为深入了解化工产品聚乙烯超细纤维制备现状，从纤维细度出发，对国内外聚乙烯超细纤维非织造工艺进行综述分析。梳理了凝胶纺丝、闪蒸相分离、静电纺丝、熔喷4条路线的成丝机理、细化方法及目前存在的问题，剖析了凝胶纺丝中溶胀、溶解行为及高品质凝胶液与超倍拉伸的关联；探讨了闪蒸相分离中的相态变化、超临界CO₂“绿色制造”方法；针对聚乙烯非极性、分子量大、黏度高的物性，归纳了使用溶剂、添加导电粒子的溶液电纺以及通过共混小分子极性物质、提高降解温度升温降黏、增设环境温度延长鞭动时间来细化纤维的熔体电纺；分析了工艺参数对共混熔喷后开纤剥离多组分纤维的影响。最后指出使用超临界绿色流体、无卤素环境友好型溶剂等绿色制备方式为未来热点研究方向。

To understand the development status of polyethylene （PE） ultrafine fibers as a chemical product， the nonwoven technology of ultrafine fibers at home and abroad was introduced and analyzed from the aspect of fiber fineness， and the spinning mechanisms， refining methods， and existing problems of wet spinning， flash phase separation， electrospinning， and melt blowing methods were reviewed. The key factors of wet spinning were high⁃quality gel solution and super drawing. The morphology of the prepared fibers was directly influenced by the degree of entanglement of polymer molecular chains， phase changes， and degree of synergistic curing and stretching of multiphase flow in flash evaporation phase separation. Due to the non⁃polar nature， high molecular weight， and high viscosity， PE is mostly electrospun through using solvents and conductive particles in solutions. However， greener melt electrospinning has attracted attention， because it can refine the fibers through blending small molecular substances， improving degradation temperature， lowering viscosity， and setting environmental temperature to extend whip time. The effect of process parameter on the separation of multi⁃component fibers after blending and melt spraying was analyzed. Finally， the hot research directions in future were pointed out， including the sustainable development technologies for supercritical green fluids and halogen⁃free environmentally friendly solvents.

Textile-based triboelectric nanogenerator (T-TENG) devices, particularly, narrow-gap mode, have been conceived and developed for obtaining energy harvesting and tactile sensing devices unaffected by the external environment. Enhancing the interfacial area of T-TENG materials offers exciting opportunities to improve the device output performance. In this work, a narrow-gap T-TENG was fabricated with a facile process, and a new strategy for improving the device output is proposed. The new structural sensor (polydimethylsiloxane (PDMS)-encapsulated electroless copper plating (EP-Cu) cotton) with multiple electricity generation mechanism was designed and fabricated for enhancing recognition accuracy. The result shows that only PDMS layer strain was established at an external stress of 1.24-12.4 kPa and the fibers laterally slip at a stress of 12.4-139 kPa; more importantly, the output performance of the TENG displayed a linear relationship under corresponding stress ranges. The as-fabricated device demonstrated the ability to convert different energies such as vibration, raindrops, wind and human motions into electrical energy with excellent sensitivity. Interestingly, the output signal of the as-fabricated TENG device is a combination of output signals from PDMS/EP-Cu and PDMS/recognition object devices. To be precise, there are two TENG devices (PDMS/EP-Cu and PDMS/recognition object) that work when the as-fabricated TENG device is under 12.4-139 kPa stress. Accompanied by unique characteristics, the generated TENG signals are capable of recognition of contact materials. Combining the TENG signal and deep learning technology, we explore a strategy that can enable the as-fabricated device to recognize 8 different materials with 99.48% recognition accuracy in the natural environment.

