Effect of compressibility on heat transport phenomena in aerogel-treated nonwoven fabrics

The heat transport properties observed in nanostructured materials such as aerogel-treated nonwoven fabrics are promoting revolutionary breakthroughs as thermal insulators. This article is focused on the thermal transport characteristics of nonwoven fabrics treated with aerogel for potential uses in thermal protective applications. Highly efficient aerogel thermal blankets are now considered a viable option in applications such as clothing, building, and pipelines. A variety of fiber and fabric structures or finishing parameters influence the functional properties of nonwoven materials. In order to assess the thermal properties of aerogel-treated nonwoven fabrics, the KES Thermolabo II and NT-H1 (plate/fabric/plate method for thermal conductivity, q_max cool/warm feeling, and thermal insulation) was used. Fabrics of higher thicknesses show lower heat conductance and therefore higher thermal insulation properties. It has been found that thermal insulation is also related to the weight and compressional properties of the fabric. To make an insulating material effective, it should have low compression set and high resiliency to make the still air to be entrapped into the fibrous material.     

Characterization and analysis of ridge gourd (Luffa acutangula) fibres and its potential application in sound insulation

Ridge gourd, the fruit of Luffa acutangula, is extensively used throughout the world. Nevertheless, there is a dearth of scientific information related to the thermal, mechanical and chemical properties of these fibres to explore its potential application in textile industry. This research work is aimed to characterize the L. acutangula plant and investigate its potential application in sound insulation. The fibres are arranged in a cell like structure, when opened it gives a very lower fibre length of less than 10 mm. The chemical composition of fibres is as like other lignocellulosic fibres having around 64% cellulose, 21% hemicellulose and 10% lignin. The density is of fibre is around 1.46 g/cc and having the average linear density of 432 denier. The nonwovens were produced by blending the L. acutangula fibre with cotton as well polyester fibre webs using layering technique at three different blend proportions and their influence on bulk density, sound insulation, thermal resistivity and air permeability has been analysed. The ANOVA analysis showed that all the properties mentioned above was significantly influenced by the blend proportion of L. acutangula. The nonwoven sample produced from 50/50 blend proportion of cotton/luffa and polyester/luffa samples showed better sound reduction and thermal resistivity compared to other samples. The cell-like structure of luffa combined with low bulk density and higher thickness resulted in better results.     

Sound and thermal insulation properties of flax/low melt PET needle punched nonwovens

Noise pollution is an ever increasing problem in the world because of the industrial revolution. Recently, researchers have begun investigating natural fiber composites as potential materials for the manufacture of sound absorption structures. In this work, flax/low melting point polyester needle punched nonwoven fabrics were manufactured and characterized for sound and thermal insulation applications. Nonwovens were developed by blending flax fibers with low melt PET at three blend ratios (10%, 20%, and 30%) with 7 mm and 10 mm needle penetration depth. The test results showed that there was a decrease in thermal resistance value with increase in low melt PET % and needle penetration depth. The developed nonwovens had better sound insulation value at medium and high frequency. There was no significant change in sound insulation value with increase in low melt PET %.     

Manufacturing and properties of ultra-low density fiberboards with an unsaturated polyester resin by a dry process

Although ultra-low density fiberboards (ULDFs) have good sound and thermal insulation performance, formaldehyde emission in the manufacturing process and in the subsequent use of the products limits their field of application. The objective of this study was to employ an unsaturated polyester resin (UPR) in the manufacturing of the boards as a substitute of formaldehyde-based adhesives in order to develop environment-friendly ULDFs. The effects of UPR dosage, fiber treatment agent, press time and fiber consumption on the properties of fiberboards were studied. Sound absorption and thermal conductivity were also measured to ensure sound and thermal insulation properties of the fiberboards. Board density, modulus of rupture and thickness swelling in 2 h were 320 kg/m³, 4.14 MPa and 3.75%, respectively, under optimal conditions such as 12% UPR dosage, 1% fiber treatment agent, 400 g fiber consumption and 210 s press time. Noise reduction coefficient and thermal conductivity of the boards were found within a range of 0.68–0.58 and 0.038–0.048 W/(m K), respectively, while the density of boards ranged from 150 to 400 kg/m³. Therefore, sound absorption property of the fiberboards developed in this study satisfies the requirement of high-efficiency sound absorption materials, which is close to the value (0.67) of ULDF having a density of 56.3 kg/m³ obtained by a wet process. Thermal insulation property of boards was close to that of commonly used insulation materials such as rock wool [0.036 W/(m K)] and glass fiber [0.045 W/(m K)]. In conclusion, fiberboards can be used for non-structural furniture materials, sound and thermal insulation materials in buildings because of their environmental friendliness, good mechanical properties, and excellent sound and thermal insulation properties.     

