CO2 into recyclable polyester: New process uses carbon dioxide to make circular plastics

Researchers from Colorado State University and Northwestern University report a way to turn carbon dioxide into high-performance polyester that can be chemically recycled. The work, published in Nature, uses bicycloalkane monomers in a direct alternating copolymerization with CO2, reaching up to 50 mol% CO2 incorporation in the final polymer. The materials show tailorable thermal and mechanical properties, and in tests the BCB-based polyester could be depolymerized back to its monomer at more than 90% isolated yield. The key advance is circularity. Instead of being burned or downcycled, the polyester can be broken down into reusable building blocks and re-polymerized. The BCP-based version follows a different route, producing bicyclolactones that can also be re-polymerized. That means the CO2 is locked into a material that can cycle through multiple use phases. This is early-stage lab research, so questions remain about cost, scale, and energy use. But it points toward a practical use for captured CO2 in durable plastics rather than just storing it underground.