Influence of silane coupling on BaTiO3 resin composites

L. RAMAJO; M. REBOREDO; M. CASTRO

Foz do Iguazú

Congreso; 11th International Meeting on Ferroelectricity; 2005

The dielectric behaviour of composite materials (epoxy resin – barium titanate) were analysed as a function of ceramic content. Also, the influence of silane coupling agents was studied. Epoxy resin and Nb2O5-doped BaTiO3 were chosen because of their good dielectric properties. Epoxy was diluted using tetrahydrofuran as solvent in order to reduce matrix viscosity and to facilitate the mixing step. Ceramic particles were milled using a planetary mill in order to reduce the particle size and increase the filler content in the composite. Methoxy silane Z-6040 (Dow Corning) was applied onto ceramic particles as a dilute aqueous solution to obtain 0.5% wt of silane/BaTiO3 in order to improve processability and increase filler wet-out and dispersion. Particles with and without silanes were mixed with the resin using an electric mixer at 2000 rpm. Dipping technique was used to obtain the composite films onto glass plates on which gold electrodes were deposited by sputtering. Dielectric measurements were performed from 20 Hz to 1 MHz and 20 ºC to 120 ºC. It was found that the final materials had high permittivities and a strong dependence with the filler amount. Electrical relaxation was generated by resin dominions detected in the composite and it was influenced by temperature and solvent concentration.