Study On The Preparation And Properties Of PVDP Composites

With the development of information technology and microelectronics industry, the application of high performance dielectric material could promote the development of microelectronics industry. More attention on dielectric materials with high dielectric constant, low dielectric loss and excellent processing properties are attracted. Polyvinylidene fluoride(PVDF) possesses a relatively higher dielectric constant than that of other polymer materials. In this paper, nanocomposite materials that are cinsisted of the multi-wall carbon nanotubes(MWNTs), zirconium oxide(ZrO2) and PVDF are fabricated. Their properties were studied. It is theoretical value for excellent dielectric polymer composite material to study the preparation process and the relationship of structure and property with the system performance.In this paper, MWNTs and ZrO2 are used as fillers, and PVDF is used as matrix. These nanocomposites with different inorganics content were prepared by solution and melting method. The ptoperties of the microstructure, crystallization properties, thermal behavior and dielectric property of these nanocomposite materials are characterized. The results were discussed and analysed.Nanocomposite materials with different inorganics content were prepared by solution method, which their morphology, crystallinity and the thermal behavior were investigated. The results indicated that nano fillers are uniformly dispersed in PVDF through ultrasonic dispersion. Particularly, when the two types of fillers are added simultaneously, it made the crystallization in the matrix performs as a superposition.The origin of this penomena is the heterogeneous nucleation effect of the inorganic materials.MWNTs/PVDF and ZrO2/PVDF composite materials with different inorganics content were prepared by melting method. The results of the crystallization behavior and thermal properties are showed that nano fillers could enhance the degree of crystallization of the composites. Besides, the decomposition temperature of the composites is raised, and the thermal stability of the nanocomposite material is enhanced.The dielectric properties(ε′) and dielectric loss(tanδ) of composites were investigated under 10-1~107 Hz and-100~100℃. The dielectric constant increased with temperature increasing or frequency decreasing. The reason is that raised temperature induces more rapid molecular chain segment motions, and the orientation behavior of the material is increased. When the frequency is increased so the orientation of molecular chain segments could not catch the electric field and the molecular kinetic energy is converted to the material internal heat, the results show that the dielectric constant decreased, and the dielectric loss increased. The fillers are help of the dielectric constant increasing. However, the effect on the dielectric loss was not remarkable. The dielectric modulus M″ and the activation energy is calculated, which is to further analysis of dielectric behavior. The polarization behavior requires activation, through the analysis of the influence of temperature on the polarization behavior. The results show that the interface polarization increases the activation energy with effect of frequency on the dielectric behavior.