Sequential polymerization of ethylene oxide, epsilon-caprolactone and L-lactide: a one-pot metal-free route to tri-and pentablock terpolymers

Metal-free polymerization of ethylene oxide (EO) catalyzed by a relatively mild phosphazene base (t-BuP2) was proven feasible, which enabled the one-pot sequential polymerization of EO, epsilon-caprolactone, and L-lactide. Using either 3-phenyl-1-propanol or water as an initiator, the corresponding triblock or pentablock terpolymers were easily prepared.