以2种熔体流动速率（MFR）不同的再生聚乙烯为原料，二氟一氯甲烷和四氟二氯乙烷混合物为溶剂，采用闪蒸法制备了2种再生聚乙烯无纺布，并通过扫描电子显微镜（SEM）、差示扫描量热仪（DSC）、电子强力机和数字透气度仪等对其表观形貌、热性能、力学性能、透气性和抗水压性等进行了表征和测试。结果表明，基于闪蒸法制备的再生聚乙烯无纺布由超细纤维黏连堆叠而成，其最大拉伸断裂强力为233 N/5 cm，最大断裂伸长率为77 %，且具有良好的透气性、抗静水压性、印染性和阻隔性；制备的再生聚乙烯无纺布具有良好的综合性能，实现了再生聚乙烯赋能增值的目标，符合可持续发展理念，具有广阔的市场前景。

Two types of recycled polyethylene non?woven fabrics were prepared by a flash evaporation method using two types of recycled polyethylene with different melt flow rates as raw materials and a mixture of difluorochloromethane and tetrafluorodichloroethane as solvents. Their morphology， thermal properties， mechanical properties， air permeability， and water resistance were investigated using a scanning electron microscope， a differential scanning calorimeter， an electron intensity meter， and a digital air permeability meter. The results indicated that the recycled polyethylene non?woven fabrics were both composed of ultra?fine fibers. They exhibited maximum tensile breaking strength of 233 N/5 cm， maximum elongation break of 77 %， good air permeability， high resistance to hydrostatic pressure， good printing and dyeing properties， and satisfactory barrier performance. With such good comprehensive properties， the recycled polyethylene non?woven fabrics reach the goal for achieving addition value in the recycled polyethylene. This matches the sustainable development target and shows a broad market prospect in near future.

Recently, the usage of melt blown products in many areas has increased. In melt blown process, generally polymers have been used. There are a variety of polymers. Characteristics of melt blown nonwovens have changed significantly depending on the polymer type. Also, there are several parameters such as die temperature, die-to-collector distance (DCD), air pressure, etc. that modify the nonwovens in melt blown process. The purpose of this paper is to investigate the effect of these parameters on the characteristics of nonwovens made up of polyethylene (PE).

Since the 1970s and 1980s, a major effort has been made to study UHMWPE (Ultra-High Molecular Weight PolyEthylene) fibers with remarkable mechanical properties, based on a basic polymer such as PE (PolyEthylene). These performances are above all associated with a very strong alignment of the molecules and the microfibrillar structures formed using various processes. However, they vary greatly depending on many parameters, and particularly on the draw ratio. Thus, these characteristics have been extensively analyzed by dynamic, static tensile, and creep tests, and are predominantly viscoelastic. The behavior appears to be associated with physical considerations and with the characteristic orthorhombic-hexagonal solid phase transition. The presence of a hexagonal phase is detrimental to the behavior because the chains slide easily relative to each other. Shifting this transition to higher temperatures is a challenge and many factors influence it and the temperature at which it takes place, such as the application of stress or annealing. The objective here is to give an overview of what has been done so far to understand the behavior of UHMWPE yarns. This is important given future numerical modeling work on the dimensioning of structural parts in which these UHMWPE yarns will be reinforcements within composites.

Flash-spun nonwoven (FS-NW) is gaining attention in the PPE field due to its excellent barrier and mechanical properties resulting from its non-uniform diameter distribution and unique filament morphology. The unique network structure of flash-spun filaments (FSF) comprising the FS-NW can be controlled by phase separation behavior in the supercritical fluid (SCF) process. This study proposes a simple method to control the microstructure of FSFs by controlling the pressure-induced phase separation (PIPS) process in polymer/SCF solution. This phase separation behavior of an HDPE/SCF solution was confirmed by using a high-pressure view cell. A multistage nozzle allowing for phase-separated pressure to form different phases was also designed. HDPE-FSFs were synthesized by flash-spinning, and their morphology, crystallinity, and mechanical properties were investigated. The results demonstrated that the filaments obtained by PSP control at 220 °C and with an HDPE concentration of 8 wt% showed a network structure composed of strands, wherein the diameters ranged from 1.39 to 40.9 μm. Optimal FSF was obtained at 76 bar, with a crystallinity of 64.0% and a tenacity of 2.88 g/d. The PIPS method can thus effectively control the microstructure more feasibly than temperature- or solvent-induced techniques and can allow the effective synthesis of various products.

