Improving the strength and toughness performance of urea-formaldehyde adhesive using a biomimetic strategy

Developing a urea-formaldehyde adhesive (UF) with excellent mechanical strength and toughness, particularly with regard to water resistance, for plywood production remains a challenging task. Inspired by the biomineralization process of the shell, a facile yet effective biomimetic strategy was proposed. Clay, serving as an inorganic reinforcer, and dopamine, as an organic crosslinker, were utilized to fabricate a robust and resilient UF wood adhesive. The wet shear strength and toughness of poplar plywood prepared using the biomimetic adhesive increased by 126% and 57%, respectively. This enhancement in strength and toughness can be attributed to the formation of an organic-inorganic hybrid structure, featuring multiple interactions throughout the UF resins, due to the phenolic amine chemistry and mineral reinforcement. This environmentally friendly strategy offers a straightforward yet efficient approach for the rapid preparation of high-performance UF adhesives, with promising implications for the advancement of wood-based panel production.