Influence of filler on dielectric properties of silicone rubber particulate composite material

Abstract This paper deals with the development of silicone rubber particulate composites filled with strontium titanate to improve dielectric properties of neat silicone rubber. The composite material is prepared by a solution casting method with three different volume percentages of the filler. The composite samples prepared are tested for dielectric properties as per standards. The influence of filler on dielectric properties of composite material is studied by testing for dielectric permittivity, loss tangent, and ac conductivity. The dielectric permittivity experimentally obtained is compared with the available empirical models. The dielectric permittivity, loss tangent, and ac conductivity of silicone rubber composite increased with the increase of volume percentage of strontium titanate. Compared to neat silicone rubber the dielectric permittivity, loss tangent, and ac conductivity of the silicone rubber composite filled with 10% volume of strontium titanate is increased by 66%, 117%, and 267% respectively. Further, the empirical models confirmed that dielectric permittivity obtained is within the limit. The microscopic study reveals that the improved dielectric properties attributed to the stronger bond between the silicone rubber and the strontium titanate particles.