STUDY ON POLYMER-POLYMER INTERACTION PARAMETER FOR TERNARY-SYSTEM SOLVENT-POLYDIMETHYLSILOXANE-POLYSTYRENE - INFLUENCE OF CONCENTRATION AND MOLECULAR MASS

This paper presents the results of a study of the thermodynamic properties of a ternary system viz. solvent (ethylacetate or benzene)-polydimethylsiloxane-polystyrene. The interaction parameter between the two polymers χ23, determined both from light scattering and studies of the critical conditions of phase separation, has been studied as a function of the molecular weights of the two polymers. Using a polystyrene of fixed molecular weight, we observe a large decrease in χ23 for increasing molecular weight of polydimethylsiloxane. When the molecular weights of the two polymers are very high, the parameter χ23 becomes very small (of the order of 0.01). The values of χ23 obtained for these two polymers are compared to those found for comparable systems, viz. polystyrene-polyisobutene and polydimethylsiloxane-polyisobutene. © 1979.