Effect of Prepolymerization on Kinetics and Morphology in Polymerization of Propylene with a Ziegler-Natta Catalyst

摘要

The effect of prepolymerization on the kinetics and morphology in the polymerization of propylene using a conventional, commercially available Ziegler-Natta catalyst was tested. It was shown that the use of a fixed prepolymerization for 10 minutes at 40°C increased reaction rates at higher polymerization temperatures. This was explained by the prevention of thermal runaway on particle scale. Next to that, this fixed prepolymerization did significantly influence the morphology of the produced polymer powder. Particles produced in main polymerization at higher temperatures showed higher bulk densities, better shape replication and smoother particle surfaces, when a prepolymerization step was used.