Dielectric performance of composites of <scp>BaTiO<sub>3</sub></scp> and polymers for capacitor applications under microwave frequency
Suat Bahar Baştürk, C.E.J. Dancer, Tony McNally
Abstract
Abstract Composites of nano‐sized barium titanate (BaTiO 3 ) with volume fractions up to 0.5 and poly(butylene terephthalate) (PBT) or linear low‐density polyethylene (LLDPE) were made via extrusion. Scanning electron microscopy demonstrated that BaTiO 3 is well dispersed in the polymer matrices. The crystalline content (DSC) and thermal stability (TGA) of both polymers decreased with increasing BaTiO 3 loading. Dielectric properties of the composites were measured using a vector network analyzer. Both dielectric permittivity and tangent loss increased with increasing BaTiO 3 content. At 2.45 GHz, the dielectric permittivity for 48 vol% BaTiO 3 ‐filled LLDPE and 43 vol% BaTiO 3 ‐filled PBT was 25 and 21.2, respectively. There was a good fit between the Lichtenecker model and experimental data obtained up to a certain value, with the permittivity variations being dependent on volume fraction. The improved dielectric performance achieved on inclusion of BaTiO 3 confirms both composite systems as potential candidates for microwave frequency capacitor applications.