Viscosity-temperature-concentration relationship for starch-DMSO-water solutions

The rheological behavior of starch-DMSO-water solutions was monitored using a cone-plate rheometer at different temperatures and concentrations. A sol vent ratio DMSO/water = 80/20 was used and viscosity was correlated with te mperature through the Arrhenius equation. The dilute to semidilute flow reg ime transition concentration, c* (which was independent of temperature), wa s characterized by a change in the value of apparent energy of activation. At c < c*, it was shown that the pre-exponential term in the Arrhenius equa tion was a function of concentration. Deviations from the predicted depende nce was also used to characterize change in the flow regime. The value of c *, obtained from the apparent energy of interaction and the pre-exponential term agreed with the one obtained from the usual plot of log eta(sp) vs. l og c. (C) 2000 Elsevier Science Ltd. All rights reserved.