Paper Number
PS18 

Session
Polymers in Solution

Title
Extensional flow behavior of methylcellulose solutions containing fibrils

Presentation Date and Time
October 16, 2018 (Tuesday) 11:30

Track / Room
Track 4 / Post Oak

Authors (Click on name to view author profile)

1. Morozova, Svetlana (University of Minnesota, Department of Chemistry)
2. Schmidt, Peter W. (University of Minnesota, Department of Chemical Engineering and Materials Science)
3. Metaxas, Athena E. (University of Minnesota, Department of Chemical Engineering and Materials Science)
4. Bates, Frank S. (University of Minnesota, Department of Chemical Engineering and Materials Science)
5. Lodge, Timothy P. (University of Minnesota, Department of Chemical Engineering and Materials Science)
6. Dutcher, Cari S. (University of Minnesota, Mechanical Engineering)

Author and Affiliation Lines (in printed abstract book)
Svetlana Morozova¹, Peter W. Schmidt², Athena E. Metaxas², Frank S. Bates², Timothy P. Lodge², and Cari S. Dutcher^3
1Department of Chemistry, University of Minnesota, Minneapolis, MN; ²Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN; ³Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455

Speaker / Presenter 
Metaxas, Athena E.

Text of Abstract
Methylcellulose (MC), a methoxy-substituted cellulose ether, is used in a variety of food, pharmaceutical, construction, and consumer applications due to its solubility in water at low temperatures. In addition to its solubility at low temperatures, MC reversibly transitions to a turbid hydrogel upon heating or upon the addition of NaCl to the solution. The gelation phenomenon in aqueous MC solutions is due to the formation of a fibrillar network. While the small amplitude oscillatory and large amplitude oscillatory shear rheological behavior has been characterized for MC solutions, the extensional flow behavior has not been reported. Capillary breakup extensional rheometry (CaBER) was used to characterize aqueous MC solutions with 8 wt% NaCl and aqueous solutions without salt at room temperature. Without NaCl, the solutions only exhibit power law behavior whereas solutions with NaCl exhibit both power law and elastic deformation profiles. As MC concentration increases, both the extensional relaxation time and the apparent extensional viscosity increase. This behavior is attributed to the presence of fibrils in the MC solutions containing NaCl annealed at room temperature. The study of the extensional behavior of this already commercially relevant polymer enables new ways to process MC, such as fiber spinning and extrusion. Finally, ongoing work using microfluidic filament stretching will be presented for determining the extensional viscosity for MC systems.