Print: | ISSN 0256-1115 |
Online: | ISSN 1975-7220 |
Korean Journal of Chemical Engineering,
Vol.16, No.2, 156-160, 1999 Cocatalytic Activities of Methylaluminoxane Prepared by Direct Water Addition Method in Ethylene Polymerization over Cp2ZrCl2
The characterization of ethylene polymerization behaviors catalyzed over Cp2ZrCl2/MAO homogeneous system using methylaluminoxanes prepared by the direct hydrolysis of AlMe3 (Me=methyl) were reported. The MAO was prepared at the ratio of [H2O]/[Al]=1 and 0.5 and at three different temperatures, i.e., -40, -60 and -80℃. The polymerization rate was not decreased with polymerization time when the MAO prepared at the ratio of [H2O]/[AlMe3]=1 at -60℃ was used as a cocatalyst regardless of the ratio of Al/Zr and the polymerization temperature. The polymerization rate drastically decreased with polymerization time above 60℃ in case of using MAO prepared at the ratio of [H2O]/[AlMe3]=1 at -80℃. However, in case of the MAO prepared at the ratio of [H2O]/[AlMe3]=0.5 at -80℃, the rate continuously increased with polymerization time at the polymerization temperature of 70℃ and 80℃. The amount of MAO needed to activate Cp2ZrC12 was larger than that of MAO prepared at the ratio of [H2O]/[Al]=1. The viscosity molecular weight of polyethylene (PE) cocatalyzed with MAO prepared at the ratio of [H2O]/[Al]=0.5 was lower than that of polyethylene obtained with MAO prepared at the ratio of [H2O]/[Al]=1.
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