RARE-EARTH-METAL INITIATED POLYMERIZATIONS OF POLAR AND NONPOLAR MONOMERS TO GIVE HIGH-MOLECULAR-WEIGHT POLYMERS WITH EXTREMELY NARROW MOLECULAR-WEIGHT DISTRIBUTION

Organolanthanide(III) initiated polymerizations of alkyl methacrylates and alkyl acrylates proceed in a living fashion and yield high molecular weight polymers with extremely narrow molecular weight distribution at high conversion. Random and block copolymerizations of alkyl acrylates are carried out successfully to give almost ''monodisperse'' polymers. Rare earth metal initiated polymerizations of lactones such as epsilon-caprolactone and delta-valerolactone produce again high molecular weight polymers with narrow molecular weight distribution. Bulky divalent and trivalent rare earth metal complexes catalyze the living polymerization of ethylene and alpha-olefins and the Sm(OR)(3)/AlR(3)-H2O initiator system catalyzes the polymerization of propylene oxide to give polymers with narrow molecular weight distribution.