Multifunctional soy protein gels with excellent initial adhesion and bonding strength based on a mussel-inspired redox self-catalytic and oyster-inspired organic-inorganic hybrid dual-bionic strategy

Fabricating multifunctional soy protein (SP) adhesives with excellent cold-pressing initial adhesion and hot-pressing cured bonding strength to meet the plywood practical production is challenging. Herein, inspired by the mussel and oyster, a redox self-catalytic and organic-inorganic hybrid dual-bionic strategy was proposed to design redox TA@BN/Ag nanosheets via in-situ deposition of Ag nanoparticles (NPs) on the tannic acid (TA)-encapsulated two-dimensional boron nitride nanosheets (BNNS). The nanosheets activated ammonium persulfate followed by free-radical polymerization of acrylamide monomers in the SP matrix to rapidly fabricate an organic-inorganic hybrid SP gel. Due to the abundance of catechol groups derived from dynamic redox balance, the cold-pressing shear strength of the gel increased by 818.2% to 1.01 MPa. The dry shear strength of the gel increased by 145.4% to 2.38 MPa under the stable organic-inorganic hybrid structure. Meanwhile, the wet shear strength of the gel increased by 247.4% to 1.32 MPa. Additionally, the gel exhibited long-term effective antibacterial properties and more than 60-day mildew resistance due to the introduction of Ag NPs and TA. The gel also showed favorable flame retardance and thermal conductivity after incorporating of TA@BN/Ag nanosheets. This work provides a promising method for the design and application of multifunctional high-performance bio-based adhesives.