Cationic ring‐opening polymerization of lactones in the presence of alcohol

Abstract Cationic ring‐opening polymerization of e‐caprolactone using triethyloxonium hexafluorophosphate initiator in the presence of alcohol to produce low molecular weight polyester glycol was examined. The polymerization proceeded by an activated monomer mechanism; thus the polymer molecular weight increased directly with the monomer conversion. Polymerization of lactones other than ϵ‐caprolactone were also examined, and the overall rate of polymerization was in the order δ‐valerolactone> ϵ‐caprolactone>> β‐butyrolactone> diketene> γ‐butyrolactone.