Enzymatic Conversion of Lignosulfonate into Wood Adhesives: A Next Step towards Fully Biobased Composite Materials

Synthesis and Mechanical Performances of Polyurethane Bio-Based Adhesives Resulted from the Depolymerization of Lignocellulose Biomass

The purpose of this study is to valorize biomass waste into products with added value for indoor applications. Thus, broadleaf sawdust was chemically processed by the solvolysis reaction in acid catalysis in the presence of diethylene glycol at 160 °C for 4 h. After filtration and removal of the unreacted biomass, the glycolysis product was used in 6 different polyurethane adhesive formulations for wood bonding. The adhesive films were characterized by FT-IR, TGA, and DMA, while the mechanical performances were investigated by tensile and three-point bending tests. An innovative method for the determination of the working time was proposed. After the displacement of the wood substrates by the tensile test, the bonded area was investigated by SEM analysis. To confirm a correlation between the mechanical performances of the adhesives and their structure/formulation, two-dimensional (2D) simulations were performed based on the tensile tests.

The Biomodified Lignin Platform: A Review

A reliance on fossil fuel has led to the increased emission of greenhouse gases (GHGs). The excessive consumption of raw materials today makes the search for sustainable resources more pressing than ever. Technical lignins are mainly used in low-value applications such as heat and electricity generation. Green enzyme-based modifications of technical lignin have generated a number of functional lignin-based polymers, fillers, coatings, and many other applications and materials. These bio-modified technical lignins often display similar properties in terms of their durability and elasticity as fossil-based materials while also being biodegradable. Therefore, it is possible to replace a wide range of environmentally damaging materials with lignin-based ones. By researching publications from the last 20 years focusing on the latest findings utilizing databases, a comprehensive collection on this topic was crafted. This review summarizes the recent progress made in enzymatically modifying technical lignins utilizing laccases, peroxidases, and lipases. The underlying enzymatic reaction mechanisms and processes are being elucidated and the application possibilities discussed. In addition, the environmental assessment of novel technical lignin-based products as well as the developments, opportunities, and challenges are highlighted.