为探究高效制备工艺,获得综合性能优良的超细聚乙烯非织造材料,以低密度聚乙烯(LDPE)为原料,制备了低密度聚乙烯熔喷非织造布。研究了热风温度、热风流量、模头温度、接收距离和熔体流量等熔喷工艺参数对LDPE纤维平均直径的影响规律,并进一步考察了熔喷非织造布的过滤性能和力学性能。结果表明:提高热风温度、热风流量和模头温度等均有助于降低纤维的平均直径,所制备纤维最小平均直径可达5.3 μm,熔喷非织造布的最大拉伸强力为6.12 N,抗拉强度为2.16 MPa;经过热压工艺处理后,面密度为120 g/m²的LDPE非织造布在32 L/min流量下的过滤效率可达75%以上,平均过滤阻力为80 Pa。

<p id="p00010"><strong>Objective</strong> Polyethylene (PE) nonwovens have excellent characteristics such as softness, corrosion resistance and hydrophobicity, and have broad application prospects in medical packaging, clothing, filtration and other fields. However, the traditional preparation process of high-performance polyethylene nonwovens is cumbersome, and the production process involves a large number of toxic solvents, and the production efficiency is low. Exploring the efficient preparation process of ultrafine polyethylene nonwovens has become an urgent research problem to be solved. Melt-blown technology is a common and efficient preparation method for microfiber, and the preparation of polyethylene microfiber by melt-blown method is rarely reported.</p><p id="p00015"><strong>Method</strong> The preparation of low-density polyethylene(LDPE) melt-blown nonwovens was achieved by using a self-assembled melt-blown testing machine. The effects of different processes on the diameter of LDPE fibers were studied by controlling a single variable and adjusting the melt-blown process parameters in the experiment, including hot air temperature, hot air flow, mold temperature, melt flow and receiving distance. In addition, the filtration efficiency and tensile properties of LDPE melt-blown nonwovens were also studied.</p><p id="p00020"><strong>Results</strong> The effects of melt-blown process parameters on the diameter of LDPE fibers were studied, including different hot air temperature, hot air flow rate, die temperature, receiving distance and melt flow rate. The results showed that increasing the hot air temperature, hot air flow rate and die temperature would reduce the average diameter of the fiber, and the average diameter of the fiber would increase after increasing the receiving distanc and melt flow rate. The minimum average diameter of the prepared fibers reached 5.3 μm, offering reference value for further preparation of polyethylene microfibers. The filtration performance of LDPE melt-blown nonwovens with different areal densities was explored, and the effect of areal density on LDPE filtration efficiency and filtration resistance was established, with the increase of areal density, the filtration efficiency and filtration resistance of melt-blown nonwovens showed a gradual upward trend. The filtration resistance was increased from 5.1 Pa to 20.9 Pa, and the filtration efficiency increased from 52.89% to 59.32%. After hot pressing treatment, the filtration efficiency of the 120 g/m² nonwoven fabric reached more than 75% at a flow rate of 32 L/min, and the average filtration resistance is 80 Pa. The mechanical properties of LDPE melt-blown nonwovens with areal densities of 25 g/m², 50 g/m² and 120 g/m² were investigated. The nonwovens with higher areal density were found to withstand greater tensile strength, and when the areal density is 25 g/m², the LDPE melt-blown nonwovens demonstrated the highest elongation at break, up to 75%. When the areal density was 120 g/m², the maximum pulling force and tensile strength of melt-blown nonwovens were the highest, reaching 6.12 N and 2.16 MPa, respectively.</p><p id="p00025"><strong>Conclusion</strong> The melt-blown process can realize the efficient preparation of LDPE nonwovens, and the average diameter of the fiber decreases with the increase in hot air temperature, hot air flow rate and die temperature, and increases with the increase of receiving distance and melt flow, and the filtration efficiency, filtration resistance and tensile strength of melt-blown membrane increase with the increase of surface density of nonwoven. Process parameters would affect the microstructure and pore morphology of the fiber membrane, resulting in changes in mechanical properties and filtration properties. Furthermore, the microstructure of the melt-blown nonwoven can be changed by post-treatment processes such as hot pressing, and products with better performance can be obtained. So as to enhance the market potential and application value of polyethylene melt-blown nonwovens in the field of medical protection.</p>

