Ring Opening Polymerization of ε-Caprolactone by Rare Earth Alkoxide–CCl4 Systems

Abstract

Rare earth alkoxides are highly active initiators for ring opening polymerization of ε-caprolactone in CCl4. The molecular weight of the polymer obtained can be as high as 1.8×105 (Mv) at 60°C in an hour. The influence of solvent, rare earth element, ligand, monomer, and catalyst concentration, as well as the polymerization temperature and time was investigated. A mechanism study by IR, UV, and 1H NMR spectra showed that the polymerization of ε-caprolactone catalyzed by rare earth alkoxides proceeds through a “coordination-insertion” mechanism and selective cleavage of acyl–oxygen bonds of the monomer. © 1995, The Society of Polymer Science, Japan. All rights reserved.