Kinetics and mechanism of cyclic esters polymerization initiated with tin(II) octoate, 1. Polymerization ofη-caprolactone

Kinetics of polymerization of ε-caprolactone (CL) initiated with tin(II) octoate (Sn(Oct)2) in THF as a solvent at 80°C was studied. The results strongly indicate that polymerization initiated with Sn(Oct)2 proceeds on the tin(II)-alkoxide bond and are not compatible with a mechanism in which propagation was proposed to proceed by a nucleophilic attack of the …OH ended macromolecules on the monomer-Sn(Oct)2 complex.