Investigation of thermal comfort properties of electrospun thermoplastic polyurethane fiber coated knitted fabrics for wind-resistant clothing

The integration of nanofibers into conventional fabrics may open up new opportunities such as improving the comfort performance and thermal management properties of outdoor clothing. Nanofibers are able to form a highly porous mesh and their large surface-to-volume ratio improves performance for many applications. This study shows the possible utility of the nanofiber coating on conventional knitted fabrics for improving the wind-resistance and breathability properties. It was seen that nanofiber coating did not cause a significant effect on water vapor and thermal resistance of electrospun thermoplastic polyurethane nanofiber coated cotton (CO), modal (CMD), viscose (CV), and lyocell (CLY) single jersey fabrics, while resistance to air permeability was increased with the increased nanofiber coating. High level of air resistance was achieved with 30 min of coating. In terms of comfort properties, the nanofiber coating proved to be advantageous due to its lower air permeability with its water vapor permeable structure. However, thermal insulation level of these fabrics was still low and fragile nanofiber layer needed to be protected. Therefore, a multi-layered fabric form was derived from combination of cotton and lyocell fabrics with a nanofiber layer. The results showed that nanofibers could be used to improve the wind-resistance and comfort properties of multi-layered knitted structures.     

消防服用多层织物的热防护性能

研究了消防服用多层织物的热防护性能,对单层织物的热防护性能及十种多层组合织物的热防护性能分别进行了研究分析,得出以下结论:就单层纤维成分相同的阻燃面料而言,热防护系数(TPP)值与织物的厚度、面密度具有显著的正相关性;多层组合织物中,外层及防水透湿层为覆聚四氟乙烯(PTFE)膜的阻燃帆布、隔热层为芳纶1313针刺毡、舒适层为芳纶-阻燃黏胶的8#样品的防护性能最好,就阻燃防护性能方面而言,是最适合用于消防员灭火消防服的面料。     

Optimization of SiC–ZrC high emissivity composite flexible coating for thermal protection with high interfacial bond strength and temperature resistance

Aluminum silicate fiber fabric (ASFF) has been widely used in the outer surface of flexible insulation felt on the leeward side of aerospace vehicle. In order to improve the temperature resistance of ASFF, a kind of SiC–ZrC composite coating was prepared on the surface of fiber fabric via spraying method with SiC as emittance agent and ZrC as additive. The surface morphology and mechanical properties of the coating were studied. Compared with the single-component SiC coating, the composite coating could effectively avoid coating spalling and improve the surface integrity at high temperature. After thermal treatment at 1100 °C for 2 h, the interface bond strength of the composite coating/substrate was 52.41% higher than that of SiC coating/substrate. The tensile strength of fiber fabric with SiC–ZrC composite coating could reach 91.75 MPa, which was 101.76% higher than that of raw ASFF. Therefore, the SiC–ZrC coating could greatly improve the temperature resistance of ASFF, and has an attractive application prospect in the field of thermal protection system.     

Improvement in poly(lactic acid) fabric performance via hydrophilic coating

The effects of a hydrophilic coating on poly(lactic acid) (PLA) fabric using polyethylene glycol-dimethyloldihydroxyethyleneurea (PEG-DMDHEU) were studied to obtain highly cross-linked polyethylene glycol (PEG) with acceptable fastness properties owing to the possibility of fixation PEG on the fibres surface at lower temperature than melting point of PLA fibres. PEG as a Phase Change Materials (PCMs) imparts thermal adaptability, which is so important for the comfort of textiles, to the substrate. While there is a good adhesion between the fibre and the PEG polymer for cotton and polyester fibres, polymer adhesion to PLA fibres and its effects on PLA fabrics have never been studied. The effect of hydrophilic coating on the PLA fabric was studied in comparison to polyethylene terephthalate (PET) fabric by measuring the thermal regulating effect, antistatic, air permeability, and mechanical properties. The results exhibit the possibility of multipurpose finishing on both fabrics samples leading to permanent thermal regulating effect and durable antistatic finish.     

