THERMOGRAVIMETRIC KINETIC-STUDY OF POLY(VINYL CHLORIDE) PYROLYSIS

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