为解决聚乙烯纤维细化难题，实现聚乙烯超细纤维及其膜材的制备与应用，在传统熔喷工艺的基础上改进熔喷模头并引入静电场，制备了低密度聚乙烯（PE⁃LD）超细纤维及其非织造布。研究了静电场强度和静电场作用距离对非织造布形态、纤网结构和直径分布的影响，进一步地，对比了引入电场前后非织造布在过滤、疏水和力学性能方面的差异。结果表明，随着静电场强度增加，纤维的平均直径从9.82 μm减少到8.07 μm，纤维的直径分布变窄，非织造布的过滤效率增加。在流量为32 L/min时，最高过滤效率可达73.65 %，过滤阻力19.1 Pa，且随着电场的增强，非织造布的疏水效果得到提升。这种静电喷纺方法可适用于高黏度熔体的微纳纤维及其非织造布的连续性制备，在滤材及包装等市场具备广阔的应用前景。

To address the challenges in refining polyethylene （PE） fibers and realize the preparation and applications of ultra⁃fine PE fibers and their membranes， a type of low⁃density PW （PE⁃LD） ultra⁃fine fibers and their nonwoven fabrics were successfully produced through improving the traditional melt⁃blown process by modifying the melt⁃blown die and introducing an electrostatic field. The effects of electrostatic field strength and distance on the morphology， web structure， and diameter distribution of the nonwoven fabrics were investigated. Furthermore， the differences in filtration， hydrophobicity， and mechanical properties of the nonwoven fabrics before and after introducing the electrostatic field were compared. The results indicated that the average fiber diameter decreased from 9.82 μm to 8.07 μm with an increase in the electrostatic field strength， and the fiber diameter distribution became narrow. This improved the filtration efficiency of the nonwoven fabrics. At a flow rate of 32 L/min， the highest filtration efficiency reached 73.65 % at a filtration resistance of 19.1 Pa. In addition， the hydrophobic performance of the nonwoven fabrics was enhanced with an increase in the electrostatic field. Such an electrostatic spinning method is suitable for the continuous preparation of high⁃viscosity melt micro⁃nano fibers and their nonwoven fabrics. The obtained products presented broad application prospects in the markets such as filtration materials and packaging.

Polymer crystallization is accompanied by a partial macromolecular chain alignment process, which has significant effects on the mechanical, thermal, and optical properties of polymer materials. Particularly, the properties of such widely used nonwoven products as spunbond webs are strongly affected by the degree of crystallinity achieved during their manufacturing. The present work aims at predicting the degree of crystallinity of spunbond webs accounting for thermally-driven and flow-induced crystallization coupled with the dynamics and thermal history of spunbond fibers. In principle, the degree of crystallinity could be in the 0–1 range; however, for semi-crystalline polymers, the degree of crystallinity practically saturates at a lower-than-one value. The degree of crystallinity of 100 spunbond fibers is predicted coupled with the fiber evolution and the final three-dimensional structure of a nonwoven web. The predicted evolution of the degree of crystallinity and its distribution in a three-dimensional spunbond web is discussed in detail. The results reveal that the distribution of the degree of crystallinity over the spunbond web is non-uniform. The effects of nozzle temperature, air-blowing speed, and belt speed on spunbond web characteristics, including the degree of crystallinity, are also investigated in detail.

