Dielectric behavior of filled silicone rubbers: effects of cross-linking agent and surface modified fillers

The influence of amount of cross-linking agent and surface modification of alumina trihydrate (ATH) fillers on dielectric properties of silica filled silicone rubber were investigated. It was found that the cross-linking agent did not affect the dielectric properties of the silica filled silicone rubber if the samples were electrically aged before. There were two clear processes in these systems, relaxation polarization and DC conduction. Introduction of surface modified and non-surface modified ATH fillers changed these characteristics to low frequency dispersion dominated. The losses were higher in the sample with silanized ATH filler. The losses increased with surface modified fillers when the filler concentration increased.