SiO2包覆石墨烯/双马来酰亚胺复合材料的表征及性能

采用硅烷偶联剂乙烯基三甲氧基硅烷(VTMO)改性石墨烯(GE)，利用溶胶-凝胶法在GE表面包覆SiO₂微球，得到SiO₂包覆改性石墨烯(SiO₂@(VTMO-GE))，以二烯丙基双酚A(BBA)和双酚A双烯丙基醚(BBE)为活性稀释剂，4,4′-二氨基二苯甲烷型双马树脂(MBMI)为单体，制备MBMI-BBA-BBE(MBAE)树脂基体；同时，以SiO₂@(VTMO-GE)为增强体，采用原位聚合法制备SiO₂@(VTMO-GE)/MBAE复合材料。对VTMO-GE及包覆效果进行表征和分析，研究SiO₂@(VTMO-GE)增强体与SiO₂@(VTMO-GE)/MBAE复合材料性能之间的关系。结果表明:VTMO成功改性GE，且SiO₂微球均匀包覆在VTMO-GE表面；SiO₂@(VTMO-GE)提高了SiO₂@(VTMO-GE)/MBAE复合材料性能。当SiO₂@(VTMO-GE)掺杂量为2.0wt%时，SiO₂@(VTMO-GE)/MBAE复合材料的冲击强度和弯曲强度达到最大，分别为23.0 kJ/m2和157.4 MPa，较聚合物基体分别提高了150%和58%；在频率为102~104 Hz范围内，介电常数较为平稳，约为70.0；介电损耗约为3.7×10?3，耐热性能随SiO₂@(VTMO-GE)掺杂量的增加有所提高。SiO₂@(VTMO-GE)/MBAE复合材料具有优异的综合性能，为其进一步应用奠定了基础。 

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.