Chemical Recycling of Thiol Epoxy Thermosets via Light-Driven C–C Bond Cleavage

Nguyen, Suong T.; Fries, Lydia R.; Cox, James H.; Ma, Yuting; Fors, Brett P.; Knowles, Robert R.

doi:10.1021/jacs.3c00958

Title: Chemical Recycling of Thiol Epoxy Thermosets via Light-Driven C–C Bond Cleavage

Journal Article · 11 May 2023 · Journal of the American Chemical Society

DOI: https://doi.org/10.1021/jacs.3c00958 · OSTI ID:2280838

^[1]; Fries, Lydia R. ^[1];

^[1]; Ma, Yuting ^[2];

^[2];

^[1]

Princeton Univ., NJ (United States)
Cornell Univ., Ithaca, NY (United States)

Epoxy thermosets are high-volume materials that play a central role in a wide range of engineering applications; however, technologies to recycle these polymers remain rare. Here, we present a catalytic, light-driven method that enables chemical recycling of industrially relevant thiol epoxy thermosets to their original monomer at ambient temperature. This strategy relies on the proton-coupled electron transfer (PCET) activation of hydroxy groups within the polymer network to generate key alkoxy radicals that promote the fragmentation of the polymer through C–C bond β-scission. The method fully depolymerizes insoluble thiol epoxy thermosets into well-defined mixtures of small-molecule products, which can collectively be converted into the original monomer via a one-step dealkylation process. Notably, this process is selective and efficient even in the presence of other commodity plastics and additives commonly found in commercial applications. Finally, these results constitute an important step toward making epoxy thermosets recyclable and more generally exemplify the potential of PCET to offer a more sustainable end-of-life for a diverse array of commercial plastics.

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Research Organization:: Princeton Univ., NJ (United States); Energy Frontier Research Centers (EFRC) (United States). Bio-inspired Light-Escalated Chemistry (BioLEC)

Sponsoring Organization:: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

Grant/Contract Number:: SC0019370; CHE-2203758; DGE-2039656

OSTI ID:: 2280838

Journal Information:: Journal of the American Chemical Society, Vol. 145, Issue 20; ISSN 0002-7863

Publisher:: American Chemical Society (ACS)Copyright Statement

Country of Publication:: United States

Language:: English

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Title: Chemical Recycling of Thiol Epoxy Thermosets via Light-Driven C–C Bond Cleavage

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