PROPYLENE POLYMERIZATION THROUGH SUPPORTED METALLOCENE MAO CATALYSTS - KINETIC-ANALYSIS AND MODELING

Several propylene polymerizations are carried out with supported metal locene catalyst, prepared by reaction of silica gel with methylalumino xane and then with dimethylsilanediylbis(indenyl)zirconiumdichloride. The rate-time curves obtained are analyzed to understand the influence of support and triisobutylaluminium on the reaction. As a first attem pt to model this system we developed a partially new particle growth m odel, based on a shell by shell fragmentation hypothesis (gradual brea k-up from the outside to the inside of the particle), and a final mult igrain structure of the particle. A kinetic scheme including the TIBA interaction with the supported catalyst is also presented. The model p rediction and the experimental data are compared for the rate-time cur ves and polymer properties. (C) 1995 John Wiley & Sons, Inc.