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Stereochemical Structure of Polypropylene Obtained in the Presence of Half-Sandwich Titanium Complexes

✍ Scribed by Zsolt Csok; Dario Liguori; Irene Sessa; Carla Zannoni; Adolfo Zambelli

Publisher
John Wiley and Sons
Year
2004
Tongue
English
Weight
120 KB
Volume
205
Category
Article
ISSN
1022-1352

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✦ Synopsis

Abstract

Summary: The polymerization of propene in the presence of CpTi(CH~3~)~3~/B(C~6~F~5~)~3~, at low temperature, affords prevailingly syndiotactic elastomeric polypropylene. In the presence of methylalumoxane (MAO) and under the same polymerization conditions, both CpTi(CH~3~)~3~ and CpTiCl~3~ afford elastomeric polypropylene with a stereochemical structure ranging from prevailingly syndiotactic to prevailingly isotactic, depending on the concentration of MAO. A tentative rationalization of these results is provided.

The methyl regions of the ^13^C NMR spectra of polypropylenes obtained for different amounts of MAO (0.001 mol: top and 0.09 mol: bottom).

magnified imageThe methyl regions of the ^13^C NMR spectra of polypropylenes obtained for different amounts of MAO (0.001 mol: top and 0.09 mol: bottom).

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