Structural studies on a solid self-supported Ziegler-Natta-type catalyst for propylene polymerization

The article describes structural studies on a solid MgCl2-based TiCl4 Ziegler-Natta catalyst for propylene polymerization prepared via emulsion technique. Surface area of the catalyst sample was found to be very low. Polymerization activity of the catalyst was nevertheless high. Powder X-ray diffraction (XRD) measurements indicated the presence of delta-MgCl2 in the catalyst sample, and IR and Raman studies the presence of a Mg-Cl bond. Scanning electron microscopy (SEM) measurements revealed an intriguing structure: evidently the catalyst particle is composed of chains (or nanoribbons) that extend from the center of the particle to the surface. SEM measurements further revealed spherical species (diameter about 60 nm) on the surface. Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) mappings indicated a high content of titanium evenly distributed throughout the particle, but after moisture treatment of the sample the content was evenly decreased. (c) 2007 Elsevier B.V All rights reserved.