Developing protective textile materials as barriers to liquid penetration using melt‐electrospinning

Electrospun polypropylene fiber webs and laminates were developed using melt‐electrospinning, to explore an alternative way of manufacturing protective clothing materials for agricultural workers. Electrospun polypropylene webs were fabricated in two levels of thickness. To examine the effect of lamination on the protection/thermal comfort properties, the webs were laminated on nonwoven fabric substrates. Barrier performance was evaluated for the electrospun webs and laminates, using two pesticide mixtures that represent a range of surface tension and viscosity. Effects of web thickness and lamination on air permeability and water vapor transmission were assessed as indications of thermal comfort performance. Penetration testing shows that electrospun polypropylene webs provide excellent barrier performance against the high surface tension challenge liquid, whereas the laminated fabrics of electrospun polypropylene webs exhibited performance of 90–100% for challenge liquids with varying surface tension. Air permeability of electrospun polypropylene webs decreased by ～20% because of the lamination and web thickness, but was still higher than most of the materials currently in use for protective clothing. Water vapor transmission of electrospun polypropylene webs reduced by up to 12% from the lamination and web thickness as well, but was still in a range comparable to woven work clothing fabrics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3430–3437, 2006     

Mechanical, thermal and ablative properties of interply continuous/spun hybrid carbon composites

The mechanical and thermal properties of interply hybrid carbon fiber (continuous and spun fabric)/phenolic composite materials have been studied. Hybrid carbon/phenolic composites (hybrid CP) with continuous carbon fabric of high tensile, flexural strength and spun carbon fabric of better interlaminar shear strength and lower thermal conductivity are investigated in terms of mechanical properties as well as thermal properties.Through hybridization, tensile strength and modulus of spun type carbon fabric reinforced phenolic composites (spun CP) increased by approximately 28% and 20%, respectively. Hybrid CP also exhibits better interlaminar shear strength than continuous carbon fabric/phenolic composites (continuous CP).The in-plane thermal conductivity of hybrid CP is 4-8% lower than that of continuous CP. As continuous filament type carbon fiber volume fraction increases, the transversal thermal conductivity of hybrid CP decreases.The erosion rate and insulation index were examined using torch test. Spun CP has a higher insulation index than continuous CP and hybrid CP over the entire temperature range. Hybrid CP with higher content of spun fabric exhibits higher insulation index as well as lower erosion rate.     

聚乙二醇/氧化锑锡纳米复合纤维结构及保温透气性能

功能户外防护材料中热能管理是一个重要的方面。对于功能织物开发而言，大都采用涂层后整理技术，但是其功能性和透气性的平衡是关键。本文以静电纺丝技术制备了聚乙二醇/氧化锑锡（PVA/ATO）纳米复合纤维膜，采用扫描电镜（SEM）、傅里叶红外光谱（FTIR）、X射线衍射（XRD）、热重（TG）对纳米复合纤维进行了表征，并对PVA/ATO/黏胶热轧复合材料的保温性能及透气性进行了测试。结果表明：PVA中ATO具有良好的分散性，部分ATO纳米颗粒镶嵌在纤维表面。PVA/ATO/黏胶热轧复合材料的保温率相对于基材黏胶热轧布提高了28.9%，达到37.1%，相应传热系数为12.62W/m²·℃，克罗值0.32。ATO纳米颗粒的加入可以直接改善PVA纳米纤维膜的堆积结构，使得PVA/ATO/黏胶热轧复合材料的透气性相对于PVA/黏胶热轧复合材料有明显提高，但趋势随纳米纤维层厚度的增加而降低。PVA/ATO纳米复合膜可以复合到多种基材上，从而为基于纳米纤维功能材料开发保温透气功能提供了思路。     

Study of the relationship between thermal insulation behavior and microstructure of a fire‐resistant gel containing silica during heating

Adding a transparent gel containing silica between 2 sheets of glass could improve the fire resistance of laminated glazing by its thermal intumescent behavior at high temperature. In this study, a custom fire test shows that the glazing reaches the highest thermal insulation rating of 40 minutes when the molar ratio of SiO₂ and Na₂O in the gel is 4.0, but above this ratio, the thermal insulation rating of the glazing decreases with the increasing silica content. Thermal and scanning electron microscopic analyses have been used to investigate the thermal behavior and microstructure of the residual layer, respectively. The results indicate that, although the high silica content is responsible for the high amount of residue that is essential in the formation of a protection barrier between fire‐exposed and unexposed sides of the glass, it is not the only factor that resulted in the improved thermal insulation of the glazing.     

