PHASE-EQUILIBRIA OF QUASI-BINARY SYSTEMS CONSISTING OF MULTICOMPONENTPOLYMER-1 AND POLYMER-2 .4. POLY(ETHYLENE OXIDE) POLY(PROPYLENE OXIDE) SYSTEMS

To confirm the reliability of the theory of phase equilbria of multico mponent polymer 1/multicomponent polymer 2 systems (i.e. quasi-binary systems) and the method of-computer experiment based on this theory (B rit. Polym. J., 23(1990)285; 23(1990)299; Polym. Int., 29(1992)219), c loud point curves (CPC), two-phase volume ratios (R) and critical solu tion points (CSP) have been determined experimentally for the quasi-bi nary mixtures of poly(ethylene oxide) (M(w)BAR = 647, M(w)BAR/M(n)BAR = 1.15; M(w)BAR and M(n)BAR, the weight-average and number-average mol ecular weights, respectively) and poly(propylene oxide) (M(w)BAR = 202 8, M(w)BAR/M(n)BAR = 1.08 and M(w) = 2987, M(w)/M(n) = 1.13). The hydr oxyl end groups of both polymers were methoxylated in advance by the C ooper & Booth method (Polymer, 18(1977)164). The thermodynamic interac tion parameter between both polymers, chi12 and the concentration depe ndence parameters for the above quasi-binary systems were determined b y the method proposed in a previous paper (Brit. Polym. J., 23(1990)29 9). CPC, R and CSP values calculated on the basis of the theory are in good agreement with the values determined experimentally.