Structure Design and Performance Research Based on Enhancing the Dielectric Constant of BT/PVDF Composites

In order to improve the dielectric constants of BT/PVDF composites, two-layer and three-layer BT/PVDF composites were designed, which were PVDF parallel to BT/PVDF and PVDF parallel to BT/PVDF parallel to PVDF, respectively. These layered composites were prepared by combining a spin coating method and a solution casting method in which BT contents were 7 vol%similar to 45 vol%. The results show that the dielectric constants of the composites with the same thickness increase with the increase of BT content. The dielectric constants of the composites are 7 similar to 39, 13 similar to 50 and 14 similar to 79 for the one, double and triple layers, respectively. When the BT content is the same, the dielectric constant of the composite increases with the number of layers increasing. The dielectric constants of the three composites are found to be significantly higher than those of the two layers and one layer when the BT contents are 15 vol%. At the same time, when the test frequency is 40 similar to 1000 Hz, the multi-layered BT/PVDF composites exhibit strong polarization relaxation, which indicates that the interfacial polarization of the composites increases, leading to the increase of the dielectric constant of the composites. In the present study, the breakdown properties of these composites with BT content of 7 vol%similar to 45 vol% were also investigated. It is found that the breakdown strength of the composites decreases with the increase of BT content (7 vol%similar to 23 vol%) in the range of 100 similar to 45 kV/mm.