Clouding surfactant-polymer systems

The effect of water soluble polymers on the phase behavior of the anionic mlcroemulslon system was studied as a function of surfactant H/L properties. The cloud point temperatures for the neat mlcroemulslons and those containing 1500 ppm HPAM, partially hydrolyzed polyacrylamide, and 1000 ppm Xanthan gum are given In figure 4. The addition of either xanthan blopolymer or HPAM results In an Increase In the cloud point temperature of the mlcreomulslon. Both polymers have similar Interactions with the mlcroemulslon. Again one observes a lipophilic shift of the mlcroemulslon system Indicative of a repulsive interaction between the polymer and these anionic surfactants. 

Alkyl ethylene oxide condensates and nonionic polymers such as poly(vinyl alcohol) or poly(propylene oxide)-poly(ethylene oxide) block copolymers become insoluble in water above a certain temperature, usually designated as the cloud point. The polymer chains collapse at this temperature, and, consequently, flocculation of aqueous dispersions or emulsions stabilized by these surfactants occurs when the system is heated above the cloud point. 

Recently, Wellington and Richardson [J5] presented an interesting paper discussing the mechanism of low surfactant concentration enhanced water flood. The surfactant system consisted of alkyl-PO-EO glyceryl sulfonate with small amounts of an ethoxylated cationic surfactant to control phase behavior, interfacial activity, and surfactant loss. The surfactant systems had the ability to reduce their cloud point and interfacial tension when diluted, which was regarded as very useful for an effective flood performance. A surfactant concentration of about 0.4% removed essentially all the residual oil from sand packs in just over f PV with a surfactant loss of less than O.f PV. Mobility control by polymer was strongly required for good displacement and sweep efficiency and to reduce surfactant loss. 

Latexes constitute a subgroup of colloid systems known as lyophobic sol. Sometimes they are called polymer colloids. The stability of these colloids is determined by the balance between attractive and repulsive forces affecting two particles as they approach one another. Stability is conferred on these latexes by electrostatic forces, which arise because of the counterion clouds surrounding the particles. Other forces of an enthalpic or entropic nature arise when the lyophilic molecules on the surfaces of the latexes interact on close approach. These can be overcome by evaporation of the water, heating, freezing, or by chemically modifying the surfactant, such as by acidification. 

Uses Surfactant, wetting agent, pigment dispersant, lubricant, solubilizer for cosmetic and industrial emulsions, emulsion polymerization, metal cleaning, rubber and monomer systems, floor waxes, paper finishes textile scouring agent stabilizer for emulsion polymers emollient for pharmaceuticals Properties Wax HLB 16.9 cloud pt. > 95 C (1%) pH 6.5 (1%) 100% act. Rhodasurf LA-15 [Rhodia Novecare]... 

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