Study On Preparation And Dielectric Property Of BaTiO₃/PVDF Composites

Ceramic/polymer composites, which combines processibility and flexility of polymer, is a promising material in electrical engineering and electronic industry fields, such as dielectric in capacitors with all kinds of shape. The trend of miniaturization and multi-functionality of electron components requires that dielectric materials have dielectric constant as high as possible. Therefore, it is very significant for improving the dielectric constant of the ceramic/polymer composites.In this study, preparation and properties of BaTiO₃/polyvinylidene fluoride (BaTiO₃/PVDF) composites were studied. The results showed that both the preparation process and diameter of BaTiO₃ played a significant role on dielectric property of the composites. The optimal mass fraction of KH550 coupling agent was 1.0 wt % when the BaTiO₃/PVDF composites were prepared by solution method. The BaTiO₃/PVDF nanocomposites were fabricated by a novel technique that utilized the natural absorption of between BaTiO₃ and PVDF particles in absolute ethanol. And dielectricconstant of the nanocomposites was as high as that prepared by other solutions. Dielectric constant of the composites with double diameter BaTiO3 was more than that of the composites with single diameter BaTiO3 at a ceramic loading volume less than 50 vol. %. But the values of dielectric loss of the composites were just contrary at measured frequency of less than 105 Hz. The diameter of BaTiO3 particle had also an important effect on dielectric permittivity of the BaTiO3/PVDF composites, which resulted from the microstructure of the BaTiO3/PVDF composites and dipole-dipole interaction among ceramic particles when the BaTiO3 with different sizes was utilized.In general speaking, the results in the work have a great help for the application of the novel high-dielectric-constant BaTiO3/PVDF composites.