THERMOGRAVIMETRIC KINETIC-STUDY OF POLY(VINYL CHLORIDE) PYROLYSIS

The kinetics involved in the PVC decomposition under nitrogen atmosphere has been studied by applying two kinetic models to dynamic thermogravimetric data. Models proposed correlate the thermograms obtained at different heating rates with the same set of kinetic parameters. The first stage of PVC decomposition, where the dehydrochlorination of the polymer and the formation of a proportion of volatile organic compounds takes place, can only be fitted satisfactorily when a model based on two parallel reactions is used. The second stage, corresponding to the pyrolysis of the polyene chains formed, can be correctly represented by a model based on a single reaction. A discussion about the applicability of the Friedman method is presented and the results obtained are compared with those obtained by the two models.