Rigid Polyurethane Foam Flame‐Retardanted by Environmentally Friendly Polyether Polyol Based on Dialdehyde Starch

ABSTRACT Polyurethane foam (PUF) is widely recognized for its excellent mechanical properties, yet its inherent flammability and potential toxicity of certain additives limit its compliance with green and safe production principles. In this study, a novel melamine‐based polyether polyol (MFPPG) was synthesized using dialdehyde starch as the key bio‐based feedstock. Compared with previously reported melamine‐based polyether polyols, MFPPG has lower viscosity and toxicity, and better flame‐retardant performance in PUFs. Under the optimal molar ratio of raw materials, MFPPG showed favorable hydroxyl value and viscosity. When replacing 3% of commercial polyether polyol PPG4110, the modified polyurethane foams (MPUFs) exhibited significantly improved flame retardancy, thermal insulation, and mechanical performance; further increasing MFPPG loading led to poor compressive strength. Specifically, the compressive strength of MPUF was greatly enhanced, and the 3% MFPPG‐loaded MPUF also showed obviously improved thermal insulation performance compared with commercial foam.