INFLUENCE OF LIGANDS AND COCATALYST ON THE ACTIVITY IN ETHYLENE POLYMERIZATION OF SOLUBLE TITANIUM COMPLEXES

Known and new titanium complexes bearing alkoxy, phenoxy, carboxylate and cyclopentadienyl ligands in addition to chlorine have been tested towards ethylene polymerization after activation with aluminum alkyls (AlR3) or methylalumoxane (MAO). In the absence of cyclopentadienyl li gands the optimal productivity obtained is very similar either with Al R3 or MAO, but higher MAO/Ti than AlR3/Ti ratios are necessary. In the case of complexes with the Cp ligand much better productivity can be obtained with high MAO ratios thus confirming that under these conditi ons a different activation mechanism is operative.