Synthesis and Surface Measurements of Surfactants Derived from Dehydroabietic Acid

摘要

Dehydroabietates wich poly(ethylene oxide) chains of average m = 12, 17, and 45 units [DeHab(E)_m] were synthesized. The adsorption at the liquid-vapor interface was measured, and the adsorbed amount and critical micelle concentrations (CMC) were determined. The foamability, the foam stability, wetting roperties, and cloud points, with and without salt content, were studied. The results were compared with common linear alkyl ethoxylates, nonylphenol ethoxy-lates, and cholesterol ethoxylates. The dehydroabietic acid as hydrophobe was found to result in the same CMC as a linear dodcyl chain. DeHab(E)_45 was found to be insoluble above 400 mg/L, but the surface tensions at lower concentrations were similar to those of the C_(11-13)E_(38-40) surfactants, which exhibit CMC in aqueous media. The foaming behavior of the DeHab(E)_12 and DeHab(E)_17 surfactants was about the same as for common linear C_nE_m surfactants. The foamability as well as the foam stability increased with ethylene oxide (EO) chain length. The cloud point was depressed by increased salt concentration and increased with the number of EO units in the head group. The cloud point was significantly lower than for the corresponding surfactant with a dodecyl chain with similar EO chain length. The wetting results, obtained by measuring the contact angle at similar surface tensions, indicate that surfactants of the DeHab(E)_m type are more efficient wetting agents than both disaccharide sugar surfactants and C_nE_m type surfatants.