Effect of Hydrogen and External Donor on the Microstructure of Polypropylene Made with a 4th Generation Ziegler-Natta Catalyst

Abstract

The effect of adding hydrogen and/or electron donor on the microstructure of polypropylene polymerized with a 4th generation Ziegler-Natta catalysts at two temperatures on the molecular weight distribution, tacticity, and crystallinity of polypropylene is thoroughly investigated in this article. Polypropylene tacticity and crystallinity increases not only when external donors are added, but also when hydrogen is used as a chain transfer agent. The molecular weight distribution of the resins is deconvoluted into several Flory's most probable distributions to show how different active site types respond to the presence of electron donor and hydrogen. The effect of adding hydrogen (H) and/or an electron donor (D) on the microstructure of polypropylene produced with a 4th generation Ziegler-Natta catalysts at two temperatures on the molecular weight distribution and tacticity of polypropylene is thoroughly investigated in this paper. The figure shows how CEF (tacticity) profiles of polypropylene are significantly affected as these conditions are varied at 70°C. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.