Development of all-bio-based xylan adhesive: Simple preparation and excellent performance

Nowadays, the development of green wood adhesives with high bonding strength and waterproofing is still challenging due to the abundance of hydrophilic groups in biomass materials resulting in suboptimal properties. Firstly, dialdehyde xylan (DAX) and aminated xylan (AX) were prepared from xylan (X) through oxidation and grafting reactions, respectively. Then, a high-performance xylan-based adhesive (DAX-2AX) was prepared by directly cross-linking DAX and AX. The chemical structure of DAX-2AX was analyzed by FTIR, 13C NMR, and XPS. The results showed that the DAX-2AX-based crosslinked network increased cohesion through covalent bonds (C=N, Si-O-Si, and Si-O-C bond), intermolecular hydrogen bonding as well as entanglement between xylan chains, which endowed the adhesive with excellent bonding properties. Compared with unmodified xylan (X), the wet bonding strength of DAX-2AX at 55% solids broke through from 0 to 1.49 MPa (soaked in water at 63 °C for 3 h). This work provides a new strategy for the simple and efficient preparation of high-performance all-bio-based adhesives.