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Vanadium‐based Ziegler‐Natta catalyst supported on MgCl 2 (THF) 2 for ethylene polymerization
Author(s) -
Czaja Krystyna,
Białek Marzena
Publication year - 1996
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.1996.030170407
Subject(s) - polymerization , catalysis , vanadium , polyethylene , ziegler–natta catalyst , ethylene , polymer chemistry , solution polymerization , magnesium , chemistry , materials science , inorganic chemistry , organic chemistry , polymer
A supported magnesium‐vanadium‐aluminium catalyst was prepared by depositing –with the use of a milling technique–VOCl 3 on the MgCl 2 (THF) 2 support and subsequent activation with diethylaluminium chloride. Catalytic activity of the obtained system for ethylene polymerization was evaluated as a function of Mg/V and Al/V ratios as well as catalyst ageing time and polymerization temperature. High concentrations of THF in the catalytic system and considerable excess of an organoaluminium co‐catalyst were found to have no deactivating action on vanadium active sites. The catalyst obtained is stable and its activity for ethylene polymerization is high. It yields polyethylene with higher molecular weight and higher melting point than offered by the materials produced with the use of a corresponding unsupported vanadium catalyst or a titanium‐based system on the same magnesium support. Kinetic investigations confirmed stability of this catalyst irrespective of its concentration in the polymerization medium or of monomer concentration. Moreover, analysis of the kinetic findings revealed that over 80% of vanadium employed forms active polymerization sites.