压力膨化处理对正极性聚丙烯蜂窝膜的驻极体性质的影响

压力膨化处理工艺能够显著改善聚丙烯蜂窝薄膜（cellular polypropylene） 驻极体的压 电活性.通过热脉冲技术、表面电位衰减测量及TSD 电流谱分析等研究了经恒压正电晕充电 的聚丙烯蜂窝膜的陷阱能级分布特征，讨论了压力膨化处理工艺对这类蜂窝膜驻极体电荷稳 定性及电荷输运特性的影响.结果说明，PP 蜂窝膜内存在着位于中能级区的能值各异的三种 分立陷阱，深能值陷阱和浅能值陷阱的大多数位于孔洞膜近表面的体层或体内，而中等能值 陷阱则主要位于自由面附近.压力膨化处理改变了PP 蜂窝膜的能阱状态并在一定程度上降低 了这类孔洞膜驻极体的电荷储存稳定性，但没有明显影响其由慢再俘获效应占主导地位的脱 阱电荷输运特性.关键词：压力膨化处理聚丙烯蜂窝膜驻极体电荷储存与陷阱分布电荷输运

Influence of pressure expanding treatment on electret properties of positively corona charged cellular PP films

Pressure expanding treatment is an effective method for improving the piezoelect ric activity of cellular PP films. In this work, the character of trap-level dis tribution for positively corona charged cellular PP films and the influence of t he pressure expanding treatment on its charge stability and charge transportatio n have been studied by means of thermal pulse technique, surface potential decay measurements, SEM and TSD spectrum analyses, etc. The results point out that th ere are three kinds of traps with different energy values in the range of middl e energy level for the cellular PP films, i.e. most of the deep traps and the shallow traps in the bulk, and most of the traps with middle energy values near the free surface. The pressure expanding treatment changes the state of traps a nd also, to a certain extent, reduces the charge storage stability of the cellul ar PP films, but has not impact on its charge transportation rule, in which the slow retrapping effect is dominant.