Effect of the ß-Crystal Formation on Electrical Properties in Propylene-Ethylene Copolymer

In this paper, the β nucleating agent, N, N'-dicyclohexyl-2, 6-naphthalenedicarboxamide (TMB-5), and propylene-ethylene copolymer (PEC) was melting blended to create the β-crystal in PEe. The content of β nucleating agent is from 0.1 to 0.3 wt%. The crystal form, crystallinity were characterized by wide angel X-ray diffractometer, differential scanning calorimeter. The thermal stimulated current test, space charge test and DC electrical breakdown test at room temperature and 90°C were conducted to characterize the electrical properties of these samples. The experimental results show that the TMB-5 could form β-crystal and more content of TMB-5 more β-crystal in PEC. At room temperature and 90°C, the DC electrical breakdown strength of 0.1 wt% content β-nucleated PEC increased 17 % and 14 % higher than pure PEC. And there was no obvious space charge accumulated in pure PEC and PEC containing TMB-5.