Development of acoustic nonwoven materials from kapok and milkweed fibres

Acoustic properties of textile materials have been studied for several decades. But, mostly used materials were synthetic, and hence, they were not eco-friendly in nature. Therefore, an attempt was put forward to try the sound absorption property of natural fibres and their blends by needle-punched nonwoven techniques. Nonwoven fabrics of ideal materials are used as acoustical insulation products because they have high total surface area. The effect of blend proportion of kapok and milkweed fibres with cotton, fabric GSM, bulk density and distance of fabric from sound source on sound reduction of nonwoven fabrics was investigated. The sound reduction increases with increase in blend proportion of kapok and milkweed fibres. A nonwoven fabric of cotton/milkweed 40/60 shows the highest sound reduction potential. As the distance between the fabric and sound sources increases, the sound reduction also increases linearly due to reduction of sound intensity which reduces the transmission of sound through the fabric. There is a positive correlation between fabric GSM and sound reduction and negative correlation between bulk density and sound reduction. Further, the thermal conductivity of nonwoven samples decreases with increase in kapok and milkweed blend proportion due to increase in thickness of samples. Hence, the kapok- and milkweed-blended nonwoven samples provide sound as well as thermal insulation characteristics.     

SiO2气凝胶/聚酯-聚乙烯双组分纤维复合保暖材料的制备及其性能

为开发综合性能优异的复合保暖非织造材料,以聚酯-聚乙烯(PET-PE)双组分皮芯结构复合纤维为主体,通过热风工艺,采用自然沉降法使SiO₂气凝胶粉末粘附于复合纤维表面,制得SiO₂气凝胶/聚酯-聚乙烯纤维复合非织造材料。对复合非织造材料表面SiO₂气凝胶粉末质量分数、微观结构、保暖性能、压缩回弹性能、拉伸性能、透气性能进行测试与分析。结果表明:SiO₂气凝胶粉末与聚酯-聚乙烯复合纤维可有效结合,SiO₂气凝胶粉末的加入对纤维网具有一定的支撑作用,提升了复合非织造材料的压缩回弹性能、拉伸性能,同时因增加了纤维间静止空气的含量,使复合非织造材料的保暖性能得到提升。     

非织造布在汽车工业中的应用

非织造布在汽车工业中扮演着重要的角色,大约有40种以上的用途,包括空气过滤器、模压制椅、顶篷布、行李箱衬垫和地毯等,起着隔音、滤气、绝热、加固及保护的作用,同时也增强了乘客的舒适感和安全感。文章概述了非织造布在汽车工业中的应用现状和未来的发展趋势,介绍了汽车用非织造布的应用种类、性能及其进展,并对今后的产品开发提出了建议。     

羊毛及其混合纤维非织造材料的吸声性能

为优化羊毛非织造材料的吸声性能,以羊毛、毛/涤、毛/麻3种纤维制备非织造材料。通过阻抗管对3种非织造材料的吸声性能进行测试,分析了声波频率在250-6 300 Hz范围内,材料的纤维种类、厚度和空腔深度对其吸声性能的影响。结果表明,3种样品的平均吸声系数均大于0.2,纯毛非织造材料的吸声性能略好于毛/涤材料与毛/麻非织造材料;通过增加材料厚度或设置空腔的方式均可提高材料全频段（尤其中低频段）的吸声性能,其中厚度对材料吸声系数的影响程度更大;从环保、材料价格、便于施工等方面考虑,以厚度为6 mm的毛/麻非织造材料作为吸声材料,并设置6 mm的空腔, 即可达到较为优异的低频吸声性能。     

