高密度聚乙烯/石墨半导体复合物的压阻特性

STUDY ON PIEZORESISTIVITY OF HIGH DENSITYPOLYETHYLENE/GRAPHITE SEMICONDUCTIVE COMPOSITES

研究了聚乙烯／石墨半导体复合物（ＨＤＰＥ／ＧＰ）在轴向压力下的压阻特性。结果表明，这种复合物的导电性有较显著的压力依赖性。在低压力范围内电阻随压力增加而降低，在较高压力下则随压力增大而升高，呈现出所谓的“电阻负压力系数（ＮＰＣＲ）”和“正压力系数（ＰＰＣＲ）”效应。电阻的压力依赖性，以及在恒压力作用下表现出来的“电阻蠕变”行为，被认为与导电粒子网络在应力作用下的破坏与重组有关。

The piezoresistivity of high density polyethylene/graphite (HDPE/GP) semiconductive composites was studied through measuring the resistance change under uniaxial pressure. The results show that there exists a marking pressure dependence of the conductivity in HDPE/GP composites, in which the socalled negative pressure coefficient of resistive ( NPCR )and positive pressure coefficient of resistive ( PPCR ) are observed under minute and moderate pressures. Under constant pressures, timedependent resistivity is an outstanding characteristic for the composites, which is defined as resistance creep. The breakdown and rebuildup process of conductive network under pressure may be responsible for the pressureand timedependence of resistivity.