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Characterization and evaluation of supported rac ‐dimethylsilylenebis(indenyl)zirconium dichloride on ethylene polymerization
Author(s) -
Franceschini Fernando C.,
Tavares Tatiana T. da R.,
Bianchini Daniela,
Alves Maria do Carmo M.,
Ferreira Maria Lujan,
dos Santos João H. Z.
Publication year - 2009
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.29430
Subject(s) - zirconium , catalysis , polymerization , dispersity , post metallocene catalyst , crystallinity , materials science , polymer chemistry , ethylene , polyethylene , molar mass , polymer , metallocene , nuclear chemistry , chemistry , organic chemistry , composite material , metallurgy
rac ‐Dimethylsilylenebis(indenyl)zirconium dichloride was grafted onto commercial methyl aluminoxane modified silica (SMAO) at different loadings (0.1–1.5 wt % Zr/SMAO). Supported catalysts were evaluated in ethylene polymerization with isoprenylaluminum as a cocatalyst. The characterization of two supported catalysts bearing 0.3 and 0.8 wt % Zr/SiO 2 by extended X‐ray absorption fine structure indicated that the number and the intensity of the peaks beyond the coordination shell, associated with the next nearest neighbors, depended on the Zr concentration. For the catalyst with a higher Zr content, only one peak (2.8 Å) was observed. The catalyst with 0.3 wt % Zr/SMAO presented two small peaks at 2.8 and 3.8 Å. Polymers produced with the supported catalysts presented lower crystallinity and higher molar mass and polydispersity values in comparison to that produced by the homogeneous one. Gel permeation chromatogram deconvolution suggested the presence of four catalyst sites for the supported systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009