Effect of hybrid-SiO2 particles on characterization of EPDM and silicone rubber composites for outdoor high-voltage insulations

Abstract

Ethylene propylene diene monomer (EPDM) and silicone rubber (SiR) are well-known polymers for high-voltage (HV) outdoor applications. In this research work, the effect of hybrid SiO2 (a mixture of 15% micro-sized and 5% nanosized silica) has been investigated on the mechanical, thermal, and electrical properties of EPDM and SiR composites. Using the ASTM standard procedure, the EPDM and SiR composites filled with hybrid silica were compounded by two roll mill and simple blending techniques, respectively. It was observed that with the addition of hybrid SiO2, the composites exhibited improved tensile strength of similar to 2500 kPa, reduced elongation at break, and enhanced hardness. The samples filled with SiR hybrid silica showed higher thermal stability and volume/surface resistivities relative to EPDM hybrid composites. However, EPDM hybrid composites showed higher dielectric strength of similar to 23.4 kV/mm as compared with SiR composites. From these characterization results, it can be suggested that SiR hybrid composites are more suitable for outdoor HV insulation applications.