Unlocking Circularity Through the Chemical Recycling and Upcycling of Lignin-Derivable Polymethacrylates

The synthesis of polymers from lignin-derivable compounds can replace petrochemical building blocks with a renewable feedstock. However, the end-of-life management of bioderivable, nonbiodegradable polymers remains an outstanding challenge. Herein, the chemical recycling and upcycling of two higher-glass-transition temperature (>100 °C), lignin-derivable polymethacrylates, poly(syringyl methacrylate) (PSM) and poly(guaiacyl methacrylate) (PGM), is reported. Neat PSM and PGM were thermally depolymerized to quantitative conversions, producing their constituent monomers at high yields and purity. The deconstruction atmosphere influenced the depolymerization reaction order, and depolymerization was thermodynamically favored in air over N2. Further, monomer bulkiness and volatility impacted depolymerization activation energies. Notably, bulk depolymerization of PSM and PGM was performed without solvent or catalyst to high polymer conversions (89–90 wt %) and monomer yields (86–90 mol %) without byproduct formation. The resultant monomers were then upcycled to narrow-dispersity polymers and phase-separated block polymers. The findings herein offer a pathway to material circularity for higher-performance, lignin-derivable polymethacrylates.
This article was originally published in Macromolecules. The version of record is available at: https://doi.org/10.1021/acs.macromol.3c01985. Copyright © 2023 The Authors. Published by American Chemical Society.
Christoff-Tempesta, Ty, Robert M. O’Dea, and Thomas H. Epps. “Unlocking Circularity Through the Chemical Recycling and Upcycling of Lignin-Derivable Polymethacrylates.” Macromolecules 56, no. 23 (December 12, 2023): 9796–9803. https://doi.org/10.1021/acs.macromol.3c01985.