Studies on the Solution Properties of Anionic Surfactants, Alkanamide Poly (oxyethylene) Sulfates I.

Abstract

In the present work, the surface viscosities, closely related to the practical characteristics such as properties of foam, have been measured to depict the iso-surface-viscous curves on the triangular diagrams for alkanamide poly (oxyethylene) sulfate/N, N-diethanoldodecanamide (thickener) /water systems (concentration 00.1%). The surfactants used were sodium dodecanamide, tetradecanamide and hexadecanamide poly (oxyethylene) sulfates, and sodium dodecyl poly (oxyethylene) sulfate for comparison. Consequently, the following informations were obtained. (1) There lie 3 high surface viscosity regions, where the thickener is added slightly in the surfactant solutions (α), the surfactant is added slightly in the thickener solutions (β), and the thickener is added comparably to or more than the surfactants (γ). (2) While, with increase in the number of oxyethylene units in the surfactant molecule, α region is shifted to higher concentration of the surfactant and becomes more contracted, this region is shifted to lower concentration of the surfactant and surface viscosity increases remarkably with increase in alkane chain length. (3) As to, β region, no noticeable difference is found among the surfactants used. (4) γ region is the most extensive of 3 regions, and especially in the case of hexadecanamide poly (oxyethylene) sulfate it extends much more toward the water corner. (5) with increase in the number of oxyethylene units and in alkane chain length, surface viscosity in γ region increases, and in the latter case this region is shifted to higher concentration of the thickener. (6) In the case of dodecyl poly (oxyethylene) sulfate, α region is situated in higher concentration of the surfactant and more contracted than in corresponding alkanamide poly (oxyethylene) sulfate. However, γ region is more extensive and surface viscosity is higher.