Cellulose-based ultrastrong wood adhesive and composites constructed through “sandwich” profile bonding interface

The present paper investigates the bonding interface between cellulose-based adhesive and chemically activated wood to explore the contribution of cohesion and interaction force between adhesive and substrate to the bonding properties. The activated wood surface rich in –NH2 groups is produced by brushing 3-amino-propyl triethoxysilane (APTES) on the natural wood. The amine-functionalized cellulose is made by grafting microcrystalline cellulose with APTES and the adhesive is developed by crosslinking the branched epoxide with the aminated cellulose. Subsequently, a super strong wood laminates is developed by reacting the –NH2 groups on the activated wood surface reacted with the epoxy groups in the adhesive to construct an "amino-epoxy-amino" sandwich bonding interface. The bonding strength of laminates at dry condition and after hot and boiling water treatment is 4.04 MPa, 2.42 MPa and 1.64 MPa, respectively. The strength after boiling water treatment of the plywood laminates made of all-component adhesive enhanced from 0 MPa to 1.64 MPa contrasted with that made of pure aminated cellulose and that prepared from the activated wood surface enhanced from 0.77 MPa to 1.64 MPa contrasted with that made by the nonactivated wood surface. The cohesion of the adhesive and the interaction force between the adhesive and the wood substrate played an important role in the bonding properties.