Confidence interval on the activation energy obtained from differential isoconversional methods

Abstract In complex condensed phase reactions, the effective activation energy depends on both conversion degree and temperature. In our previous research, we introduced a modification to the Friedman method allowing for the calculation of activation energy as a function of conversion and temperature. In this study, we introduced an approach based on the least squares method to assess the confidence interval for activation energy obtained from the traditional and modified Friedman methods. The variance of the activation energy in the modified Friedman approach is estimated using the delta method. Additionally, we have presented a criterion for comparing and assessing the accuracy of results obtained through both conventional and modified isoconversional techniques. The proposed method was applied to the kinetic data of a simulated reaction and the thermal degradation of polyethylene to evaluate their activation energies and corresponding confidence intervals. GNU Octave/MATLAB codes were provided for evaluating activation energy and its confidence interval using both isoconversional methods.