Hydrogen-Bond-Assisted Chemical Recycling of Trithiocarbonate-Terminated PMMA via Diverse Alcohol Additives

Plastic waste management requires sustainable recycling routes beyond mechanical processes that often downcycle materials. Chemical recycling via depolymerization can enable closed-loop use by regenerating monomers. However, vinyl polymers remain particularly challenging targets because conversion of σ-bonded backbones to π-bonded monomers is thermodynamically disfavored. Here, we develop a hydrogen-bond-assisted depolymerization strategy for trithiocarbonate-terminated poly(methyl methacrylate) (PMMA) at high polymer concentration using fluorinated alcohols as additives. Fluorinated alcohols act as strong hydrogen-bond donors owing to the inductive effects of fluorine substituents, interacting strongly with the electron-rich carbonyl groups of PMMA. These interactions tune the local steric and electronic environment, promote depropagation, and regulate depropagating radical behavior to suppress side reactions during depolymerization, improving depolymerization efficiency and thereby lowering the effective thermal requirement for monomer recovery. Hydrogen-bonding interactions were examined by ¹H-NMR, including variable-temperature measurements, as well as FT-IR spectroscopy. Propagating and depropagating methyl methacrylate (MMA) radicals were further probed by electron paramagnetic resonance under varied additive structures and concentrations. Monomer recovery was quantified by quantitative NMR and gas chromatography, demonstrating approximately doubled conversion efficiency compared to additive-free conditions. Overall, this work provides mechanistic insights into hydrogen-bond-assisted depolymerization and demonstrates a viable pathway for sustainable chemical recycling of vinyl polymers.