Viscometric behaviour of hydrophobically modified poly(sodium acrylate)

Summary Hydrophobically associating poly(acrylic acid) was obtained by reaction of a small amount of octadecylamine on the carboxyl groups of the polymer. In pure water, this modified polymer exhibits a very high thickening power. By increasing the ionic strength of the aqueous solution a strong viscosity increase can be obtained instead of the decrease classically observed with polyelectrolytes. For instance, in 1% NaCl the modified poly(sodium acrylate) is of several orders of magnitude more viscous than the precursor polymer.