P–N synergy with lignocellulosic biomimetic flame-retardant aerogels for effective fire-safe and thermal insulation

Traditional petroleum-based foams, such as polyurethane and expanded polystyrene, are widely used due to their light weight nature and low thermal conductivity. However, their high flammability and significant environmental impact remain critical challenges. Developing green and sustainable insulation materials from lignocellulose has therefore become a pressing need. In this study, phosphorylated lignin was synthesized using a simple, solvent-free mechanochemical method. Polydopamine (PDA), known for its nitrogen- and catechol-rich composition, was introduced to establish a phosphorus-nitrogen (P-N) synergistic flame-retardant system. This innovation led to the creation of a biomass-based thermal insulation material with excellent fire resistance and heat insulation properties. The composite aerogels demonstrated remarkable performance under high-temperature conditions, forming a robust and stable carbon layer due to synergistic flame-retardant effects. Notably, the fabricated aerogel achieved a limiting oxygen index (LOI) of 35.6% and reduced heat release by over 50%. Additionally, the aerogels exhibited outstanding properties, including superior thermal insulation, effective fire protection, and exceptional UV resistance. These attributes make the material a promising solution for demanding environments, offering a novel approach for the development of next-generation fire-resistant insulation materials.