| Abstract: | A theoretical study is made of three-phase separation in a ternary solution consisting of a pure solvent and two homologous monodisperse polymers with relative chain lengths P1 and P2. The Flory—Huggins interaction parameter X is assumed to depend linearly on the volume fraction ? of the polymer mixture: χ = χ0(T) + k(T)?. For a given P1 the ratio of P2 to P1 for the onset of three-phase separation increases with an increase in k, first gradually and then sharply. Loci of critical points for this condition on the χ0 vs. ? diagram are determined for a series of fixed values of P1 and their significance is discussed. |
