene bags, crafted from polyethylene film, are prevalent in the packaging industry, valued for their lightweight, transparent, soft, and durable properties. They find extensive use in varied sectors, including garment and food packaging. However, these bags contain migratable components such as openers, plasticizers, and other unstable polymers. These components can migrate, causing adverse effects, such as surface stains on nylon fabrics, impacting the quality and visual appeal of the fabrics. Therefore, investigating the adsorption mechanism between the migratable components in LDPE film and the surface of PU nylon fabrics is crucial to mitigate the impact of retained stains on PU nylon fabrics.
To elucidate the mechanism behind the visually visible oily stains on the surface of polyurethane (PU)-coated nylon garments wrapped in low-density polyethylene (LDPE) film, this study employed a combination of experimental testing and molecular dynamics simulation. Initially, the composition of the oily stains on the surface of the PU-coated nylon fabrics and the migratory components of the LDPE film were identified. Subsequently, a comparative analysis of the compositions was conducted. This comparison identified two chemicals: oleic acid amide and erucic acid amide, which are fatty amide slip agents in LDPE. Therefore, this research, via a blend of experimental testing and molecular dynamics simulation, determined that the main contributors to the oily stains appearing on the surface of PU nylon fabrics are the fatty amide slip agents present in LDPE films. Further microstructural analysis illustrated that the migratable components interact closely with the surface of the nylon fabric, forming a cauliflower-like structure. The PU-coated surface of the nylon fabric demonstrated notable oleophilic and hydrophobic properties. Molecular dynamics simulation results revealed that the migratory components in the polyethylene film and the nylon fabric surface primarily adhered through H-bonds and van der Waals forces, with -OH, -NH2, and -CO in the PU producing the principal bonding sites with the polar groups (NCO) of fatty amides.
Through this multifaceted approach, the research clarified the microscopic adsorption mechanism between the fatty amide slip agents—oleamide and erucic acid amide—and PU, in LDPE films. These insights can guide the development of strategies to understand and prevent the occurrence of oily stains during the garment packaging process, offering technical support for the selection of suitable slip agents in garment packaging materials.


Preparation of MoS2/RGO and its flame-retardant finishing effect on polyester fabrics

LI Wei, HAN Binbin, XUE Yangbiao, ZHENG Min

2024, 32(2):  130-146. 

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In recent years, the fire risk associated with textile combustion has increasingly drawn people's attention, leading to higher demands for flame-retardant safety in textiles. Polyester (PET) possesses properties such as high strength, high temperature resistance, abrasion resistance, corrosion resistance, and light resistance. Therefore, it has been widely used in military, agricultural, industrial,and textile fields.However, PET fabrics are highly flammable and generate toxic gases and dense smoke when burned,causing significant loss to human life and property. This exacerbates the hazards of fires. Consequently, conferring good flame retardancy and smoke suppression properties to PET fabrics holds great practical significance and application value in achieving low-smoke, halogen-free flame retardancy in PET textiles.
Graphene is a two-dimensional (2D) honeycomb nano-material composed of sp2-hybridized carbon atoms. It has garnered considerable attention due to its well-known properties, including superior mechanical strength, extremely high carrier mobility, and excellent thermal conductivity. Graphene has been successfully applied in various fields. Particularly, graphene exhibits high thermal stability. Compared to existing flame retardants, graphene and its derivative, reduced graphene oxide (RGO), are considered environmentally friendly halogen-free flame retardants that can improve the flame retardancy of polymer composites. However, the flame retardant effect of a single agent is limited, especially in suppressing the dense smoke generated during the combustion of PET. The inhibitory effect of graphene-based flame retardants is not ideal. To address this, we introduce molybdenum disulfide nano-materials. Molybdenum disulfide nano-materials prepared by hydrothermal method exhibit excellent thermal stability and can maintain the stability of the layered structure at higher temperatures, thus exerting the barrier effect of the layered structure. The transition metal molybdenum promotes the formation of a char layer during fabric combustion, accelerating the formation of a dense carbon layer, which acts as a physical barrier, slowing down the heat and mass transfer during the combustion process, and improving the flame retardancy of the fabric. Additionally, molybdenum elements can suppress smoke, effectively reducing the toxicity and smoke density of the fabric during combustion, thereby providing more valuable time for fire escape and rescue.
A MoS2/reduced graphene oxide (MoS2/RGO) composite material was prepared using a hydrothermal method, and the PET fabric was then treated by an immersion-rolling process. The structure and properties of the MoS2/RGO composite material and the MoS2/RGO-modified PET fabric were characterized using scanning electron microscopy, transmission electron microscopy, Raman spectroscopy,infrared spectroscopy,smoke density chamber, and cone calorimeter.The results showed that the MoS2/RGO composite material was well coated on the fabric. The thermal stability of the treated PET fabric was significantly improved, with a 35% increase in residual char yield compared to pure PET fabric at 700℃. The limiting oxygen index of the fabric modified with MoS2/RGO reached 28.2%, which was 8.9% higher than that of pure PET. The total heat release rate decreased by 60.5% compared to pure PET fabric, and the smoke density was reduced by 56.9% compared to the pure fabric. The modified fabric achieved self-extinguishment in vertical burning tests,and the char length decreased to 10.6 cm. After treatment,the contact angle of the PET fabric decreased to 0° at 2.2 s, effectively improving the wearing comfort of PET.