The self-bodying action of the mixed emulsifier cetrimide-cetostearyl alcohol.

Abstract

Liquid paraffin emulsions stabilized by the mixed emulsifier cetrimide/cetostearyl alcohol have been examined by microscopy, particle size analysis, continuous shear rheometry, and creep. The disperse phase of each emulsion was aggregated, and many of the nonspherical particles contained crystals of cetostearyl alcohol. The rheological properties of each emulsion were not related directly to the particle size distribution but to a gel network present in the continuous phase. This gel network was shown to be similar to that formed by dispersing cetrimide and cetostearyl alcohol in water so as to form a ternary system. All the systems showed complex flow properties in continuous shear experiments, e.g., hysteresis loops denoting irreversible shear breakdown. Additional complex flow properties, i.e., spur points and dilatancy, apparent in emulsions containing greater than 5% mixed emulsifier, were related to the structure in the continuous phase. In creep, mechanical models of three Voigt Units in series with a Maxwell Unit were deduced. In ternary systems and emulsions, the compliances decreased and the viscosities increased as the cetrimide/cetostearyl alcohol concetration increased. The creep parameters indicated that emulsions containing greater than 5% mixed emulsifier increased in consistency on aging, owing to the orientation of gel structure in the continuous phase.