Development of electrically conductive composites based on recycled resources

Abstract

The current study was focused on the development of electrically conductive composites of carbon particle filled cotton fabric/epoxy systems. The carbon particles were refined to the scale of micro/nanoparticles using ball milling and morphological properties were studied by Malvern zetasizer and SEM. The influence of different concentrations of carbon particles in green epoxy resin for electrical conductivity was studied. Additionally, the electrical conductivity and electromagnetic shielding ability of conductive composites were analyzed. Waveguide method at high frequency (i.e. at 2.45?GHz) was used to investigate the EMI shielding. Similarly, the effect of different concentrations of carbon particles in composites was also studied for mechanical strength (tensile and flexural). A comprehensive study showed the improvements in electrical and mechanical properties with increase in the concentration of carbon particles and their even distribution in resin. The composites with higher carbon filler concentration showed maximum electrical conductivity (1.0E–02), shielding effectiveness 23.13?dB and mechanical properties.     

Comparison of thermal comfort properties of single jersey fabrics produced by hollow yarns with different hollowness ratio

In this study, the thermal comfort properties of single jersey fabrics produced by conventional and hollow cotton yarns with different hollowness ratio have been investigated and compared. For this purpose, thermal conductivity, thermal resistance, thermal absorptivity, air permeability and water vapour permeability of core spun, hollow and conventional yarn fabrics were measured and evaluated statistically. It was observed that thermal comfort properties of single jersey fabrics were affected by the yarn structure and the fibre distribution within the yarn. The results showed that hollow yarn fabrics had better thermal comfort properties than that of conventional yarn fabrics. In hollow yarns, as the hollowness ratio increases, air permeability and thermal conductivity of single jersey fabrics decrease but thermal resistance, thermal absorptivity and water vapour permeability increase. Statistical analysis also indicated that the differences between properties of hollow yarn fabrics and conventional yarn fabrics were significant. Furthermore, the yarn hollowness ratio significantly affects thermal comfort properties of single jersey fabrics.     

几种电磁屏蔽面料屏蔽效能的研究

选择铜镍涂层织物、银纤维交织织物、铜镍金属丝织物、不锈钢交织织物4种电磁屏蔽面料进行研究,利用同轴传输线法测试它们的电磁屏蔽效能。结果表明:材料中的金属丝比例越大,织物的电导率越大,电磁屏蔽效果越好。在金属丝含量相同的情况下,银丝的电磁屏蔽性能优于不锈钢。经洗涤后,银纤维交织织物和不锈钢交织织物的电磁屏蔽效果没有明显变化,而铜镍涂层织物和铜镍金属丝织物的电磁屏蔽性能均有明显衰减。     

Analysis of thermal comfort properties of fabrics for protective applications

Protective clothing protects the body from external influence like heat, chemicals, mechanical hazards, bad weather, etc. by shielding the human body from harsh environmental effects. The maintenance of thermal balance is one of the most important aspects of protective clothing. The study aims to investigate the thermal comfort properties of woven hybrid fabrics produced with high performance core spun yarns. For this purpose, meta-aramid, e-glass, Technora® and Dyneema® fibres were combined using core yarn spinning method in order to enhance the protective performance characteristics. The effects of the core/sheath ratio and type of core materials on the thermal comfort characteristics were investigated and evaluated statistically. The results revealed that, core/sheath ratio, types of core materials have significant effects on thermal comfort characteristics of the fabrics. As the core ratio increases from 19 to 56%, the air permeability of the fabrics increases whereas their thermal conductivity and thermal absorptivity properties decrease. Meta-aramid/E-glass core fabrics can be preferable for protective clothing due to high air permeability and thermal conductivity values.     

