Activated wood flour as adhesives for bonding activated wood veneer to produce sustainable wood composites

The use of biomass as a binder for the development of high-performance wood products has become a popular research topic in the context of sustainable development. In this work, wood flour obtained from agroforestry processing residues was used as an active functional filler. The wood flour was oxidized and chemically cross-linked with hyperbranched polyamines and used as a binder matrix. By applying the same oxidative treatment to the wood surface, a chemically activated bonding interface was formed. Analysis by FTIR, 13C NMR, XPS and XRD characterization showed that the key to the improved bonding property was the formation of multiple covalent cross-linked networks during hot pressing of the plywood. It is clear that the specimens with untreated wood surfaces showed no water resistance and the dry strength was only above the standard value. On the contrary, after activation of the veneer surfaces, the bond strength and water resistance were significantly improved, meeting the requirements of GB/T 17657–2013 for Class I panels. Activation of the chemically active adhesive interface by oxidation of wood materials is an effective means of improving the performance of plywood, and also provides a new idea for high-value utilization of biomass resources.