Study On Dielectric Performance Of Polyvinylidene Fluoride Composite

With the rapid development of microelectronics products, more and morehigh-efficiency embedded passive components are needed, especially the capacitors getmore attention. Organic polymer material has low density, good flexibility and easymachining characteristics, it is important to study the dielectric properties of polymermaterials used in capacitor. Among polymer materials, poly(vinylidene fluoride)(PVDF)has excellent dielectric properties with dielectric constant in the range of6-8and dielectricloss about0.04-0.2, and it has important research and application value in the field of filmcapacitor.In the paper, organic nanometer montmorillonite(OMMT) is used to modify PVDF,and the PVDF/OMMT nanocomposites were prepared by melt blending and compressionmoulding. Poly(vinylidene fluoride-co-hexafluoropropylene)/OMMT nanocomposites andpoly(vinylidene fluoride)/CaCu3Ti4O12composites were prepared by the same way;multilayered PVDF and PVDF/CCTO films were prepared by compression moulding. Thematerial dielectric properties and breakdown strength are studied, and the structure andmorphology were characterized using X-ray diffraction(XRD), Differential ScanningCalorimetry(DSC), Fourier Transform Infrared Spectroscopy(FTIR).The study shows that:200℃is the optimal temperature for melt blending ofmontmorillonite and PVDF; the best dielectric properties are realized for PVDF/OMMTnanocomposites with3wt%of OMMT; P(VDF-HFP)/OMMT nanocomposites with2wt%of OMMT have the highest dielectric constant; CCTO with high dielectric constant canimprove dielectric constant of PVDF/CCTO composite and the effective dielectricconstant of the composite increased with the increase in the mass fraction of CCTO, butthe dielectric loss also increase; the breakdown strength of PVDF-PVDF/CCTO multilayerfilm is better than that of PVDF/CCTO composite material, and enhance with increase inthe number of composite layer; the addition of CCTO and OMMT lead to α-phasedecreasing and β-phase formation, and the melting temperature and crystallizationtemperature are improved.