Polymerization of olefins with zirconocene catalysts using methylaluminoxane modified with hydroquinone as cocatalyst

Methylaluminoxane (MAO) was reacted with a small quantity of p-hydroquinone to obtain a modified MAO insoluble in toluene. Ethylene and propylene homo- and copolymerization were conducted with zirconocene using the modified MAO as cocatalyst both in the presence and absence of triisobutylaluminium. It was found that the modified MAO alone cannot activate the zirconocene catalyst, whereas polymers with high molecular weights are obtained when combined with triisobutylaluminium. The catalytic activity is markedly dependent on the mole ratio of p-hydroquinone to MAO as well as the amount of triisobutylaluminium.