Production of electromagnetic shielding fabrics by optimization of electroless silver plating conditions for PET fabrics

This study aimed to investigate the optimal electroless silver plating conditions on poly (ethylene terephthalate) (PET) to develop electromagnetic shielding fabrics by comparison with two different activation agents (silver nitrate mixture and palladium chloride mixture). The add-on yield and thickness of plated fabrics were improved when the electroless silver plating was performed after the activation by silver nitrate mixtures compared to the activation by palladium chloride mixtures. The stability of plated surfaces after the activation by silver nitrate mixtures was proved after laundering by surface morphology and electromagnetic wave shielding effectiveness. The electroless silver plating condition was optimized to temperature of 15 °C, plating time of 30 min, dextrose concentration of 45 g/L, and silver nitrate concentrations as a plating material of 50 g/L. The electromagnetic wave shielding effectiveness and electrical conductivity of plated fabrics were maintained even after repeated laundering cycles. Electron probe microanalysis was concluded that the silver was attached on plated PET surfaces, and about 17.8% of silver was observed by inductive coupled plasma spectrometer.     

Functional finishing of cotton fabrics using graphene oxide nanosheets decorated with titanium dioxide nanoparticles

This study examined an innovative approach for imparting multi-functional properties, i.e. self-cleaning, electrical conductivity, ultraviolet (UV) blocking as well as antimicrobial properties onto cotton fabric. Graphene oxide/TiO₂ nanocomposites were successfully prepared, by a simple method of mixing and sonication, and used for multi-functional treatment of cotton fabrics by dip-drying technique. The physicochemical properties of the prepared samples were characterized with field emission scanning electron microscope, transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy. Self-cleaning performance, electrical resistance, antimicrobial properties, and UV blocking activity of treated fabrics were also assessed. The coated cotton fabrics with graphene oxide/TiO₂ nanocomposite showed excellent photocatalytic self-cleaning activity measured by degradation of methylene blue in aqueous solution under sunlight irradiation. Results showed that the electrical conductivity of the graphene oxide/titanium dioxide nanocomposite-coated fabrics was improved significantly after sunlight irradiation. Moreover, the nanocomposite finished cotton fabric demonstrated proper antimicrobial properties and UV blocking activity.     

The influence of distribution and deposit of conductive coating on shielding effectiveness of textiles

This study presents the investigation of electrically conductive fabrics with low resistivity, coated with formulation containing the conjugated polymer system – poly(3,4-ethylenedioxythiophene)-polystyrene sulphonate (PEDOT-PSS). The samples of fabrics were coated with PEDOT-PSS, using a screen printing method, by different patterns or coating their surface fully with different coating deposit. Methods for measurement of electrostatic properties, reflection and transmission as well as the assessment of electromagnetic radiation (EMR) shielding effectiveness were used for the characterization of electrical properties of developed samples. EMR shielding properties were investigated within 2–12 GHz frequency bands. The highest attenuation of the electromagnetic energy among tested fabrics was obtained on the fabrics fully coated with paste and it depended on deposit considerably. The influence of distribution and deposit of conductive coating on shielding effectiveness of textiles were determined. Correlation between shielding effectiveness and electrostatic properties of developed coated fabrics was also discussed. Electrical properties of samples coated with formulation containing PEDOT-PSS were compared with these of fabrics with metalized yarns, developed by us earlier. The results of EMR shielding measurements showed that fabrics coated with the paste containing conductive polymer system compared to fabrics with in-weaved conductive metalized yarns have certain advantages as EMR shields.     

Steady-state thermal comfort properties of fabrics incorporated with microencapsulated phase change materials

This study focused on assessing the thermal comfort properties of the fabrics incorporating microencapsulated phase change materials (microPCMs) under steady-state condition. Air permeability and water vapor permeability of the fabrics were also investigated. Poly(methyl methacrylate)/n-hexadecane microcapsules were applied to the cotton and cotton/polyester fabrics using pad-cure methods. Thermal comfort properties of the fabrics were measured using Alambeta. The results indicated that the thickness of the fabrics incorporated with microcapsules increased depending on the amount of microcapsules added on the fabric. Thermal conductivity of the fabrics treated with polyurethane (PU) resin decreased while addition of microPCMs had almost no effect on the thermal conductivity. However, thermal resistance of the fabric increased as the fabric thickness increased or the thermal conductivity decreased. Air permeability and water vapor permeability of the fabrics treated with microPCMs were found to be lower than those of pristine fabrics while water vapor permeability of the fabrics treated with PU was found higher than pristine fabrics.     

