Preparation And Properties Of Multi-Walled Carbon Nanotube/Polyvinylidene Fluoride Nanocomposites With High Dielectric Constant

High dielectric constant polymer matrix composites have a significant future in electron and electric industry, so it is important to enhance the dielectric constant. Carbon nanotubes (CNT) with large aspect ration and high electric conductivity have been pursued with the hope of delivering CNT properties to a processable and synergistic host. In past years, dielectric performance and percolation effect were studied, but the law of polarization and the mechanism of electric conductance under the alternating current (AC) field are still uncertain.In this thesis, preparation and properties of multi-walled carbon nanotube/polyvinylidene fluoride (MWNT/PVDF) nanocomposites were studied. In order to improve the compatibility between the filler and the matrix materials, MWNT were modified by acid and/or Grignard reagent. And then, MWNT/PVDF composites were prepared by using very simple physical blending, and subsequently, hot-molding technologies. The results show that the treated MWNT have better dispersion in PVDF. The MWNT have an obvious effect on the increase of polar phase of the PVDF crystalline form. With the increasement of MWNT, the degree of crystallinity of PVDF enhances gradually and then reduces. Furthermore, PVDF crystalline forms and crystallinity affect the dielectric performance of the composites. As reported, MWNT, especially the modified MWNT,...