Dielectric Spectroscopy Characteristics Of PVDF And Its Composites

The dielectric constant of a dielectric is a result of the contribution of multiple polarization mechanisms,and the composite structure can increase the dielectric constant of the dielectric.In this paper,the dielectric properties of polyvinylidene fluoride(PVDF)-based composites are studied,the dielectric spectrum of polymer composites is tested,and the influence of interfacial polarization on dielectric constant is analyzed.The ceramic fillers with different microstructures are used to adjust the composite materials.Dielectric properties,in-depth analysis of the polarization mechanism of composite materials,to provide a theoretical basis for the study of composites with high dielectric constant and low dielectric loss.In order to study the effect of fillers on the dielectric properties of composites,the polymer matrix and inorganic fillers were first analyzed.Preparation of calcium zirconate titanate nanoparticles(BZT-BCT NPs)by sol-gel method,and preparation of calcium zirconate titanate nanofibers(BZT-BCT NFs)by electrospinning.The dielectric spectra of polymer matrix PVDF and BZT-BCT NPs,and BZT-BCT NFs at different temperatures and different frequencies were tested.The dielectric spectra were analyzed.The data matrix fitting method was used to calculate the polarization and dipole of the polymer matrix.The polarization activation energy of the polarization obtains the basic polarization characteristic parameters of the polymer matrix material and the filler.The PVDF matrix composites were further prepared by using BZT-BCT NPs and BZT-BCT NFs as the filling phase of the PVDF matrix.The effects of different filling phases of the microscopic morphology and the filling ratio on the dielectric properties of the composites were investigated.Two-layer low-density polyethylene(LDPE)/PVDF composites and LDPE/PVDF composites uniformly mixed by volume fraction were prepared.The dielectric polarization properties of the two materials were investigated by dielectric spectroscopy.An effective analysis methodfor establishing interface polarization characteristics.Based on the obtained PVDF matrix materials and the basic polarization characteristics of the fillers,combined with the analysis method of interfacial polarization,the polarization characteristics and mechanism of the composites were studied in depth.The results show that interfacial polarization is an important mechanism for the polarization behavior of composites.Fillers with different shape factors have an important influence on the dielectric constant of composites.The dielectric constant of composites conforms to the EMT effective medium model.