A drying method involving the use of a thermobalance was employed to determine the bound water in mechanical and chemical pulp fibers. The precision of this method is dependent on the uniformity of the test materials. The coefficient of variability of bound water determination on mechanical pulps ranged from 15 to 18% based on one in dividual sample. This variability decreased in chemical pulps, 10 to 12%, and about 2% in α-cellulose. For a precision superior to ±10% (95% confidence level) a minimum of 10 individual mechanical pulp samples have to be tested. Similary, seven and one tests have to be made on chemical pulps and α-cellulose, respectively. The method should be useful to the study of the drying behavior of homogenous materials such as low-yield pulps and cotton or other textile materials.

为研究光敏剂在纺织材料上负载的抗菌效果和其在纺织品改性中应用的可能性,通过文献调研的方式对光动力抗菌的研究背景、光敏剂的种类、抗菌纺织品的应用情况、光敏剂常用的负载形式进行归纳整理。研究表明:作为一种能高效杀菌的新型抗菌材料,光动力抗菌纺织品具有良好的发展前景;通过化学共价键合光敏剂的改进负载方法能够解决常见负载方式中出现的结合牢度差、重复利用性不佳等问题,进一步拓宽抗菌材料的研发途径;目前光敏剂对其光敏抗菌性能均未能做到精准调控,今后的研究应当通过控制光敏剂的种类及光敏剂浓度等因素实现对光敏抗菌性能的把控。

In order to study the antibacterial effect of photosensitizers loaded on textile materials and the possibility of its application for textile modifications, the research background of photodynamic antibacterial, types of photosensitizers, current applications of antibacterial textiles, and photosensitizers were systematically reviewed. The commonly used loading forms of the drug are examined, and the conclusions and future prospects are summarized. The review indicates that photodynamic antibacterial textiles are a new type of antibacterial material that can be effectively sterilized and has a good development prospect. The improved loading method through chemical covalent bonding of photosensitizers can solve the problems of poor binding fastness and poor reusability associated with the commonly used loading methods, and can further broaden the research and development path of antibacterial materials. At the same time, it is realized that the current photosensitizers have not been able to control accurately their photosensitizing antibacterial properties. Future research should control the photosensitive antibacterial properties by controlling the types of photosensitizers and the concentration of photosensitizers.

For many antibacterial polymer fibres, especially for those with natural functional additives, the antibacterial response might not last over time. Moreover, the mechanical performance of polymeric fibres degrades significantly during the intended operation, such as usage in textile and industrial filter applications. The degradation process and overall ageing can lead to emitted volatile organic compounds (VOCs). This work focused on the usage of pine rosin as natural antibacterial chemical and analysed the weathering of melt-spun polyethylene (PE) and poly lactic acid (PLA) polyfilaments. A selected copolymer surfactant, as an additional chemical, was studied to better integrate rosin with the molecular structure of the plastics. The results reveal that a high 20 w-% of rosin content can be obtained by surfactant addition in non-oriented PE and PLA melt-spun polyfilaments. According to the VOC analysis, interestingly, the total emissions from the melt-spun PE and PLA fibres were lower for rosin-modified (10 w-%) fibres and when analysed below 60 ℃. The PE fibres of the polyfilaments were found to be clearly more durable in terms of the entire weathering study, i.e., five weeks of ultraviolet radiation, thermal ageing and standard washing. The antibacterial response against Gram-positive Staphylococcus aureus by the rosin-containing fibres was determined to be at the same level (decrease of 3–5 logs cfu/mL) as when using 1.0 w-% of commercial silver-containing antimicrobial. For the PE polyfilaments with rosin (10 w-%), full killing response (decrease of 3–5 logs cfu/mL) remained after four weeks of accelerated ageing at 60 ℃.

