Crosslinking in bio-based hemicellulose adhesives

As the demand for sustainable products rises, substitution of fossil-based adhesives becomes increasingly desirable. In the wood sector, legislation also limits the application of traditional, formaldehyde-based chemistry, creating an additional incentive for innovation. Biopolymers such as polysaccharides, proteins and lignin have great potential as adhesives due to their large-scale availability and high functionality. Unfortunately, many suffer from inferior hydrolysis resistance. This can be addressed through crosslinking of the biopolymer chains. In our work, chemical modifications introducing greater hydrophobicity and functional groups which can participate in crosslinking were examined. Hemicellulose obtained as a by-product from pulping processes was used as a model, and the adhesive strength was evaluated. A significant impact of the solvent medium was observed so particular attention was also paid to the application viscosity. The insights gained can be transferred to other biopolymer systems and we thus hope to contribute to the wider development of sustainable adhesives.