High molar mass ethene/1-olefin copolymers synthesized with acenaphthyl substituted metallocene catalysts
| Autor: | Erkki Aitola, Kimmo Hakala, Timo Repo, Markku Leskelä, Hedvig Byman-Fagerholm |
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| Rok vydání: | 2007 |
| Předmět: |
Molar mass
Polymers and Plastics Comonomer Organic Chemistry Solution polymerization 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound End-group chemistry Polymerization Hexene Polymer chemistry Materials Chemistry 0210 nano-technology Metallocene Isomerization |
| Zdroj: | Journal of Polymer Science Part A: Polymer Chemistry. 46:373-382 |
| ISSN: | 1099-0518 0887-624X |
| DOI: | 10.1002/pola.22387 |
| Popis: | The influence of ligand structure on copolymerization properties of metallocene catalysts was elucidated with three C1-symmetric methylalumoxane (MAO) activated zirconocene dichlorides, ethylene(1-(7, 9)-diphenylcyclopenta-[a]-acenaphthadienyl-2-phenyl-2-cyclopentadienyl)ZrCl2 (1), ethylene(1-(7, 9)-diphenylcyclopenta-[a]-acenaphthadienyl-2-phenyl-2-fluorenyl)ZrCl2 (2), and ethylene(1-(9)-fluorenyl-(R)1-phenyl-2-(1-indenyl)ZrCl2 (3). Polyethenes produced with 1/MAO had considerable, ca. 10% amount of trans-vinylene end groups, resulting from the chain end isomerization prior to the chain termination. When ethene was copolymerized with 1-hexene or 1-hexadecene using 1/MAO, molar mass of the copolymers varied from high to moderate (531–116 kg/mol) depending on the comonomer feed. At 50% comonomer feed, ethene/1-olefin copolymers with high hexene or hexadecene content (around 10%) were achievable. In the series of catalysts, polyethenes with highest molar mass, up to 985 kg/mol, were obtained with sterically most crowded 2/MAO, but the catalyst was only moderately active to copolymerize higher olefins. Catalyst 3/MAO produced polyethenes with extremely small amounts of trans-vinylene end groups and relatively low molar mass 1-hexene copolymers (from 157 to 38 kg/mol) with similar comonomer content as 1. These results indicate that the catalyst structure, which favors chain end isomerization, is also capable to produce high molar mass 1-olefin copolymers with high comonomer content. In addition, an exceptionally strong synergetic effect of the comonomer on the polymerization activity was observed with catalyst 3/MAO. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 373–382, 2008 |
| Databáze: | OpenAIRE |
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