Enhancing Circularity of High-Performance, Biobased Polymers Through Advanced Recycling

Lignin is the largest natural source of aromatic carbon on the planet, and thus, lignin-derived products have emerged as critical elements in the next generation of polymers. However, the valorization of lignin to high-performance and cost-competitive materials remains a challenge due to lignin’s perceived recalcitrance, inherent structural variability, and complexity of deconstructed lignin bio-oil mixtures. Recently, we have demonstrated that materials with reproducible thermal and mechanical characteristics can be synthesized in a controlled and predictable manner from real biomass with complex and somewhat variable compositions, such as minimally processed bio-oils obtained from deconstructed lignin. As one example, we have combined polymer science and catalysis to generate new, high-performance, pressure-sensitive adhesives from compounds obtained directly from raw biomass (poplar wood) deconstruction with properties, cost, and processing methods that were competitive and compatible with commercial tapes. Moreover, we leverage biobased solvents, such as glycerine, to dramatically enhance the scalability of our process. Additionally, we have developed structure-activity relationships for lignin-derived compounds that were used to design new systems that had drop-in potential in both synthesis and materials properties (relative to petroleum-based analogues), yet most importantly, demonstrated reduced environmental impacts when screened by several common toxicity assays. Finally, we have leveraged these activities to design processes that enable the recovery and advanced recycling of aromatic macromolecules derived from biobased sources.