Polymerization of higher α‐olefins using a Cs‐symmetry hafnium metallocene catalyst. Kinetics of the polymerization and microstructural analysis |
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| Authors: | Vasilios Kotzabasakis Konstantinos Kostakis Marinos Pitsikalis Nikos Hadjichristidis David J. Lohse Thomas Mavromoustakos Constantinos Potamitis |
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| Affiliation: | 1. Industrial Chemistry Laboratory, Department of Chemistry, University of Athens, Panepistimiopolis Zografou, Athens 15771, Greece;2. ExxonMobil Research and Engineering Co., 1545 Route 22 East Annandale, New Jersey 08801‐3059;3. Organic Chemistry Laboratory, Department of Chemistry, University of Athens, Panepistimiopolis Zografou, Athens 15771, Greece;4. Institute of Organic and Pharmaceutical Chemistry, National Hellenic Research Foundation, 48 Vasileos Konstantinou Ave., Athens 11635, Greece |
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| Abstract: | The Cs‐symmetry hafnium metallocene [(p‐Et3Si)C6H4]2C(2,7‐di‐tert‐BuFlu)(C5H4)Hf(CH3)2 and tetrakis(pentafluorophenyl) borate dimethylanilinium salt ([B(C6F5)4]?[Me2NHPh]+) were used as the catalytic system for the polymerization of higher α‐olefins (from hexene‐1 to hexadecene‐1) in toluene at 0 °C. The evolution of the polymerization was studied regarding the variation of the molecular weight, molecular weight distribution and yield with time. The effect of the monomer structure on the polymerization kinetics was established. The role of trioctylaluminum in accelerating the polymerization was investigated. 13C NMR spectroscopy was used to study the microstructure of the poly(α‐olefins) by the determination of the pentad monomer sequences. The thermal properties of the polymers were obtained by differential scanning calorimetry, DSC. The results were discussed in connection with the polymer microstructure. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4314–4325, 2009 |
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| Keywords: | α ‐olefins glass transition kinetics metallocene catalyst microstructure |
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