Flame-retarded polyurethane foam conferred by a bio-based nitrogen‑phosphorus-containing flame retardant

Flammable polyurethane foam (PUF) is still an essential material related to buildings and furniture, causing loss of property and lives every year. A novel compound containing phosphorus and nitrogen (referred to as DOPO-NIBAM) was successfully synthesized from camphene as a renewable raw material and applied as a flame retardant in polyurethane foam (DNPUF). During the combustion of DNPUF, DOPO-NIBAM produced phosphorus-free radicals and incombustible gases and promoted the formation of a phosphorus-rich char layer, both of which reduced the flammability of DNPUF. Compared with pure PUF, the limiting oxygen index of DNPUF increased by 41.7%. The peak heat release rate (PHRR) of DNPUF decreased by 40.3%. The compressive strength of DNPUF is significantly enhanced by 166% due to the rigid groups of DOPO-NIBAM. This work demonstrates that the novel phosphorus and nitrogen flame retardant (DOPO-NIBAM) can improve the flame retardancy and mechanical properties of polyurethane foam. DNPUF materials containing DOPO-NIBAM may act as the potential candidate for fireproof building materials.