基于提高BT/PVDF复合材料介电常数的材料结构设计与性能研究

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

摘要:

本研究从增加界面极化的角度出发,设计了两层和三层的钛酸钡/聚偏氟乙烯(BT/PVDF)复合材料,分别表示为PVDF||BT/PVDF和PVDF||BT/PVDF||PVDF,并通过溶液浇铸法结合旋涂法来制备这些层状复合材料。对复合材料中BT含量分别为7~45vol%的复合材料进行了介电性能测量,结果表明,当总材料厚度相同时,一层、两层及三层复合材料介电常数分别为7~39、13~50和14~79,且都随BT含量和材料层数的增加逐步增大。多层BT/PVDF复合材料在40Hz-1000Hz范围内的介频谱测量结果显示,所制备的复合材料(BT, 15vol%)表现出强烈的极化弛豫现象,两层和三层材料表现更强,说明所设计材料的界面极化强度随结构的复杂程度而增强,由此导致复合材料介电常数的提高。本研究还测量了BT含量为7~30vol%的三种复合材料的击穿性能,结果发现,随着BT含量,复合材料的击穿场强虽然呈下降趋势,整体保持在100~60KV/mm范围内。三层BT/PVDF复合材料击穿性能优于两层材料,说明所设计的多层结构对击穿性能影响较小。

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.