THE ROLE OF ADDITIVES FOR THE IMPROVEMENT OF DELTA-TICL3 CATALYST PERFORMANCE

The influence of ethylaluminium compounds (AlEt3 and AlClEt2) modified by 2,6-di-tert-butyl-methylphenol (BHT), tributylamine (TBA) and trip henylphosphine (TPP) on the polymerization of propene was investigated using catalysts based on TiCl3 modified by internal Lewis bases. Two catalysts were employed in this study, one (Cat. A) was prepared by th e reduction of TiCl4 complexed with dibutyl ether (DBE) - mole ratio D BE/TiCl4 = 0,67 - with AlClEt2 and the other one (Cat. B) was prepared in the same way, but a second internal base (ethyl benzoate (EB)) was added in a mole ratio EB/TiCl3 = 0,04. Activity and stereospecificity of the catalyst systems were strongly affected by these modified coca talysts. The role of the modifiers is discussed.