Preparation of natural adhesives with high-strength and low temperature fast-curing properties.

The development of natural adhesives to substitute petroleum-based products is crucial for sustainable progress. However, the bond strength of most existing natural adhesives still falls short of that of commercially available adhesives and the curing process often demands prolonged high-temperature treatment. Herein, we prepared pure natural adhesives using gelatin (GE), tung oil (TO), and dopamine (DA) as the main raw materials. The shear strength of the adhesive to wood reached up to 6.35 MPa, a significant improvement over most natural wood adhesives reported. Additionally, the tensile strength of the adhesive to wood reached 10.50 MPa, which is comparable to commercially available neoprene-phenolic wood adhesives (9.99 MPa) and cyanoacrylate instant adhesives (9.48 MPa). In addition, the natural adhesive prepared by us exhibits fast curing performance at room temperature and can be fully cured in only 12 min, which is significantly better than the commercially available adhesive. The adhesives prepared in this study also possessed excellent reversible curing properties, antimicrobial properties, low toxicity, and degradability. These characteristics offer new insights for the advancement and dissemination of natural adhesives.