Synthesis and catalytic properties for olefin polymerization of new vanadium complexes containing silsesquioxane ligands with different denticity |
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| Authors: | Marzena Bia?ek Monika Pochwa?a Adrian Franczyk Krystyna Czaja Bogdan Marciniec |
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| Affiliation: | 1. Opole University, Faculty of Chemistry, Department of Chemical Technology and Polymer Chemistry, Opole, Poland;2. Adam Mickiewicz University in Poznan, Centre for Advanced Technologies, Poznan, Poland;3. Adam Mickiewicz University in Poznan, Faculty of Chemistry, Department of Organometallic Chemistry, Poznan, Poland |
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| Abstract: | A series of new vanadium‐silsesquioxanes ( 2a ? 2d ) was prepared by reacting VCl4 with not fully condensed silsesquioxanes (having from one to four silanol groups) and evaluated as pre‐catalysts in olefin polymerization. The activation of 2a ? 2d with EtAlCl2 generated highly active catalysts for ethylene polymerization, yielding high molar mass polymers with narrow dispersity. Ultra‐high molar mass polyethylenes, M w up to 4 × 106 g mol?1, were obtained with methylaluminoxane and Al(i Bu)3/Ph3C]B(C6F5)4] as activators. Upon treatment with methylaluminoxane and boron compounds, all vanadium pre‐catalysts were active in 1‐octene polymerization as well, and produced isotactic‐rich poly(1‐octene)s with moderate monomer conversion (up to 23%). The polymerization parameters were optimized and the effect of the silsesquioxane structure on the catalytic activity and polymer properties was studied. © 2017 Society of Chemical Industry |
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| Keywords: | vanada‐silsesquioxane POSS Ziegler − Natta polymerization polyolefin polymer microstructure |
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