Development of new ionomer blend membranes, their characterization, and their application in the perstractive separation of alkenes from alkene-alkane mixtures. I. Polymer modification, ionomer blend membrane preparation, and characterization

Kerres, Jochen; Zyl, Andre J. Van

doi:10.1002/(sici)1097-4628(19991010)74:2<428::aid-app26>3.0.co;2-o

Cited by 19 publications

(5 citation statements)

References 16 publications

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“…The transport properties of the two materials are typical for these classes of membrane materials, based on perfluorinated and hydrocarbon polymers. This is clear from a compilation of D σ , D H 2 O , and D H 2 O P data for a variety of membrane materials, including Dow membranes of different equivalent weights, 226,255,260 Nafion/SiO 2 composites 243,244,[304][305][306] (including unpublished data from the laboratory of one of the authors), cross-linked polyarylenes, [307][308][309][310][311][312][313][314][315] and sulfonated poly-(phenoxyphosphazenes) 301 (Figure 19). The data points all center around the curves for Nafion and S-PEK, indicating essentially universal transport behavior for the two classes of membrane materials (only for S-POP are the transport coefficients somewhat lower, suggesting a more reduced percolation in this particular material).…”

Section: Hydrated Acidic Polymersmentioning

confidence: 99%

“…318 The gas permeability is much . Transport coefficients of diverse membranes based on perfluorinated polymers (Dow 226,255,260 and Nafion/ silica composites 174,243,244,[304][305][306] ), polyarylenes (S-PEK/PSU blends, ionically cross-linked S-PEK/PBI), [307][308][309][310][311][312][313][314][315] and sulfonated poly(phenoxyphosphazene)s (S-POPs), 301 as a function of the water volume fraction X V . Lines represent data for Nafion and S-PEK (given for comparison); for data points, see Figure 14.…”

Section: Pbi−h 3 Po 4 Adductsmentioning

confidence: 99%

“…For DMFC applications (where the membrane is in contact with a liquid water/methanol mixture), this type of transport determines the crossover, which is only acceptably low for solvent volume fractions smaller than ∼20 vol % (see Figures 14 and 15). Consequently, recent attempts have been focused on strengthening the polymer, e.g., by cross-linking [307][308][309][310][311][312][313][314][315]321 or forming co-polymers of sulfonated arylenes and polyvinylidene difluoride (PVDF). 322 Initial fuel-cell tests are actually quite promising; 313 however, the brittleness of highly cross-linked polymers may cause mechanical failure of the membrane.…”

Section: Recent Approaches Toward New Proton-conducting Materials Formentioning

confidence: 99%

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Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Kreuer¹,

Paddison²,

Spohr³

et al. 2004

ChemInform

126

193

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Section: Hydrated Acidic Polymersmentioning

confidence: 99%

Section: Pbi−h 3 Po 4 Adductsmentioning

confidence: 99%

Section: Recent Approaches Toward New Proton-conducting Materials Formentioning

confidence: 99%

See 1 more Smart Citation

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Kreuer¹,

Paddison²,

Spohr³

et al. 2004

ChemInform

126

193

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“…Kerress group synthesized several different types of basic, sulfonated or sulfinated polymer, and developed blend concepts for the fuel cell ionomer membranes [107][108][109][110][111][112][113][114][115][116][117][118][119][120][121][122]. Different types of polyaryl blend membranes -that is, ionic, ionic-covalent, and covalent crosslinking -have been studied, and the results have shown that, in the case of ionic crosslinking, the ionic bonds have an unsatisfactory thermal stability which makes the use of such membranes questionable.…”

Section: Reinforced Composite Membranesmentioning

confidence: 99%

Polymer and Hybrid Materials: Electrochemistry and Applications

Xing

2009

Solid State Electrochemistry I

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Due to substantial practical interest in proton-exchange membrane fuel cells (PEMFCs) during the past few decades, significant improvements have been achieved in polymer and hybrid materials. Much of the research effort has centered on the development of composite membranes and new proton-conducting materials, aimed to improving their performance, durability, and cost. Attention has also been focused on new membranes operating under high-temperature/low-humidity conditions. This chapter presents a brief review on the motivation for novel proton-exchange membrane developments, together with details of recent progress and technology gaps.