Preparation,characterisation of bamboo charcoal particles and the effect of their application on thermo-physiological comfort properties of woven fabrics

Abstract

Bamboo charcoal particles were prepared at micro level and applied on three types of woven fabric, namely 100% cotton, 100% polyester and 65/35 p/c blend. The thermo-physiological comfort properties such as wetting, wicking, water vapour permeability, air permeability and thermal resistance of the control and treated fabrics were investigated to study the effect of bamboo charcoal particles application on these fabrics. The results reveal that the bamboo charcoal treated fabrics show a good improvement in wetting, wicking and water vapour permeability. The charcoal particle finished fabrics also showed a slight decrease in thermal resistance thereby contributing to a corresponding improvement in thermal conductivity with a reduction in air permeability when compared with the control fabrics. The bamboo charcoal treated fabrics showed a good fastness to washing thus exhibiting good durability on the fabrics selected for the study. Also, the charcoal treated fabrics revealed a higher wickability than the control fabrics even after 20 washes.     

Study on effect of blend ratio on thermal comfort properties of cotton/nylon-blended fabrics with high-performance Kermel fibre

This study presents the thermal comfort properties of woven fabrics made of Kermel, cotton/nylon and cotton/nylon /Kermel-blended yarns. Our aim in this study is to combine the high comfort properties of cotton/nylon fibres with high thermal protective properties of Kermel fibre in different woven fabrics. Thus, Kermel (100%), cotton/nylon (50:50) and four blends of the 50% cotton fibres with nylon and Kermel (40:10, 30:20, 20:30 and 10:40) were spun on a ring-spinning frame and twisted into two-folded yarns with the same yarn count of 30/2(Ne) and twist level of 560 TPM. Using the produced yarns, woven fabrics with identical characteristic and structure were also produced. Then, the thermal comfort and physical properties of fabrics were studied in terms of fabric porosity, thermal resistance, thermal conductivity, water vapour resistance and air permeability. The results show that the porosity, air permeability and thermal resistance increase with Kermel fibre blend ratio. Conversely, the water vapour resistance decreases with increase of Kermel fibre blend ratio up to 40%, while 100% Kermel-woven fabric exhibits a higher water vapour resistance value. Nevertheless, the thermal conductivity of cotton/nylon-blended Kermel woven fabric is unchanged with increase of Kermel fibre blend ratio up to 40%, whereas at 100% Kermel fibre blend ratio, the lowest thermal conductivity is obtained. The obtained results implied that woven fabric produced from cotton/nylon (50/10) blended with 40% Kermel fibre resulted in proper thermal comfort properties.     

氧化石墨烯/聚苯胺功能膜对棉织物电磁屏蔽性能的影响

为制备轻质高效的吸波型电磁屏蔽织物,采用层层组装方法在棉织物表面涂层氧化石墨烯/聚苯胺(GO/PANI)电磁屏蔽功能膜。研究苯胺单体浓度、氧化石墨烯质量浓度、组装层数对整理棉织物电性能及电磁屏蔽性能的影响,并分析了屏蔽电磁能的吸收率、反射率以及吸收屏蔽效能和反射屏蔽效能。结果表明:苯胺单体浓度和组装层数的增加有利于提高棉织物的电磁屏蔽效能,而随着氧化石墨烯质量浓度的增加,织物的电磁屏蔽效能先增加后减小;组装4层GO/PANI功能膜后棉织物的屏蔽效能达到19.91 dB,可屏蔽98.98%的电磁能,其吸收率达到57.63%,而反射率为41.35%,主要屏蔽机制是吸收。     

