A one-pot synthesis of a triblock copolymer from propylene oxide/carbon dioxide and lactide: intermediacy of polyol initiators.

Just add water: The copolymerization of propylene oxide and CO2 catalyzed by a cobalt complex is tolerant to the addition of water as chain-transfer reagent to afford polyols (HO-(PPC)-OH) with narrow molecular weight distributions (see picture; PPC=poly(propylene carbonate); PLA=polylactide). The addition of an organocatalyst to these polyols in the presence of lactides produces well-defined triblock copolymers (PLA-b-PPC-b-PLA).