Phosphorus-containing soybean oil-derived polyols for flame-retardant and smoke-suppressant rigid polyurethane foams

To overcome the fire risk of rigid polyurethane foams (RPUFs) and comply with the sustainable development, this work aimed to develop a bio-based flame-retardant polyol (PESO) for rigid polyurethane foams (RPUFs) without deteriorating other physical properties. The effect of the PESO content on the morphology, thermal stability and flammability of the resulting flame-retardant RPUFs was investigated by SEM, TGA and cone calorimeter. The addition of the PESO slightly affected the thermal conductivity and the initial thermal stability. The char yield at the high temperature region was increased with the increment of the PESO content. As expected, the incorporation of the PESO significantly improved the flame-retardant property of the resulting RPUFs. Specifically, the peak heat release rate, total heat release, and total smoke production of the flame-retardant RPUF sample containing 12.3 wt% PESO were declined by 40%, 35%, and 49%, respectively, compared to those of the unmodified RPUF. The enhanced flame-retardant property of the resulting RPUFs could be attributed to the PESO promoted the charring ability of the polymer matrix and thus formed a protective barrier layer to suppress the heat release and the smoke emission during the combustion.