Effects of polar molecules on direct current performance of EPDM for cable accessories

Abstract

Due to the excellent insulation performance, ethylene-propylene-diene monomer (EPDM) is used as cable accessories. To obtain EPDM materials with high dielectric breakdown strength (DBS), special polar molecules and chemistry grafting/crosslinking technique are used in this paper. In this paper, we choose Maleic anhydride (MAH) as an additive to introduce deep traps, which generates an increase in dielectric breakdown strength(DBS) and a decrease in conductivity. The result shows that MAH molecules can be grafted onto EPDM molecular chains in the process of cross-linking. Thermal stimulation currents (TSC) tests and the first-principles calculations consistently demonstrate that MAH can introduce deep charge traps, inhibiting migration of carriers, and increasing the DBS of EPDM. The grafting weight of MAH is small, which does not affect the process properties of the material.