| abstract |
A catalyst composition for the polymerization of propylene is provided. The catalyst composition includes one or more Ziegler-Natta procatalyst compositions having one or more transition metal compounds and an internal electron donor, one or more aluminum containing cocatalysts, and an external electron donor. The internal electron donor is a bidentate compound excluding plithalates. Suitable bidentale compounds include diethers, succinates, dialkoxybenzenes and diol esters. The external electron donor is a mixture of an activity limiting agent and selectivity determining agent. The present catalyst composition has high catalyst activity and high stereoselectivity, and is self-extinguishing. |