Bioinspired interface engineering of soybean meal-based adhesive incorporated with biomineralized cellulose nanofibrils and a functional aminoclay

Plant-derived protein adhesives have received widespread attention as sustainable alternatives to formaldehydebased engineered wood products, but their practical applications are severely limited by the poor mechanical and antibacterial properties. Inspired by the amphiphilic and ionic features of mussel chemistry, we have developed a facile and green strategy for fabricating a soybean meal-based biomass adhesive with high bonding strength and antibacterial activity. The strategy incorporates a supramolecular system of biomineralized cellulose nanofibril (MCF) and a cationic long-alkyl-chain quaternary salt (LAQ) functionalized aminoclay (LAQ@AC). The functional MCF was prepared by in situ biomineralization of inorganic particles regulated by a cellulose nanofibril biotemplate, thus constructing a rigid mineralized skeleton structure in the protein matrix. The cohesion and adhesion strength of the protein composites were significantly improved by the supramolecular crosslinking of MCF/LAQ@AC hybrids via hydrogen bonds and electrostatic interactions. The dry and wet shear strengths of the resultant adhesive increased to 2.58 and 1.87 MPa, respectively, 130% and 197% higher than the pristine soybean meal adhesive, and remarkably exceeded those of other protein-based adhesives. By establishing a biomineralized architecture and a positively charged surface, the incorporated MCF/LAQ@AC hybrids endow the adhesive with desirable flame retardation and antibacterial activity. This novel and sustainable strategy provides a strong and stable supramolecular network for fabricating high-performance environmentally friendly biomass adhesives in biological and engineering applications.