钛化合物填充的聚合物导电复合材料的PTC特性及微观结构

PTC Characteristics and Microstructures of a Polymer Based Conductive Composite Filled with Various Titanium Compounds

以高密度聚乙烯 (PE HD)及热固性环氧树脂为基体 ,钛的硼化物、碳化物、氮化物或碳氮化物为导电粒子 ,研究了PE HD/钛化合物、环氧树脂 /钛化合物导电复合体系的逾渗行为、PTC/NTC现象及微观结构行为。结果表明 ,PE HD/钛化合物及环氧树脂 /钛化合物导电复合体系均具有强PTC开关特性 ,其逾渗阀值为 3 5 %～ 65 % (体积分数 ) ;电阻温度系数高达 (5 5 .7%～ 64 .3 % )·℃ -1。钛化合物导电颗粒以粒度不等的非均匀分布分散在聚合物基体中 ,其中在PE HD基体中颗粒之间在室温下紧密接触导通 ;而在环氧树脂基体中颗粒之间易产生团聚。

The percolation behavior and PTC/NTC (positive temperature coefficient/negative temperature coefficient) characteristics of PE-HD/titanium compounds and epoxy resin/titanium compounds were investigated.Both systems showed an intensive PTC switch performance,the percolation threshold was between 35 vol% and 65 vol%,the resistance-temperature coefficient was between 55.7 %·℃ -1 and 64.3 %·℃ -1.The particle size of titanium compounds was widely distributed in the polymer matrix.They were more easily coagulated in epoxy resin than in PE-HD.