Relation between huggins constant and compatibility of binary polymer mixtures in the aqueous ternary systems

Abstract

We have classified a number of aqueous ternary systems containing two different polymers into three types by focusing on the deviation of the Huggins constantk′ from the additivity line. Systems of type I have negative deviations ofk′; the repulsive interaction between the two different polymers dominates. In systems of type II,k′ almost follows the additivity relation; the repulsive and attractive interactions between the two different polymers are balancing. Type III systems have positive deviations ofk′; the attractive interactions are relatively dominant. This classification of systems is supported by the fact that the positive and negative deviations ofk′ from the additivity line also correspond to the sign of interaction parameter between polymer 2 and 3, Δb ₂₃. Furthermore, we have verified the relatively high compatibility between dextran and poly(vinyl alcohol) by determining the binodal concentration of a liquid-liquid phase separation for a water/dextran/poly(vinyl alcohol) system, which is classified as type III. Thus, we found that the compositional dependence ofk′ closely relates to the compatibility of binary polymer mixtures in aqueous ternary systems.