Non-linear viscoelastic models for semi-flexible polysaccharide solution rheology over a broad range of concentrations

Abstract

The experimental linear viscoelastic and steady-state shear data over a broad concentration range of several aqueous semi-flexible polysaccharide solutions can be quantitatively predicted by the multimode Phan-Thien Tanner, Giesekus, and extended Pom-Pom non-linear viscoelastic models using a single set of parameters. Experimental data from an aqueous solution of the polysaccharide guar galactomannan (Mw=1.12×106 g/mol), aqueous phosphopolysaccharide “viilian” solution excreted by Lactococcus lactis subspecies cremoris SBT 0495 (Mw=2×106 g/mol), and aqueous Propionibacterium acidi-propionici polysaccharide solution (Mw≈106 g/mol) are taken from literature. A master curve can be constructed by shifting data from different concentrations over the horizontal and vertical axes. A simple model to describe the concentration dependence of the relaxation time and plateau modulus over the entire concentration range is presented. Transient shear viscosity data are quantitatively and first normal stress coefficient are qualitatively predicted for the guar galactomannan solution. Due to their proven performance in finite element simulations, these non-linear viscoelastic constitutive equations could help us to improve predictive modeling of time-dependent complex flow problems for polysaccharide solutions with variations in concentration and temperature in the spatial domain using only a single set of parameters. However, as a previous step, the performance of additional rheological experiments in simple flows, i.e., transient and steady-state extensional measurements, is recommended.