Biaxial elastic–viscoplastic behavior of Nafion membranes

Silberstein, Meredith N.; Pillai, Priam V.; Boyce, Mary C.

doi:10.1016/j.polymer.2010.11.032

Cited by 64 publications

(35 citation statements)

References 20 publications

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“…A biaxial drawing process was shown to remove orientational anisotropy of Nafion . A biaxial study of the mechanical properties revealed similar features to uniaxial behavior of Nafion . Recently, we reported the shape memory effect for radiation grafted ion exchange membranes to reduce in‐plane swelling for this material …”

Section: Introductionmentioning

confidence: 86%

Reduced In-Plane Swelling of Nafion by a Biaxial Modification Process

Hink

Henkensmeier

Jang

et al. 2015

Macromol. Chem. Phys.

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A biaxial modifi cation process to reduce the in-plane swelling of perfl uorosulfonic acid polymers is demonstrated for Nafi on 212 membranes. The process is based on the one-way shape memory effect of the polymer, which can be installed by drying under constrained conditions and observed by water swelling. The through-plane/in-plane swelling ratio at 30 °C for treated Nafi on 212 increases from 1.4 to 5.8 (ex situ) and ≈25 (after humidity cycling in a fuel cell). Young modulus and tensile strength increase. X-ray diffraction analysis shows an increase of crystallinity. The infl uence on through-and in-plane proton conductivity is studied. Finally, fuel cell tests are presented. The results suggest that the process enhances the durability of fuel cell systems under changing humidity conditions.

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Section: Introductionmentioning

confidence: 86%

Reduced In-Plane Swelling of Nafion by a Biaxial Modification Process

Hink

Henkensmeier

Jang

et al. 2015

Macromol. Chem. Phys.

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“…The cyclic behavior (not shown) is qualitatively similar to the uniaxial cyclic behavior: there is a non-linear unloading and reloading with a reduced yield upon reloading. The cyclic behavior is also captured by the model [4]. We can see that the framework used to incorporate the uniaxial behavior into a threedimensional model is in fact capable of predicting the multiaxial deformation response of the membrane.…”

Section: Constitutive Model Reviewmentioning

confidence: 96%

“…Biaxial tests were conducted on the thin film multi-axial tensile machine developed in the Bio-Instrumentation lab at MIT modified from the design of Herrmann [4,5].…”

Section: Biaxial Tensionmentioning

confidence: 99%

“…Based on this data a constitutive model was created to describe the hygro-thermal elastic-viscoplastic stress-strain behavior of Nafion. The model was shown to capture the stress-strain behavior of Nafion over a wide range of uniaxial loadings histories [3] and later shown to accurately predict the stress-strain behavior of Nafion over a range of biaxial loading histories [4]. This paper explores the constrained swelling induced and hydration dependent mechanical response of the material and the model.…”

Section: Introductionmentioning

confidence: 99%

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Hygro-thermal mechanical behavior of Nafion during constrained swelling

Silberstein

Boyce

2011

Journal of Power Sources

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“…Park et al analyzed the hygrothermal stress state in a biaxially constrained membrane under transient temperature and humidity conditions [28]. Silberstein et al investigated the effects of uniaxial and biaxial loading on Nafion and proposed an elastic-viscoplastic stress model [29,30]. Solasi et al proposed a two-layer viscoplastic model for a constrained membrane that consists of an elastoplastic network in parallel with a viscoelastic network (Maxwell model) [22].…”

Section: Introductionmentioning

confidence: 99%

Linear Hygrothermal Viscoelastic Characterization of Nafion NRE 211 Proton Exchange Membrane

et al. 2012

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The tensile relaxation modulus of a commercially available proton exchange membrane, Nafion® NRE 211, was obtained over a range of humidity levels and temperatures using a commercial dynamic mechanical analyzer (DMA). Hygral stress relaxation master curves were first constructed, followed by a hygrothermal master curve using the time temperature moisture superposition principle. The hygrothermal master curve was fitted using a 10‐term Prony series and validated using longer term stress relaxation tests. To validate the results from the stress relaxation experiments, short and long‐term creep compliance was converted into stress relaxation modulus using a well‐known viscoelastic conversion formula, and compared with the relaxation modulus obtained under identical conditions. Good agreement was found between the two datasets. It was evident that relaxation data at 2% RH at the test temperatures was not superposable with the master curves obtained at higher relative humidity (10% < RH < 90%) at the temperature range 70 °C < T < 90 °C. It was observed that the longer term relaxation modulus under humid conditions matched well with the hygrothermal master curve; however, the longer term relaxation modulus under dry conditions was significantly higher than the relaxation master curve obtained under dry conditions, raising the possibility of a physical aging process in the ionomer and/or irreversible morphological changes in the membrane under dry conditions.

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Biaxial elastic–viscoplastic behavior of Nafion membranes

Cited by 64 publications

References 20 publications

Reduced In-Plane Swelling of Nafion by a Biaxial Modification Process

Reduced In-Plane Swelling of Nafion by a Biaxial Modification Process

Hygro-thermal mechanical behavior of Nafion during constrained swelling

Linear Hygrothermal Viscoelastic Characterization of Nafion NRE 211 Proton Exchange Membrane

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