Development of soybean meal-based adhesive with multiple functions via a dual cross-linked tailoring-making strategy

Abstract

As a renewable biomass resource, soy protein adhesives are a potential alternative to petroleum-based ones. However, synthesizing soy protein adhesives with excellent performance via a low-cost and facile strategy for practical application in the wood industry remains challenging. Herein, an innovative approach for fabricating a strong, tough, low-cost soy protein adhesive via dual cross-linked tailoring-making technology was proposed to impart multiple excellent performances. Specifically, the new strategy involved using calcium lignosulfonate (CLS), a residue from the pulping industry, as an anionic surfactant to untwist the spherical structure of soy protein, stretch the protein chains, and knit a reversible dynamic network structure with the protein chains and soybean polysaccharide molecules by multiple non-covalent interactions, and synergize with the robust cross-linked network of 1,6-hexanediol diglycidyl ether (HDE) to tailor the adhesive structure system. Notably, this design reflects the vital role of remolding the protein structural and soybean polysaccharide molecules network in optimizing the adhesive properties, including excellent bonding strength, anti-mildew, and flame retardancy performances. Therefore, this facile strategy can be explored to develop green and renewable protein adhesives for industrial wood applications.