Method for quantitative evaluation of kinetic constants in olefin polymerizations. II. Kinetic study of a high-activity Ziegler-Natta catalyst used for bulk propylene polymerizations

A method for quantitative evaluation of kinetic constants in Ziegler-Natta and metallocene olefin polymerizations presented previously (Matos, V.; Mattos Neto, A. G.; Pinto, J. C. I Appl Polym Sci 2001, 79, 2076) is adapted to allow the estimation of kinetic constants for bulk propylene polymerizations by using a conventional fourth-generation high-activity Ziegler-Natta catalyst (HAC). In this particular case, reaction rate profiles are not available, so that estimation of kinetic data must rely on average polymer yields. The method comprises some fundamental steps, including the initial design of a statistical experimental plan, the execution of the designed experiments, the development of simple mathematical models to describe the polymerization, and the estimation of kinetic parameters from available yields, gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) data. It is shown that the proposed method allows the successful interpretation of experimental olefin polymerization data and the quantitative evaluation of kinetic parameters, which can be inserted into a process simulator to provide an accurate picture of actual industrial plant behavior. (C) 2002 Wiley Periodicals, Inc.