Low-temperature curing, flame-retardant and water-resistant modified cellulose-chitosan adhesive based on organic-inorganic hybridization.

The development of novel formaldehyde-free low-temperature curing biomass-based adhesives is important for the construction of high-performance flame-retardant wood composites. Chitosan is a polysaccharide extracted from the shells of crustaceans such as crab and shrimp shells. Its great productivity and low cost make it an ideal material for the development of bio-based adhesives. However, its high curing temperature, poor water resistance, high viscosity and other problems limit its industrialized application. In this study, an environmentally friendly low-temperature curing flame-retardant bio-based adhesive HM-CS@BN was prepared by an "organic-inorganic hybridization" strategy. Chitosan, hydroxyethyl cellulose, maleic anhydride and boron nitride were used as raw materials. A dense cross-linked cohesive network was constructed through non-covalent interactions to enhance the adhesion and water resistance of the adhesive. Plywood was also fabricated to study its mechanical and flame retardant properties. The results showed that the synergistic interaction between covalent and hydrogen bonds is the main reason for the good properties of wood composites. The hot-water wet shear strength could reach 0.71 ± 0.077 MPa even at a hot-pressing temperature of 60 °C. The adhesive in this study was easy to prepare and had good properties. It is promising for the manufacture of high-performance adhesives.