Preparation of the water-resistant eco-friendly carbohydrate wood adhesives by Schiff base reaction

To prepare biomass-based wood adhesives with good bonding properties and water resistance is still a challenge and meaningful work in the field of the wood industry. Thus in this present study, under low reaction temperature conditions (50 degrees C), sodium periodate was used as an oxidant to treat carbohydrates such as glucose, sucrose and starch to form biomass-derived aldehydes solutions. Then oxidized glucose- hexamethylenediamine (OGLH), oxidized sucrose- hexamethylenediamine (OSUH) and oxidized strarch-hexamethylenediamine (OSTH) resins were prepared via Schiff base reaction from these solutions with hexamethylenediamine. The resins obtained were applied to the preparation of three-layer laboratory plywood. The whole synthesis was a simple process and low energy consumption; meanwhile, OGLH and OSUH resins show excellent bonding performance, allowing them to be able to consider as a substitute for the current widely used urea-formaldehyde (UF) and its modified resin wood adhesives. Furthermore, this study provides a new process reference for the preparation of carbohydrate-based adhesives.