Sliding wear,mechanical, flammability,and water intake properties of banana short fiber/Al(OH)3/epoxy composites

ABSTRACT

Banana short fiber/Al(OH)₃/epoxy composite laminates were prepared by dispersing short banana fiber and Al(OH)₃ particulates in an epoxy matrix and investigated for their specific wear rate, water intake, flammability and mechanical properties. The sliding wear results showed that due to the synergistic effect of both fiber and filler in epoxy matrix enhanced the wear resistant in the composites. Similarly, the tensile stress and hardness improved significantly due to the addition of banana fiber in the composite material. Also, it is found that the composite becomes more fire resistant due to the addition of Al(OH)₃. However, the higher percentage of fiber and filler increases the water absorption rate due to voids in the composite. The results of this study provide the insights of solid–solid interface leading to different bulk properties.     

废旧羊毛非织造布的制备及其吸声性能

为研究废旧羊毛纤维非织造材料的吸声性能,利用非织造材料的生产工艺,以废旧羊毛纤维为主要原料,制备一种新型羊毛非织造材料。通过使用传递函数法和驻波管法,对羊毛非织造材料的吸声性能进行了测试,分析了声波频率为250-6300 Hz范围内,材料的厚度、密度和空腔深度对其吸声性能的影响。结果表明,羊毛非织造材料吸声性能优异,对高频的吸声性能优于低频;在中低声波频率,随材料厚度、密度和空腔深度的增加,其吸声性能越好。材料厚度和空腔深度是影响羊毛非织造材料吸声性能的主要因素;通过增加空腔深度提升材料的吸声性能,是较为经济合理的办法。     

竹原纤维/聚氨酯复合材料的隔音性能

为充分发挥天然竹原纤维的可再生性和生物分解性,减少隔音复合材料对环境的负荷,并进一步改善竹原纤维/聚氨酯复合材料的隔音性能,以天然环保和可再生的竹原纤维为增强材料,以聚氨酯为基体,制备了一系列不同方式复合的隔音复合材料。研究了竹原纤维的排列方式与质量分数、及氢氧化钠溶液表面处理对复合材料隔音性能的影响。结果表明：竹原纤维采用直铺法制成的复合材料隔音性能最好;竹原纤维经氢氧化钠溶液处理后制成的复合材料其隔音性能显著提高;随着竹原纤维质量分数增加,复合材料的隔音性能增大。     

玻纤细度对玻纤/PVC复合材料隔声性能的影响

为进一步研究玻璃纤维/PVC复合材料的隔声性能,使其性能更加优越,以不同细度的玻璃纤维制成的织物和高阻尼的聚氯乙烯为原料,制备玻璃纤维织物/聚氯乙烯隔声复合材料,并采用双声道分析仪、SEM等对样品的隔声性能、形态结构进行分析测试。结果表明:玻璃纤维的细度对织物及复合材料的隔声性能都有较大的影响;在面密度、厚度等条件基本相同的情况下,玻璃纤维的直径越小,制成的织物及聚氯乙烯复合材料的隔声性能越好。     

木棉系列絮料的保暖性

木棉是一种天然纤维素纤维,中空度85%以上,非常适合制作保暖材料,但是由于传统木棉絮料的强力低,持久回弹性差,使其用量越来越小,所开发的木棉絮料制作新技术克服了上述缺陷。为进一步探明木棉絮料的综合性能,比较研究了木棉絮料和其他现有絮料的静态热阻和对流散热量,发现木棉絮料的保暖性仅次于羽绒,明显优于四孔、七孔涤纶棉絮料和喷胶棉,与化纤絮料相比木棉纤维将絮料中的空隙分割的很小,使得絮料的对流散热量大幅度降低,而且木棉絮料的传导热阻也明显高于现有化纤絮料。     

Airlaid nonwoven panels for use as structural thermal insulation

Thermal-bonded airlaid nonwoven webs consisting of fiber glass and polyester bicomponent fibers were manufactured, and then multilayer webs were formed into composite panels using compression molding technique. The consolidation process was optimized and the effect of bulk density on air permeabilites, mechanical properties, and thermal resistance was studied. Increasing binder amount and bulk density improved the flexural and tensile strength. Thermal resistance of the panels were found to be very dependent on the bulk density such that the resistance increased exponentially with an initial increase in density, then leveled off and decreased linearly with further increment in density. Depending on the composition and bulk density, the panels provided thermal resistance between 0.52 and 0.88 Km²/W, tensile strength between 2 and 7 MPa, and flexural strength between 600 and 3500 kPa. The findings revealed that airlaid nonwoven panels can be designed to use as structural thermal insulation materials in constructions.     

