Cation exchange membranes by pre-irradiation grafting of styrene into FEP films. II. Properties of copolymer membranes

Gupta, Bhuvanesh; Büchi, Félix N.; Staub, Markus; Grman, D.; Scherer, Günther G.

doi:10.1002/(sici)1099-0518(19960730)34:10<1873::aid-pola4>3.0.co;2-q

Cited by 56 publications

(14 citation statements)

References 5 publications

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“…[18] wet and m dry are the weight of the membrane before and after swelling. We found earlier that the relationship between water uptake and graft level is quadratic, [35,36] while the dependence on the crosslink level is hyperbolic. [16,18] Using the simple mass model outlined above and applying these findings, we can write an empirical formula quantifying water uptake…”

Section: Discussion Of Proton Conductivity and Water Uptakesupporting

confidence: 78%

Correlation between Morphology, Water Uptake, and Proton Conductivity in Radiation‐Grafted Proton‐Exchange Membranes

Balog

Gasser

Mortensen

et al. 2010

Macro Chemistry & Physics

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An SANS investigation of hydrated proton exchange membranes is presented. Our membranes were synthesized by radiation‐induced grafting of ETFE with styrene in the presence of a crosslinker, followed by sulfonation of the styrene. The contrast variation method was used to understand the relationship between morphology, water uptake, and proton conductivity. The membranes are separated into two phases. The amorphous phase hosts the water and swells upon hydration, swelling being inversely proportional to the degree of crosslinking. Hydration and proton conductivity exhibit linear dependence on swelling. Proton conductivity and volumetric fraction of water are related by a power law, indicating a percolated network of finely dispersed aqueous pores in the hydrophilic domains.magnified image

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Section: Discussion Of Proton Conductivity and Water Uptakesupporting

confidence: 78%

Correlation between Morphology, Water Uptake, and Proton Conductivity in Radiation‐Grafted Proton‐Exchange Membranes

Balog

Gasser

Mortensen

et al. 2010

Macro Chemistry & Physics

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“…This means that the grafting of styrene sulfonic acid into the ECTFE skeleton was successful. Similar grafting and sulfonation protocol for polystyrene grafted films was reported …”

Section: Resultsmentioning

confidence: 68%

Styrene grafted ethylene chlorotrifluoroethylene (ECTFE‐g‐PSSA) protonic membranes: Preparation, characterization, and transport mechanism

Abdel-Hamed

2017

Polymers for Advanced Techs

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The main goal of the present work is the development of partially fluorinated, low-cost proton exchange membranes. The styrene grafted onto commercial ethylene chlorotrifluoroethylene (ECTFE) membranes using solution grafting technique, and after that the membranes were sulfonated. Diluting styrene on ECTFE with a solvent mixture of methanol plus methylene chloride (1:1) was highly effective in promoting the grafting reaction as indicated by the increase in the degree of grafting (DG) to 21.3% compared to other solvents. The DG in ECTFE membranes increased with an increase in the monomer concentration up to 60% and then declined. Fourier transform infrared spectroscopic analysis confirmed grafting and sulfonation onto ECTFE films.The maximum value of proton conductivity for ECTFE-g-PSSA film with DG = 21.3% was observed to be 141 mS cm, which is also higher than those of Nafion 212 membrane. Furthermore, the activation energy of ECTFE-g-PSSA membranes was obtained ranging from 8.27 to 9.726 kJ mol −1 . So both proton transport mechanisms (hopping and vehicle) have been commonly accepted. The mobility of the charge carriers calculated from proton conductivity data has robust dependence on the grafting yield and temperature. Moreover, the tensile strength and elongation at break ratio decreases with the increase in DG. The water and methanol uptakes increase up to 0.97% and 30%, respectively, for the highest DG value. Finally, the ECTFE-g-PSSA has lower cost and higher conductivity they could be better used instead of Nafion in direct methanol fuel cells. From the principle of fuel cells, the membrane has to have a good proton conductor, high dielectric constant, low methanol and gas permeability, high chemical balance, and exact mechanical properties.Because of these requirements, only a few membrane sorts are suitable for technical packages. The typically used membrane is Nafion, advanced with the aid of DuPont. Nafion has the greatest interest because of its high proton conductivity with chemical and mechanical stabilities at moderate temperature (<90°C). Despite this, Nafion ® membranes have some disadvantages such as high cost, difficulty in synthesis, and impracticable use at temperatures above 90°C where the membrane would be dry. 4,11 In addition, the high permeability of methanol through Nafion membrane (methanol crossover) leads to unaccepted low cell performance. 4 All these drawbacks combined to limit their commercial application especially in DMFC. Currently, there is much ongoing research for developing membranes with improved The membranes applicability in DMFCs was studied by measuring water and methanol uptakes, tensile strength, and ion exchange capacity (IEC). Measurements of the proton conductivity and mobility of protons at different temperatures were also included. | EXPERIMENTALThe ECTFE film of 80 μm thickness purchased from CS Hyde Company, United States, was used as a polymer matrix. It was washed with methanol and then dried in a vacuum oven at 70°C for 1 hour. The different parameters a...

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“…The former can be prepared either by direct grafting of acrylic monomers like acrylic [40][41][42][43][44], methacrylic acids [45][46][47][48][49] and their mixtures with acrylonitrile [50,51] and vinylacetate [52] or by grafting of epoxy acrylate monomers, such as glycidyl acrylate or glycidyl methacrylate onto polymer films followed by the conversion of the epoxy group into carboxylic group, such as iminodiacetate groups which were obtained by post-grafting ring opening reaction [53]. Strongly acidic membranes are commonly prepared by grafting of styrene onto polymer films and the resulted graft copolymer films are subsequently sulfonated [54][55][56][57][58][59][60][61].…”

Section: Homogeneous Ion Exchange Membranesmentioning

confidence: 99%

Ion exchange membranes: State of their development and perspective

2005

Journal of Membrane Science

1,205

497

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Cation exchange membranes by pre-irradiation grafting of styrene into FEP films. II. Properties of copolymer membranes

Cited by 56 publications

References 5 publications

Correlation between Morphology, Water Uptake, and Proton Conductivity in Radiation‐Grafted Proton‐Exchange Membranes

Correlation between Morphology, Water Uptake, and Proton Conductivity in Radiation‐Grafted Proton‐Exchange Membranes

Styrene grafted ethylene chlorotrifluoroethylene (ECTFE‐g‐PSSA) protonic membranes: Preparation, characterization, and transport mechanism

Ion exchange membranes: State of their development and perspective

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