Bioinspired struvite mineralization for fire resistant wood.

High-performance wood materials have attracted significant attention in recent years due to excellent property profiles achieved by relatively easy top-down processing of a renewable resource. A crucial flaw of the renewable wood scaffolds is the low flame retardancy, which we tackled by bio-inspired mineralization in an eco-friendly processing step. The formation of the biomineral struvite, commonly found in urinary tract stones, was used for the infiltration of hierarchical wood structures with the necessary ions followed by an in-situ synthesis of struvite by ammonium steam fumigation. Struvite decomposes prior to wood, which absorbs heat and releases non-flammable gas and amorphous MgHPO4 resulting from the degradation promotes insulating char formation. As a result, the mineralized wood can hardly be ignited and the treatment strongly suppresses heat release rate and smoke production.