Thermal Stability and Flame Retardancy Properties of Epoxy Resin Modified with Functionalized Graphene Oxide Containing Phosphorus and Silicon Elements

Phosphorus- and silicon-modified graphene oxide was prepared to improve the thermal stability and flame retardancy properties of epoxy resin. 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and vinyltriethoxysilane (VTES) were successfully grafted onto the surface of graphene oxide (GO) through solvothermal synthesis and hydrolysis–condensation reaction, respectively. Subsequently, the functionalized graphene oxide grafted by DOPO and VTES (DOPO–VTES–GO) was incorporated into the epoxy resin by the solution blending method. The effect of DOPO–VTES–GO on the thermal stability and flame-retardant properties of epoxy resin was systematically studied. Thermogravimetric analysis showed that the thermal stability and char residue yield of DOPO–VTES–GO/epoxy were increased obviously compared with those of pure epoxy resin and DOPO–GO/epoxy. Cone calorimeter test results showed that DOPO–VTES–GO/epoxy had better flame retardancy than pure epoxy resin and DOPO–GO/epoxy on reducing the peak of heat releas...