Mussel-inspired gallic acid/cellulose-based adhesive with boiling-water-resistance for bonding wood

To comply with the modern demands of green and sustainable development, it is necessary to develop a renewable and eco-friendly biomass-based adhesive as an alternative to fossil-based materials. In this study, a high-performance bio-based wood adhesive was prepared by incorporating gallic acid (GA) into dialdehyde cellulose (DAC), inspired by biomimetic principles to simulate wet adhesive mechanism of marine mussels. This modification significantly enhanced the water resistance and bonding strength of the adhesive. Under the optimized conditions (mass ratio of deionized water, DAC, and GA of 10:2:1), the dry shear strength of the composite adhesive increased by 39 % compared to that of DAC adhesive. Due to the synergistic actions of hydrogen bonds, covalent bonds and mechanically interlocked structures, the DAC-GA adhesive demonstrated a shear strength of 0.96 ± 0.04 MPa in boiling water. This represents a significant enhancement compared to DAC (0 MPa) and complies with the requirements for Class I panels, as specified in the standard (GB/T 9846-2015). The biomimetic design of incorporating natural polyphenols into cellulose matrix overcame the poor water resistance of conventional cellulose-based adhesives. The resultant adhesive, featuring both high performance and eco-friendly attributes, holds potential for replacing petrochemical-based adhesives in plywood applications.