Wood bonding properties of cellulose cross-linked with a synthesized branched epoxy and enhanced by interfacial covalent bond

In this study, the aminated cellulose (AC) and branched epoxy (BE) were prepared. After the chlorination and amination of microcrystalline cellulose, its hydroxyl groups were replaced by amino groups. Through thiol-ene click chemical reaction, a branched epoxy was synthesized from trithiocyanuric acid and glycidyl methacrylate. A covalent bond network was formed by epoxy groups crosslinked with amino groups on AC. Furthermore, a new concept of chemical wood bonding interface was adopted on this basis. Due to the hydrolytic condensation of 3-aminopropyltriethoxysilane, the amino groups were grafted onto the surface of wood skeleton for increasing the reactive site and enhancing the synergistic effect between adhesive and interface. By constructing the chemical crosslinking network of “amino-epoxy-amino”, the bonding between adhesive and wood interface got obvious improvement. Compared with the plywood made by natural wood, the dry strength of the plywood prepared by activated wood was increased from 1.46 MPa to 2.19 MPa, which increased by 50%, and the strength of soaking in 63 o C water for 3 h was increased from 0.36 MPa to 2.20 MPa, and the wet strength of boiling water increased from 0 to 0.83 MPa. FT–IR and XPS were used to prove the chemical covalent cross-linking reaction between adhesive and activated wood surface. Graphical abstract The preparation of AC-BE adhesive and bonding with activated wood surafce