Gas-solid dual barrier strategy to efficiently enhance flame-retardancy and smoke-suppression of cellulose aerogel

Addressing the inherent flammability of cellulose aerogel (CA) remains crucial for ensuring its safety-critical application. Prevailing studies predominantly focuses on flame retardant synthesis and interfacial compatibility, yet neglect the fundamental analysis of cellulose's intrinsic thermal degradation behavior. Herein, a gas-solid dual barrier strategy was provided for enhancing the flame retardancy of CA according to its competitive thermal degradation process involving random chain scission and intramolecular dehydration reactions. Concretely, as the solid barrier, LDH was uniformly dispersed in matrix to alleviate the thermal decomposition process of CA and inhibit gas phase fuel generation at source during thermal exposure. Meanwhile, TP played the role of gas barrier to quench the combustion reaction chain and suppress the heat feedback. Under the dual action of gas-solid phase, a high-quality char layer that effectively blocked heat and mass transfer formed rapidly, the residual mass of the TP/LDH/CA at 800 °C in the air increased to 12.8 % compared with CA. As a result, the obtained TP/LDH/CA had extremely high fire safety, which could extinguish within 2 s after removal from the flame, and the total smoke release (TSR) decreased by 90.54 %.