Fabrication and Characterization of BaTiO3/Al2O3/Epoxy Composites with Tunable Dielectric Permittivity

In order to get polymeric materials with tunable dielectric permittivity, epoxy composites filled with the combination of micro-size alumina and barium titanate particles were prepared. In this paper, firstly appropriate surface modification method for the inorganic fillers employing silane coupling agent (KH550) was experimentally selected. Then, epoxy resin based composites were prepared with BaTiO3 and Al2O3 in different proportions. Fillers dispersion as well as dielectric properties of the composites were studied. The results show that compared with pure epoxy, the dielectric permittivity of BaTiO3 Al2O3/EP composites were improved obviously and changes with the increase of the volume fraction of BaTiO3. The composites containing KH550 treated fillers have better performance in all aspects than the composites with untreated fillers. Maxwell-Garnett effective median models were used to explore the mechanism of the polarization of the composite. The results show that the dielectric permittivity of KH550 treated composites fit theoretical value better, which indicates that the mechanism of the polarization of the KH550 treated composites we prepared fit Maxwell-Garnett theoretical model better.