Effect of thermal inertia-induced distortions of DSC data on the correctness of the kinetics evaluated

Abstract

Influence of certain experimental factors and methods of data processing on the correctness of the resultant kinetics is considered on the basis of dynamic model of differential scanning calorimeter, DSC. Firstly, essential effect of sample temperature deviation from linearity or from constant outer temperature due to heat accumulation in the sample on reaction proceeding is discussed. Disregard of this effect may and will be one of the reasons of obtaining the inadequate kinetics. The method for calculation of sample temperature deviation (reconstructing sample temperature) is proposed. Secondly, influence of a DSC curve distortion due to thermal inertia of the cell on the results of kinetic analysis is considered. The method for correction of this distortion (data deconvolution) is presented which can be safely used for processing of data of kinetic experiments. Special attention is paid to the importance of data deconvolution when the kinetic experiment is carried out under isoperibolic conditions. Finally, the combined effect of temperature deviation and inertia-induced distortions is considered. It should be emphasized that the matters considered are especially important when energetic materials are tested due to big heat release and rate of heat generation. At first, all the matters are discussed on the basis of simulated data. This allows elimination of various uncertainties of real experiment and influence of unknown kinetic model and gives vivid illustration of the subject. Then, the effects are demonstrated on the basis of real experimental data. Both the model-free and model-based kinetics evaluation methods were used. The simple method is proposed which allows vivid cross-verification of both these types of kinetics.