纳米SiO2/低密度聚乙烯复合介质的击穿特性

聚合物纳米复合介质的击穿强度与纳米填充颗粒的质量分数、粒径和表面处理密切相关。以不同表面处理的纳米SiO2颗粒为填料,制备了不同填充质量分数、粒径的纳米SiO2/低密度聚乙烯(low density polyethylene,LDPE)复合介质,测试了其在交流、直流正极性和直流负极性3种不同类型电场下的击穿场强。结果表明:在所研究范围内,填充纳米SiO2颗粒可以提高低密度聚乙烯的击穿场强,并且随着填充质量分数的增加,复合介质的击穿场强有升高的趋势。纳米颗粒填充质量分数相同时,在12~16 nm粒径下,复合介质的击穿场强有随纳米SiO2粒径的升高而降低的趋势;在7 nm小粒径下,可能由于纳米颗粒容易团聚,导致击穿场强较粒径大时要低。另外,纳米SiO2颗粒表面经疏水性处理后,能够有效提高复合介质的击穿场强。

Breakdown Properties of Nano-SiO2/LDPE Composite

The breakdown strength of polymer nanocomposite is related to the properties of nano-additive,such as doping concentration,particle size and surface treatment.Specimen with different doping concentration,particle size and particle surface treatment were made to test the breakdown strength under AC,positive DC and negative DC voltage,respectively.It is shown that in the context of this study,doping nano-SiO2 can increase the breakdown strength of low density polyethylene(LDPE);and the breakdown strength of nano-SiO2/LDPE composite increases with the increasing of doping concentration.Under the same doping concentration,when particle size is between 12 nm and 16 nm,the breakdown strength of nanocomposite decreases with the increasing of particle size.When particle size is 7 nm,the breakdown strength is smaller than that of the bigger particle size,which is probably caused by the coalescence of 7nm nano-SiO2 particles.Besides,hydrophobic surface treatment of nano-SiO2 particles can enhance the breakdown strength of nanocomposite.