Online Viscometric Monitoring of Ultrasonic Sodium Poly (Styrene Sulfonate) Scission

Abstract

Ultrasonic chain scission (degradation) of a polyelectrolyte, sodium poly(styrene sulfonate) is investigated in saline solutions by online continuous viscometric monitoring. Ultrasound intensity and the polymer concentration are kept constant while the solvent quality is varied by varying the salt concentration between 0.68 and 7.65 mM. The scission rate is found to depend strongly on the solvent quality. As the salt concentration is increased, hydrodynamic volume of the polymer is decreased. This effect is reflected in the scission rate which also shows a steep decrease. During sonication, the molecular weight approaches a limit value, beyond which no degradation takes place. This limit molecular weight, is observed to be relatively insensitive to salt concentration.

Keywords:

• Scission
• polystyrene sulfonate
• viscosity
• sonochemistry
• online monitoring

Acknowledgments

This work was supported in part by ITU-BAP unit. The donation of the peristaltic pump by Pakmaya is acknowledged.