Preparation And Proterties Of Carbon Fiber/Polyvinylidene Fluoride Composites With High Dielectric Constant

With the rapid development of electronic and informational industries, it puts forward more requirements for the properties of dielectric materials. Because one kind of material can not reach these requirements, integrating two or more materials with complementary properties and preparing composite with high dielectric constant and easy processing properties has been the key point of the research among the researchers in this field. Carbon fiber (CF) with excellent mechanical property, large aspect ratio and high electrical conductivity has been broadly used to prepare the composites with excellent mechanical properties. According to the percolation theory, fillers with high electric conductivity and large aspect ratio are quite suitable for preparing the composites with high dielectric constant. Therefore, it is very significant to investigate the dielectric property of CF/polyvinylidene fluoride (PVDF) composite.In this work, the dielectric properties of CF/PVDF composites prepared by solution methods which were filled with different kinds and volume fraction of CF were mainly studied. The results show that the CF/PVDF composites with dielectric constant of 85 and low percolation threshold of 0.066 was obtained. Surfaces of the CF were modified by nitric acid and p-(trifluromethy)laniline. The results show that the compatibility has been enhanced by increasing the oxygen groups and coarseness on the surface of CF. At the low frequency (1000 Hz), the dielectric constant of composite filled with acid treated CF is as high as 315 proximately. The percolation threshold of the composite filled with acid treated CF is higher than that of composites with untreated carbon fibers. The chemical modifications on the surface of the CF using p-(trifluromethy) laniline were also investigated in this work.