Associative polyelectrolyte thickener with optimal rheological profile for versatile stabilizing properties

  • March 19, 2014
  • 2 mins of read time

Associative polyelectrolyte thickener with optimal rheological profile for versatile stabilizing properties

Emmanuelle Mérat, Alicia Roso, Céline Sauré, Cécile Taillebois
2017, NYSCC Rheology symposium

To come up to consumer expectations of efficacy and pleasant sensory profile, cosmetic Manufacturers need improved stabilizing performance versus oil and active ingredients. To discriminate the stabilizing properties of thickeners, rheology methods fit with the request by simulating the final use conditions, giving quantitative and precise assessment.The objective of this work is to evaluate in comparison the rheology behavior of synthetic hydrophobically-modified polyelectrolyte and natural polymers, in simple dilution situation as well as in more stressing conditions, with oil (cream gel formula) or electrolyte content (sodium chloride to simulate the effect of an active ingredient). The evaluations were performed with a cone-plate rheometer.

First, we evaluated the flow profile of aqueous gels depending on the electrolyte concentration. Surprisingly, hydrophobically-modified polyelectrolyte produced a high rate index, specifically in presence of sodium chloride, leading to a preserved consistency upon spreading.

Secondly, we determined the viscoelastic features of the aqueous gels. We demonstrated that the microstructure of the associative polymer contributes to a higher stability versus frequencies. Moreover, viscoelasticity is slightly affected by the addition of salt. In a cream-gel with salt, viscoelastic properties depend on the nature of the oil, but the network is still sufficient to stabilize the internal phase.

Finally, we found that the yield stress depends largely on the nature of the polymer and the presence of sodium chloride. The yield stress of the hydrophobically-modified polymer was confirmed at low concentration in accordance with the ability to suspend particles.

To conclude, rheology experiments help to have a better understanding of the polymer behavior, depending on its nature and on the product composition. It helps especially to predict the polymer resistance in the presence of destabilizing salt content. The hydrophobically-modified polymer demonstrated a distinct rheology profile with high structure resistance and versatile stabilizing properties in the various studied formulations.

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