Kinetic constants in a proposed reaction scheme act as a set of parameters that are to be tuned with the experimental data and henceforth any model-based optimization study related to the concerned reactor performance assumes the values of these kinetic parameters as fixed as obtained from the previous curve fitting exercise. However, it is known that these parameters are subjected to inherent source of uncertainties such as errors in measurement, change in concentrations for which they are not tuned for, etc. Assuming these kinetic parameters fixed for rest of the optimization is, therefore, not realistic and one should ideally check the sensitivity of these parameters on the final results. Fuzzy Chance Constrained Programming (FCCP) is one such approach that allows a decision maker to carry out such an analysis and this has been depicted here for determining the effect of uncertain kinetic parameters on the optimal performance of a semibatch epoxy polymerization reactor. Additionally, this study captures the tradeoff between solution quality and solution reliability that provides the angle of parametric sensitivity to this study. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers.