CLOUDING BEHAVIOR OF AN ETHYLENE-OXIDE PROPYLENE-OXIDE BLOCK-COPOLYMER

Cloud point (CP) studies on aqueous solutions of several ethyleneoxide -propyleneoxide block copolymers and their mixtures in an aqueous solu tion show some interesting features. While single copolymers yield a p hase behaviour similar to conventional ethyleneoxide based non-ionic s urfactants, their mixtures show marked deviations from ideality. One c opolymer shows double cloud points over a certain concentration range. Ionic surfactants show a marked increase in the CP of block copolymer solutions, the CP increasing effect is more distinct for anionic surf actants. Increasing the nonpolar chain of the surfactant favors the in crease in the cloud point.