A Novel and Versatile Calcium-Based Initiator System for the Ring-Opening Polymerization of Cyclic Esters

• Published in: Macromolecules Vol. 34; no. 12; pp. 3863 - 3868
• Main Authors: Zhong, Zhiyuan, Dijkstra, Pieter J, Birg, Christin, Westerhausen, Matthias, Feijen, Jan
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 05.06.2001; Amer Chemical Soc
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physical Sciences; Physicochemistry of polymers; Polymer Science; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; Science & Technology; YTTRIUM ALKOXIDES; COORDINATION POLYMERIZATION; L-LACTIDE; EPSILON-CAPROLACTONE; ALIPHATIC POLYESTERS; KINETICS; ALUMINUM ALKOXIDES; POLYLACTONES; COPOLYMERIZATION; MINERAL REQUIREMENTS; Ring opening polymerization; Lactone copolymer; Lactic acid copolymer; Priming activity; Living polymer; Experimental study; Lactone polymer; Solution polymerization; Lactic acid polymer; Caprolactone copolymer; Initiator; Calcium compound; Diblock copolymer; Kinetics; Secondary alcohol; Polycaprolactone
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma0019510

A novel and efficient calcium alkoxide initiating system, generated in situ from bis(tetrahydrofuran)calcium bis[bis(trimethylsilyl)amide] and an alcohol, for the ring-opening polymerization of cyclic esters has been developed. The solution polymerization in THF using mild conditions is living, yielding polyesters of controlled molecular weight and tailored macromolecular architecture. The polymerizations initiated with the 2-propanol−Ca[N(SiMe3)2]2(THF)2 system are first-order in monomer with no induction period. At high 2-propanol/Ca[N(SiMe3)2]2(THF)2 ratios, complete conversion of 2-propanol occurs due to fast and reversible transfer between dormant and active species.