Related Experiment Video
Updated: Sep 15, 2025

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
Resin-to-Resin Circularity in Chemical Recycling of Dicyclopentadiene-Based Cycloolefin Resins
Zhen Xu1, Mason L Witko2, Hongqian Zheng3
1Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720, California, United States.
Abstract:
Cycloolefin resins (CORs) comprising dicyclopentadiene (DCPD) cross-linkers are high performance thermosets for diverse single-use applications. If it were possible to carry out deconstruction of DCPD thermosets through exclusive reformation of the cyclopentene ring in DCPD, then linear polyDCPD chains could re-enter subsequent manufacturing cycles and enable resin-to-resin circularity. Here, we develop a chemical recycling process whereby linear polyDCPD recyclates are generated from end-of-life commercial and model CORs, including copolymers, using a second-generation Hoveyda-Grubbs ruthenium(II) alkylidene catalyst for deconstruction via ring-closing metathesis. The properties of first-generation DCPD thermosets were reproduced across subsequent generations of recycling and reuse, where up to 84% of linear DCPD was retrievable from end-of-life thermosets after deconstruction. We further quantify how comonomer incorporation, the curing process, and aging affect round-trip material efficiency and the quality of regenerated thermosets.
Related Concept Videos
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Cycloaddition Reactions: Overview
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry

