EFFECT OF PROTIC COMPOUNDS ON ETHYLENE POLYMERIZATION BY HF-TI SUPPORTED CATALYSTS

The effect was investigated of the addition of different protic compou nds, such as water, n-butanol, butanoic acid and methyl ethyl ketone, to triisobutylaluminium used as the cocatalyst for an Hf-Ti bimetallic catalyst supported on magnesium dichloride (Ti1.0Hf1.3Mg2.0Al0.85Cl12 .45) in the polymerization of ethylene. All the above compounds show a similar behaviour by decreasing catalyst activity, increasing polymer molecular weight and narrowing polymer molecular weight distribution. Minor differences are observed in the end-group unsaturations. An att empt has been made to correlate these effects to the interaction of ha fnium and titanium sites with the reaction products from AlR3 and the different protic compounds.