STUDIES ON METHYLALUMINOXANE AND ETHYLENE POLYMERIZATION

The preparation and structure of methylaluminoxane (MAO) was studied. MgCl2.6H2O was chosen as the new hydrolyzing agent for trimethylalumin ium (TMA). The effects of the temperature, reaction time and ratio of MgCl2 . 6H2O to TMA on TMA hydrolyzing were observed. The yields of MA O were 23-50%. The molecular weights, determined cryoscopically in ben zene, varied from 300 to 1700 and the degree of oligomerization from 6 to 30. MAO characterization was made using H-1-NMR, C-13-NMR spectros copy. The Cp2ZrCl2/MAO catalyst system was used for ethylene polymeriz ation. MAO prepared under different conditions had great influence on the activity of ethylene polymerization. The catalytic activity depend ed on the oligomerization degree of MAO. The catalytic activity and mo lecular weight (Mw) of polyethylene increased with increasing Al/Zr. T he optimum polymerization temperature range for maximum activity was 6 0-70-degrees-C. The M(W) of polyethylene decreased with increasing pol ymerization temperature.