Multiscale Interface Engineering of Fire‐Safe Structural Bamboo/Epoxy Composites for Sustainable Construction Applications

ABSTRACT Natural bamboo is limited by flammability, mildew susceptibility, and poor dimensional stability, restricting its use in building and household materials. Herein, a multifunctional bamboo‐based composite with enhanced mechanical strength, flame retardancy, dimensional stability, and mildew resistance was developed through surface delignification, in situ calcium silicate mineralization, impregnation with diammonium hydrogen phosphate and flame‐retardant epoxy resin, followed by hot pressing. Notably, the flame‐retardant epoxy resin accounted for only 5.1 (±0.3) wt% of the composite. After densification, the composite exhibited a flexural strength of 212.6 MPa and a flexural modulus of 21.5 GPa. The combined effects of resin impregnation and calcium silicate mineralization markedly improved dimensional stability, with width and thickness swelling ratios of only 0.7% and 0.3% after 24 h water immersion. Owing to the synergistic flame‐retardant action of epoxy resin and phosphorus‐nitrogen components, the composite achieved a UL‐94 V‐0 rating, an LOI of 36.6%, and a 60.0% reduction in total heat release. Additionally, the densified structure and imine groups contributed to improved mildew resistance, highlighting its potential for indoor furniture, decorative panels, interior partitions, and other non‐load‐bearing building components.