M. Galán Vallejo

Anionic surfactants—water systems: Specific refractive index, specific volume and viscosity

Abstract Specific refractive index, specific volume and viscosity were studied in several systems containing sodium alkyl-ether-sulfate (10; 20; 25; 27.5 and 30% w/w), sodium dodecyl sulfate (5; 10; 15; 20; 25; 27.5 and 30% w/w) and sodium dodecylbenzenesulfonate (5; 7.5; 10; 12.5; 15; 17.5 and 20% w/w) in water for a temperature range of 278–313 K. Systems with concentrations above 20% w/w of sodium dodecylbenzenesulfonate were not studied, as biphasic systems occurred throughout the temperature range. The study led to the following conclusions: (1) All systems studied showed Newtonian rheological behavior. (2) For concentrations equal to or below 20% w/w, the viscosity of systems with sodium dodecyl sulfate is lower than in systems containing sodium alkyl-ether-sulfate, at the same concentration and temperature; this tendency is reversed at concentrations above 20% w/w. (3) Systems with sodium dodecylbenzenesulfonate show the highest viscosity values, in comparison with the other two anionic surfactants studied, at the same concentration and temperature.

Rheological behaviour of rectified concentrated grape musts

Abstract Rheological behaviour of rectified concentrated grape musts was studied in order to establish a relationship between viscosity and sugar concentration or temperature. Concentrated musts show Newtonian rheological behaviour and their behaviour is described by Doolittles equation, which relates viscosity and specific volume.

Anionic surfactant-water systems : influence of lecithin addition on the rheological behavior

The viscosity values of ternary systems containing anionic surfactant, lecithin, and water have been studied using sodium alkyl‐ether‐sulfate, sodium dodecylsulfate, and sodium dodecylbenzenesulfonate as surfactants. The highest concentrations of surfactant and lecithin studied were 30% and 3% in weight, respectively. The following conclusions may be drawn: (1) All the systems present Newtonian rheological behavior, except those containing: 30% sodium alkyl‐ether‐sulfate and 2% or more lecithin, 30% sodium dodecylsulfate and 3% lecithin. These non‐Newtonian systems behave like pseudoplastic fluids. (2) The addition of lecithin improves the solubility of sodium dodecylsulfate in water, but diminishes the solubility of sodium dodecylbenzenesulfonate. (3) The systems containing sodium alkyl‐ether‐sulfate show an abnormal temperature dependence on viscosity, with maximum values at temperatures around 283–288 K. These viscosity maxima are related to the existence of ethylene oxide groups in surfactant molecules. (4) The addition of lecithin causes an increase in viscosity values of surfactant–water systems and also a shift of the maximum viscosity temperature toward higher values.The viscosity values of ternary systems containing anionic surfactant, lecithin, and water have been studied using sodium alkyl‐ether‐sulfate, sodium dodecylsulfate, and sodium dodecylbenzenesulfonate as surfactants. The highest concentrations of surfactant and lecithin studied were 30% and 3% in weight, respectively. The following conclusions may be drawn: (1) All the systems present Newtonian rheological behavior, except those containing: 30% sodium alkyl‐ether‐sulfate and 2% or more lecithin, 30% sodium dodecylsulfate and 3% lecithin. These non‐Newtonian systems behave like pseudoplastic fluids. (2) The addition of lecithin improves the solubility of sodium dodecylsulfate in water, but diminishes the solubility of sodium dodecylbenzenesulfonate. (3) The systems containing sodium alkyl‐ether‐sulfate show an abnormal temperature dependence on viscosity, with maximum values at temperatures around 283–288 K. These viscosity maxima are related to the existence of ethylene oxide groups in surfactant molecule...

EFFECT OF THE GRADE OF ETHOXYLATION OF SURFACTANT ON THE RHEOLOGICAL BEHAVIOR OF SODIUM LAURYL-ETHER-SULFATE/LECITHIH/MATER SYSTEMS

ABSTRACT The lecithin concentration and temperature effects on the Theological behavior of two linear sodium alkyl-ether-sulfate with different average ethoxylation grade (2.3 and 3.1 moles of ethylene oxide) has been studied. Experimental results show: the addition of lecithin causes higher increases of dynamic viscosity in the systems prepared with the alkyl-ether-sul fate which presents less ethoxylation grade. all the systems prepared with the alkyl-ether-sulfate which contents 3.1 mole of ethylene oxide show newtonian Theological behavior. However, some of the systems prepared with the other alkyl-ether-sulfate show non-newtonian Theological behavior (pseudoplastic or viscoelasic)

WATER/SODIUM ALKYL-ETHER-SULFATE/SODIUH XYLENE-SULFONATE SYSTEMS: SPECIFIC REFRACTION, SPECIFIC VOLUME AND VISCOSITY*

ABSTRACT The specific refraction, specific volume, and viscosity of systems containing sodium alkyl-ether-sulfate(NaEOS)(10, 20, 25, 27.5, and 30% w/w)and sodium xylene-sulfonate(NaXS) (1, 2, and 3% w/w) has been studied in the temperature range of 278 to 313 K. From this study, the following conclusions may be drawn: All systems show Newtonian behavior for the shear-rate range 0 to 28.5 s-1. The addition of sodium xylene-sulfonate produces a progressive viscosity reduction for a constant concentration of sodium alkyl-ether-sulfate.