Tunable and Recyclable Polyesters from CO2 and Butadiene

Carbon dioxide is inexpensive and abundant, and its prevalence as waste makes it attractive as a sustainable chemical feedstock. Although there are examples of copolymerizations of CO2 with high-energy monomers, the direct copolymerization of CO2 with olefins has not been reported. Herein, an alternate route to tunable, recyclable polyesters derived from CO2 and butadiene via an intermediary lactone, 3-ethyl-6-vinyltetrahydro-2H-pyran-2-one, is described. Catalytic ring-opening polymerization of the lactone by 1,5,7-triazabicyclo[4.4.0]dec-5-ene yields polyesters with molar masses up to 13.6 kg/mol and pendent vinyl sidechains that can undergo post-polymerization functionalization. The polymer has a low ceiling temperature of 138 ºC, allowing for facile chemical recycling. These results mark the first example of a well-defined polyester derived solely from CO2 and olefins, expanding access to new feedstocks that were once considered unfeasible.