A crosslinked organic/inorganic functionalized graphene containing hybrid engineering to improve the flame retardancy of epoxy resin

A flame retardant precursor named DTDO, which contains phosphorus, nitrogen and silicon, was synthesized and grafted to graphene oxide (GO) to prepare functional graphene oxide (FGO), which was further applied to prepare a crosslinked organic/inorganic hybrid intumescent flame retardant (FGOS) through in situ sol gel process. 3 wt% loading of FGOS can reduce the combustion parameters of inflammable epoxy resin (EP) obviously, such as the heat release rate (28.1% reduction), smoke production rate (19.6% reduction), and average mass loss rate (61.2% reduction). The EP/FGOS-3 sample shows a LOI value of 29.1% and passes UL-94 and V-0 flammability rating, and the char residue increased from 0.3% to 8.5%. The results indicates a significant enhanced flame retardancy of EP, phosphorus, nitrogen, silicon, and GO in FGOS promoted the forming of a compact and porous char layer, thus to prevent further combustion and improve the flame retardancy of EP.