▎ 摘　　要

Lightweight bio-based foams from renewable cellulose nanofibers (CNF) and phosphorus-hybridized graphene nanosheets (PGN) were prepared by means of a simple freeze-drying process. By comparison, the CNF-Graphite, CNF-chemically reduced graphene nanosheets (CRG), CNF-red phosphorus (RP)composite foams were also fabricated. The CNF-PGN composite foam showed porous structures and the PGNs were uniformly distributed in the pore wall of the cellulose foams. The resultant CNF composite foams exhibited a thermal conductivity in the range of 0.0299-0.0310W/(mK). The CNF-PGN composite foam exhibited a high char residue (25.6wt%) at 800 degrees C, which was 205% higher than the calculated value, suggesting the excellent char formation ability. In the vertical burning tests, the CNF foam burnt out with rapid flame propagation, while the CNF-Graphite, CNF-RP and CNF-CRG composite foams cannot stop the smoldering behaviors. In contrast to these composite foams, the CNF-PGN composite foam displayed self-extinguishing behaviours and the flame spread was suppressed completely. Cone calorimeter measurements further manifested excellent fire retardancy of the CNF-PGN composite foam, which showed that the peak heat release rate was reduced to 14.6kW/m(2), lower than most of the reported by state-of-the-art flame retardant polymeric foams. [GRAPHICS]