Development of nano-fibers and the application to apparel science

本研究系以服装及服装科学之观点，探讨高分子与填充物复合材料之机械性质。通过混合常见的导电填料的复合材料的特征在于由渗流阈值或临界值，在该临界值处，导电性开始作为填料含量的函数增加。以多壁碳纳米管（MWNTs）和碳纤维（CF）为填料，超高分子量聚乙烯（UHMWPE）为基体，制备了纳米复合材料。采用凝胶法制备复合材料。从溶液中结晶。以十氢萘和石蜡为溶剂制备了UHMWPE和MWNT复合材料。对原始复合材料和热处理后的复合材料进行了电导率测量。在石蜡中制备的复合材料的电导率在低MWNT含量时急剧增加，而在十氢萘中制备的复合材料的电导率在10wt% MWNT含量时略有增加。扫描电子显微镜 ...更多信息 观察发现，在十氢萘中制备的复合材料中的MWNTs被UHMWPE覆盖，并且它们的平均直径远大于原始MWNTs的平均直径，而在石蜡中制备的复合材料中的MWNTs的平均直径与原始MWNTs的直径相似。这种不同的形态是由于不同的结晶。一些UHMWPE -碳填料复合材料在接近聚合物熔点的高温下表现出电阻率的急剧增加，这被称为正温度系数（PTC）效应。提出了一种简单的电阻-电容电路模型，用于研究HDPE/CF复合材料的交流电导率和介电常数行为。复合材料被认为是一个系统组成的随机阵列的紧密排列的导体分散在绝缘UHMWPE矩阵和宽频测量进行探测的导电路径和空间间隙显示的实验证据解释PTC机制。少

This research deals with the mechanical properties of composite materials of polymer and fillers in terms of apparel and clothing science. The composites by admixing common conductive fillers are characterized by a percolation threshold or a critical value at which the conductivity starts to increase as a function of filler contents. Multi-wall carbon nenotubes (MWNTs) and carbon fibers (CF) were uesed as fillers and ultra-high molecular weight polyethylene (UHMWPE) were used as matrix.. The composite materials were prepared by gelation./crystallization from solution.. UHMWPE and MWNT composites were prepared using either decalin or paraffin as solvent. Electrical conductivity measurements were performed for the original and heat-treated composites. The drastic increase in conductivity occurred at low MWNT content for the composite prepared in paraffin, while the conductivity of the composite prepared in decalin increased slightly up to l0wt% MWNT content. Scanning electron microscopy … More observations revealed that the MWNTs within the composite prepared in decalin were covered by UHMWPE, and their average diameters were much greater than those of the original MWNTs, while the average diameter of the MWNTs within the composite prepared in paraffin was similar to the diameter of the original MWNTs. Such different morphology was found to be due to the different crystallization.Some of UHMWPE - carbon filler composites showed a sharp increase in electrical resistivity at elevated temperature close to the polymer melting point, which is known as the positive temperature coefficient (PTC) effect. A simple resistor-capacitor circuit model id proposed to explore the alternating current (AC) conductivity and dielectric permittivity behavior of UHMWPE-CF composites. The composites are considered as a system composed of random arrays of closely spaced conductors dispersed in an insulating UHMWPE matrix and broad frequency measurements are carried out to probe the conducting path and the space gaps to show the experimental evidence for explaining PTC mechanism. Less