STUDIES IN RING-OPENING POLYMERIZATION .12. THE RING-OPENING POLYMERIZATION OF OXETANE TO LIVING POLYMERS USING A PORPHINATO-ALUMINUM CATALYST

The polymerization of oxetane has been carried out with catalysts derived from the reaction of 5,10,15,20-tetraphenyl-21H,23H-porphine and aluminium diethyl chloride, catalysts that have been described as immortal systems. The polymerization of oxetane with this catalyst leads to a polymerization that is slower than the corresponding polymerization of oxirane but high conversions of monomer to polymer occur and the polymerization shows the properties of a living polymerization; the molecular weight average of the polymer increases with conversion of the monomer to polymer closely correlating with the ratio of monomer polymerized to initiator used and NMR spectra show the presence of the porphinato and other end groups.