Analysis of heterogenized zirconocene catalysts using a micro-PIXE technique

Et(lnd)(2)ZrCl2 and the MAO co-catalyst, which polymerize ethylene and prop ylene, were heterogenized on partially dehydroxylated Davison silica 955, f ollowing the method of equilibrium adsorption. The dispersion of these cata lyst components on the silica support was investigated by measuring the spa tial concentration profiles of Si, Al, and Zr using a micro-PIXE technique. These components were found to be uniformly distributed over the support i rrespective of the variation in the heterogenization procedures and the exp erimental conditions used. The Si:Al ratios determined by the micro-PIXE te chnique were similar to those measured by the spectrophotometric method. Ho wever, the Al:Zr ratios measured by the former were somewhat lower than tho se determined bq the latter. Micro-PIXE measurements confirmed the presence of several trace impurities such as K, Ca, Ti, Fe, Ni, Cu, and Zn which ma y potentially poison the resulting catalyst.