Strong and Fireproof Regenerated Wood via a Combined Phosphorylation-Surface Nanofibrillation and Ionic Cross-Linking Strategy

To reduce the environmental impact of plastics, an increasing number of high-performance sustainable materials have emerged. Among them, wood-based high-performance structural materials have gained growing attention due to their outstanding mechanical and thermal properties. Here, we introduce phosphate groups onto the wood veneers for surface nanofibrillation, effectively altering both the molecular structure and surface morphology of wood, which enhances the interactions between wood veneers and endows the wood with excellent fire resistance properties. With these phosphorylated wood-based building blocks, "chemical welding" structural materials (CWSMs) obtained through chemical cross-linking exhibit excellent mechanical properties. The flexural strength of CWSM reaches 225 MPa, and the modulus reaches 16 GPa, surpassing those of various types of natural wood. At the same time, phosphorylation has endowed CWSM with excellent fire resistance, with a limiting oxygen index reaching 49%, making it completely noncombustible. More importantly, as a biomass-based structural material, CWSM exhibits mechanical, thermal, and fire resistance properties and degradability far superior to those of traditional petroleum-based plastics, making it an ideal candidate for plastic replacement.