Effect of blend proportion on thermal behaviour of bamboo knitted fabrics

This study presents the thermal comfort properties of single jersey knitted fabric structures made from cotton, regenerated bamboo and cotton–bamboo blended yarns. Cotton, bamboo fibre and blends of the two fibres (100% cotton, 100% bamboo, 50:50 cotton:bamboo, 67:33 cotton:bamboo, 33:67 cotton:bamboo) were spun into yarns of identical linear density (20?tex). Each of the yarns so produced was converted to single jersey knitted fabrics with loose, medium and tight structures. The thermal conductivity of the fabrics was generally found to decrease with increase in the proportion of bamboo fibre. The relative water vapour permeability and air permeability of the fabrics were observed to increase with increase in bamboo fibre content. Statistical analysis also indicates that the results are significant for air permeability, thermal resistance, thermal conductivity and relative water vapour permeability of the fabrics.     

基于灰色关联模型的针织物热湿舒适性分析与预测

为了实现对针织物热湿舒适性能的预测,对7种针织物进行物理性能测试,对影响针织物热湿舒适性的因素进行了灰色关联度分析,得出对热湿舒适性影响显著的针织物性能指标主要为瞬间冷暖感、导热系数、透湿量、厚度;在此基础上,运用灰色预测方法建立了针织物热湿舒适性与针织物测试性能指标之间的灰色关联模型,从而在得知针织物的瞬间冷暖感、导热系数、透湿量、厚度的情况下实现对针织物热湿舒适性的预测分析。     

Stab resistance and thermophysiological comfort properties of boron carbide coated aramid and ballistic nylon fabrics

This research presents the stab resistance and thermo-physiological comfort properties of the fabrics prepared from high-performance fibres of aramid (i.e. Kevlar®) and ballistic nylon. The fabric samples were coated with boron carbide to improve the stab resistance properties. The quasistatic stab tests were performed using NIJ 0115.00 standard knife (P1) on the Instron tensile testing machine. The thermo-physiological comfort properties of the fabric samples were evaluated by measuring the air permeability, water-vapour resistance and thermal resistance. It was observed that the application of the coating significantly increased the stab resistance properties of the fabrics. Furthermore, the air permeability was significantly reduced; whereas, the water-vapour resistance and thermal resistance were significantly increased with the application of coating. Hence, the coated fabrics will have to compromise the comfort aspects to achieve the desired protection level, which is the prime requirement for the stab resistant textile materials.     

Electrical,electromagnetic shielding,and some physical properties of hybrid yarn-based knitted fabrics

Recently, increasing number of studies are performed on protective fabrics containing metal wires for electromagnetic shielding purposes. In the present paper, the hybrid fabrics in plain and rib structures were knitted by using single and double ply hybrid yarns obtained by acrylic (PAC) yarns plied with stainless steel wires having two different diameters. The physical properties including conductivity, air permeability, pilling, and abrasion resistance as well as electromagnetic shielding effectiveness (EMSE) were measured. The variations in EMSE as well as reflection, absorption, and transmission and in other physical properties of knitted hybrid fabrics were investigated considering wire content and weave structure. It was seen that an increase in the wire content significantly increased the conductivity. Rib fabrics exhibited better EMSE values as compared with plain fabrics. Fabrics using two-folded yarns exhibited better EMSE values. Fabrics using thinner wire exhibited higher EMSE values. The highest EMSE value was obtained for rib-knitted fabric with 35 micrometer (μm) stainless steel wire.     

还原氧化石墨烯涂层织物的电加热性能

为研究可穿戴织物的电加热性能以及水洗对其性能的影响,通过简单安全可大规模产业化的无转移液相浸涂沉积法在涤纶针织物上沉积并原位还原,制备了还原氧化石墨烯(RGO)涂层织物加热器。借助扫描电子显微镜和傅里叶红外光谱仪对制备的RGO涂层涤纶织物进行表观形态与化学结构分析,同时研究了RGO涂层涤纶织物的导电、力学、电加热性能。结果表明:RGO涂层涤纶织物的电导率为430.9 mS/cm,在10 V电压下可达到65.58 ℃的稳定温度,最大升温速率为3.41 ℃/s;经过2次水洗循环后,在10 V的电压下,RGO涂层涤纶织物可达到43 ℃。本文研究表明,RGO涂层涤纶织物具有优异的电热性能,在医用电热、运动康复等领域具有良好的应用潜力。     

