纳米颗粒填充对LDPE/silica纳米复合介质阈值电场的影响  

Influence of Nano-filler on High Field Threshold Property in LDPE/silica Nanocomposites

作　　者：吴建东[1] 兰莉[1] 尹毅[1] 李喆[1] 李旭光[1] 

机构地区：[1]上海交通大学电气工程系,上海市闵行区200240

出　　处：《中国电机工程学报》2013年第22期201-206,29,共6页Proceedings of the CSEE

基　　金：国家863项目(2012AA030310);国家自然科学基金项目(51007057)~~

摘　　要：为研究纳米颗粒填充对复合介质阈值电场特性的影响,以低密度聚乙烯（low-density polyethylene,LDPE）为基料、纳米二氧化硅（silica）为填充颗粒,制备了填充粒径分别为7和16 nm、填充浓度在0~5.0%范围的LDPE/silica纳米复合介质,并测试了复合介质的准稳态直流电导。研究表明：低电场下纳米颗粒对复合介质直流电导的影响不大;在高电场下,低填充密度（1.0%附近）时复合介质的电导比纯LDPE的值大,阈值电场均低于纯LDPE的值;仅当填充浓度较高时,复合介质的电导才下降,并且阈值电场高于纯LDPE的值。纳米颗粒填充粒径7和16 nm时,纳米复合介质的阈值电场特性基本一致,但在高电场下,填充粒径7 nm时的复合介质电导小于填充粒径为16 nm的值,且填充粒径7 nm时复合介质的阈值电场都高于填充粒径为16 nm时的值,表明填充粒径越小的纳米颗粒越能提升复合介质的阈值电场。另外,基于空间电荷限制电流理论（space charge limitedcurrent,SCLC）分析可知：纳米颗粒填充浓度较低时,纳米复合介质中总陷阱浓度H相对于纯LDPE都明显下降,仅当填充浓度进一步升高时,总陷阱浓度H才高于纯LDPE中的值。填充浓度在0.1%~5.0%时,纳米复合介质内部总陷阱浓度H随填充浓度的升高而升高,这主要与纳米颗粒引入颗粒/基料界面结构的增多有关。The high field conduction was investigated in low-density polyethylene（LDPE） and LDPE/silica nanocomposites filled with various size and concentration of nanosilica.The concentration was from 0~5.0% and the average particle size was 7 nm and 16 nm,respectively.It is found that the effect of nanofiller is not distinct for conduction at low electric field.The introduction of nanofiller at low concentration about 1.0% could not suppress the conduction at high electric field.The threshold fields are significantly lower in the nanocomposite,compared with that of pure LDPE.However,the conduction current at a high field remarkably reduces at high concentrations and the threshold fields apparently increase.The conduction current at high field is smaller in nanocomposite filled with 7 nm nanofiller,compared with that filled with 16 nm nanofiller.Moreover,the threshold fields are also lower in nanocomposite filled with smaller particle.In addition,the total trap density H evaluated from the high field conduction based on space charge limited current（SCLC） theory decreases at low nanosilica concentration and increases at high nanosilica concentration.Moreover,H increases with the increase of nanosilica concentration from 0.1% to 5.0%.It is considered that the increase of total trap density H in nanocomposite with the nanofiller concentration is caused by the increase of interface between nanofiller and LDPE matrix.

关 键 词：纳米复合介质 低密度聚乙烯 纳米二氧化硅 高场电导 空间电荷限制电流 

分 类 号：TM85[电气工程—高电压与绝缘技术]