This paper presents an emulsion-polymerization model that is designed for an industrial, semi-batch reactor. The model consists of a reaction model and a calorimetry model, and as such enables us to predict the reactor temperature and the batch-output parameters, i.e., the conversion, the solids content and the viscosity. The model was validated on real-plant data and used in the analysis and design of the reactants dosing control. The control strategy proposed is valid for cases where evaporative cooling is either the only or an additional way to remove the heat of the reaction. It consists of an initiator and monomer dosing control, using the reactor temperature as a controlled variable. The simulation results and the real-plant testing show that the proposed reactants dosing control significantly reduces the variations in the reactor temperature and at the same time results in more uniform batch results. (C) 2011 Elsevier Ltd. All rights reserved.