Influence of the Morphology of Alumina Filler on Electrical and Thermal Properties of Epoxy Resin Composites

Abstract

Epoxy resin composites filled with alumina (Al2O3) particles of different morphology and content were fabricated by vacuum casting method. Electric and thermal properties of the composites were tested at room temperature to investigate the influence of Al2O3 morphology on epoxy resin composites. Electrical tests demonstrated that, volume resistivity of epoxy resin composites filled with spherical Al2O3 was bigger than with spherical-like Al2O3, relative permittivity and dielectric loss of epoxy resin composites increased with increasing of Al2O3 content, the effect on dielectric properties of spherical-like Al2O3, which had larger specific surface areas, was larger than spherical Al2O3 for the same content of filler. Thermal conductivity tests proved that, at the same content, thermal conductivity of epoxy resin composites filled with spherical-like Al2O3 was higher than with spherical Al2O3. According to the Agari model, spherical-like Al2O3 particles were easier to form conducting pathways in epoxy resin composites than spherical Al2O3 particles, considering their matte edges.