HEAT ACTIVATION OF HIGH MOLECULAR WEIGHT SODIUM POLYSTRYRENE SULFONATE

High molecular weight sodium polystyrene sulfonate is used in heat sensitive cosmetic products such as mousses and hair conditioners. When heat is applied to such solutions they acquire a permanent elastic structure that can be quantified by measuring the viscoelasticity.

A 30% polymer solution in an aqueous base was measured in oscillatory flow at 2 Hz in a 1 mm diameter tube. As shown above, the viscosity decreases with increasing temperature but then acquires higher values upon cooling. At the initial low temperature the solution exhibited no measurable elasticity; with increasing temperature it developed a substantial elasticity that remained after cooling to room temperature. This permanent change in elasticity is due to heat-induced irreversible changes in the structure of the sodium polystyrene sulfonate solution.

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