The Effect of Catalyst Isomerization on Polypropylene Properties

Albert J. van Reenen and Omar Sultan Department of Chemistry and Polymer Science, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa Reprint requests to Dr. A. J. van Reenen. Fax: +27-21-8084967. E-mail: [email protected] Z. Naturforsch. 2007, 62b, 362 – 366; received November 1, 2006 Dedicated to Prof. Helgard G. Raubenheimer on the occasion of his 65th birthday TwoC2-symmetric metallocene catalysts in solution were exposed to light, and the rac-meso conversion followed by NMR spectroscopy. Both exposed and unexposed catalyst solutions were used, in conjunction with a suitable cocatalyst, to polymerize propylene. The polymers were characterized with respect to their microstructure and fractionated according to crystallinity. The relationship between the catalyst isomerization and the polymer structure is illustrated. The effect of pre-activation of the catalyst before exposure to light was also studied and is reported on.