DSC kinetic study of the transitions involved in the thermal treatment of polymers. Methodological considerations

The transitions and reactions involved in the thermal treatment of polyethy lene (PE) and EVA at a heating rate of 10 degreesC min(-1) in an inert atmo sphere (N-2), have been studied by differential scanning calorimetry (DSC). A brief discussion on the methodology related to the mathematical treatment of the DSC data is presented. The physical meaning of the kinetic paramete rs and the objectives of the DSC data reduction procedures are also comment ed on, emphasising the necessity of complex models in order to explain comp lex behaviours in detail. Different kinetic models have been suggested and applied involving one or two fractions susceptible of undergoing transition s or reactions. In addition, the variation of the heat capacities of the di fferent fractions has been considered yielding a remarkable improvement in the fitting of the whole of DSC curves. The models applied are capable of r epresenting the different processes observed and can be of great interest i n the understanding of such phenomena, as well as in modelling the heat inv olved in the processing of these type of products. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.