Electrical, thermophysical and micromechanical properties of ethylene-vinyl acetate elastomer composites with surface modified BaTiO3 nanoparticles

In this study, we investigated the influence of the surface modified BaTiO3 nanoparticles on the electrical, thermophysical and micromechanical properties of ethylene-vinyl acetate (EVM) vulcanizates. Gamma-aminopropyl triethoxysilane was used as a silane coupling agent for the surface treatment of the BaTiO3 nanoparticles. It was found that the incorporation of surface modified BaTiO3 nanoparticles into the EVM matrix not only increased the permittivity, thermal conductivity and the mechanical strength but also showed a comparative dielectric loss tangent with pure EVM vulcanizates. In particular, the nanocomposites exhibit relatively high dielectric strength and good ductility even at the loading level of 50 vol%. The improved properties not only originate from the homogeneous dispersion of BaTiO3 nanoparticles but also should be ascribed to the strong interfacial interaction between the surface modified BaTiO3 nanoparticles and EVM matrix. We also investigated the dielectric relaxation behaviour of the BaTiO3 filled EVM nanocomposites by using Jonscher's theory of universal dielectric response.