为深入了解无机抗菌剂的优缺点,制备性能更加优异的抗菌织物,对国内外相关研究进展进行了综述。分析了金属型和光催化型无机抗菌剂的抗菌机制,介绍了银系、铜系、锌系以及复合型的无机抗菌剂在纺织品领域的研究进展。指出:与其他类型的抗菌剂相比,无机抗菌剂具有广谱性强、不易使细菌产生耐药性等优点,但是在实际应用中也存在着一些问题,如银系抗菌剂价格昂贵;铜系抗菌剂颜色较深;锌系抗菌剂抗菌效果较弱等,通过与其他抗菌剂进行复合可以制备性能优异的复合抗菌织物,未来的研究方向应该是开发具有功能复合化、智能化、舒适性好等特性的多功能抗菌织物。

To gain an in-depth understanding of the advantages and disadvantages of inorganic antimicrobial agents and to prepare antimicrobial fabrics with improved performance, the relevant research progress was reviewed. The antimicrobial mechanisms of metal-based and photocatalytic inorganic antimicrobial agents were briefly introduced, and the research progress of silver-based, copper-based, zinc-based, and composite inorganic antimicrobial agents in the field of textiles was mainly introduced. Compared with other types of antimicrobial agents, inorganic antimicrobial agents have the advantages in strong broad-spectrum and are not easy to make bacteria resistant, but there are some problems in practical application, including silver antimicrobial agents being expensive, copper antimicrobial agents darker, zinc antimicrobial agents weaker and so on. By compounding with other antimicrobial agents, compound antimicrobial fabrics with excellent performance are possible to be achieved. The future research direction should be the development of multi-functional antibacterial fabrics with the characteristics of functional compounding, intelligence, and good comfort.

Serving as matrices, polypropylene (PP) melt-blown nonwoven fabrics with 4% electrostatic electret masterbatch were incorporated with a 6%, 10%, 14%, or 18% phosphorus-nitrogen flame retardant. The test results indicate that the incorporation of the 6% flame retardant prevented PP melt-blown nonwoven fabrics from generating a molten drop, which, in turn, hampers the secondary flame source while increasing the fiber diameter ratio. With a combination of 4% electrostatic electret masterbatch and the 6% flame retardant, PP melt-blown nonwoven fabrics were grafted with ZIF-8 and Ag@ZIF-8. The antibacterial effect of ZIF-8 and Ag@ZIF-8 was 40% and 85%, respectively. Moreover, four reinforcing measures were used to provide Ag@ZIF-8 PP melt-blown nonwoven fabrics with synergistic effects, involving lamination, electrostatic electret, and Ag@ZIF-8 grafting, as well as a larger diameter because of the addition of phosphorus-nitrogen flame retardants. As specified in the GB2626-2019 and JIS T8151-2018 respiratory resistance test standards, with a constant 60 Pa, Ag@ZIF-8 PP melt-blown nonwoven membranes were tested for a filter effect against PM 0.3. When the number of lamination layers was five, the filter effect was 88 ± 2.2%, and the respiratory resistance was 51 ± 3.6 Pa.

With the increased scientific interest in green technologies, many researches have been focused on the production of polymeric composites containing naturally occurring reinforcing particles. Apart from increasing mechanical properties, these additions can have a wide range of interesting effects, such as increasing the resistance to bacterial and fungal colonization. In this work, different amounts of two different natural products, namely neem and turmeric, were added to polyethylene to act as a natural antibacterial and antifungal product for food packaging applications. Microscopic and spectroscopic characterization showed that fractions of up to 5% of these products could be dispersed into low-molecular weight polyethylene, while higher amounts could not be properly dispersed and resulted in an inhomogeneous, fragile composite. In vitro testing conducted with Escherichia coli, Staphylococcus aureus, and Candida albicans showed a reduced proliferation of pathogens when compared to the polyethylene references. In particular, turmeric resulted in being more effective against E. coli when compared to neem, while they had similar performances against S. aureus. Against C. albicans, only neem was able to show a good antifungal behavior, at high concentrations. Tensile testing showed that the addition of reinforcing particles reduced the mechanical properties of polyethylene, and in the case of turmeric, it was further reduced by UV irradiation.