Dielectric properties of silicone rubber based composites with nano-sized fillers

Room Temperature Vulcanized Silicone Rubber (RTVSR) is one of the forms of silicone rubber used in outdoor insulating systems, usually in order to improve the pollution performance of ceramic insulation. RTV silicones are used to withstand mechanical and thermal stress. Introduction of nanosized particles inside RTVSR alters the dielectric properties of the polymer. In this work, we study the change in dielectric properties of silicone rubber on introduction of nanofillers. The dielectric properties investigated include complex permittivity and space charge accumulation. The nanofillers incorporated are alumina and barium titanate at 1% concentration (by volume). The nanofillers are mixed mechanically and by ultrasonication to obtain well dispersed nanocomposites.

It is seen from the dielectric spectroscopy measurements that the alumina nanocomposite shows a higher complex permittivity compared to the barium titanate nanocomposite. Space charge measurements are carried out by the Pulsed Acoustic Method (PEA). The results indicate that the incorporation of nanoalumina leads to more space charge accumulation. On the other hand, the depletion of charge is faster with the incorporation of nanofillers.