INFLUENCE OF NONIONIC SURFACTANT ON AGGREGATION STATE OF SCLEROGLUCAN IN AQUEOUS-SOLUTION

The interactions between nonyl phenol polyethylene oxide and scleroglucan are investigated by turbidimetry, viscosimetry filterability tests and measurements of elastic modulus and adsorption. The phase diagrams of this ternary system have been established as a function of temperature and composition. It is shown that the surfactant molecules are adsorbed by the polymer at a low surfactant concentration, c(s): the adsorption induces a breaking down of the polymer aggregates and the filterability properties of the solutions are greatly improved. An excess of surfactant phase separation is observed by heating at a temperature that is a decreasing function of c(s). This is explained by the formation of a complex polymer-surfactant which has the same thermodynamic properties (lower critical solution temperature) as polyethylene oxide and the derived nonionic surfactants.