Polymerization of Butadiene and Isoprene with Lanthanide Catalysts; Characterization and Properties of Homopolymers and Copolymers

Abstract

The lanthanide polymerization catalysts represent a significant achievement in the synthesis of stereospecific high-cis cis-polybutadiene, high-cis cis-polyisoprene, and high cis random and block copolymers of butadiene with isoprene. In contrast to the conventional 3d transition metal catalysts, changes in lanthanide metals, halogens, and ligands do not significantly affect the cis-1,4 content of the polymer. But, the catalyst activity is greatly dependent on the choice of lanthanide elements, counterions, and donor ligands. Energy efficient processes are possible by performing the polymerizations in low boiling aliphatic hydrocarbon solvents with high solids content and possibly, in the gas phase. In addition, the described lanthanide catalysts are very effective for producing high cis polymers with a broad range of molecular weights.