Turning Timber By-Product into Safe and Sustainable Glue
Glue guns typically use toxic petroleum-based adhesives
Shutterstock/Ekaterina43​
A breakthrough in the adhesive industry has been achieved by researchers at Beijing Forestry University in China. They have successfully transformed a by-product of the timber industry into a safe and reusable hot-gun glue that has the potential to replace toxic solvent-based adhesives.
Ziwen Lv and his team utilized xylan, a component found in plant cell walls, to create this innovative glue. While xylan is not traditionally considered a glue, the team chemically modified it into dialcohol xylan using sodium periodate and sodium borohydride.
The resulting glue, which can be extruded from a hot gun, boasts a bonding strength of 30 megapascals, outperforming conventional adhesives like epoxy resin. Notably, the glue can be reused by simply re-melting it and maintained its original adhesion strength even after 10 cycles.
Furthermore, the researchers tested the glue by constructing plywood using thin walnut timber sheets bonded with xylan glue. The performance of the xylan glue was comparable to plywood made with phenol-formaldehyde resin adhesives.
However, a drawback was identified when the xylan plywood was soaked in water for an hour, causing the glue to dissolve and the layers to separate.
Jonathan Wilker, a researcher at Purdue University, emphasized the need for sustainable alternatives to petroleum-based adhesives. While acknowledging the substantial bonding performance of the new glue, Wilker noted that further improvements are required in terms of life cycle assessment and water resistance.
Nick Aldred from the University of Essex expressed optimism about the potential impact of this eco-friendly glue in the plywood industry. He highlighted plywood as one of the few consumer products still containing banned substances like phenol and formaldehyde, making the introduction of xylan glue a transformative development.
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