Synthesis of bifunctional ϵ-caprolactone oligomers initiated by p-toluenesulphonic acid☆

Abstract The mechanism of the cationic polymerization of ϵ-caprolactone initiated by p -toluenesulphonic acid in the presence of ethylene glycol was studied. Ethylene glycol sharply increases the rate of the process, transforming it to the hydroxomechanism where chain growth occurs on monoalkyloxonium ions ∼OH 2 + , most of which are associated with the anion in inactive ion pairs.