Mild and Efficient Preparation of Block and GradientCopolymers by Methanesulfonic Acid Catalyzed Ring-Opening Polymerizationof Caprolactone and Trimethylene Carbonate.

Polycaprolactone/polytrimethylenecarbonate copolymers of differentmicrostructures have been prepared in toluene solution under mildconditions by controlled ring-opening polymerization of ε-caprolactoneand trimethylene carbonate with methanesulfonic acid as catalyst.Sequential addition of the monomers led to the formation of well-defineddi- and tri-block copolymers, demonstrating the ability of the catalyticsystem to cross-propagate. Simultaneous copolymerization yielded gradientcopolymers as a result of the different copolymerization reactivityratios and absence of undesirable redistribution reactions. DSC analysesshowed a noticeable impact of the copolymer microstructure on thethermal properties. [ABSTRACT FROM AUTHOR]