Proton exchange membranes prepared by radiation grafting of styrene/divinylbenzene onto poly(ethylene-alt-tetrafluoroethylene) for low temperature fuel cells

Gubler, Lorenz; Prost, N.; Gürsel, Selmiye Alkan; Scherer, Günther G.

doi:10.1016/j.ssi.2005.09.045

Cited by 118 publications

(104 citation statements)

References 33 publications

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“…Nasef et al [29] and Gubler et al [30] outlined in detail the problems encountered during proton conduction measurements for the grafted PEMs, in which grafting was conducted on polymer film substrates. It was described that at low DG, the polystyrene grafts are located near the surface of the film while the membrane interior remains ungrafted and subsequently exerts a high local resistance to proton conduction due to inhomogeneous distribution of ion exchange sites over the area of the membrane.…”

Section: Proton Conductivity/methanol Permeabilitymentioning

confidence: 99%

Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

Sherazi

Guiver

Kingston

et al. 2010

Journal of Power Sources

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Styrene was grafted onto ultrahigh molecular weight polyethylene powder (UHMWPE) by gamma irradiation using a 60 Co source. Compression moulded films of selected pre-irradiated styrene-grafted ultrahigh molecular weight polyethylene (UHMWPE-g-PS) were post-sulfonated to the sulfonic acid derivative (UHMWPE-g-PSSA) for use as proton exchange membranes (PEMs). The sulfonation was confirmed by Xray photoelectron spectroscopy (XPS). The melting and flow properties of UHMWPE and UHMWPE-g-PS are conducive to forming homogeneous pore-free membranes. Both the ion conductivity and methanol permeability coefficient increased with degree of grafting, but the grafted membranes showed comparable or higher ion conductivity and lower methanol permeability than Nafion ® 117 membrane. One UHMWPE-g-PS membrane was fabricated into a membrane-electrode assembly (MEA) and tested as a single cell direct methanol fuel cell (DMFC). Low membrane cost and acceptable fuel cell performance indicate that UHMWPE-g-PSSA membranes could offer an alternative approach to perfluorosulfonic acidtype membranes for DMFC.Crown

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Section: Proton Conductivity/methanol Permeabilitymentioning

confidence: 99%

Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

Sherazi

Guiver

Kingston

et al. 2010

Journal of Power Sources

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“…This gradually increased with higher DG, reaching 0.29 S/cm at 90 • C for the highest DG value of 58%. The conductivity data show a regularly increasing trend, contrary to other grafted membranes where some degree of experimental scatter was observed [38]. The regularly increasing trend is explained by a greater homogeneity of the DG on the surface as well as throughout the interior of the membrane, since grafting was performed on powder substrate prior to film formation and the styrene has better access to the radiation-activated polymer.…”

Section: Discussionmentioning

confidence: 66%

“…In many previous studies, a wide variation in the DS was observed when film (rather than powder in the present study) was used as substrate for the grafting reaction and subsequently sulfonated [37,38]. The origin of this variation is due to the local differences in graft level due to inhomogeneities over the area of the membrane.…”

Section: Ion Exchange Capacity/degree Of Substitutionmentioning

confidence: 63%

“…It is also described in the literature [16,37,38] that as the DG approaches ∼20%, more grafts are distributed near the membrane interior, resulting in a diminution of the local resistance. Consequently, the proton conductivity increases and an additional increase in the DG does not bring about considerable increases in the conductivity because of the achievement of a possibly more homogenous distribution of the sulfonated polystyrene grafts within the membrane.…”

Section: Proton Conductivitiesmentioning

confidence: 90%

“…Nasef et al [37] and Gubler et al [38] outlined in detail the problems encountered during proton conduction measurements for the grafted PEMs, in which grafting was conducted on polymer film substrates. It was described that at low DG, the polystyrene grafts are located near the surface of the film while the membrane interior remains ungrafted and subsequently exerts a high local resistance to proton conduction due to inhomogeneous distribution of ion exchange sites over the area of the membrane.…”

Section: Proton Conductivitiesmentioning

confidence: 99%

See 2 more Smart Citations

Radiation-induced grafting of styrene onto ultra-high molecular weight polyethylene powder for polymer electrolyte fuel cell application

Sherazi

Ahmad

Kashmiri

et al. 2009

Journal of Membrane Science

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Radiation‐grafted proton conducting membranes

Gubler

Scherer

2010

Handbook of Fuel Cells

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Proton exchange membranes have to fulfil two main functionalities in the membrane electrode assembly (MEA) of a polymer electrolyte fuel cell (PEFC): (i) transport protons from the anode to cathode and (ii) separate anode and cathode electrodes and reactants. Radiation grafting offers a versatile method to introduce proton conductivity into a preformed base polymer film. Base polymers and graft monomers can be selected from a wide range of commercially available commodity products. In this article, synthetic routes and parameters to control membrane composition and morphology are discussed. The choice of a base film and monomers, in particular crosslinkers, has large influence on the resulting membrane properties and fuel cell performance. To fulfil and sustain the separator functionality, dimensional stability and mechanical properties are of high importance. The development of materials for fuel cells and the need to further the understanding of limiting processes and degradation phenomena require a well‐assorted toolbox for ex situ and in situ characterization of properties and performance. Implementation of accelerated test methods and post mortem analysis on a local scale have helped in enhancing the throughput of samples and gain further insight into prevailing degradation mechanisms.

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Proton exchange membranes prepared by radiation grafting of styrene/divinylbenzene onto poly(ethylene-alt-tetrafluoroethylene) for low temperature fuel cells

Cited by 118 publications

References 33 publications

Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

Radiation-grafted membranes based on polyethylene for direct methanol fuel cells

Radiation-induced grafting of styrene onto ultra-high molecular weight polyethylene powder for polymer electrolyte fuel cell application

Radiation‐grafted proton conducting membranes

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