Influence of Additives in Electret Nonwoven Fabric on Thermally Stimulated Current

Abstract

Polypropylene fibers consist of a complicate higher-order structure and contain additives such as antioxidant, polar polymer and nucleating agent, hence, the origin of carrier traps is complicated. After carriers were trapped adequently into a nonwoven fabric by corona charging, the effect of additives was investigated by thermally stimulated current. As results, even a small amount of additives affected largely upon thermally stimulated current and enlarged the intensity of peak and the polarization charge. These phenomena may be the result of increase of physical and chemical traps formed by additives. The thermally stimulated current originated from trapped carriers and polarization of electret polypropylene fibers was found to closely concern with the molecular motion of polypropylene. Furthermore, the polarization charge increased by additives affected upon filter performance.