A STUDY OF THE PVC-PLASTICIZER INTERACTIO N BY MEANS OF THE BREKNER-SCHNEIDER EQUATION PREDICTING THE TG-COMPOSITION BEHAVIOR

A new method for characterising the PVC-plasticizer interaction is cla imed, by using the Brekner-Schneider equation, developed initially for polymer mixtures, for studying the Tg = f (composition) dependence of the PVC-plasticizer mixtures. The PVC-plasticizer interaction is char acterised energetically and enthropically by means of the parameters i n the Brekner-Schneider equation. Their values are in concordance with the usual PVC-plasticizer compatibility criteria. A precise significa nce is conferred to the cusp - the specific discontinuity determined e xperimentally when studying the Tg = f (composition) dependence. The c usp appears as a result of the changes in the PVC-plasticizer interact ion mechanism, and has also been related to variations of some physico chemical properties with the mixture composition.