交变载荷下PP/SSFs复合材料导电性

通过熔融共混、注塑成型的方法制备聚丙烯(PP)/不锈钢短纤维(SSFs)导电复合材料,用万能试验机对试样进行循环加载实验,实时采集试样的应力、应变和电压信号,研究SSFs含量不同的PP/SSFs试样在交变载荷作用下电阻率的变化规律。结果表明,随着SSFs含量的增加,PP/SSFs复合材料的导电性不断增强。在交变载荷作用下,应变对应力有所滞后,电阻率与应变呈现反向对应关系,应变增加时电阻率减小,其电阻率整体变化趋势呈先上升后趋于稳定的状态,这是由于在加载过程中,PP/SSFs复合材料的内部同时存在旧导电通路的破坏和新导电通路的形成两个过程,当这两个过程处于动态平衡状态时,材料的电阻率便趋于稳定。通过扫描电子显微镜观察了导电填料的分布以及载荷作用下的损伤。

Electrical Conductivity of PP/SSFs Composites Under Alternate Loading

Polypropylene (PP)/stainless steel fibers (SSFs) conductive composites were prepared by melt-blending and injection molding. Cyclic loading experiments were carried out by universal testing machine,and the stress,strain and voltage of the specimens were measured during compressive process. Resistivity of the composites with different SSFs contents were investigated under cyclic compressive loading. The results show that the conductivity of PP/SSFs composites is increasing with the increase of SSFs. The strain is lagging behind the stress under alternating load. The resistivity and the strain present a reverse relation and the resistivity decreases with the increasing strain. The overall trend of resistivity is increasing gradually and then become relatively stable. During the compressive process,the destruction of the old conductive path and the formation of the new conductive path exist simultaneously in the composite material. The resistivity of the material tends to be stable when two processes are in a state of dynamic equilibrium. The distribution of conductive filler and the damage due to compressive loading were observed by scanning electron microscope.