NEW NONIONIC SURFACTANTS FROM LYSINE AND THEIR PERFORMANCE

In this paper a new class of multichain non-ionic surfactants based on lysine with two octyl, decyl, dodecyl or tetradecyl chains and one po lydispersed polyoxyethylene diethanolamide head group are introduced. Measurements at air/water interface and bulk solution of surface-activ e properties such as surface tension and critical micelle concentratio n were made.These compounds were obtained by condensation of the corre sponding long chain N(alpha), N(epsilon) diacyl lysine with a polydisp ersed oxyethylene diethanolamine which was prepared in our laboratory. A preliminary study of their water solubility properties is also desc ribed. The surface-active properties were evaluated by measuring the v ariation of surface tension and the formation of a presumable CMC as a function of concentration in the aqueous solution. All compounds were soluble in water up to 0.5% (w/v). They showed normal surface tension values in water solution and presented higher CMC than classical poly oxyethylene alcohols non ionic surfactants with the same number of car bon atoms in the hydrophobic moiety. In this series when each chain is increased by four methylene units, the CMC falls to about one-hundret h of its previous value.