The Modification Of New Carbon Materials And The Research Of Its Composite Materials’Dielectric Properties

As a new carbon material, graphene and carbon nanotubes become the focus of scientific research workers for its unique physical and chemical properties, and using the excellent electrical properties of these two carbon material to prepare composite with high dielectric constant is one of the hotspots of this study. Due to the particularity of these two carbon materials structure itself, dispersed in the polymer matrix is difficult, so this article is based on the chemical modification of carbon nanotubes, graphene oxide for physics processing, prepared composite with high dielectric constant via a new experimental ideas, the main work is as follows:1、By using FeSO4/K2S2O8as the initiator of radical reaction, octamethacryl polyhedral oligomeric silsesquioxane coated multi-walled carbon nanotubes (PMA-POSS/MWNT) hybrids were synthesized under homogeneous and heterogeneous polymerization system, respectively. Transmission electron microscopy (TEM) revealed the PMA-POSS coated MWNT hybrids with uniform thickness were obtained under the homogeneous system. The thickness of PMA-POSS layer coated on MWNT can be controlled from15-25to35-50nm through controlling the relative usage of MMA-POSS. The shape of coated PMA-POSS changed to microspheres and suspended on the surface of MWNT in the heterogeneous systems. The PMA-POSS/MWNT hybrids were characterized by using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman) and thermal gravimetric analysis (TGA). Through the Raman characterization, the interaction between the MMA-POSS and the MWNT were also proved. Thermal gravimetric analysis (TGA) revealed the amount of the coated MMA-POSS on the surface of the MWNT, when the coated achieved more than35nm, the mass loss near45%. The promise of synthesizing gram-scale functionalized MWNT from a wide range of polymers in a small volume of solvent may greatly improve the ability to engineer novel MWNT composites.2、By using BPO as the initiator of radical reaction, octamethacryl polyhedral oligomeric silsesquioxane coated multi-walled carbon nanotubes (PMA-POSS/MWNT) hybrids were synthesized under homogeneous polymerization system, respectively. Transmission electron microscopy (TEM) revealed the PMA-POSS coated MWNT hybrids with uniform thickness were obtained under the homogeneous system. The thickness of PMA-POSS layer coated on MWNT can be controlled from5-10to15-25nm. The PMA-POSS/MWNT hybrids were characterized by using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman) and thermal gravimetric analysis (TGA).3、The hybrids of coated MWNTs showed controlled electrical performance with varied coating layer thicknesses and were well dispersed in the polymer matrix. The POSS-coated MWNT was compounded with polyvinylidene fluoride to obtain a kind of composite which had both high dielectric permittivity and low dielectric loss.4、In this study, we report a facile and effective method for preparation of graphene oxide/polyvinylidene fluoride hybrid films (GO-PVDF). And successfully get the high dielectric pemittivity GO-PVDF composites through controlling the time and the temperature of heat pressing. The graphene oxide/polyvinylidene fluoride hybrid films (GO-PVDF) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) patterns, Thermo gravimetric analysis (TGA), Dielectric Test. After heat pressing, the GO-PVDF composites exhibit excellent dielectric properties and greatly enhance the heat resistance.