Particle Control of Supported Ziegler-Natta Catalysts

A good catalyst for olefin polymerization should exhibit, among other characteristics, good morphological control of the resulting polymers, as well as high activity, control of the molecular weight and molecular weight distribution. Thus, in regard to the polymer morphology, particles with spherical shape, having an average diameter of about 500 u, no fine content, narrow particle size distribution and high bulk density, these particles are very desirable either for fluidized gas-phase and slurry processes, because they can eliminate many problems in plant operation. To achieve good polymer particle control, catalysts with good mechanical properties and morphology have to be prepared, due to the fact that the catalyst imposes its shape on the polymer (replication phenomena).1,2