Structure design and performance research based on enhancing the dielectric constant of BT/PVDF composites

Abstract:

In order to improve the dielectric constants of BT/PVDF composites, two-layer and three-layer BT/PVDF composites were designed, which were PVDF||BT/PVDF and PVDF||BT/PVDF||PVDF, respectively. These layered composites were prepared by combining a spin coating method and a solution casting method in which BT contents were 7~45 vol%, respectively. 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 7-39, 13-50 and 14-79 for the one, double and tripper layers respectively. When the BT content is the same, the dielectric constant of the composite increases with the number of layers. The dielectric constants of the three composites were found to be significantly higher than those of the two layers and one layer when the BT contents were both 15vol%. At the same time, when the test frequency was 40Hz-1000Hz. 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 this study, the breakdown properties of three composites with BT content of 7~30 vol% were investigated. It was found that the breakdown strength of composites decreased with the increase of BT content and the number of layers in the range of 60-100 KV/mm.

Key words:Multilayer; Structure Design; Composites; Dielectric properties; Polarization