Ring-opening polymerization of lactones catalyzed by ion-exchanged clay montmorillonite and the application to well-defined block copolymer synthesis with seven-membered cyclic carbonate

Tin ion-exchanged montmorillonite catalyzed the ring-opening polymerization of δ-valero-lactone in solution. The polymerization proceeded in living manner, giving rise to poly (δ-valerolactone)s with controlled molecular weights. Acid ion-exchanged montmorillonite was also effective for the polymerization. Furthermore, the controlled ring-opening block copolymerization of 7CC with δ-VL by EtOH/Sn-Mag initiator system was investigated to obtain the corresponding copolymer quantitatively with narrow polydispersity. The molecular weights of the obtained polymers could be controlled with the feed ratio of the monomer and initiator.