THE EVALUATION OF KINETIC-PARAMETERS FROM THERMOGRAVIMETRIC DATA - COMPARISON BETWEEN ESTABLISHED METHODS AND THE GENERAL ANALYTICAL EQUATION

This paper presents a methodology for the study of thermal decomposition kinetics of polymeric materials by means of dynamic thermogravimetry (linear temperature increase). We have developed a general analytical solution relating conversion to temperature by means of integral procedures. This equation is a recurrent series providing a rigorous method to determine kinetic parameters such as activation energy and frequency factor. We have also conducted an extensive review of the different computing methods available in the literature leading to the determination of the kinetic parameters of thermal decomposition reactions. We have compared the results obtained by using the general analytical solution with those evaluated by means of established methods which were classified into three categories: integral, differential and special methods. Finally we have analyzed the accuracy of the computing methods by considering the simplifications inherent in each of them.