A mathematical model was developed to simulate the emulsion copolymerization of acrylonitrile/butadiene, otherwise known as nitrile rubber. Our goal was to develop a practical tool to predict polymer production rate and product quality on an industrial scale. Model predictions include the polymerization rate, the polymer composition, the number- and weight-average molecular weights, branching averages, and the number and average size of the polymer latex particles. The prediction of conversion was compared to a limited amount of industrial pilot-plant data and was found to be adequate. The model is currently being applied in two ways. The first application involves the testing of nonlinear model-based control schemes for an industrial nitrile rubber reactor. The second application involves using the model as a storehouse of prior knowledge for the implementation of a Bayesian sequential design of emulsion terpolymerization experiments as part of a larger, systematic study of multicomponent polymerization kinetics.