Logistic mixture model versus Arrhenius for kinetic study of material degradation by dynamic thermogravimetric analysis

In this work, an alternative method to the Arrhenius equation for thermogravimetric analysis (TGA) is presented. It is based in performing a logistic regression of the raw TGA data. This model assumes that more than one physical process may be involved in each mass loss step and that each physical process may extend along all the experiment. The logistic mixture obtained explains the complete TGA trace, including as many mass loss steps as the experiment has. The typical asymptotic tendency of the mass loss steps is perfectly reproduced by the model. A discussion of the model from the statistical point of view is presented as well as a comparison with other classical models. Copyright (c) 2007 John Wiley & Sons, Ltd.