A study of the influence of impurities when discriminating between the terminal and penultimate copolymerization models

We investigate the effect of the presence of reactive impurities during cop olymerization on mathematical model discrimination and determine if impurit ies adversely affect the model discrimination process, depending on the cri teria and response(s) used. Nonlinear mechanistic process models are employ ed in a multiresponse statistical discrimination scenario. The investigatio n also considers, via several case studies, the extremely interesting quest ion of whether impurity effects could lead to incorrect choices about the c opolymerization mechanism itself (terminal versus penultimate model). The a nswers to the above questions are that reactive impurities do affect the mo del discrimination process and, what is more, they may mislead researchers as to the choice of the copolymerization mechanism. The latter unexpected r esult is further illustrated with experimental data from the literature. (C ) 2000 John Wiley & Sons, Inc.