Phase Behaviors Of Fatty Acid Soaps And Its Stability

Fatty acid soaps have been commonly used in the personal cleansing products with its popular properties for a long time. However, there were still some problems that limit the application the fatty acid soaps in storage time and using. The objective of our present work were by having studied the phase behaviors of soaps prepared with single fatty acids, binary fatty acid mixtures, and ternary fatty acids mixtures, discovered the relationship between phase and stability, based on which the additions such as polyols, surfactants, emollients and emulsifiers were selected to improve the stability of fatty acid soaps by influencing the phase behavior of them. The rheological properties of fatty acid soaps were also studied. The results of the studies are as follows, the phase behavior of soaps prepared with binary and ternary fatty acids mixtures were rich than that those prepared with single fatty acids. Glycerin or propylene glycol had a significant influence on the phase behavior of soaps prepared with 30% fatty acids except 25% fatty acids. SLES, CAPB, APG, CMEA all have obvious influence on the phase behavior of fatty acid soaps, because of the similar structure to the fatty acid salts, making some of the micellar phase structure transformed into the cubic liquid crystal and hexagonal liquid crystal phase structure, soaps with IPM or Cetiol CC had a large proportion area with a cubic liquid crstal and hexagonal liquid crystal phase, and soaps with Cetiol HE displayed the difference phase behavior were a small area of micellar and lamellar phase, and a small area of cubic liquid crystal phase and hexagonal liquid crystal phase. And the emulsifier stearate glyceride or stearate sucrose both made the area of cubic and hexagonal phase smaller by transforming to micellar phase. A single addition had different influence on the steady and other rheological properties. Glycerin, IPM and stearate glyceride made zero shear viscosity and shear viscosity of soap system increased, enhanced the shear thinning properties, and enhanced the system deformation ability, the thixotropic structure of the system was more stable at the same time.