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TiCl 4 /MgH 2 ‐supported Ziegler‐type catalyst system, 4 . The influence of 14 CO contact time and mole ratio Al(C 2 H 5 ) 3 /Ti on concentration of active sites in ethylene homo‐ and copolymerization
Author(s) -
Jaber Isam A.,
Fink Gerhard
Publication year - 1994
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.1994.021950718
Subject(s) - copolymer , ethylene , mole , catalysis , polymerization , polymer chemistry , polymer , chemistry , materials science , nuclear chemistry , organic chemistry
The effect of varying 14 CO contact time upon the concentration of active centres C * in ethylene homopolymerization using the TiCl 4 /MgH 2 · Al(C 2 H 5 ) 3 catalytic system shows that the polymer radioactivity, and hence C *, increase sharply in the first sixty minutes of 14 CO contact with the polymerization centres. For contact times longer than one hour, the polymer radioactivity continues to increase, but very slowly. Studies on the effect of the mole ratio Al(C 2 H 5 ) 3 /Ti on ethylene homopolymerization show that both the catalytic activity and C * increase sharply when increasing the mole ratio Al(C 2 H 5 ) 3 /Ti in the range from 5 to 20. When increasing the mole ratio Al(C 2 H 5 ) 3 /Ti above 50, C * tends to decrease very slightly. In ethylene/1‐hexene copolymerization a similar effect of the mole ratio Al(C 2 H 5 ) 3 /Ti on the polymerization is observed. However, even though the catalytic activity in copolymerization is observed to be higher than in homopolymerization, at the same mole ratio Al(C 2 H 5 ) 3 /Ti, yet C * in both cases is found to be more or less the same.