TRANSITION-METAL CATALYSTS FOR OLEFIN POL YMERIZATION .2. PREPARATIONOF STEREOREGULAR POLY-(1-OLEFINS)

The insertion polymerization of propene by using chiral transition met al compounds leads to a variety of polypropene products with different stereoregularities. The classical, heterogeneous Ziegler-Natta cataly sts, based on Ti(III) as active species, produce isotactic, highly cry stalline materials with melting points above 160 degrees. These materi als find manifold applications, e.g. for packaging as well as in the c ar industry. Within the last 15 years molecular defined organometallic complexes were developed. These catalysts allow the production of new stereoregular polyolefins and a precise control of its properties by tailoring the ligand environment.