双层亚麻-涤纶交织汽车座套面料的开发

基于汽车座套面料的要求,利用涤纶长丝和亚麻纱交织的方式设计了7种不同产品,并对亚麻-涤纶交织的汽车座套面料性能进行分析和评价,最终得到影响汽车用纺织品舒适性和耐用性的主要因素。结果表明:表层亚麻、里层涤纶双层交织的斜纹织物透气性、悬垂性、耐磨性、起毛起球性、抗皱性和拉伸性能等综合性能较好,是一种理想的汽车座套面料。     

Production and characterization of starch-based films reinforced by ramie nanofibers (Boehmeria nivea)

In this study, the use of cellulose nanofibers from ramie, a plant species with important characteristics of reinforcement, was investigated in the production of bio-based polymer films. A central composite rotatable design was applied to produce the films, analyze the effects of cassava starch, glycerol, and nanofibers content on their properties, obtain mathematical models, response surface plots, and determine an optimum composition. The films produced were characterized by mechanical properties, water vapor permeability (WVP), solubility, and opacity. Microstructure and thermal behavior were also evaluated. The ramie nanofibers content had a positive effect on mechanical and barrier properties, as it increased tensile strength by 207.9%, and decreased WVP and solubility by 52.9 and 72.9%, respectively. Furthermore, the obtained films exhibited homogeneous and cohesive structures, which encourages the use of ramie nanofibers as a reinforcement material in the production of green plastics. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47919.     

Enhancement of thermal conductivity for epoxy laminated composites by constructing hetero-structured GF/BN networks

Due to the rapid development of multifunctional and miniaturized electronic devices, the demand for polymer composites with mechanical properties, high-thermal conductivity, and dielectric properties is increasing. Therefore, the heat dissipation capacity of the composite must be improved. To solve this problem, we report a glass fabric (GF)/boron nitride (BN) network with a highly thermally conductive hetero-structured formed using polyvinyl alcohol (PVA) as an adhesive. The GF and BN are furtherly modified by (3-aminopropyl)triethoxysilane (APTES) for better thermal conductivity enhancement. When the BN content is 30%, the thermal diffusion coefficient and thermal conductivity of obtained PVA-mBN@mGF (PBG) are 2.843 mm²/s and 1.394 W/(m K), respectively. Epoxy (EP) resin is then introduced to prepare PBG/mBN/EP laminated composites via the hot pressing method as applied as thermal conductive composites. A highest thermal conductivity of 0.67 W/(m K) of PBG/mBN/EP laminated composites is obtained, three times higher than that of pure EP. In addition, the PBG/mBN/EP laminated composites also present favorable mechanical, electrically insulating, and dielectric properties.     

Injection molding of delamination‐free ultra‐high‐molecular‐weight polyethylene

When ultra‐high‐molecular‐weight polyethylene (UHMWPE) in powder form is injection molded, the so‐called delamination layering occurs near the skin of the parts. This layering defect hampers UHMWPE's superior wear resistance property and part surface quality. The delamination layer was caused by a combination of excessive shear stress near the part surface and high degree of molecular entanglement of UHMWPE. A mold insulation method that delays the rapid cooling of UHMWPE to reduce the shear stress and improve the polymer chain “interdiffusion” across the entangled chain bundles was used to eliminate the delamination layer. When the insulation layer thickness and mold temperature were optimized, the delamination layer was eliminated completely while still maintaining a reasonable cooling/cycle time. The delamination‐free parts were found to regain UHMWPE's superior impact resistance and tensile properties. POLYM. ENG. SCI., 59:2313–2322, 2019. © 2019 Society of Plastics Engineers     

Atmospheric plasma application to improve adhesion of electrospun nanofibers onto protective fabric

