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Robert F Savinell - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane fuel cell applications ii Methanol uptake and Methanol Permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct Methanol fuel cell applications. Methanol uptake and Methanol Permeability were measured in liquid and vapor phase as a function of temperature, Methanol vapor activity, and silica content. Decreased Methanol uptake from liquid Methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %. The hybrid membrane with silica content of ≈20 wt % showed a significant lower Methanol permeation rate when immersed in a liquid Methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower Methanol vapor Permeability was seen only in the hybrid membrane with silica content of ≈20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct Methanol fuel cells operating either on liquid or vapor-feed fuels. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane fuel cell applications ii Methanol uptake and Methanol Permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct Methanol fuel cell applications. Methanol uptake and Methanol Permeability were measured in liquid and vapor phase as a function of temperature, Methanol vapor activity, and silica content. Decreased Methanol uptake from liquid Methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %, The hybrid membrane with silica content of 20 wt % showed a significant lower Methanol permeation rate when immersed in a liquid Methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower Methanol vapor Permeability was seen only in the hybrid membrane with silica content of 20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct Methanol fuel cells operating either on liquid or vapor-feed fuels.
Ahmad Fauzi Ismail - One of the best experts on this subject based on the ideXlab platform.
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Thermal Stability and Water Content Study of Void-Free Electrospun SPEEK/Cloisite Membrane for Direct Methanol Fuel Cell Application
Polymers, 2018Co-Authors: Nuha Awang, Juhana Jaafar, Ahmad Fauzi IsmailAbstract:Void-free electrospun SPEEK/Cloisite15A® densed (SP/e-spunCL) membranes are prepared. Different loadings of Cloisite15A® (0.10, 0.15, 0.20, 0.25 and 0.30 wt %) are incorporated into electrospun fibers. The physico-chemical characteristics (Methanol Permeability, water uptake and proton conductivity) of the membranes are observed. Thermal stability of all membranes is observed using Thermal Gravimetry Analysis (TGA). The thrree stages of degradation range between 163.1 and 613.1 °C. Differential Scanning Calorimetry (DSC) is used to study the wettability of the membranes. SP/e-spunCL15 shows the lowest freezing bound water of 15.27%, which contributed to the lowest Methanol Permeability. The non-freezing bound water that proportionally increased with proton conductivity of SP/e-spunCL15 membrane is the highest, 10.60%. It is suggested that the electrospinning as the fabricating method has successfully exfoliated the Cloisite in the membrane surface structure, contributing to the decrease of Methanol Permeability, while the retained water has led to the enhancement of proton conductivity. This new fabrication method of SP/e-spunCL membrane is said to be a desirable polymer electrolyte membrane for future application in direct Methanol fuel cell field.
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thermal stability and water content study of void free electrospun speek cloisite membrane for direct Methanol fuel cell application
Polymers, 2018Co-Authors: Nuha Awang, Juhana Jaafar, Ahmad Fauzi IsmailAbstract:Void-free electrospun SPEEK/Cloisite15A® densed (SP/e-spunCL) membranes are prepared. Different loadings of Cloisite15A® (0.10, 0.15, 0.20, 0.25 and 0.30 wt %) are incorporated into electrospun fibers. The physico-chemical characteristics (Methanol Permeability, water uptake and proton conductivity) of the membranes are observed. Thermal stability of all membranes is observed using Thermal Gravimetry Analysis (TGA). The thrree stages of degradation range between 163.1 and 613.1 °C. Differential Scanning Calorimetry (DSC) is used to study the wettability of the membranes. SP/e-spunCL15 shows the lowest freezing bound water of 15.27%, which contributed to the lowest Methanol Permeability. The non-freezing bound water that proportionally increased with proton conductivity of SP/e-spunCL15 membrane is the highest, 10.60%. It is suggested that the electrospinning as the fabricating method has successfully exfoliated the Cloisite in the membrane surface structure, contributing to the decrease of Methanol Permeability, while the retained water has led to the enhancement of proton conductivity. This new fabrication method of SP/e-spunCL membrane is said to be a desirable polymer electrolyte membrane for future application in direct Methanol fuel cell field.
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transport properties and direct Methanol fuel cell performance of sulfonated poly ether ether ketone cloisite triaminopyrimidine nanocomposite polymer electrolyte membrane at moderate temperature
Separation and Purification Technology, 2013Co-Authors: Hamid Ilbeygi, Juhana Jaafar, Ahmad Fauzi Ismail, Alireza Mayahi, Mohamed Mahmoud Nasef, Esmat JalalvandiAbstract:Abstract This paper presents an investigation on the transport properties represented by proton conductivity and Methanol Permeability of the sulfonated poly (ether ether ketone) (SPEEK) nanocomposite membranes filled with Cloisite 15A® clay (CC) compatibilized with 2,4,6-triaminopyrimidine (TAP) under various temperatures. The membranes were prepared through sulfonation of PEEK, followed by the formation of polymer composite dope by using solution intercalation and membrane casting. The composite membrane properties were evaluated using H NMR, field emission scanning electron microscope (FESEM), AC impedance spectroscopy and Methanol diffusion test cell. The Methanol Permeability increased with the rise in temperature and reached a value of 0.52 × 10−6 cm2 s−1 at 60 °C; which coincided with proton conductivity of 47.10 mS cm−1 and a Methanol selectivity of 9.1 × 104 S s cm−3. The Methanol Permeability was found to be lower than that of Nafion® 117 membrane at all investigated temperatures. The nanocomposite SPEEK membranes were tested in a direct Methanol fuel cell (DMFC), and the membrane denoted as SPEEK/CC2.5/TAP5.0 achieved a power density of 54.93 mW cm−2 at 60 °C. The results of this study suggest that SPEEK/CC2.5/TAP5.0 nanocomposite membrane has a potential to be an alternative polymer electrolyte for DMFC application.
