Kinetic analysis of solid‐state reactions: Precision of the activation energy calculated by integral methods

Abstract

The integral methods are extensively used for the kinetic analysis of solid-state are very popular for determining activation energies. In fact, we have found more than 4500 citations (1300 in the last five years) for the papers were these methods were proposed. However, a systematic analysis of the errors involved in the determination of the activation energy from these methods is still missing. A comparative study of the precision of the activation energy as a function of x and T computed from the different integral methods has been carried out.

Mechanically induced polymorphic phase transformation in nanocrystalline TiO2 powder

“…As it can be seen, a sigmoidal curve can be suitably fitted with the experimental data. In order to assess which model properly governs the kinetics of this solidstate transformation, the following general equation is applied [21]:…”

Thermal and thermo-oxidative stability of reprocessed poly(ethylene terephthalate)

“…(5) would provide the best n for the modelisation, and thereafter provide the most accurate A, by averaging the Aˇobtained from the intercept at y = 0 of Coats-Redfern [43] expression (Eq. (6)), since among the different methods that calculate the Ea from a given f(˛), this one was demonstrated to offer precise results [44]. The calculations were performed taking into account all h experiments with different ˇ, and the integral form of the model A n .…”

Limitations of model-fitting methods for kinetic analysis: Polystyrene thermal degradation

“…Model-fitting methods are frequently used for performing the kinetic modeling of the pyrolysis of polymers and plastic waste because of their simplicity. A number of methods have been proposed, but all basically consist on fitting the experimental data to a conversion function, also known as kinetic model, which relates the extent of conversion with the reaction rate (Perez-Maqueda et al , 2005b). Kinetic models are mathematical functions developed from certain physico-geometrical assumptions regarding the reactants shape and the reaction driving force.…”