Enzymatically polymerized lignosulfonates as binders in biocomposites

The aim of this study was to form biocomposites by combining polymerized lignosulfonates plasticized with polyols and impregnated and non-impregnated wood particles. The laccase-mediated polymerization process was examined for changes in viscosity and molecular weight. The resulting polymers were analyzed rheologically and chromatographically. From the resulting polymerization products, biocomposites were produced. These were then subjected to mechanical tests for thickness swelling, bending and tensile strength and compared with a particleboard reference. The results showed that the mechanical properties of the biocomposites did not come close to those of the standard, but that the swelling tests met the European requirements for particleboards in humid conditions. Sorbitol proved to be the best plasticizer in terms of board cohesion. This study highlights the potential to use polymerized lignosulfonates as a sustainable alternative to formaldehyde-based wood adhesives and to generate added value from paper production, which could contribute to a more sustainable and circular economy.