Metallocenes for Polymer Catalysis

Metallocenes are very versatile catalysts for the production of polyolefins, polystyrene and copolymers. Some polymers such as syndiotactic polypropene, syndiotactic polystyrene, cycloolefin copolymers, optically active oligomers, and polymethylenecycloalkenes can be produced only by metallocene catalysts. It is possible to tailor the microstructure of polymers by changing the ligand structure of the metallocene. The effect and influence of the ligands can more and more be predicted and understood by molecular modeling and other calculations. It is estimated that by the year 2000 nearly every second new polyolefin plant will run with metallocene systems. A lot of polymer-producing companies try to use mainly supported metallocene catalysts in their running plants, the so-called Dddrop in DD technology; others build plants specially equipped for these new types of catalysts. The copolymerization of olefins together with polar monomers is just beginning and has a great potential. A big step is also being made by metallocene research to understand the mechanism and the nature of the Ziegler-Natta catalysis.