Rheological investigations on the dispersions of sodium alginate and guar gum mixtures at different temperatures

Abstract

This article reports the rheological properties of the aqueous dispersions of sodium alginate, guar gum, and their blends measured by Brookfield rheometer at 298.15, 303.15, and 308.15K. The blend properties have been measured for five different compositions, in order to understand their compatibility in solution (at lower polymer concentrations, i.e., up to 0.8% (w/w)) as well as in the gel form (at higher polymer concentrations, i.e., up to 3% (w/w) where they can form gels). The solution miscibility of blends was confirmed by calculating the polymer–polymer interaction parameter using the Krigbaum and Wall equation. Rheological properties have been analyzed by using the equations of Bingham, Casson, Power-Law, and IPC Paste Analysis. Gibbs free energy of activation for enthalpy and entropy has also been calculated. Experimental and calculated results have been discussed in terms of the mixing characteristics of the polymers. The data presented here can be useful in pre-formulation studies to develop the controlled release devices for pesticides or drugs.

Keywords:

• Guar gum
• Rheology
• Sodium alginate
• Viscosity

Acknowledgments

Authors are thankful to GSFC Science Foundation (Dr. A. M. Dave for useful discussions) for supporting this research under Phase-II program sponsored through Dr. S. Rame Gowda Research Institute of Science and Technology, Dharwad.