蒙脱土改性聚乙烯复合材料的高场介电性能研究

利用熔融插层法制备了聚乙烯/蒙脱土纳米复合材料,研究蒙脱土对聚乙烯介电性能的影响。研究分析了纯聚乙烯和不同的聚乙烯/蒙脱土复合材料的树枝化性能,通过直流预电应力电树引发试验,探讨了空间电荷的极性效应对不同材料树枝化性能的影响。试验结果表明:与纯聚乙烯和其他复合材料相比,加入相容剂的聚乙烯/蒙脱土纳米复合材料的电树潜伏期更长,电树生长速度更慢,而且显示出与LDPE不同的极性效应。不同材料的热激电流(TSC)试验结果显示:聚乙烯/蒙脱土纳米复合材料的松弛时间分布展宽,峰值增高,说明在纳米复合材料中引入了更多的陷阱能级,这些陷阱调制了载流子浓度和迁移率,从而抑制了树枝的起始与生长。

Study on Dielectric Properties of Polyethylene/Montmorillonite Nanocomposites in High Field

To investigate the influence of modified Polyethylene with montmorillonite on characteristics of dielectric property,polyethylene/montmorillonite nanocomposites are prepared by means of melting intercalation process.The characteristics of electrical tree in polyethylene and various polyethylene/montmorillonite composites are investigated.The polar effects due to space charge are discussed through the characteristics of electrical tree in samples subjected to DC electrical pre-stress.The test results show that the time of initiating electrical tree is longer and the length of electrical tree is shorter in polyethylene/montmorillonite nanocomposites with compatilizer(LDPE/C/O-MMT) than pure polyethylene and other composites.Polar effects are different from LDPE.It can be observed in the test of thermally stimulated current(TSC) that the distributing of relax time becomes broad,the peak value increases in LDPE/C/O-MMT samples,which means that more trap levels are introduced into the nanocomposites.Theses traps modulate density and mobility of carriers,thus the initiating and spreading of electrical tree are inhibited.