CNFs掺杂浓度对CNFs／LDPE复合材料空间电荷的影响

为改善低密度聚乙烯的电学性能，文中将镀镍后的碳纤维添加混入低密度聚乙烯中，通过熔融共混技术，制成CNFs／LDPE半导电层＋绝缘层双层样片．采用电声脉冲法（PEA）测量其空间电荷分布．实验结果表明：随着直流电场的增加，在CNFs／LDPE半导电层＋纯绝缘层双层样片中，当CNFs质量分数低于1％时，CNFs／LDPE半导电层对电场的削弱作用相对较小，样品中残余了相对较多的空间电荷．当CNFs质量分数超过1％时，CNFs／LDPE半导电层的导电机制发生了改变，注入的空间电荷量很少且短路后几乎无残余．尤其是CNFs质量分数为5％时，样品内除阴极附近有微量电荷外，样品内部几乎无空间电荷分布．

Study on the effects of CNFs doping concentration on space charge of CNFs/LDPE nanocomposites

In order to improve the performance of the low density polyethylene, the nickel plated carbon nanofibers （CNFs） were added into low density polyethylene （LDPE） by melt blending techniques, then to make CNFs/LDPE double-layer samples by semi-conducting layer and insulating layer. The pulsed electroacoustic（PEA） method can be used to measure the space charge distribution. The experimental results showed that when the CNFs content was below 1 % （wt.）, CNFs/LDPE semi-conducting layer to the weakening of the electric field effect was relatively small, then samples had more residual space charge with the increase of direct current（DC） electric field. If the CNFs content was more than 1% （wt.）, the conductive mechanism of the CNFs/LDPE semi-conducting layer had been changed, the injection of space charge quantity rarely and after short circuit there will be almost no residual. Especially when the CNFs content was 5%, Only near the cathode there have trace charge interior of the sample almost no space charge distribution.