炭黑/低密度聚乙烯/乙烯-醋酸乙烯共聚物复合材料对交联聚乙烯空间电荷注入的影响

Influence of CB/LDPE/EVA Composites for Space Charge Injected into Crosslinked Polyethylene

采用熔融共混及热压交联的方法制备了炭黑(CB)/低密度聚乙烯(LDPE)/乙烯-醋酸乙烯共聚物(EVA)半导电电极复合材料。研究了CB含量的变化对半导电电极的电阻率的影响以及对绝缘层空间电荷的屏蔽效果。结果表明:半导电电极中CB含量增加时,电阻率降低,当CB含量(质量分数)超过25%后,电阻率减小不明显,表明试样在该CB比例下已接近过导电电阻的逾渗值;空间电荷测试时,随着电场强度的增大,绝缘层的空间电荷密度先增大后减小;半导电电极CB的含量增加时,绝缘层的空间电荷含量先增加后减小。

The carbon black(CB)/low-density polyethylene(LDPE)/ethylene-vinyl acetate copolymer(EVA)semi-conductive shielding compositeshave been prepared by melt blending and hot-press crosslinking.In this paper,the effects of the change of CB content on the resistivity of semi-conductive electrode and the injection of the space charge in the insulation layerwerestudied.The results show that with the increase of CB content,the resistivity of the semi-conductive electrode decreases.Until the content of CB exceeds 25%,the decreases of resistivity is not obvious,showing that the sample is close to the percolation value of conductive resistance under this CB content.When the space charge is tested,with the increase of the electric field strength,the space charge density of the insulating layer increases firstly and then decreases.With the increase of the content of CB in semi-conductive electrode,thespace charge of the insulating layer increases firstly and then decreases.