Preparation and properties of silaned graphene oxide/urushiol based benzoxazine-bismaleimide copolymer resin composites

A novel urushiol-based benzoxazine (UB) was synthesized from urushiol, furfuryl amine and paraformaldehyde, and its structure was characterized. Subsequently, silaned graphene oxide (SGO) and UB and bismaleimide were blended and cured to prepare SGO/urushiol-based benzoxazine-bismaleimide copolymer resin (UBB) composites. The structure and morphologies of SGO/UBB composite were characterized by FTIR, XRD and SEM. The results show that SGO is uniformly dispersed and crosslinked in urushiol based benzoxazine-bismaleimide copolymer resin, and the interfacial compatibility of the two resins is better. The thermal stability and mechanical properties of the copolymer resin are improved by SGO remarkably. When the additive amount of SGO is 0.5wt%, the 5% mass loss temperature and char yield (800℃) of SGO/UBB composite are 441.2℃ and 44.3%, respectively, which are much higher than those of the pure copolymer resin (399.0℃ and 39.2%). When the additive mass ratio of SGO is 0.3%, comparing pure copolymer resin, the Young's modulus and tensile strength of SGO/UBB composite increase by 115.4% and 309.9% and reach 962.8 MPa and 29.1 MPa, respectively. The water absorption of SGO/UBB composite is low.