Isoconversional computations for nonisothermal kinetic predictions

Abstract

Abstract Isoconversional analysis is a model-free and powerful approach that readily provide quantitative information of the kinetics of a thermally activated transformation. Activation energy and preexponential factor are the main output of isoconversional analysis. Another practical application is the kinetic predictions that are computed in a model-free way. In this communication, a computational tool of predicting nonisothermal kinetics is presented. This approach is directly derived from an advanced isoconversional analysis. It assumes that a nonisothermal program can be decomposed in a series of infinitesimal isothermal steps. For the development of computations, four kinetic models are simulated and are used as input data. Predicted nonisothermal kinetic profiles are compared to simulated curves and show excellent agreements. Accuracy, effect of sampling and noise are assessed. This approach gives excellent predictions for the four models (among them one comprises variable activation energy). The predictions are also accurate when dealing with a multistep kinetic program (alternating isothermal and nonisothermal stages). Furthermore, the authors briefly discuss the dependance of the heating rates on the shift of nonisothermal kinetics profiles.