Modifications of the active sites distribution in the Ziegler-Natta polymerization of propylene using Lewis acids

Heterogeneous Ziegler-Natta precatalysts (with phthalate as internal donor) were modified by treatments with various Lewis acids (MCln with M = Ga, Sn, Si, and Sb and n = 3, 4, or 5) before their use in the polymerization of propylene. If performed on previously "detitanated" precatalysts,...

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Veröffentlicht in:Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2010-06, Vol.48 (12), p.2631-2635
Hauptverfasser: Ribour, David, Spitz, Roger, Monteil, Vincent
Format: Artikel
Sprache:eng
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Zusammenfassung:Heterogeneous Ziegler-Natta precatalysts (with phthalate as internal donor) were modified by treatments with various Lewis acids (MCln with M = Ga, Sn, Si, and Sb and n = 3, 4, or 5) before their use in the polymerization of propylene. If performed on previously "detitanated" precatalysts, treatments with SnCl₄ and SiCl₄ lead to a slight activation but especially to an increase of the tacticity whereas GaCl₃ and SbCl₅ treatments deactivate the catalyst. The modification method applied to conventional unmodified precatalysts gave similar trends. A significant increase of tacticity (and/or of Tm) and a narrowing of the molecular weight distribution were observed in the case of SnCl₄ and SiCl₄ treatments.
ISSN:0887-624X
1099-0518
1099-0518
DOI:10.1002/pola.24043