Naoto Miyake - One of the best experts on this subject based on the ideXlab platform.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane fuel cell applications ii Methanol uptake and Methanol Permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct Methanol fuel cell applications. Methanol uptake and Methanol Permeability were measured in liquid and vapor phase as a function of temperature, Methanol vapor activity, and silica content. Decreased Methanol uptake from liquid Methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %. The hybrid membrane with silica content of ≈20 wt % showed a significant lower Methanol permeation rate when immersed in a liquid Methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower Methanol vapor Permeability was seen only in the hybrid membrane with silica content of ≈20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct Methanol fuel cells operating either on liquid or vapor-feed fuels. © 2001 The Electrochemical Society. All rights reserved.
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evaluation of a sol gel derived nafion silica hybrid membrane for polymer electrolyte membrane fuel cell applications ii Methanol uptake and Methanol Permeability
Journal of The Electrochemical Society, 2001Co-Authors: Naoto Miyake, Jesse S Wainright, Robert F SavinellAbstract:Sol-gel derived Nafion/silica hybrid membranes were investigated as a potential polymer electrolyte for direct Methanol fuel cell applications. Methanol uptake and Methanol Permeability were measured in liquid and vapor phase as a function of temperature, Methanol vapor activity, and silica content. Decreased Methanol uptake from liquid Methanol was observed in the hybrid membranes with silica contents of 10 and 21 wt %, The hybrid membrane with silica content of 20 wt % showed a significant lower Methanol permeation rate when immersed in a liquid Methanol-water mixture at 25 and 80°C. Methanol uptake from the vapor phase by the hybrid membranes appears similar to that of unmodified Nafion. Methanol diffusion coefficients, as determined from sorption experiments, were slightly lower in the hybrid membranes than in unmodified Nafion. However, in direct permeation experiments, significantly lower Methanol vapor Permeability was seen only in the hybrid membrane with silica content of 20 wt %. Based on these results, Nafion/silica hybrid membranes with high silica content have potential as electrolytes for direct Methanol fuel cells operating either on liquid or vapor-feed fuels.
Dukjoon Kim - One of the best experts on this subject based on the ideXlab platform.
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pore filling polymer electrolyte membrane based on poly arylene ether ketone for enhanced dimensional stability and reduced Methanol Permeability
Journal of Membrane Science, 2017Co-Authors: Anh Le Mong, Sungwoo Yang, Dukjoon KimAbstract:Abstract We synthesized sulfonated poly (arylene ether ketone) (SPAEK) with an 80% degree of sulfonation (DS) from 4,4-bis(4-hydroxyphenyl) valeic acid and 4,4-difluorobenzophenone. A series of pore-filling membranes were prepared by filling SPAEK into the plasma-treated porous poly (arylene ether ketone) membrane (PAEK) with various pore sizes and porosity. The porous PAEK membrane were obtained by removing the phase separated polylatide (PLA) blocks from the self-arranged PAEK-b-PLA copolymer membranes. The results from synthesis of SPAEK and porous PAEK was characterized using 1 H NMR and FTIR, and the morphology of the SPAEK-filled porous PAEK membrane was investigated using SEM and EDX-SEM. The essential properties of pore-filled membranes (e.g., ionic exchange capacity (IEC), proton conductivity, thermal and mechanical stability, and Methanol Permeability), were examined and collated to those of pristine SPAEK and commercial Nafion 117 membranes. The pore-filled membranes prepared in this study showed enhanced thermal and dimensional stability and reduced Methanol Permeability compared with the pristine SPAEK and Nafion 117 membranes. The pore-filled membrane with a pore diameter of 50 nm showed the highest proton conductivity among all pore-filled membranes and lower Methanol Permeability than commercial membrane Nafion 117.
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cross linked poly arylene ether ketone membrane bearing pendant sulfanilic acid for high proton conductivity and low water uptake
Solid State Ionics, 2012Co-Authors: Jieun Kim, Dukjoon KimAbstract:Abstract Hydrolytically stable, proton conductive membranes were prepared from cross-linked poly(arylene ether ketone). The reduction of proton conduction caused by cross-linking was compensated for using a proton conductive cross-linker, 2,2′-benzidinedisulfonic acid. Sulfonation was achieved at pendant positions using sulfanilic acid (4-aminobenzenesulfonic acid) as its acidity is greater at pendant positions than at aryl positions. Fully sulfonated membranes were prepared with up to 30% cross-linking. Despite the high degree of sulfonation, the cross-linked membranes showed much lower water uptake than Nafion®. The membranes' low Methanol Permeability, ca. 20%–25% that of Nafion®, led to selectivity, the ratio of proton conductivity to Methanol Permeability, about 3 to 4 times that of Nafion®, despite showing slightly lower proton conductivities. Small angle X-ray scattering showed ionic clusters of around 3.15 nm, which was slightly decreased by cross-linking. This decrease lessened all the investigated membrane properties, water uptake, proton conductivity, and Methanol Permeability.
