meso-Me2Si(1-indenyl)2ZrCl2/methylalumoxane catalyzed polymerization of the ethylene to ethyl-branched polyethylene
作者:Gianluca Melillo、Lorella Izzo、Roberto Centore、Angela Tuzi、Alexander Z. Voskoboynikov、Leone Oliva
DOI:10.1016/j.molcata.2004.12.002
日期:2005.4
The meso ansa zirconocene with dimethylsilyl bridge, activated by methylalumoxane, catalyses the ethylene polymerization, producing ethyl-branched polyethylene. With respect to the polymers obtained with the previously investigated meso zirconocenes, we have found higher branching amount and lower molecular weight. The rapid P-H transfer from the growing chain to the coordinated monomer could account for both these features of the polymer. The investigation on the structural parameters of the complex, through X-ray diffraction analysis, and on the electrophilicity of the cationic center, through NMR experiments, suggests, as a possible rationalization of this behavior, the obstruction in the inward site. (c) 2004 Elsevier B.V.All rights reserved.