Preparation of MgCl2-supported Ziegler-Natta catalyst systems with new electron donors

In the present work, the effect of new internal and external electron donors for Ziegler-Natta systems of the type MgCl2/Dl/TiCl4/DE/AlR3 Was compared with the conventional use of n-butyl phthalate and dimethoxy-diphenylsilane as electron donors. Catalyst systems employing various internal and external donors were evaluated in propylene polymerization. The polymers were characterized by infrared absorption spectroscopy, differential scanning calorimetry, and heptane extraction. The prepared catalysts with the new internal donors produced polypropylene with isotactic index up to 98% under the polymerization conditions employed. (c) 2009 Elsevier B.V. All rights reserved.