As most of the natural oils are used in cosmetics, especially in emulsions, these oils produce direct effects on the consistency and shelf life of the emulsions. In case of w/o emulsion, higher the viscosity of the oil, higher is the viscosity of emulsion. Other parameters of oil like spreadability, cloud point, pour point, saponification value, acid value, pH and specific gravity of oils also affect properties of emulsions. The purpose of this study was the characterization of different oils and their rheological properties. Eight different natural oils, namely olive, coconut, almond, castor, sesame, cotton seed, sunflower, and paraffin oils were used to study their rheology, viscosity, spreadability, cloud and pour points, saponification and acid values, pH and specific gravity. All the oils investigated were found to possess Newtonian behaviour with little deviation in olive and coconut oils. Castor oil possesses the maximum viscosity of 686.26 mPas.s among the other oils studied. Paraffin oil containing no fatty acids possesses the maximum spreadability. Castor oil has the maximum saponification value (187.02), while the paraffin oil has minimum value of 32.70. Olive oil has the maximum acid value of 1.361 among the oils investigated while paraffin oil has the minimum value of 0.224. The pH of castor oil is maximum (4.92), while that of cotton seed oil is minimum being 3.64. Paraffin oil has the maximum specific gravity value of 0.9999 while coconut oil has the minimum value of 0.9138.
AHMAD MAHMOOD ,NAVEED AKHTER ,QAZI ADNAN ,KALSOOM FARZANA ,MEHMOOD AHMAD ,