Studies on Electrical and Thermal Properties of Vinyloxyaminosilane Grafted Ethylene–Propylene–Diene Terpolymer/Linear Low Density Polyethylene Blends for Cable Applications

Abstract

A new terpolymer of vinyloxyaminosilane (VOS) grafted onto ethylene–propylene–diene terpolymer (EPDM) has been synthesised in a Haake Rheocord-90, torque rheometer. Vinyloxyaminosilane grafted ethylene–propylene–diene terpolymer/linear low density polyethylene (EPDM-g-VOS/LLDPE) blends with different compositions were prepared using a two roll mixing mill. The electrical properties such as surface and volume resistivities, dielectric strength and arc resistance are decreased and dielectric constant and dielectric loss are increased with increasing percentage composition of LLDPE in EPDM-g-VOS/LLDPE blends due to enhanced crosslink density. The incorporation of VOS moiety onto EPDM improves the inception decomposition and final decomposition temperatures due to stable three dimensional network and high bond energy of –Si–O–Si– linkage. The values of Tg are increased with increasing concentration of LLDPE in the EPDM-g-VOS/LLDPE blends due to enhanced crystallinity and crosslink density. Thermal aging studies on mechanical properties show that the tensile strength, elongation at break and Young modulus are decreased due to disruption of crosslinking at LLDPE sites.