Phosphorous‐nitrogen‐boron decorated graphene hybrid for flame retardancy enhancement of epoxy resin

Abstract Soaring development in widely applicable materials raises an urgent demand to develop high‐performance epoxy resin (EP) materials combining superior flame retardancy, smoke suppression and mechanical properties. Phosphorus, boron and nitrogen‐containing flame retardants are high potential environmental‐friendly flame‐retardant additives in polymer manufacturing owing to their low toxicity, molecular diversity, and efficient flame resistance. In this paper, a novel additive flame retardant of RGO‐HCCP@MPB compound was fabricated which involved the functionalization of reduced graphene oxide (RGO) with hexachlorocyclotriphosphazene (HCCP), and the simple complexing RGO‐HCCP with melamine phosphate borate (MPB). The prepared RGO‐HCCP@MPB was then directly mixed with EP matrix to evaluate its flame resistance. It found that the addition of RGO‐HCCP@MPB obviously inhibited the heat release and smoke emission behaviors of EP matrix during combustion. With 5 wt% addition of RGO‐HCCP@MPB in EP, the LOI value of EP/RGO‐HCCP@MPB reached up to 28.4%, the peak heat release rate (PHRR) and the total heat release (THR) decreased by 61.1% and 30.5% compared to neat EP, respectively. Furthermore, the flexural strength and flexural modulus of the EP/RGO‐HCCP@MPB were also promoted compared with that of the pure EP. The flame‐retardant mechanism shows that elements of boron (B), nitrogen (N) and phosphorus (P) in RGO‐HCCP@MPB compound play a synergistic role in the enhancement of the flame retardancy of EP in a combustion.