Impact of Polymerization Process Parameters on Improved Comonomer Incorporation Behavior in Ziegler-Natta Catalysis

Ziegler-Natta (ZN) based co-polymerization processes for the production of linear low-density polyethylene (LLDPE) generally give rise to a non-uniform incorporation distribution of the comonomer. It has been shown that lowering the titanation temperature during catalyst synthesis can increase the evenness of this distribution. However, polymerization process parameters also affect the resulting incorporation distribution. To investigate these factors, a ZN system using a variety of comonomer-types, at various -concentrations and polymerization temperatures is studied. The molecular properties of the polymer samples obtained are analyzed by high-temperature size-exclusion chromatography (HT-SEC). It is shown that a more uniform incorporation distribution of the comonomer can be achieved by lowering either the polymerization temperature or the comonomer concentration, and that lowering both increases the effect.