Improving coating and prepressing performance of soy protein-based adhesive by constructing a dual-bionic topological structure

Developing efficient and sustainable green adhesives to replace aldehyde-based adhesives has become an important strategy to address fossil resources depletion, environmental pollution, and clean production. Soy protein is a raw material-rich, renewable biomass material that can be used to prepare environmental-friendly adhesives. However, the weak interfacial adhesion of soy protein-based (SP) adhesives leads to poor coating and prepressing properties, thus limiting the large-scale application of the SP adhesives. In this study, a bionic bond-stitch molecular topology was designed and constructed in SP matrix to prepare a strong multifunctional adhesive. Inspiring by the strong adhesion of mussel, urushiol (U) with natural catechol structure and acrylamide were polymerized in situ into poly(urushiol-co-acrylamide) (PUAM) as stitching polymer, which was entangled with the SP network to form a bond-stitch molecular topology. The hydroxyapatite was used to construct an organic-inorganic hybridization in the SP matrix mimicking the tough cohesion of oysters. The resultant dual-bionic SP adhesive exhibited excellent coating performance, prepressing intensity (0.45 MPa), flame retard-ancy (the limiting oxygen index was 39.4%), mildew resistance (10 d), low volatile organic compounds release, and good antibacterial activity (the antibacterial rates against Escherichia coli, Staphylococcus aureus, and Candida albicans were 89.55%, 78.59%, and 99.91%, respectively.). The wet shear strength of the prepared SP adhesive was increased from 0.35 MPa to 1.17 MPa. This study provides a new strategy for the design and preparation of high-performance, sustainable, low-carbon footprint bio-adhesives and composites.

Automated summary

Developing efficient and sustainable green adhesives is crucial in addressing resource depletion, environmental pollution, and clean production. This study focuses on using soy protein to prepare environmentally-friendly adhesives. However, the weak interfacial adhesion of soy protein-based adhesives limits their application. By designing a bionic bond-stitch molecular topology and blending it with soy protein, a strong multifunctional adhesive is successfully prepared.