Highly Reactive Cyclic Carbonates with a Fused Ring toward Functionalizable and Recyclable Polycarbonates

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Monomer design is crucial for developing polymers with specific thermal properties and chemical recyclability.
• Seven-membered ring carbonates are explored as building blocks for advanced polymer synthesis.

Purpose of the Study:

• To synthesize and characterize novel seven-membered ring carbonates containing trans-cyclohexyl fused rings.
• To investigate the ring-opening polymerization (ROP) of these monomers.
• To evaluate the thermal properties and chemical recyclability of the resulting polycarbonates.

Main Methods:

• Synthesis of seven-membered ring carbonates with trans-cyclohexyl fused rings.
• Ring-opening polymerization (ROP) using a catalyst with low loading (50 ppm).
• Characterization of polymer molecular weight, thermal stability (Td), and recyclability via depolymerization and repolymerization.
• Postfunctionalization via UV-initiated cross-linking and click reactions.

Main Results:

• Monomers exhibited high ROP activity (TOF up to 6 × 10^5 h^-1).
• High-molecular-weight polycarbonates (Mn up to 673 kg/mol) with excellent thermostability (Td > 300 °C) were obtained.
• Polycarbonates demonstrated complete depolymerization into cyclic dimers, enabling repolymerization and indicating potential for chemical recycling.
• Successful postfunctionalization of unsaturated polycarbonates was achieved.

Conclusions:

• Novel seven-membered ring carbonates facilitate the synthesis of high-performance polycarbonates.
• The developed polycarbonates possess superior thermal stability and offer a viable pathway for chemical recycling.
• Postfunctionalization expands the utility of these polymers for diverse applications.