Experimental study of dielectric properties of fumed silica/silicone composites

Silicone rubbers are widely used polymer materials, particularly in high voltage insulation applications for their superior electrical, thermal, and chemical properties compared to other commonly used polymers. In industry, silicone elastomers are heavily filled with fumed silica particles in order to obtain superior mechanical properties. For a better understanding of the interaction between the silicon dioxide nano particles (fumed silica) and silicone rubber matrix as well as the dielectric properties of fumed silica/silicone composites, dielectric spectroscopy measurements were carried out over a wide frequency range from near DC up to 2MHz. Silicone rubber composite samples filled with surface treated fumed silica particles were prepared by hot pressing and the effects of filler concentration, filler surface treatment, and mixing method on the dielectric properties are investigated. The effect of filler-polymer interaction has been analyzed by comparing the dielectric spectroscopy measurement data with scanning electron microscopy (SEM) images.