PHASE-EQUILIBRIA OF QUASI-TERNARY SYSTEMS CONSISTING OF MULTICOMPONENT POLYMERS IN A BINARY SOLVENT MIXTURE .4. SPINODAL CURVE AND CRITICAL SOLUTION POINT

An attempt was made to construct a quasi-ternary system consisting of multicomponent polymers dissolved in binary solvent mixture (solvents 1 and 2) to derive the equations of spinodal and neutral equilibrium conditions and to clarify the effects of three thermodynamic interaction chi -parameters between solvent 1 and solvent 2, solvent 1 and polymer, and solvent 2 and polymer ( chi //1//2, chi //1//3, and chi //2//3) and the weight-average degree of polymerization CHI //o**w and the ratio of CHI //w**o to the number-average degree of polymerization CHI //n**o of the original polymer on the spinodal curve and the critical points (the critical concentration v//p**c) calculated from the above mentioned equations. The cloud point curve was also calculated indirectly from coexisting curve. The cloud point curve thus calculated was confirmed to coincide, as theory predicted with the spinodal curve, at the critical point.