Multiple crosslinking strategy to achieve high bonding strength and antibacterial properties of double-network soy adhesive

Abstract

The development of high-performance and sustainable bio-based adhesives has become a significant strategy for solving concerns regarding environmental pollution, resource utilization, and public health in the material engineering and production industries. In this work, hyperbranched silicone was prepared and reacted with a catecholamine-based tannic acid and soybean meal to obtain a strong and antibacterial bio-based adhesive having a hyperbranched cross-linked structure. In addition, versatile copper ions were introduced into the adhesive to form multiple interfacial coordination bonds. The resulting intertwined dual network of metal coordination bonds and covalent crosslinks in the adhesive system improved the cross-link density and cohesive interactions of the adhesives, enhancing their adhesion strength and water resistance. The maximum wet shear strength of the modified adhesive was 1.27 MPa, which was 309.68% higher than that of the pristine adhesive. Sol-gel test showed that the swelling ratio of the modified adhesive decreased from 413.8% to 52.4%, while the insoluble fraction increased by 16.47%. Furthermore, the resulting adhesives exhibited a high bacterial resistance against Staphylococcus aureus and Escherichia coli. The formation of an intertwined dual network in a bio-based adhesive to achieve excellent properties is a promising approach for the fabrication of sustainable eco-friendly biopolymer materials from agricultural byproducts used to achieve a cleaner production.