Polymer Ceramic Composites for Temperature Independent Capacitors

Abstract

The dielectric properties of polymer-ceramic composites are reported. The polymers used were high density polyethylene HDPE, a non-polar polymer; polyvinylchloride PVC, a polar polymer and polyvinylidene fluoride PVDF, a polar polymer with a high permittivity. Barium titanate was the ceramic used in particulate form. The polymer and barium titanate were mixed in different weight proportions to make polymer-ceramic composites. Dielectric, X-ray diffraction and Scanning electron microscopy studies were carried out. The dielectric permittivity of all the polymer-ceramic composites matched well with the values calculated from Yarnada’s equation, assuming polymer as continuous phase. This was confirmed by SEM studies. Dielectric measurements over a temperature range of 30° to 180°C indicated that the pure barium titanate transition temperature at 120°C is shifted to higher temperatures in presence of polymeric phase. The shift of transition temperature was much higher for PVDF than for HDPE.

Chemistry Department