Characterization and Dielectric Properties of Bismaleimide Modified by SiO2-Coated Graphene Composites

The silane coupling agent vinyl trimethoxysilane (a171) was used to modify graphene (GE), SiO2 microspheres prepared by the Sol–Gel method coated on the surface of GE to obtain SiO2-coated modified GE (SiO2@a171-GE). The matrix (MBAE) was synthesized from 4,4′-diaminodiphenyl methane bismaleimide (MBMI) and diallyl bisphenol A (BBA), Bisphenol A bisallyl ether (BBE), in which BBA and BBE were used as reactive diluents. At the same time, SiO2@a171-GE/MBAE composites were prepared by in situ polymerization, which has SiO2@a171-GE as the reinforcement and MBAE as the matrix. The effect of SiO2@a171-GE on the MBAE material properties was studied by characterizing and analyzing the modified graphene and the coating function. The results show that GE is successfully modified by silane coupling agent, and SiO2 microspheres are uniformly coated on the surface of a171-GE. SiO2@a171-GE component improves the composite properties. The dielectric constant and the dielectric loss are about 70 and 3.7 × 10−3 in the frequency range of 102–104 Hz, and the heat resistance enhances with the increase of SiO2@a171-GE. This composite has excellent dielectric, mechanical and thermal properties and has the potential to be an electrolyte material for supercapacitors.