Effect of physical and subsequent processing parameters of glass fiber felts on sound insulation

The aim of this study is to explore the effect of physical parameters (fiber diameter, thickness, and resin content) and subsequent processing parameters (heat treatment and rolling compaction) on sound insulation of glass fiber felts. The results show an inversely proportional relationship between fiber diameter and sound insulation. The decrease of fiber diameter results in improvement of sound transmission loss (STL). Alternatively, the thickness of glass fiber felts increase leading to the increase of corresponding sound insulation. With the increase of resin content, STLs of glass fiber felts do not increase monotonically. The STLs of glass fiber felt are also improved with the increase of heat treatment temperature. Compressing can reduce the STL due to the reduction of thickness.     

墙体用非织造材料的结构表征及其保温性能

利用三维视频显微镜和电镜对厚型非织造材料试样的结构进行分析,表明非织造材料截面由垂直和水平两类纤维互相穿插和交缠组成,纤维与纤维之间由低熔点的热熔纤维紧密粘合在一起,形成致密的三维结构。对研制样品的保温性进行测试,结果显示墙体用非织造材料的厚度越大,其保温性越好;在采用相同加工条件时,墙体用非织造材料的保温性随其本身的面密度的降低而减小,与材料本身的孔隙率成正相关性。     

Effects of total surface area and fabric density on the acoustical behavior of traditional thermal‐bonded highloft nonwoven fabrics

Nonwoven fabrics are ideal materials for use in acoustical insulation products because they have a high total surface area, which is directly related to the denier and cross‐sectional shape of the fiber. The smaller the denier, the more fibers for the same material density, the higher the total fiber surface area is. This results in a greater opportunity for interaction between the sound wave and the fibers in the structure. Another important parameter is the density of the nonwoven material, which affects the geometry and the volume of the voids in the structure. The acoustical properties of fabric materials are measured using one of two methods: the impedance tube method and the reverberation room test method. The impedance tube method uses very small test samples (5–15 cm), whereas the reverberation room test method requires large test samples and is expensive to set up. For making comparative analysis of the test samples and overcoming the disadvantages of the current test methods, a direct comparative acoustical properties measurement device has been developed and fabricated in the School of Materials Science and Engineering at Clemson University in an attempt to overcome some of the disadvantages of the other method.     

中空纤维的中空形状设计及有限元分析

作为一种保暖纤维,中空纤维最大的问题是经过纺织各道工序后中空度的保有率问题。中空度的保有率高,纤维的保暖性以及保暖持久性就好。建立纤维结构的力学模型,考察纤维受压后截面上应力、应变、位移等的变化,间接反应中空度的变化即保暖性的好坏。     

双层复合非织造材料基吸声体吸声性能研究

以熔喷丙纶非织造材料和玻璃纤维水刺非织造材料为受声面和背衬层,通过热粘合方式制成双层复合非织造材料基吸声体。通过分析吸声体受声面和背衬层非织造材料的厚度、面密度、孔径、孔隙率等结构参数与复合吸声体的吸声系数之间的关系,探讨各层非织造材料结构参数对复合吸声体吸声性能的影响。实验结果表明,随着熔喷丙纶非织造材料和玻璃纤维水刺非织造材料厚度和面密度的增加,吸声体中高频段吸声系数显著提高;受声面和背衬层的孔径尺寸和孔隙率的变化对双层复合非织造材料基吸声体的吸声性能影响较为显著。     

非织造布在驻极体传声器中的应用

非织造布作为驻极体传声器极头防尘布 ,不仅起到阻挡灰尘的作用 ,而且具有吸声隔音、调节传声器频率响应曲线的功能。本文结合声学理论和实验 ,分析比较了不同纤维材料和不同结构防尘布对传声器频率响应曲线的影响 ,为防尘布的设计和制备提供了初步参考