Mechanistic insights into the ageing of EPDM micro/hybrid composites for high voltage insulation application

Abstract

In this work, we explore the mechanistic insights into the aging of EPDM based micro/hybrid composites under following environment namely acid rain, cryogenic temperature, high temperature and UV irradiation. Physical properties and cross-link density changes were measured before and after aging which confirms the degradation of EPDM samples under high temperature and UV environment. Surface properties were also measured for the samples under various aging conditions. High-temperature aging resulted in an increase in contact angle whereas, UV has led to a major loss in contact angle for all the samples. Based on the chemical changes predicted by FTIR and NMR we propose a photo-oxidative degradation mechanism under UV irradiation and the influence of nano-micro filler at cryogenic and high temperature aging. Surface morphology and dielectric property of the samples were found to undergo major changes under high temperature and UV aging which directly influences the electrical insulation property of the composite. Finally, the study gives insights into the factor affecting the shelf life of the EPDM composites which are exposed mainly under the mentioned environment for its application in outdoor high voltage insulation applications and can help in overcoming the aging issues mainly faced by polymer composites.