Ethylene Polymerization Kinetics and Microstructure of Polyethylenes Made with Supported Metallocene Catalysts
Saeid Mehdiabadi, Olivier Lhost, Aurélien Vantomme, João B. P. Soares
Abstract
The microstructure of polyolefins made with a metallocene supported on a porous carrier is generally less homogeneous than when the polyolefin is made with the same unsupported metallocene. For instance, the molecular weight and chemical composition distributions of ethylene/1-olefin copolymers are often broader when they are made with a supported metallocene. In this article, a mathematical model is used to quantify this phenomenon. The polymerization of ethylene was investigated in parallel semi-batch reactors using a metallocene catalyst supported on an inorganic porous carrier. Ethylene pressure, polymerization temperature, and H2 concentration were the factors changed to study ethylene polymerization kinetics with this catalyst system. Modeling results showed that a three-site model was needed to describe the molecular weight distributions of the polyethylene samples made with this catalyst.