Lignin-based vitrimer for circulation in plastics, coatings, and adhesives with tough mechanical properties, catalyst-free and good chemical solvent resistance

Lignin is the most abundant renewable natural source of aromatic compounds but is the least utilized biomass resource. In a drive to increase both the value and utilization of lignin, whilst simultaneously reducing the environmental impact of petroleum products, we have designed a solvent-resistant recyclable lignin-based vitrimer, which has excellent mechanical performance. The vitrimer, which contains 73.0% lignin, has very high tensile strength (up to 68 Mpa), high elongation at break (up to 80.0%), very good solvent resistance and multiple recycling options (hot press recycling, ethylene glycol recycling, alkali recycling). The lignin-based vitrimer can be prepared without the need for catalyst or hot press molding and can be photothermally bonded. When used as a glass coating or a rubber adhesive, it not only has very good solvent resistance, but can also be easily disassembled for recycling. This work provides an efficient and high value method for utilizing lignin and also provides practical solutions to the problems of environmental pollution caused by non-renewable plastics and under-use of biomass resources.