Cationic and anionic ring-opening polymerization in supercritical CO2. Preliminary results

The ionic ring-opening polymerization of several heterocycles in supercriti cal CO2 is described for the first time. Octamethylcyclosiloxane (D-4) as w ell as phenyloxazoline have been polymerized with cationic initiators (trif lic acid or methyl triflate). Anionic and pseudo-anionic polymerizations of epsilon-caprolactone initiated respectively with tBuOK and isopropoxides o f aluminum, yttrium and lanthanum are also reported. They are the first exa mples of anionic polymerization in the presence of CO2 for which no incorpo ration of CO2 has been observed.