Synergy of binary plasticizer systems for creating migration-resistant PVC compositions

Abstract

The problem of plasticizer migration from polyvinyl chloride (PVC) is a crucial one in the development of stable polymer compositions. A promising approach is the use of binary plasticizer systems. In the present paper the PVC compatibility has been investigated for binary mixtures of dioctyl phthalate (DOP) with esters of adipic acid and phenoxyethanol. For the first time, a synergistic effect for such systems has been demonstrated by way of determining the critical dissolution temperature and calculating the Hansen solubility parameters (HSP). An increase in compatibility for the studied systems has been established in comparison with individual esters, which is reflected in a decrease in the critical dissolution temperature. The greatest synergistic effect (ΔA ≈ 21%) has been recorded for the mixture of DOP and decylphenoxyethyladipate. Calculation of the HSP parameters has confirmed the thermodynamic predictability of synergy: the RED criterion value for all mixtures has been less than 1 (0.55–0.73). A synergy mechanism based on complementary action of the components has been proposed. The results of the work open the way to creation of migration-resistant PVC compositions.