Analysis of the effect of fiber cross section and different bonding methods on sound absorption performance of PET fiber based nonwovens using Taguchi method

Abstract

In this study, sound absorption coefficients (SACs) of needle-punched and thermal-bonded nonwovens produced from polyester (PET) fibers with various cross sections, i.e., hollow, round and hexaflower, blended with a low melt PET, was reported. The acoustic performance of a hexaflower PET fiber was studied for the first time. Fibers were carded and then one set of samples was bonded by needle punching while the other set was air-through thermal bonded. A third set of samples was needled at various punch densities. Design of experiments was planned according to Taguchi method. Relationship between production parameters and SAC was analyzed using Minitab software. The most important independent variables affecting the sound absorption were areal density and web bonding method. The sample produced according to optimum production levels reached to a SAC value of 0.57 at 2000?Hz which could be a suitable choice for acoustic applications in the automotive industry.     

Investigation of electromagnetic shielding effectiveness of needle punched nonwoven fabrics with staple polypropylene and carbon fibres

Conductive needle punched nonwoven fabrics are developed from staple polypropylene (PP) and varying weight fractions (10, 20 and 30 wt.%) of staple carbon fibres. A fibrous webs of staple PP and carbon fibres were formed at a wool-type carding machine, and these webs subsequently bonded on needle punching machine with 132 punches/cm² and 13.5 mm needle penetration depth. The electromagnetic shielding effectiveness (EMSE), absorption and reflection characteristics of as-produced needle punched nonwoven fabrics were determined using a network analyser as specified in ASTM D4935-10 in the frequency range 15–3000 MHz. The surface resistivity measurements were carried out in accordance with ASTM D 257-07 standard. These results indicate that the EMSE values increase incrementally with frequency in the 15–3000 MHz range. The nonwoven sample with 30 wt.% carbon fibre showed the lowest surface resistivity of 3.348 kΩ and corresponding highest EMSE of ~42.1 dB in the 3000 MHz frequency range. In comparison, the highest EMSE values from 10 to 20 wt.% staple carbon fibre were found to be 15.6 and 32.2 dB in the 3000 MHz frequency, respectively. It was observed that the absorbance and reflectance curves of each nonwoven fabric move at opposite directions to each other. It was found that as the amount of carbon fibre in the nonwoven fabric increases, absorbance values decrease, but reflectance values increase. The resultant nonwoven fabric samples are expected to be used as garment interlining after thermal bonding and wall interlayer in the future.     

Electrical resistance of jute needle-punched non-woven fabric – effect of punch density,needle penetration and area density

The electrical resistance of jute needle-punched non-woven fabric has been studied. Statistical model using central composite rotatable experimental design is developed for electrical resistance depending on the three important parameters of needled non-woven fabric, i.e. punch density, depth of needle penetration and mass per unit area. From this model and its contour diagrams, the effects of different parameters can be understood on electrical resistance of those fabrics. Prediction of electrical resistance can be made knowing the values of independent parameters. The correlation coefficients between observed and predicted values are found to be significant in all the cases. As depth of needle penetration increases for a particular punch density, electrical resistance increases and after reaching to maximum, it decreases having optimum at about 140 punches/cm² and 12?mm depth of needle penetration. With the increase of area density, resistance decreases. As punch density increases for a particular area density, resistance increases for high needle penetration.     

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.     

新型轻质透气保暖复合材料的制备及性能

为克服传统保暖服装臃肿、厚重的缺点,以乙烯-醋酸乙烯共聚物为主体材料,通过开发的炼制工艺,将气凝胶与乙烯-醋酸乙烯共聚物混合一体后制成轻质透气保暖的复合片材.气凝胶的添加可以显著提高复合片材的保暖性能,用量为5％～20％时,复合片材可以达到不同的保暖效果.复合片材的厚度对保暖性能影响较大,随着厚度增加,复合片材的克罗值...     

Study on Some Functional Properties of Mesta Needle Punched Nonwoven Fabrics Using Central Composite Rotatable Design

The combined effect of two structure forming process parameters i.e. punch density and needle penetration on properties of Mesta needle punched nonwoven fabric has been studied using central composite rotatable design. As properties are structure dependent, the relationship between compressional behavior and other functional properties was studied. It was observed that compressional (α) and recovery (β) parameters are well correlated with tensile, air permeability and thermal insulation value of Mesta needle punched fabric. The regression equations were also suggested. Therefore, the α and β may be used for indirect approximation of these properties with reasonable accuracy.     

Development of Unconventional Fabric from Banana (Musa Acuminata) Fibre for Industrial Uses

ABSTRACT

Banana fiber is a lingo-cellulosic under-exploited bast fiber, which obtained from the pseudo-stem of banana plant (Musa acuminata). In this study, an attempt has been made to explore the possibility of production of needle-punched nonwoven from fibrous material of biowaste for value addition and diversified uses. Mechanical processing for preparation of all banana, banana-jute (1:1), and banana-polypropylene (1:1) blended needle punched nonwoven has been optimized and processing parameters have been suggested. Softening treatment of banana fibre has been done successfully for better processing. Boiling in water with 1% nonionic detergent has been suggested as pre-processing for softening. Tenacity, elongation-at-break, initial modulus, breaking energy, stress relaxation, creep, compressibility, recovery-from-compression, bending load, electrical insulation, thermal insulation, sound insulation, air permeability, and frictional force have been evaluated and analyzed for all the above-mentioned samples. Based on those properties the probable use has been suggested as insulation (thermal and sound) and filter material.     

