SIMPLEX-CENTROID DESIGN WITH SURFACTANT MIXTURE

The effects of the relative proportions? of three anionic surfactants on the properties of shampoo formulas based on prethickened and opacif ied mixtures were ?analysed with a Scheffe simplex-centroid design. Th e design was used to develop models for two responses : wetting power and foam height in the presence of soil. The authors developed and ver ified models that could predict the response contours for the system w ith a correlation coefficient of over 95% for each of the responses st udied. These models allow one to determine, in the ternary diagram, th e optimal zone of compositions :fora mild shampoo?, low wetting power associated with a high foaming height is needed.