Green and sustainable metal-reinforced bamboo composites with high self-bonding performances

Although the metallization of wood and bamboo has been successfully achieved, challenges such as low efficiency, high costs, and environmental pollution caused by liquid chemical wastes have impeded its widespread adoption in manufacturing. This study presents a novel approach to fabricating metal-reinforced bamboo composite (MRBC) with exceptional performances, utilizing bamboo residues and nano-CuO without use of adhesives. The impact of raw material characteristics, including moisture content of bamboo powder and the amount of nano-CuO additive, on functional properties such as water resistance, flame retardancy and smoke suppression of MRBC was investigated. Also, the forming mechanism of MRBC was elucidated through examination of its microstructure, chemical composition, and thermal stability. Results indicated that the MRBC containing 20 wt% nano-CuO exhibited a high modulus of rupture (MOR) of 54 MPa, an impressive modulus of elasticity (MOE) of 9.3 GPa, a notable surface hardness of 44.4 kgf/mm, and low 24 h water absorption-thickness swelling of 6.5 %, all significantly surpassing those observed in conventional panels. The MRBC exhibited a tightly wrapped, adhered, and cross-linked process under high temperature and pressure conditions, facilitated by multiple synergistic effects such as lignin melting, hydrogen bond networking, physical structure entanglement, and material redox reaction, which contributed to a dense intertwined and consolidated structure. The MRBC demonstrated exceptional structural integrity throughout the combustion process, effectively mitigating potential damage caused by structural collapse due to the incorporation of nano-CuO, which also successfully suppressed smoke and toxic CO gas emissions during combustion. The MRBC showcased advantages of environmental friendliness, water resistance, high strength, flame retardancy and smoke suppression. These attributes position it as an optimal substitute for conventional panels and make it suitable for replacing metals in specific applications. Thus, it demonstrates significant market potential and promising prospects for sustainable development.