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.     

Ranking fibre and process parameters affecting thermal resistance of needle-punched blankets using neural network model

In this paper, an artificial neural network (ANN) model has been designed to predict the thermal resistance of needle‐punched blankets. Web‐laying (parallel‐ and cross‐laid), fibre fineness, fibre degree of hollowness, fabric weight, depth of needle penetration and needle punch density are considered as input parameters to predict the thermal resistance of needle‐punched nonwoven blankets. In order to reduce the dependency of the results on a specific partition of the data into training and testing sets, three‐way cross validation tests were performed, that is, total data were divided into training and testing sets in three different ways. The predicted thermal resistance correlated well with the experimental thermal resistance. The relative contribution of each parameter to the overall prediction of the thermal resistance was studied by carrying out a sensitivity analysis of the test data set. The results of sensitivity analysis show that web‐laying is the most important input parameter, followed by depth of needle penetration, fabric weight, degree of fibre hollowness, needle punch density and fibre fineness.     

麻/丝非织造布农用地膜的研制和性能分析

塑料地膜在自然界难以降解,越来越多的塑料地膜残留物也给农业生产与生态环境带来危害。采用亚麻和蚕丝纤维的纺织下脚料制备麻/丝非织造布农用地膜,通过正交试验法对其工艺参数进行优化,并对地膜的农用性能进行了测试。结果表明：亚麻与丝的质量比为96﹕4,面密度为35 g/m2,粘合剂质量分数为12%时,制成地膜的断裂强力为30 N,厚度为0.1148 mm,回潮率为6.7%,红外分析显示麻/丝非织造布地膜可完全自然降解;地膜具有较好的保温性和保墒作用,且土壤的含氮量随地膜降解而提高。     

分层复合水刺/热风非织造材料的吸声性能研究

以水刺非织造材料、热熔纤网和热风非织造材料为原料,分层叠加,置于烘箱中热风加热,制得两层和三层复合非织造材料。对分层非织造材料的厚度、透气性、孔隙率以及吸声性能等进行测试,探讨各因素对材料吸声性能的影响。测试结果显示:随着非织造材料厚度增加,同一声波频率的吸声系数提高;单层非织造材料的吸声系数随声音频率的增大而提高;双层复合材料吸声系数随着热风非织造材料面密度增加而提高,最高吸声系数向低频段偏移,吸声频段拓宽,吸声系数随着频率增加呈先上升再下降的趋势;双层分层吸声材料选择孔隙率梯度从受声面开始由低到高排列,三层复合材料的孔隙率按照低—高—低排列,可获得较好的吸声效果。     

减震隔声降噪地垫的研发

介绍我国分户楼板隔声及其隔声研究现状,详细阐述多层复合结构的减震隔声降噪地垫的结构、性能和安装,减震隔声降噪地垫与木地板配合使用,将其铺装于扫平层的140 mm厚现浇钢筋混凝土楼板之上,经江苏省建工建材检测中心检测,撞击声隔声为61 dB,能很好地满足住宅分户楼板撞击声隔声L'nT,W≤65 dB的要求。     

PP/PET针刺过滤材料热老化性能研究

为探索聚丙烯(PP)/聚酯(PET)针刺过滤材料的耐热老化性能,采用烘箱法对试验制备的3种PP/PET针刺过滤材料样品进行不同热老化温度和热老化时间的处理,研究热老化温度和热老化时间对PP/PET针刺过滤材料各项性能的影响。结果表明:随着热老化时间的延长和热老化温度的升高,PP/PET针刺过滤材料的质量、厚度、断裂强度降低,尺寸缩小;当热老化温度超过120℃、热老化时间超过4.0 h后,热老化程度明显加剧。     

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.     

Polyester apparel cutting waste as insulation material

Polyester waste is the dominant component of the clothing industry waste stream, yet its recycling in this industry is rarely addressed. This paper proposes using polyester cutting waste as an insulation blanket for roofing and buildings’ internal walls in order to reduce environmental pollution. The designed textile structures used waste cuttings from different polyester fabrics without opening the fabric to fibre. Thermal insulation, acoustic insulation, fire resistance and biodegradation of the new insulation structure were investigated and compared to commercial insulation materials. Standard investigation methods were modified to fit the samples voluminous nature. The coefficient of thermal conductivity ranged between 0.0520 and 0.0603 W/mK. The achieved sound absorption with NRC ranging from 54.71 to 74.77%, surpassing standard commercially used insulators. The insulating structure did not conduct flame, the radius of impaired place was 1.60–2 cm while the depth was 0.4–1.3 cm, and showed lack of biodegradability, with loss of mass ranging from 0 to 0.3%.     

