Creep and stress-rupture of Nafion (R) membranes under controlled environment
Abbreviated Journal Title
Nafion (R); Creep; Stress-rupture; Time-dependent failure; Fuel cell; Time-temperature-hydration parameter; POLYMER ELECTROLYTE MEMBRANE; FUEL-CELL MEMBRANES; MECHANICAL-PROPERTIES; WATER-UPTAKE; TEMPERATURE; TRANSPORT; HYDRATION; HUMIDITY; IONOMERS; BEHAVIOR; Materials Science, Multidisciplinary; Mechanics
Nafion(R) as a polymer shows time-dependent behavior including creep and relaxation. Application of this material in automotive fuel cells and targeted lifetimes require consideration of time-dependent failure of Nafion(R) in fuel cell design. In this work, creep tests for Nafion(R) were conducted in a controlled environment at different hydrations and temperatures. Stress-rupture curves for Nafion(R) were obtained for different hydrations (RH = 5%, 50% and 90%) at room temperature and also for two different temperatures (25 degrees C & 80 degrees C) at 50% relative humidity. Time-dependent failure was observed for all these conditions regardless of temperature and hydration level (state of water in Nafion(R)). Ionic forces created by cross linkings (by introducing water to membrane) do not seem to prevent disentanglements of the chains since there is no change in rate of time-dependent failure results. A time-hydration/temperature equivalence method (Sherby-Dorn) is suggested as a method to use short-term test data to estimate rupture times for other conditions. (C) 2010 Elsevier Ltd. All rights reserved.
Mechanics of Materials
"Creep and stress-rupture of Nafion (R) membranes under controlled environment" (2010). Faculty Bibliography 2010s. 812.