A Preliminary Approach to Model Discrimination for Ziegler-Natta Polymerizations

Kinetic models for Ziegler-Natta polymerizations differ from those for many other types of chemical reactions in that their kinetic parameters depend upon the values of operating conditions such as catalyst composition, temperature, and moisture level. This complication makes the use of established procedures for discriminating among a set of candidate polymerization models much more difficult, requiring additional experimental effort to identify the functional dependencies and modification of the model discrimination criterion to take account of those dependencies. In this paper a procedure is described, using available data for the reaction under study, to provide guidance in the selection of further experimental runs for effective model discrimination. This approach is illustrated using data for polymerization of butadiene initiated with a cobalt catalyst.