Nylon 6 electrospun nanofibers were deposited on plasma-pretreated woven fabric substrates with the objective of improving adhesion between them. The prepared samples were evaluated for adhesion strength and durability of nanofiber mats by carrying out peel strength, flex resistance, and abrasion resistance tests. The test results showed significant improvement in the adhesion of nanofiber mats on woven fabric substrates due to atmospheric plasma pretreatment. The samples also exhibited good flex and abrasion resistance characteristics. X-ray photoelectron spectroscopy and water contact angle analyses indicate that plasma pretreatment introduces radicals, increases the oxygen content on the substrate surface, and leads to formation of active chemical sites that may be responsible for enhanced cross-linking between the substrate fabric and the electrospun nanofibers, which in turn increases the adhesion properties. The work demonstrates that the plasma treatment of the substrate fabric prior to deposition of electrospun nanofiber mats is a promising method to prepare durable functional materials.     

Flexible Electrospun strawberry-like structure SiO2 aerogel nanofibers for thermal insulation

Herein, a novel flexible SiO₂ aerogel composite nanofiber membrane with strawberry-like structure and excellent thermal insulation properties, in which SiO₂ aerogel particles act as thermal insulation filler, was prepared by electrospinning technology. With the addition of nano-pore structure SiO₂ aerogel particles, the heat transfer path of the fibers inside the membrane became discontinuous, endowing the as-prepared membrane an ultra-low thermal conductivity of 30.3 mW/(m?K) and large surface area of 240 m²/g. Moreover, the nanofibers membrane also possesses the combined merits of excellent fire resistance, high-temperature stability, and temperature-invariant flexibility, rendering it a promising in the application of insulation and gas adsorption. The successful preparation of this flexible nanofiber membrane paves a new way to design materials with excellent thermal insulation and adsorption properties.     

预处理对微胶囊改性聚酯织物舒适凉爽性的影响

由于聚酯纤维的化学性质稳定、纤维表面光滑,不易与后整理剂相结合,因此利用薄荷油微胶囊后整理对聚酯织物进行舒适凉爽改性时,存在附着量少、改性效果差的缺点。为解决这一问题,本文在后整理前增加了碱预处理和等离子体预处理。通过对聚酯织物原样、无预处理后整织物、碱预处理后整织物和等离子体预处理后整织物进行舒适凉爽性能测试,深入分析两种预处理方法对聚酯织物改性效果的影响。结果表明：等离子体预处理在织物透湿、导水、润湿、速干和凉爽性改性方面促进作用更明显,相比无预处理后整织物,等离子体后整织物的透湿率、经向和纬向芯吸高度、滴水扩散时间、蒸发速率及接触凉感系数分别提高了3.32%、40.24%、27.25%、80.39%、21.21%和5.59%;碱预处理则在织物透气性和吸水性改善方面的效果更佳,相比无预处理的后整织物,可将织物的透气率和吸水率分别提高43.43%和13.03%。因此,两种预处理方法对聚酯织物舒适凉爽性的改性效果有显著促进作用。     

Preparation and properties of flame‐retardant damping polyurethane and its application in floating deck

Flame‐retardant modified polyurethane (PU) damping layers were prepared using the combination of expandable graphite (EG), aluminum hydroxide, and phosphorus‐nitrogen flame‐retardant HF600B. The mechanical, thermal, damping, and flame retardancy properties of PU damping layer and the sound insulation, vibration damping, and fire resistance of the deck components were studied systematically. The results revealed that the incorporation of flame retardant depressed the mechanical performance in general, and there was no significant change in damping property. At the same time, the residual char ratio of damping layer increased obviously with the addition of HF600B, the vertical burning rating was upgraded from V‐2 to V‐0 and passed the low flame test of marine materials. The A60 fire test showed that the floating deck system with damping layer had a maximum temperature rise of 75°C on the backfire surface during the test, which is much lower than 180°C required in the A60 grade fire resistance and has good fire resistance. Sound insulation test of the deck components showed that only a 2 mm damping layer increased the average sound insulation by 3 dB, especially in the low‐frequency range by about 8 dB. The vibration test showed that the damping effect of the floating damping deck system on the steel plate surface and the dressing surface is increased by 1.1 and 4.0 dB in the range of 10–200 Hz, 9.2, and 4.7 dB in the range of 200–1,500 Hz, respectively. POLYM. ENG. SCI., 59:2136–2147, 2019. © 2019 Society of Plastics Engineers     

