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 (BaTiO
₃
) or strontium titanate (SrTiO
₃
) as micro-fillers (1 μm in diameter). Different studies on epoxy/BaTiO
₃
and relatively few ones on epoxy/SrTiO
₃
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/BaTiO
₃
, little is known regarding epoxy/SrTiO
₃
. In this paper, a comparison between these two types of composites will be presented. The main interest of SrTiO
₃
is that the dielectric strength of the bulk ceramic material is 7 times-higher (35 kV/mm) than that of BaTiO
₃
even though its dielectric constant is 10 times-lower (around 200-300).