Flame Retardant Material Based on Cellulose Scaffold Mineralized by Calcium Carbonate

Abstract

Wood-based functional materials have developed rapidly. But the flammability significantly limits its further application. To improve the flame retardancy, the balsa wood was delignified by NaClO 2 solution to create a cellulose scaffold, and then alternately immersed in CaCl 2 ethanol solution and NaHCO 3 aqueous solution under vacuum. The high porosity and wettability resulting from delignification benefited the following mineralization process, changing the thermal properties of balsa wood significantly. The organic-inorganic wood composite showed abundant CaCO 3 spherical particles under scanning electron microscopy. The peak of the heat release rate of delignified balsa-CaCO 3 was reduced by 33% compared to the native balsa, according to the cone calorimetric characterization. The flame test demonstrated that the mineralized wood was flame retardant and selfextinguish. Additionally, the mineralized wood also displayed lower thermal conductivity. This study developed a feasible way to fabricate a lightweight, fire-retardant, self-extinguishing, and heat-insulating wood composite, providing a promising route for the valuable application of cellulosic biomass. KEYWORDSCellulose scaffold; delignification; CaCO 3 ; mineralization; fire retardancy Recently, wood mineralization concepts have been used for multifunctional hybrid organic/inorganic materials [10,11]. CaCO 3 , as a commonly used mineral, is environmentally friendly and highly efficient in gas-phase flame retardancy. It absorbs part of the heat by thermal decomposition and releases CO 2 to This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.