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Stereochemical Structure of Polypropylene Obtained in the Presence of Half‐Sandwich Titanium Complexes
Author(s) -
Csok Zsolt,
Liguori Dario,
Sessa Irene,
Zani Carla,
Zambelli Adolfo
Publication year - 2004
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200400138
Subject(s) - tacticity , polypropylene , propene , polymerization , polymer chemistry , elastomer , nmr spectra database , titanium , materials science , chemistry , spectral line , polymer , organic chemistry , composite material , catalysis , astronomy , physics
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).