Paper Number
PO120 

Session
Poster Session

Title
Viscosity of an industrial, engineered polysaccharide slurry

Presentation Date and Time
October 23, 2019 (Wednesday) 6:30

Track / Room
Poster Session / Ballroom C on 4th floor

Authors (Click on name to view author profile)

  1. Giacomin, Caroline E. (University of Delaware, Chemical and Biomolecular Engineering)
  2. Kim, Kyle (DuPont Biomaterials, Experimental Station)
  3. Wagner, Norman J. (University of Delaware, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Caroline E. Giacomin1, Kyle Kim2, and Norman J. Wagner1
1Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716; 2Experimental Station, DuPont Biomaterials, Wilmington, DE 19806

Speaker / Presenter 
Giacomin, Caroline E.

Text of Abstract
An industrial polysaccharide ((1?3)-α-D-glucan), produced from an enzymatic reaction of sucrose, is characterized in aqueous solution. This study focuses on the rheological behavior when dispersed in water with varied dispersion techniques, concentration, and polymer chain lengths. A rheological protocol is developed to yield accurate and reproducible rheological measurements. Concentrated slurries show a pronounced yielding behavior that is followed by a flowing sample that further shear thins at higher shear rates, while more dilute samples show gravitational settling. The slurry viscosity observed beyond the yield stress can be approximated with a Cross model and the required constants have been determined: An exponent value of 1.18 and a characteristic shear relaxation time of 0.077 s. These constants are found to vary systematically with degree of polymerization. High shear processing is shown to reduce the skeletal density of the polysaccharide and increase the yield stress at constant weight fraction. The high and low shear viscosities can be approximated by a modified Mooney equation and percolation-like scaling is observed for the yield stress. These model parameters are interpreted in terms of the structure of the polysaccharide in solution. The shear rheology of this engineered polysaccharide viscosity can therefore be fully modelled when processing technique and solids weight percentage are known.