Flame-retardant properties of chitin liquefaction-based polyurethane foam

The conversion of solid chitin into liquid low-molecular-weight polyol compounds using liquefaction technology can realize the high-value utilization of shrimp and crab shell marine waste. In this study, chitin liquefaction was conducted using sulfuric acid as the catalyst and propanetriol and polyethylene glycol as the liquefying agents. Thereafter, the acid number, hydroxyl value, viscosity and molecular weight of the chitin liquefaction product were tested and characterized. A polyurethane foam with low thermal conductivity and high mechanical strength was successfully synthesized. The preparation process was regulated by reacting the hydroxyl group that is abundant in chitin liquefaction with isocyanate instead of polyether polyol. Moreover, adding dimethyl methyl phosphate into the polyurethane to prepare flame retardant polyurethane foam. The flame retardance and thermal-insulation properties of the polyurethane foam synthesized using the chitin liquefaction product are significantly better than those of traditional polyol polyurethane foam, which broadens the application scope of polyurethane foam.