TiCl4/MgH2-supported Ziegler-type catalyst system, 4. The influence of 14CO contact time and mole ratio Al(C2H5)3/Ti on concentration of active sites in ethylene homo- and copolymerization

✍ Scribed by Isam A. Jaber; Gerhard Fink

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 544 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950718

✦ Synopsis

Abstract

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.