Kinetic models for the thermal decomposition of PVC plastisols

In previous work the effect of the plasticizer and resin on the thermal decomposition of plastisols was studied. The derivative curves of the thermograms showed complex behaviour as a consequence of the interactions between the plasticizer and the resin prior to the decomposition. In this work, two groups of kinetic models are proposed in order to explain this complex behaviour. Both groups consider that the plasticizer volatilises from the sample following a single reaction. The M1P16 model considers that the PVC decomposition takes place via two sets of parallel/consecutive reactions with an intermediate species that undergoes further decomposition. The M2P17 model considers that the interactions between the plasticizer and the resin leads two differentiated fractions in the PVC with different levels of plasticisation, both decomposing at well differentiated temperatures. From M1P16 and M2P17, different models have been derived and the corresponding parameters have been obtained. A discussion is presented regarding the interpretation of the kinetic parameters obtained by the different models. (C) 1996 Elsevier Science Limited