Activation of hafnocene catalyzed polymerization of 1-hexene with MAO and borate
| Autor: | Timo Repo, Sanna Santamäki, Erkki Aitola, Esa Kokko, Jukka Seppälä, Markku Leskelä |
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| Rok vydání: | 2009 |
| Předmět: |
Molar mass
Polymers and Plastics 010405 organic chemistry Ligand Organic Chemistry General Physics and Astronomy Chain transfer 010402 general chemistry 01 natural sciences 0104 chemical sciences Catalysis 1-Hexene chemistry.chemical_compound Monomer chemistry Polymerization Polymer chemistry Materials Chemistry Metallocene |
| Zdroj: | European Polymer Journal. 45:863-869 |
| ISSN: | 0014-3057 |
| DOI: | 10.1016/j.eurpolymj.2008.11.027 |
| Popis: | A study of 1-hexene polymerization with ethylene-bis(9-fluorenyl) hafnium dichloride has been carried out using two different cocatalyst systems, methyl-aluminoxane/trimethylaluminum (MAO/TMA) and tris-isobutyl-aluminum/N,N-dimethylanilinium tetrakis(pentafluorophenyl) borate (TIBA/borate). When MAO/TMA was used, 1-hexene polymerized into a low molar mass poly(1-hexene) with low catalytic activity. Activation with TIBA/borate increased polymerization activity drastically as well as the molar mass of the polymers. In order to analyze differences in the activity profiles, UV–Vis spectroscopy was employed to investigate ligand to metal charge transitions (LMCT) of the hafnocene dichloride during the activation process. The low catalytic activity and the fast chain transfer to the cocatalyst with MAO/TMA may originate from strong bonding between the metallocene cation and the MAO/TMA species thus obstructing monomer coordination and insertion. |
| Databáze: | OpenAIRE |
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