PVC-plasticizer interactions during the thermal decomposition of PVC plastisols. Influence of the type of plastizicer and resin

The effect of the type of plasticizer and resin on the thermal decomposition of PVC plastisols has been studied by thermogravimetric analysis. Eight plasticizers of different solvent power and ten commercial resins were employed. The shape of the thermograms of the plastisols is strongly influenced by the behaviour of their components. When the plasticizer is in the plastisol, its evolution suffers a delay as compared to when the plasticizer is alone. This behaviour is a consequence of the interactions resulting between the plasticizer and the resin prior to the decomposition process. In the same way, the resin decomposes at lower temperatures when it is in the plastisol. Both effects, the delay in the evolution of the plasticizer and the advance in the decomposition of the resin, are more marked for the more compatible plasticizers. For the more compatible plasticizers, a splitting of the peak corresponding to the resin into two differentiated peaks can be observed in the derivative curve. The first peak has been ascribed to a part of the PVC more susceptible to the plasticizer (i.e. plasticized PVC), while the second probably proceeds from a part of the PVC which suffers less interaction with the plasticizer. (C) 1996 Published by Elsevier Science Limited