Studies on the Fractional Precipitation of Polymers. V. Interaction Parameters between Solvent-Polymer, Solvent-Nonsolvent and Nonsolvent-Polymer, and Precipitation Point

Abstract

The phase-separation in the ternary system of solvent-1, nonsolvent-2, and polymer-3 was studied and the volume fraction of each component in the dilute phase (v₁', v₂', v₃') and in the concentrated phase (v₁", v₂", v₃") were calculated accordins to Flory's theoretical equations. The values at the plaint point, (v₁)_pl, (v₂)_pl, (v₃)_pl, were also calculated according to Scott's equations. In this treatment it was assumed that P₁=P₂=1, P₃=P«1 for the polymerization degree P=100, 250, 500, 1000, 2500, 5000, 10000, ∞, and A=X₁₃/P₁=X₃₁/P₃, -0.4, 0, 0.4, B=X₁₃/P₁=X₂₁/P₂, -2, -1, 0, 1, C=X₂₃/P₂=X₃₂/P₃, 0.75, 2, 5 for the interaction parameters. From these calculations, theoretical solubility limit equation was obtained of various polymerization degree and various interaction parameters ;(v₂)_ppt=f(P)-g(P)log(v₃)_ppt.and f(P)=k₁+g(P)logk₂. The linear relation between g(P) and logarithm P satisfied the equation g(P)=k₃P^-0.532.