Application of a factorial design to the study of specific parameters of a Carbopol ETD 2020 gel. Part I. Viscoelastic parameters.

This work studies the application of a 2(3) factorial design to a cosmetic gel with the aim of simplifying the analysis of the influence of the concentration of Carbopol ETD 2020 (cb), of ethanol (et) and of glycerin (gl) on the viscoelastic parameters: equilibrium modulus (Gn), critical molecular weight (Mc), degree of structuring (logG'/lognu) and viscous modulus (G"). We have obtained high linear polynomial correlations among the components and the response factors determined. The results obtained evidence the usefulness of this type of technique in detecting interactions among the components that would be difficult to foresee otherwise. Mc, logG'/lognu and G" depend on the interaction cb-et. Gn depends on the interaction of cb-et-gl. That is, an increase in gl can increase or decrease the elasticity (Gn) of the gels, depending on the concentrations of cb and et.