| 摘要 |
<p>A copolymerization process suitable for the preparation of high crystalline melting point cyclic olefin copolymers comprising contacting ethylene, and at least one cyclic olefin with an active polymerization catalyst comprising a Group 4 transition metal compound containing an asymmetrically substituted monocyclopentadienyl ancillary ligand, a bulky substituent-containing heteroatom ligand, the monocyclopentadienyl and heteroatom ligands being covalently bridged is disclosed. Ethylene/norbornene copolymers prepared in accordance with the invention exibited crystalline melting points of about 250 °C, and were prepared at high catalyst activity levels with feed ratios less than 6:1 of norbornene to ethylene.</p> |
