Studies on the mechanism of the ring opening polymerization of cycloolefins with particular reference to cycloolefin copolymerizations

The ring opening polymerization of cycloolefins in the presence of widely different transition metal catalysts leads to unsaturated polyalkenamers. The evolution of this reaction and of the catalysts is illustrated. Cycloolefin copolymerizations have allowed to elucidate aspects concerning the site of ring opening for different catalysts and classes of cycloolefins. Further studies and observations refer to the transition state and to the stereochemistry of the cycloolefin coordination. The comparison of the cycloolefin copolymerization and the cycloolefin insertion into preformed polyalkenamers allows deductions concerning the permanence of the catalytic centers. Some properties of regular model polymers derived from hydrogenated poly(methylalkenamer)s are compared with those of the corresponding ethylene/propylene copolymers.