Chemical Recycling of Polymethacrylates.

Polymethacrylates, including poly(methyl methacrylate) (PMMA), are produced on a large scale for applications ranging from optics to construction, yet their end-of-life fate remains largely linear. Chemical recycling to regenerate the monomer (depolymerization) offers a promising route to circularity, but conventional methods such as pyrolysis rely on high-temperature random scission pathways that suffer from poor selectivity and undesirable side reactions. Recent advances have demonstrated that polymethacrylates synthesized by controlled radical polymerizations can undergo efficient depolymerization under milder conditions through reactivation of thermally labile chain-end functionalities. Emerging mid-chain-initiated depolymerization strategies further extend low temperature chemical recycling to polymers produced by conventional free-radical polymerization. This review highlights these developments, comparing mechanisms, limitations, and opportunities towards scalable, energy-efficient chemical recycling of polymethacrylates to support a more sustainable plastic economy.