Development of robust adhesion and water resistance soybean meal-based adhesive with long-lasting anti-mildew via in-situ constructed interpenetrating cross-linked network inspired by marine protein

Soy protein-based adhesives are promising alternatives to petroleum-based options for industrial applications, but still face significant challenges such as weak initial adhesion, poor water resistance, limited application range, and susceptibility to mold. Inspired by the amino acid sequences of adhesion proteins in marine mussels and barnacles, we developed a protein adhesive with multifunctional properties by incorporating natural urushiol (U) and ten-alkyl dimethyl acrylamide bromide ammonium (AP) into the system to increase interface bonding sites. Additionally, in situ polymerization formed the long-chain polymer poly (AP-g-U), which functions as an adhesion protein to strengthen the cohesion of the adhesive cross-linked network. Benefiting from the poly (AP-g-U) and crosslinker 1,6-hexanediol diglycidyl ether (HDE), the synthetic adhesive demonstrated impressive pre-press bonding strength and wet bonding strength, improving from 0.64 MPa and 0 MPa to 1.08 MPa and 1.30 MPa compared to the unmodified soybean meal (SM) adhesive. Notably, the poly (AP-g-U) molecules containing numerous antibacterial quaternary ammonium salt groups anchored within the adhesive through intermolecular interactions formed a durable antibacterial network capable of providing sustained antibacterial effects upon contact. The synthetic adhesive exhibits exceptional mildew resistance for up to 150 days, surpassing most current soybean protein adhesives. Ultimately, this innovative design offers a practical approach to developing sustainable, high-performance, and environmentally friendly biomass-based adhesives for diverse industrial applications. • Using U and AP built biomimetic adhesion protein structure in SM adhesive. • Small molecular in situ suture technology was realized and verified. • Pre-pressing adhesion and water-resistance of adhesive were significantly improved. • Constructing a long-lasting anti-germ platform for biomass adhesive. • Superior dry (2.40 MPa) and waterproof (1.20 MPa) adhesion strengths were achieved.