多功能聚氨酯涂层织物的制备及性能

采用聚氨酯(PU)树脂溶液添加到适量的壳聚糖溶液中,同时调整粘度至所需涂布的粘度,经转移涂层工艺加工成PU涂层织物。通过透湿、耐静水压等仪器对PU涂层织物的透湿量、耐静水压以及抗菌性能进行测试与分析。结果表明,壳聚糖对涂层织物耐静水压有一定影响,较好地改善了PU涂层织物的透湿性能,并赋予PU涂层织物抗菌性能,从而实现防水、透湿和抗菌三效合一的多功能产品。     

石墨烯黏胶纤维机织物的功能改性研究

制备同规格的普通黏胶纤维机织物、石墨烯黏胶纤维机织物及不同不锈钢丝质量分数的石墨烯黏胶纤维/不锈钢丝机织物,对比它们的导电、防电磁辐射、防紫外线、抗静电、力学(拉伸、弯曲、耐磨)及透气等性能。结果表明:普通黏胶纤维经石墨烯改进后,所制成的石墨烯黏胶纤维机织物的导电、防电磁辐射、防紫外线、抗静电、力学(拉伸、弯曲、耐磨)等性能都有所改善,其中防紫外线与耐磨性能提高显著,透气性能下降明显;石墨烯黏胶纤维/不锈钢丝机织物的导电、防电磁辐射、防紫外线和抗静电、经向拉伸断裂强力、纬向抗弯刚度、透气性能都优于石墨烯黏胶纤维机织物,纬向拉伸断裂强力、经纬向拉伸断裂伸长率、经向抗弯刚度及耐磨性能不及石墨烯黏胶纤维机织物;随着不锈钢丝质量分数在7.0%~20.0%范围内的增加,石墨烯黏胶纤维/不锈钢丝机织物的导电、防紫外线、抗静电、经向拉伸断裂强力、纬向抗弯刚度及透气性能增强,纬向拉伸断裂强力、经纬向拉伸断裂伸长率、经向抗弯刚度、耐磨性能减小,不锈钢丝质量分数变化对防电磁辐射性能影响较小。当不锈钢丝质量分数为7.0%时,石墨烯黏胶纤维/不锈钢丝机织物的综合性能最佳。     

层层组装氧化石墨烯/聚吡咯涂层棉织物的电磁屏蔽性能

为制备高效吸波型电磁屏蔽织物,采用层层组装法在棉织物表面构筑氧化石墨烯/聚吡咯(GO/PPy)功能膜。借助傅里叶红外光谱仪和扫描电子显微镜对GO/PPy涂层织物的结构进行表征,通过万用表和矢量网络分析仪测试织物的导电性能和电磁屏蔽性能。结果表明:织物的阳离子化处理有利于氧化石墨烯和聚吡咯的沉积,适宜的GO质量浓度(0.4 g/L)有利于提升织物的电磁屏蔽效能;随着组装层数的增加,织物的电磁屏蔽性能增加,当组装层数为20时,织物的电磁屏蔽效能达到39.2 dB,可屏蔽99.98%的电磁能;织物对电磁波的吸收率始终大于50%,其主要的屏蔽机制为吸收而非反射。     

硫代硫酸钠对涤纶织物化学镀银的影响

研究硫代硫酸钠对化学镀银镀液稳定性、镀层表面形貌、镀层成分、结晶情况、镀银速率、表面电阻以及电磁屏蔽效能的影响.结果表明:添加硫代硫酸钠能使镀液的稳定性得到明显提高,但若浓度过高,会出现镀层结构疏松的现象;镀层中银的结晶形态是立方面心(fcc)结构,晶粒尺寸随硫代硫酸钠浓度的增加而减小;硫代硫酸钠的加入使镀银速率下降,...