Structure And Properties Of Polyvinylidene Fluoride Composites Modified By Nanoparticles

As a fluoride-plastic,polyvinylidene fluoride?PVDF?is widely used because of its excellent weather resistance,ultraviolet resistance,chemical stability,high dielectric and mechanical properties.In order to apply in the solar backplane film and high dielectric material fields,PVDF composites was prepared by adding inorganic nanoparticles to the PVDF matix and the properties of the composites were investigated in detail.Titanium dioxide?TiO₂?,organized montmorillonite?OMMT?and graphene oxide?GO?were used as additives to blend with PVDF.The relative properties of the composites were characterized systematically.The main researches and conclusions are as follows:1.Hexadecyl trimethyl ammonium bromide was used to modify nano montmorillonoid?MMT?and the orgnic MMT was obtained?OMMT?.Nano titanium dioxide?TiO₂?and OMMT were used to blend with PVDF and the properties of PVDF nanocomposites were studied in detail.The fourier transform infrared spectroscopy?FTIR?,X-ray diffraction?XRD?and differential scanning calorimetry?DSC?results showed the PVDF transferred from 92%?crystal to 95%?crystal and?crystal when OMMT was used to blend with PVDF.At the same time,OMMT improved the tensile toughness of PVDF.The scanning electron microscope?SEM?showed the TiO₂ nanoparticles and OMMT dispersed uniformly in the blend.By the measurement of thermo-gravimetric analysis?TGA?,TiO₂ reduced the decomposition temperature of the PVDF,but when OMMT was added,the decomposition temperature of the composites was improved.2.Graphene oxide sheets?GO?filled polyvinylidene fluoride?PVDF?nanodielectric composites with methyl methacrylate-co-glycidyl methacrylate copolymer?MG?as compatibilizer were fabricated by solution blend process.The chemical interaction between MG copolymer and graphene oxide sheets was confirmed by Fourier transform infrared spectroscopy?FTIR?and Thermo gravimetric analysis?TGA?.Compared with the PVDF/GO composites,the GO in PVDF/MG@GO composites exhibit excellent dispersion with the aid of MMA-co-GMA copolymer.The excellent dispersion and special interaction exhibit increased thermal stability of PVDF/MG@GO composite at high temperature.The melting and crystallization temperatures also have certain improvement.The good dispersion and special interaction between graphene oxide and PVDF cause the crystal transformation of PVDF from?-phase to?/?-phase and nearly 81%?/?-phase formed for PVDF/MG@GO7.0 composite.MMA-co-GMA copolymer also plays a positive role in the dielectric performance of PVDF/MG@GO composites which exhibit enhanced dielectric constant and low loss tangent than that of PVDF/GO composites.The significantly improvement of dielectric properties ascribe to MMA-co-GMA copolymers,Which not only contribute to the dispersion of graphene oxide in PVDF,but also prevent the direct connect of graphene oxide fillers.Therefore,the dielectric loss originated from leakage current can be effectively depressed.