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“…Polymer electrolyte membrane fuel cell (PEMFC) could offer high power density and efficiency with near-zero emission for various applications such as electric vehicles, potable electronics and residential power generation, etc (1)(2)(3). However, Nafion ® membrane must be well hydrated to obtain an optimum performance because its proton conduction relies on dissociation of protons from ion exchange group in the presence of water (4)(5)(6). PEMFC operating at high temperatures above 80 o C offers various advantages such as higher system efficiency, better water management and negligible catalyst poisoning by carbon monoxide (7-10).…”

Section: Introductionmentioning

confidence: 99%

Membranes with Phosphonic Acid Moieties for High Temperature PEMFC

Ghil

Rhee

2011

ECS Trans.

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Global warming expedites the development of zero emission vehicles and a lot of attention has been paid on polymer electrolyte membrane fuel cell (PEMFC). Recently special interest has been focused on PEMFC operating at high temperatures above 90 o C. The operation of PEMFCs at high temperatures and low relative humidity provides several advantages: 1) high system efficiency, 2) increased rates of reaction and diffusion, 3) better water management, and 4) low CO catalyst poisoning [1][2]. However, most commercialized membranes are based on sulfonic acid moieties and they rapidly lose conductivities at these conditions. This has been the main obstacle to the development of high temperature PEMFC [3][4].Phosphoric acid doped-polybenzimidazole (PBI) system has been well known because of high proton conductivity at high temperatures. Also they have almost zero electro-osmotic drag number compared with Nafion ® . However, phosphoric acid in PBI is washed out by water which was produced at the cathode side. It causes loss of conductivity with time in addition to such problems as corrosion of the systems and the refill of phosphoric acid [5][6].To solve these problems and to maintain the conductivities of membranes irrespective of operating conditions it is very important to keep the proton conductors inside proton channels of polymer electrolyte membranes. Therefore, we tried to chemically attach phosphoric acid at the side chains of polymers. This approach will ensure the high conductivities and long-term stability at elevated temperatures.We grafted phosphonic acid groups to Nafion ® by replacing the sulfonic acid groups with 3-aminopropyl triethoxy silane (APTES). The attached amino groups can be converted to phosphonic acid by reacting with phosphoric acid. APTES is a representative coupling agent and can also goes through sol-gel reactions under acidic conditions which would enhance the mechanical properties of the membranes at high temperatures. Nafion® was re-dissolved in dimethyl acetamide (DMAc) and mechanically mixed with desired amount of APTES. And the mixed solutions were cast on a teflon dish. To introduce the reaction between sulfonic acid and APTES, the cast membranes were boiled in aqueous formaldehyde solution, and then boiled in phosphoric acid solution. Figure 1 compares the proton conductivities of the grafted membranes from room temperature up to 110 o C. When the samples were fully humidified at temperatures less than 90 o C, all the grafted membranes showed surprisingly higher conductivities than Nafion ® . When the samples were not fully humidified above 90 o C, it was almost impossible to measure the conductivity of Nafion ® . However, the grafted samples showed very high conductivities, which were even higher than that of Nafion ® at RT. This result indicates that phosphonic acid groups could work as a proton conductors instead of sulfonic acid groups at elevated temperature.We also confirmed the chemical structures of the grafted membranes by FT-IR, 31 P-NMR, and 29Si-NMR. And we will also ...

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Development of new ionomer blend membranes, their characterization, and their application in the perstractive separation of alkenes from alkene-alkane mixtures. I. Polymer modification, ionomer blend membrane preparation, and characterization

Cited by 19 publications

References 16 publications

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Polymer and Hybrid Materials: Electrochemistry and Applications

Membranes with Phosphonic Acid Moieties for High Temperature PEMFC

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