Highly active magnesium chloride supported Ziegler-Natta catalysts with controlled morphology

Polymerizations of propylene were carried out by using the catalyst system MgCl2 . ID . TiCl4-AlEt(3) . ED, where ID (internal donor) was an organic diester and ED (external donor) was a silane. The effect of preparation conditions on the chemical composition and morphology of the supports and catalysts are discussed with the aid of elemental analysis and microscopy. The ethanol content had a strong effect on the MgCl2.nEtOH adduct preparation, and its precipitation and dealcoholation are very important factors that must be considered for good morphology to be attained in the spherical catalysts and polymers. The rate profiles in propylene EC180 suspension polymerization changed with the type of external donor and Al/Ti molar ratio.