Study of formulation and stability of emulsions with polymeric emulsifiers

Abstract

Polymeric emulsifiers have appeared recently and have got emulsifying and thickness properties. These emulsifiers provide exceptional stability to oil-in-water-emulsions. This study shows formulations of new emulsifiers. The polymeric emulsifiers used were acrylate C 10–C 30 alkyl–acrylate cross polymer (T r1 –T r2 ). They provide exceptional stability to oil-in-water emulsions at very low usage levels (0.1, 0.3%), they can be used with any oil phase, easily prepared without heat with liquids ingredients. They can be used with any oil phase. Easily prepared without heat with liquids ingredients, they resist at different pH and they provide unique aesthetic qualities on the skin. A study of film-forming polymers was realized with Mallinckrodt dynometer at room temperature by the classical method of the tearing of the ring (Norm NF ISO 304). It showed the elasticity of surface-film and the retreat of the extensibility limit which increases proportionally with the concentration. In the same time, the tensioactive power is low (T s of solution at 10 −4 g l −1 59.9 to 61.6 mN m −1). The formulations were made with many oil types like vegetal oils, synthetical ester oils. This study showed that these thickening emulsifiers cannot emulsify different oil types without a coemulsifier. Non ionic surfactants from natural origin like sucroesters (sucrose mono and distearate, sucrose palmitate) permitted a good emulsification at room temperature, with all kind of oil except mineral oil. Mineral oil permit a good emulsification at room temperature, with all kinds of oil except mineral oil. Mineral oils are more compatible with coemulsifiers like polyoxyethylated sorbitan ester and sorbitan ester. In any case, it is necessary to use HLB values between 10 and 14, to be in synergy with polymeric derivatives which have a large hydropilic portion and a small lipohilic portion. The addition of thickener of same type improves stability. The stability was controlled at room temperature and at 37°C by classical methods: rheological analysis, microscopical observation and pH measurements. This type of polymeric emulsifiers gives good results without heating if it is dispersed in the oily phase and used with a coemulsifier.