(465a) Preparation and Modeling of Polyimide/ceramic Composites with High Dielectric Constant

The traditional high dielectric constant (high K) material is typically made of ceramic. In comparison, the polymer based composites with high K contribute the advantageous candidates with better processing property and flexibility. In this work, two kinds of high K composites were prepared by blending BaTiO3, and Li/Ti co-doped NiO (LTNO) in polyimide respectively. It was found that LTNO is more effective than BaTiO3 in improving the dielectric constant of composite for its higher intrinsic dielectric constant. The dielectric constant of composite containing LTNO particle (in 40% by volume fraction) could reach 100. By comparing the measured dielectric constants with those calculated from several models, the relationship between the dielectric constant and composite structure was investigated. The results revealed that the EMT model was in close agreement with the experiment data of the polyimide/BaTiO3 composite by introducing a correction factor n to compensate for the shape of the filled particles. For the composites containing larger sized LTNO, the percolation theory also could be used to interpret their dielectric constants.