Preparation of a multifunctional bio-based adhesive inspired by the structure of dragonfly wings

Abstract

Traditional formaldehyde-based adhesives have problems such as dependence on petrochemical resources and release of formaldehyde. Therefore, preparing multifunctional bio-based adhesives with excellent mechanical properties to replace formaldehyde-based adhesives plays an important role in environmental sustainability. In this paper, a soy protein adhesive that combines high toughness and strength was developed inspired by dragonfly wings. This strategy is based on a rigid neural network (CNF) framework and SPI-based dynamic network system. Functionalized nanofibers (CNF@TP) were tightly connected to SPI through Schiff base reaction and strong hydrogen bonding. The dry and wet shear strength of plywood prepared with modified adhesive reached 1.89 MPa and 1.25 MPa respectively, which were 117.2 % and 119.3 % higher than SPI adhesive. The inorganic mineral component (ZnO) formed an organic-inorganic hybrid structure with soy protein, which improved the mildew resistance, flame retardancy and UV resistance of the adhesive. The storage time of the liquid/solid adhesive was extended to 30/50 days respectively. Cross-linker (TGA) strengthened the cross-linked network, the moisture absorption rate of the adhesive decreased to 11.9 %, the residual rate increased to 56.8 %, improved the water resistance. This bionic structure engineering (BSE) provides a research idea for the development of multifunctional composite materials with strong performance. This technology is expected to be applied to many fields such as plywood industry, aerospace and cultural relics restoration.