High field dielectric properties of clay filled silicone rubber composites

Abstract

The present research work was aimed at improving the high field dielectric properties of silicone rubber (SR) composites used for power cable insulation. Liquid silicone rubber composites were developed using two types of clays as filler materials; organically modified montmorillonite (ommt) and calcined, surface treated kaolin with the commercial name Translink 37 (T37). The results revealed that the surface chemistry of the clay had a distinct effect on both dispersion as well as electrical performance of silicone rubber-clay composites. We observed that surface treated kaolin (T37) were well dispersed in the SR matrix, but had adverse impact on the crosslinking kinetics of liquid silicone rubber resulting in higher dielectric loss at low frequencies. On the other hand, organically modified clay showed poor dispersion in the silicone rubber matrix while exhibiting much lower dc conductivity characteristics at high temperature. The agglomerated ommt macroparticles introduced the interfacial traps in SR matrix and charge carriers migration was limited within the matrix.