Construction of graphite oxide modified black phosphorus through covalent linkage: An efficient strategy for smoke toxicity and fire hazard suppression of epoxy resin

The black phosphorus (BP) can be compounded with other two-dimensional materials with flame retardant effect to achieve better synergistic effect. Herein, the multifunctional BP-RGO nanohybrids was fabricated by solvothermal strategy to improve the dispersion state of BP in epoxy resin (EP) and enhance its fire safety performance, where the reduced graphene oxide (RGO) was attached on the surface of BP via P-C and P-O-C bonds. With the incorporation of 2.0 wt % BP-RGO into EP matrix, 54.4 % reduction in total heat release (THR) was achieved along with 55.2 % decrease in peak heat release rate (PHRR) compared with neat EP. As a similar trend, the toxic CO and aromatic compounds were significantly inhibited, and the maximum decrease (28.5 %) in total smoke production (TSP) was achieved, indicating the enhanced fire safety performance of EP nanocomposites. These positive results is attributed to the synergistic effect of physical nano-barrier, free radicals trapping and char formation between BP and RGO components. Meanwhile, the EP/BP-RGO2.0 nanocomposites exhibited satisfying air stability even after being immersed in water for a month. This work enriches the strategies for enhancing the air stability of BP, and confirms its potential for smoke toxicity and fire hazard suppression in polymer nanocomposites.