Dynamic Remodeling of Covalent Networks via Ring-Opening Metathesis Polymerization.

Reversible transformations in bulk polymers offer numerous possibilities for materials remodeling and reprocessing. While reversible systems based on dynamic covalent chemistry such as the Diels-Alder reaction and transesterification have been intensively studied to enable local bond dissociation and formation, reports regarding the reversion from bulk network polymers to monomers are rare. Herein, we report a reversibly polymerizable system based on ring-opening metathesis polymerization of cyclopentene derivatives in the bulk state. The network polymer is thermodynamically stable and mechanically robust at room temperature and readily depolymerizes at elevated temperatures to yield liquid monomers that are repolymerized to cross-linked polymers by simply cooling to room temperature. This reversible process was characterized by differential scanning calorimetry and rheological tests.