Mathematical considerations for nonisothermal kinetics in thermal decomposition

In this paper we present an overview of the most relevant mathematical aspects involved in the kinetic analysis of thermal decomposition processes, especially when TG-DTG is used. The topics presented comprise errors introduced in the kinetic analysis by deviations in temperature from the preset control temperature program; treatment of 'raw-data' introducing simple techniques for filtering the data and get both smooth and accurate derivative thermogravimetric curves; comments on the correct specification of the mathematical model; fitting data to a mathematical model: the (arguably) obsolete differential methods, and the integral methods at the view of the modern computers; validity of the least-squares approach and modern techniques of optimization applied to the TG/DTG analysis; and quality of the fit and the fitted parameters.