Evaluation of model-based pre-exponential factor from differential isoconversional methods

Abstract

This study introduces a model-based technique to evaluate the effective pre-exponential factor, conversion function and rate constant of reactions using differential isoconversional methods. In complex reactions, the effective pre-exponential factor depends on conversion and temperature and can be calculated using the modified Friedman method and compensation effect relationship. The innovative approach facilitates the computation of how pre-exponential factor varies with temperature across diverse heating rates, providing a valuable improvement in isoconversional analysis. The calculations revealed that the effective rate constant might be solely influenced by temperature, irrespective of the degree of conversion. The approach suggested in this research can also be applied in conjunction with the results of the traditional Friedman method. The technique was validated by applying it to kinetic data from various simulated reactions and experimental data on the thermal degradation of polyethylene.