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Updated: Jun 2, 2026

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
Published on: December 16, 2022
Chemically Circular Poly(Orthoester) Elastomers Synthesized by Halogen-Bond Donor Catalyzed Cationic Ring-Opening
Zohaib Siddiqi1, Brooks A Abel1,2
1Department of Chemistry, University of California, Berkeley, California, USA.
Abstract:
Synthetic polymers are essential to modern life, yet their large-scale production and environmental accumulation necessitate the development of more sustainable alternatives. Existing synthetic approaches to next-generation polymers largely focus on well-established monomer classes, yet developing methodologies for the polymerization of underexplored functionalities would unlock challenging-to-access polymer classes and exploration of uncharted materials space. Poly(orthoesters) are an underexplored class of biodegradable and chemically recyclable polymers, and here we overcome long-standing synthetic challenges by developing a molecular weight-controlled synthesis via cationic ring-opening polymerization of spiro orthoesters. Polymerization control is imparted by a tridentate halogen-bond donor catalyst that selectively promotes reversible-deactivation via anion-binding, while suppressing undesired monomer activation. Mechanistic studies reveal that precise molecular weight control is maintained despite termination events, constituting a rare example of a polymerization exhibiting immortal-like behavior. Combined with controlled degradation, chemical recycling to monomer, and tunable material properties, this work establishes poly(orthoesters) as a promising platform for sustainable and circular materials.
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