The relative viscosity-concn. curves of sodium linear alkyl benzesulfonat (SLABS), 1/2譒i2SO4, 1/2譔a2SO4, NaI and N2H4CO solns. vs. water and of mixed solns. of SLABS and additive vs. the SLABS solution have been determine at 303.2?.1K. The detns. show, the thickening efficiency of inorganic salts is remarkable for concentrated SLABS solns. The max. viscosity values which various salts can reach are markedly different. When the salt concentration reaches a certain value, SLABS forms a ppt. with the salt and the thickening ability of the salt reaches its limit. These results are interpreted in terms of the structure of the micelle solution, electrostatic interactions between ions are micelles, ionic hydratability, changes in the water structure and an activity product effect Urea diminishes markedly the viscosity values of concentrated SLABS solns. When using 1/2譔a2SO4 as a thickening agent, the higher the concns. of urea are, the lower the max. viscosity values are and the higher the concns. of salt corresponding to the values. These results are interpreted in terms of forming the individual of urea adduct between urea and the hydrated individual (of surfactant), and reducing the SLABS actual concentration in the equilibrium between the hydrated individual and micelle.

Key words: SODIUM IODIDE, UREA, SODIUM SULFATE, SODIUM ALKYL BENZENE SULFONATE, LITHIUM SULFATE