Effects of filler content on dielectric properties of epoxy/SrTiO3 and epoxy/BaTiO3 composites

This paper deals with the study of the dielectric properties of polymer/high-k materials choosing an epoxy resin as the matrix and barium titanate (BaTiO₃) or strontium titanate (SrTiO₃) as micro-fillers (1 μm in diameter). Different studies on epoxy/BaTiO₃ and relatively few ones on epoxy/SrTiO₃ composites showed the increase in the permittivity with an increase in the filler content (from 0 to 50 vol.%). Whereas several authors have already investigated the dielectric strength of epoxy/BaTiO₃, little is known regarding epoxy/SrTiO₃. In this paper, a comparison between these two types of composites will be presented. The main interest of SrTiO₃ is that the dielectric strength of the bulk ceramic material is 7 times-higher (35 kV/mm) than that of BaTiO₃ even though its dielectric constant is 10 times-lower (around 200-300).