Characterization and properties of SiO2-coated graphene/bismaleimide composites

The silane coupling agent vinyl trimethoxysilane (VTMO) was used to modify graphene (GE), and SiO2 microspheres were coated on the surface of graphene by sol-gel method to obtain SiO2-coated modified graphene (SiO2@(VTMO-GE)). The 4,4'-diaminodiphenyl methane bismaleimide-diallyl bisphenol A-bisphenol A bisallyl ether (BBA-BBE-MBMI, MBAE) matrix was synthesized from BBA, BBE and MBMI, in which BBA and BBE were used as reactive diluents and MBMI was used as the monomer. The MBAE modified by SiO2-coated graphene (SiO2@(VTMO-GE)/MBAE) composites were prepared by in-situ polymerization with SiO2@(VTMO-GE) as the reinforcement. The effect of SiO2@(VTMO-GE) on the properties of the SiO2@(VTMO-GE)/MBAE composite was studied by characterizing and analyzing the VTMO-GE and the coating effect. The results show that GE is successfully modified by VTMO, and SiO2 microspheres are uniformly coated on the surface of VTMO-GE. The SiO2@(VTMO-GE) component improves global properties of the SiO2@(VTMO-GE)/MBAE composite. The impact strength and bending strength of the SiO2@(VTMO-GE)/MBAE composite reach the maximum of 23.0 kJ/m2 and 157.4 MPa, respectively, which are 150% and 58% higher than that of the MBAE, when the content of SiO2@(VTMO-GE) is 2.0wt%. The dielectric constant and the dielectric loss are about 70.0 and 3.7×10-3 in the frequency range of 102-104 Hz, while the heat resistance enhances with the increase of SiO2@(VTMO-GE) amount. The SiO2@(VTMO-GE)/MBAE composite exhibits excellent global properties and lays the foundation for further application. © 2020, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.