Constructing multiple bonding mechanisms with a novel lignin-activated modified polymer core for the fabrication of strong, water-resistant, and mildew-resistant adhesives

Biobased adhesives play a pivotal role in the development of eco-friendly wood products, and phytogenic protein as a biobased material preparation adhesive has the advantages of sustainable development and green environmental protection. Current researches focus and challenge lie in developing phytogenic protein adhesives that do not emit formaldehyde and possess high water-resistant bonding strength and anti-mold properties through the use of biobased cross-linkers instead of chemical cross-linkers. In this study, lignin, a natural polymer material, was used as raw material to fabricate a novel crosslinker, and a cross-linking network structure was constructed with lignin as the cross-linking core and multiple bonding effects of hydrogen and chemical bonds. In addition, lignin-based crosslinker was prepared to replace the chemical crosslinker while successfully activating lignin to improve the crosslinking degree between lignin and the protein matrix. This study addressed environmental pollution and cost issues associated with the extensive use of chemical cross-linkers in phytogenic protein adhesives. The water-resistant bonding strength of the prepared phytogenic protein adhesive reached 1.21 MPa, and the mechanical properties of the prepared phytogenic protein adhesive were increased by 188 % compared with the ordinary phytogenic protein adhesive and exhibited effective anti-mold properties. This research provided a novel approach for creating sustainable, environmentally friendly adhesives and held significant implications for producing industrial wood-based panels.