44 Constitutive analysis of the nonlinear shear rheology of beta-glucan/amylodextrin solution blends.

C. J. Carriere (1) and G. E. Inglett (2). (1) Biomaterials Processing Research and (2) Biopolymer Research, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, 1815 N. University Street, Peoria, IL 61604.

The nonlinear solution rheological behavior of various beta-glucan/amylodextrin blends was investigated. The rheological properties of the solutions were investigated using thixotropic loop, small- amplitude oscillatory shear, and steady-state shear experiments. The solutions were found to exhibit an unexpected region of shear-thickening behavior with a critical shear rate of 50 1/s. Startup of steady-state shear experiments, conducted above the critical shear rate for shear thickening, exhibited multiple nonlinear stress-overshoot behavior. The presentation will discuss the findings and compare the experimental results to the predictions of a strain-separable BKZ-type integral constitutive model.