Abstract
The concentration effect
of Xanthan gum (XG) solutions (1.0, 1.5, 2.0, 2.5% w/v) on the rheological flow
parameters are examined using stress controlled rheometer and gravity driven
flow set-up measurement at 25°C. Concentrated XG solutions has yielding behavior
obtained by fitting results through Herschel-Bulkley (HB) model with highest
regression coefficient R2 = 0.995 and R2 = 0.993
respectively by rheometer and set-up measurement. The results agreed well each
other from these measurements. Increasing the concentration of XG solutions
promote dynamic and static yield stresses due to increase of entanglement
structure density of XG solutions. Also, the magnitudes of consistency index, K, have
increasing trend with XG concentration as a result of increasing entanglement
density of XG structure. Static yield stress values are much closely dynamic
stress values getting from under gravity dynamic flow indicating that supplies
undisturbed moleculer structure of XG due to nature of creeping flow.