Origin of Toughness in Dispersion-Cast Nafion Membranes [electronic resource].
- Washington, D.C. : United States. Office of the Assistant Secretary of Energy Efficiency and Renewable Energy, 2015.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 2,161-2,172 : digital, PDF file
- Additional Creators:
- Los Alamos National Laboratory, United States. Office of the Assistant Secretary of Energy Efficiency and Renewable Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- In this study, the gelation behavior of Nafion dispersions was investigated using small-angle neutron scattering to better understand the mechanical toughness of dispersion-cast Nafion membranes. Three types of gelation were observed, depending on dispersing fluids: (i) homogeneous, thermally reversible gelation that was present in most aprotic polar dispersing fluids; (ii) inhomogeneous, thermally irreversible gelation as films, found in alcohols; and (iii) inhomogeneous, thermally irreversible gelation which precipitates in water/monohydric alcohol mixtures. The mechanical toughness of dispersion-cast Nafion membranes depends on the dispersing fluid, varying by more than 4 orders of magnitude. Excellent correlation between the critical gelation concentration and mechanical toughness was demonstrated with the Nafion membranes cast at 140 °C. Additional thermal effects among Nafion membranes cast at 190 °C were qualitatively related to the boiling point of dispersing fluids. Little correlation between mechanical toughness and percent crystalline area of Nafion was observed, suggesting that the origin of mechanical toughness of dispersion-cast Nafion membranes is due to chain entanglements rather than crystallinity. Finally, the correlation between critical gelation concentration and mechanical toughness is a new way of predicting mechanical behavior in dispersion-cast polymer systems in which both polymer-dispersing fluid and polymer–polymer interactions play a significant role in the formation of polymer chain entanglements.
- Report Numbers:
- E 1.99:la-ur--14-29620
- Published through SciTech Connect.
Macromolecules 48 7 ISSN 0024-9297 AM
Yu Seung Kim; Cynthia F. Welch; Rex Paul Hjelm; Nathan Harris Mack; Andrea Labouriau; E. Bruce Orler.
- Funding Information:
View MARC record | catkey: 24045151