Abstract

This paper is a comparative study of the performance of TiCl4 catalysts supported on recrystallized MgCl2, through different techniques for the polymerization of ethylene, propylene and ethylene-propylene copolymers. MgCl2 was dissolved in 1-hexanol and recrystallized through solvent evaporation, quick cooling and precipitation with SiCl4. The effect of the recrystallization conditions during the catalyst preparation on the chemical composition of catalysts was discussed with the help of IR spectroscopy. The variations of dealcoholation levels due to the different recrystallization techniques highly influenced the catalytic activity. The catalyst obtained through SiCl4 recrystallization was not only the most active, but it also showed the highest isotacticity indexes for propylene polymerization. (C) 2002 Elsevier Science Ltd. All rights reserved.