▎ 摘　　要

A novel functionalized graphene oxide (f-GO) decorated with phosphorus/nitrogen (P/N)-containing molecules is fabricated using a facile water-based procedure. The chemical structure and micro-morphology are well characterized by a combination of experimental and theoretical methods. Reactive force field-based molecular dynamics simulations reveal at the atomic level that the GO sheets are successfully functionalized with P-N flame-retardant molecules by means of hydrogen bonds. Subsequently, f-GO with extremely low loading is introduced into epoxy resin (EP) for reducing its flammability. Thermogravimetric analysis suggests that f-GO significantly reduces the maximum mass loss rate of EP and enhances the char-yield during heating. Combined with the results of a microscale combustion calorimeter and limiting oxygen index, EP/f-GO2 shows better flame retardancy than the other nanocomposites. Furthermore, the presence of 2 wt% f-GO substantially reduces the fire hazard of EP, resulting in 29.3% decline in the peak heat release rate, as well as 73% and 65% reduction in total smoke production and rate of smoke release, respectively, according to cone calorimetric tests. Based on the analyses of the char layers, f-GO is determined to promote the formation of a more protective phosphorus-containing char barrier for EP during combustion, indicating an effective condensed phase flame-retardant mechanism.