Effects of irradiation on polyethyleneterephthalate(PET) fibers impregnated with sensitizer

Polyethylene terephthalate(PET) is difficult to be irradiation cross-linked at low dose for the aromatic groups. In this paper, trimethylolpropane triacrylate (TMPTA) was incorporated in PET fibers to sensitize the cross-linking. Changes in PET fibers subjected to electron beam irradiation at dose up to 200 kGy and dose rate 12 kGy/s were investigated by gel content, scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, thermal gravimetric analysis and X-ray photoelectron spectroscopy. The gel content was 0.14% at dose of 60 kGy and it arrived at the maximum value 0.53% at 100 kGy. Irradiated fibers showed a decrease in the breaking strength and an increase in the elongation at break. The crystal form of PET fibers had not been changed and crystallinity decreased 28% with the increasing dose. The melting temperature shifted from the original 254.28 °C to 253.44 °C. The thermal stability and the amount of non-volatile residue at 800 °C increased at dose of 100 kGy. XPS analysis indicated that the number of C-C band increased to prove the occurring of cross-link. The surface of PET fibers got rougher after irradiation and the anti-dripping property had not been improved effectively for the low degree of cross-linking.     

Study on thermal and evaporative resistances of multilayered fabric ensembles

The present work deals with the study on thermal and evaporative resistance of multilayered fabric ensembles meant for cold weather applications. Three-layered structure is used to study the thermal comfort properties. Knitted fabric and polytetrafluoroethylene coated fabrics were used in inner and outer layer, respectively. Needle punched fabrics produced from polyester fibre were used in middle layer. Fifteen different non-woven fabrics were produced according to Box and Behnken experimental design for three variables and three levels by varying mass per unit area, punch density and depth of needle penetration. The produced fabrics were evaluated for thermal and evaporative resistances with and without inner and outer layer fabrics. Thickness, air permeability, bulk density and porosity of the needle punched fabrics were studied. The properties of the fabrics were analyzed for statistical significance by using ‘Design-Expert’ statistical software. Artificial neural network model was developed to predict the properties of fabrics and validation of model was done with the testing data-set. The performance of prediction was evaluated by mean square error, mean absolute error percentage and correlation coefficient. It was concluded that the predicted properties of fabric correlated well with the experimental results.     

结构参数对三维中空夹芯复合材料平压性能的影响

三维中空夹芯复合材料是一种新型夹芯结构材料,具有轻质、高强、高模、抗冲击、隔音、保温等特性,可广泛用于航空航天、汽车、储油罐、船舶、建筑、能源等领域。本文选取芯材高度分别为2、4、6和8mm,以及芯材间距分别为4、6和8 mm的两组三维中空夹芯复合材料为样品,测试其平压性能,重点研究芯材高度、芯材间距等结构参数对三维中空夹芯复合材料平压性能的影响,并分析材料的压缩特性及损伤机理。结果表明,三维中空夹芯复合材料受到平压载荷时的破坏模式为明显的脆性破坏,同时,材料破坏形式主要表现为树脂开裂、纤维断裂、界面脱粘等特征。三维中空夹芯复合材料的平压性能随着芯材高度、芯材间距的增加而下降。研究结果将为该材料的结构优化设计和性能分析奠定理论基础。     

钛系聚对苯二甲酸乙二醇酯的增黏行为及其性能

为了拓宽钛系聚对苯二甲酸乙二醇酯(PET)在聚酯工业丝领域的应用,通过超高效聚合物色谱-多角度激光光散射联用法研究其在不同温度下的增黏行为,建立增黏温度与钛系PET分子质量及其分布的关系,并利用紫外-可见分光光度计和差示扫描量热仪研究增黏PET的色相和热性能。结果表明:钛系PET分子质量随增黏温度的升高而升高,且色相受温度影响明显;增黏所需时间随温度升高而下降,270 ℃反应20 min的钛系PET重均分子量与220 ℃反应10 h时的相当,分子质量升高导致聚酯结晶性能和熔点下降;增黏温度超过熔点后,分子质量分布随温度升高而变窄,且分子质量可达到聚酯工业丝要求,高分子质量窄分布钛系聚酯的研究对其在工业丝领域的应用具有重要意义。     

低温NaOH溶液中低聚合度纤维素的溶解与析出

采用浓度为9%的NaOH溶液在低温条件下对木浆纤维素进行润胀溶解,分别测定原料和不溶纤维素的R-10值、聚合度,并采用红外光谱(FTIR)、扫描电镜(SEM)、热重(TG)以及X-射线衍射(XRD)方法对原料、不溶纤维素和水析出纤维素进行表征。结果表明低温有利于纤维素在NaOH溶液中的溶解,且在实验设计的范围内温度越低,低聚合度纤维素溶解得越多。与原料和不溶纤维素相比,水析出纤维素的热稳定性稍差。低温条件下,纤维素I晶型易转变为纤维素II晶型,同时析出纤维素也表现出纤维素II晶型。析出纤维素表面孔隙多、表面积大,有可能制备成吸附、隔音或保温材料。