AbstractPolymers are an essential product of the chemical industry and an ever-present material in our daily lives. The production of polymers comes with several chal-lenges. The challenges are not only in terms of the successful accomplishment of the synthesis that incorporates the cor-rect formulation of the reaction that high conversion of the monomers to polymers and all the other factors but also chal-lenges with regard to safety-related is-sues. The reason for this lies in the exo-thermic nature of nearly all industrially important polymerizations , regardless of the underlying reaction mechanism. Be-cause of this behavior, calorimetric meas-urements are a central part of the devel-opment of polymerization processes. In addition to experimental measurements, simulations can help in the thermal design of polymerizations. The software package PREDICI developed by Michael Wulkow  is specialized on the kinetic modeling of polymerization re-actions. The focus of this software pack-age lies in the simulation of the polymer synthesis, and especially on the molecular properties such as the molecular weight and the molecular weight distributions of the synthesized polymer. However, due to the implemented script-based language, it is possible to extend the models in order to describe further essential aspects of chemical processes (e.g. the heat bal-ance). Such a model is presented here us-ing the example of the anionic copolymer-ization of styrene and isoprene carried out in a batch process. The reason for that is that the heat balance is associated strongly with the safety of polymerization processes and provides essential infor-mation for the proper design of the large-scale synthesis process in a batch reactor.