Abstract
Emulsifiers of natural origin play an important role in producing stable emulsions for applications in food, pharmaceuticals, cosmetics, and other industries. In this work, the emulsifying properties of a new composite based on stearic acid, its salt (potassium salt of stearic acid) forming at the water/vaseline oil and polymer sodium carboxymethyl cellulose (Na-CMC) were investigated. Potassium stearate was formed directly at the interface of water and vaseline oil: a solution of stearic acid in vaseline oil was used as the oil phase, and a solution of potassium hydroxide in water was used as the polar phase. It was shown that at a 1% concentration of stearic acid, high stability was achieved for a 50% emulsion. The stability of the emulsion increased with the concentration of both the surfactant and Na-CMC. The effect of the composite emulsifier on the stability of the emulsion is associated with the interaction of its components and the formation of a mixed interfacial adsorption layer. It was found that the lifetime of the vaseline oil-in-water emulsion at the optimal concentrations of 1% potassium stearate and 0.25% Na-CMC exceeded three days. The results of this study contribute to understanding the formation of emulsions where a surface-active emulsifier is formed directly at the oil/water interface and stabilization occurs through the participation of polymers.