Covalent Adaptable Networks: Reprocessable Cross-Linked Polymers

Journal Article · Fri Jan 16 00:00:00 UTC 2026 · Chemical Reviews

DOI: https://doi.org/10.1021/acs.chemrev.4c00994 · OSTI ID:3025820

Sun, Molly  ^[1]; Felsenthal, Lillian M.  ^[1]; Kim, Subeen  ^[1]; Choi, Elizabeth Y. ^[1]; Reed, Laura J. ^[1]; Elling, Benjamin R.  ^[2]; Dichtel, William R.  ^[1]

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1. Northwestern University, Evanston, IL (United States)
2. Wesleyan University, Middletown, CT (United States)

Thermoset polymers have desirable properties, such as excellent thermal and mechanical stability, but their covalent cross-links typically prevent repair or recycling. By enabling and controlling dynamic exchange reactions within polymer networks, their covalent bonds rearrange and allow the polymer to be reshaped. These viscoelastic polymer networks, now known as covalent adaptable networks (CANs), are an important frontier for improving plastic circularity, as well as for designing valuable stimuli-responsive materials. This Review describes the history of CANs, dating back to the early days of polymer science, and the evolution of their classification and nomenclature. A comprehensive survey of dynamic reactions and linkage chemistries is provided, as well as methods to characterize and reprocess CANs. Beyond straightforward reprocessing, many advanced applications of CANs and their composites are now emerging. Lastly, we provide perspective on how the development of new chemistries, strategies to control stimuli-responsive bond exchange and mechanical properties, and a deep understanding of exchange reactions will advance this field toward scalable, sustainable, and high-value materials.

• Research Organization: Northwestern University, Evanston, IL (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: EE0007897
• OSTI ID: 3025820
• Journal Information: Chemical Reviews, Journal Name: Chemical Reviews Journal Issue: 3 Vol. 126; ISSN 1520-6890; ISSN 0009-2665
• Publisher: American Chemical Society (ACS)Copyright Statement
• Country of Publication: United States
• Language: English