Eco-friendly thermal insulation material from cellulose nanofibre

Nano cellulose is a material of current interest that has attracted considerable attention from researchers due to its interesting properties such as low toxicity, availability, natural abundance, biodegradability, and flexible surface chemistry. Cellulose fiber, usually derived from wood, plant walls or cotton is an eco-friendly thermal insulation material. The cellulose nanofibers (CNFs) described in this work were derived from cotton via sulfuric acid hydrolysis followed by ultrasonication. The formation of CNF and its morphology were analyzed using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The thermooptic parameters of the prepared sample, which to the author's knowledge has not been reported so far, were studied by the dual beam mode-matched thermal lens technique. Thermal diffusivity (2.61 × 10⁻⁸ m²/s) and thermal conductivity (0.108 W/mK) values of the prepared CNFs clearly point to the application potential of the material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48272.     

粉煤灰微珠-Ag复合颗粒的制备工艺和分析

采用化学镀的方法,以银氨溶液为镀液,甲醛为还原剂,按照一定的工艺过程对粉煤灰微珠进行表面镀银处理,得到了粉煤灰微珠-Ag复合颗粒。同时借助激光粒径分析仪、X射线衍射仪、场发射扫描电子显微镜、X射线能谱仪等检测设备对复合颗粒的粒径分布、化学成分、镀层表面形貌和结构进行了分析。对复合微珠进行保温隔热性能测试,掺镀银微珠的涂料比原微珠的涂料温度低约4℃。结果表明,按照设定的工艺过程,可以成功制备出具有保温隔热低辐射功能的粉煤灰微珠-Ag复合颗粒,作为一种功能性骨料有望用于建筑物外围护结构表面的砂浆或涂料中以降低对远红外热的辐射能力。     

Lightweight,robust, porous heterocyclic para-aramid aerogel hollow fibers for multifunctional applications

In nature, many fibers with warmth-retention properties, such as the hair of polar bears and rabbits, both have a hollow cross-section structure. The static air in fiber cavities can effectively inhibit heat conduction and serve as an effective thermal insulator. In this work, the high-performance heterocyclic para-aramid polymer was selected as the spinning solution, and aerogel hollow fiber was prepared by coaxial wet spinning and freeze-drying techniques. The effects of spinning solution concentration and lyophilized solvent on the micromorphology, mechanical properties, and specific surface area of heterocyclic para-aramid aerogel hollow fiber (HPAAHF) were systematically studied. The produced HPAAHF possessed excellent mechanical properties (tensible strength ~3.85 MPa), high specific surface area (~ 260.90 m² g⁻¹), and lightweight advantages. The thermal conductivity of HPAAHF was only 0.0278 W m⁻¹ K⁻¹, indicating its excellent thermal insulation properties. The aerogel fabric exhibited outstanding flame retardancy properties, with a total heat release of only 0.7 MJ m⁻² in the cone calorimetric experiment, making it a self-extinguishing fabric. In addition, phase change material was injected into the hollow structure to obtain aerogel-phase change material composite fibers, which exhibited great energy storage prospects. As a result, the high-performance heterocyclic para-aramid polymer-based aerogel hollow fiber was successfully prepared and had multifunctional applications in thermal insulation, flame retardancy, and heat energy storage fields.     

High-strength thermal insulating mullite nanofibrous porous ceramics

Mullite fibrous porous ceramics is one of the most commonly used high temperature insulation materials. However, how to improve the strength of the mullite fibrous porous ceramics dramatically under the premise of no sacrificing the low sample density has always been a difficult scientific problem. In this study, the strategy of using mullite nanofibers to replace the mullite micron-fibers was proposed to fabricate the mullite nanofibrous porous ceramics by the gel-casting method. Results show that mullite nanofibrous porous ceramics present a much higher compressive strength (0.837 MPa) than that of mullite micron-fibrous porous ceramics (0.515 MPa) even when the density of the mullite nanofibrous porous ceramics (0.202 g/cm³) is only around three quarters of that of the mullite micron-fibrous porous ceramics (0.266 g/cm³). The obtained materials that present the best combination of mechanical and thermal properties can be regarded as potential high-temperature thermal insulators in various thermal protection systems.