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zirconium meta sulfonphenyl phosphonic acid incorporated nafion membranes for reduction of Methanol Permeability
Journal of Membrane Science, 2008Co-Authors: Myungseop Hwang, Dukjoon KimAbstract:Zirconium meta-sulfonphenyl phosphonic acid (Zr-msPPA)/Nafion® composite membranes were prepared to reduce Methanol Permeability of the Nafion® 117 membrane in direct Methanol fuel cell (DMFC) applications. Zr-msPPA crystalline nano proton conductors were synthesized inside the membranes via the reaction of zirconium chloride octahydrate and meta-sulfonphenyl phosphonic acid that had been soaked prior. Synthesis of the Zr-msPPA in the membranes was identified from a series of chemical and physical structure characterizations using FTIR, NMR, EDS, and XRD spectroscopy. The thermal stability of the composite membranes was enhanced by addition of the Zr-msPPA, with considerable reduction in Methanol Permeability with increasing Zr-msPPA content, as the Zr-msPPA nano conductors acted as crystalline barriers to Methanol permeation. The ion conductivity also decreased with increasing Zr-msPPA content, but its effect was not as strong as with Methanol permeation given the innate, high conductivity of Zr-msPPA.
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modification of nafion membranes by incorporation of cationic polymers for reduction of Methanol Permeability
Korean Journal of Chemical Engineering, 2007Co-Authors: Donghoon Kang, Dukjoon KimAbstract:A small amount of basic polymer was incorporated in the Nafion membrane. Compared with the re-cast Nafion membrane, the Nafion/basic polymer membrane reduced the Methanol Permeability considerably. The equilibrium water uptake and proton conductivity decreased, but the thermal and mechanical stability was enhanced with increasing concentration of basic polymer. These property changes were caused by formation of cation/anion complex between acidic Nafion and basic polymer molecules. The effects of the types and molecular weights of basic polymers on the Methanol Permeability and proton conductivity were not significant.
Chuhyung Chen - One of the best experts on this subject based on the ideXlab platform.
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blended nafion speek direct Methanol fuel cell membranes for reduced Methanol Permeability
Journal of Power Sources, 2009Co-Authors: Jie Cheng Tsai, Hui Pin Cheng, Jen Feng Kuo, Yao Hui Huang, Chuhyung ChenAbstract:Abstract Sulfonated poly(ether ether ketone)s (SPEEKs) were substituted on a polymer main chain that had previously been prepared by sulfonation of poly(ether ether ketone)s in concentrated sulfuric acid for a specified time. The product was then blended with Nafion ® to create composite membranes. The blended SPEEK-containing membranes featured flaky domains dispersed in the Nafion ® matrix. These blends possessed a high thermal decomposition temperature. Additionally, owing to the more crystalline, the blended membranes had a lower water uptake compared to recast Nafion ® , the Methanol Permeability was reduced to 1.70 × 10 −6 to 9.09 × 10 −7 cm 2 s −1 for various SPEEK concentrations, and a maximum proton conductivity of ∼0.050 S cm −1 was observed at 30 °C. The single-cell performances of the Nafion ® /SPEEK membranes, with various SPEEK concentrations and a certain degree of sulfonation, were 15–25 mW cm −2 for SPEEK53 and 19–27 mW cm −2 for SPEEK63, at 80 °C. The power density and open circuit voltage were higher than those of Nafion ® 115 (power density = 22 mW cm −2 ). The blended membranes satisfy the requirements of proton exchange membranes for direct Methanol fuel cell (DMFC) applications.
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preparation of nitrated sulfonated poly ether ether ketone membranes for reducing Methanol Permeability in direct Methanol fuel cell applications
Journal of Power Sources, 2009Co-Authors: Chien Kung Lin, Jen Feng Kuo, Chuhyung ChenAbstract:Abstract Sulfonated poly(ether ether ketone)s (SPEEKs) were further substituted on the polymer main chain by nitration. All sulfonation and nitration were achieved with an inexpensive and simple post substitute reaction. The nitrated SPEEKs have a high glass transition temperature and thermal decomposition temperature, and a lower water uptake than SPEEK, which provides sufficient mechanical strength without swelling in the direct Methanol fuel cell (DMFC) application. The Methanol Permeability of nitrated SPEEKS is reduced to 1.76 × 10 −7 cm 2 s −1 for S53N22 and 1.86 × 10 −7 cm 2 s −1 for S63N17 with no loss of conductivity in the DMFC application, and a proton conductivity that reached 0.026 S cm −1 . The nitrated SPEEK membranes satisfy the requirements of proton-exchange membranes for the DMFC.