Methanol permeability and proton conductivity of direct methanol fuel cell membranes based on sulfonated poly(vinyl alcohol)–layered silicate nanocomposites (original) (raw)
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Characterization of polymer-layered silicate nanocomposite membranes for direct methanol fuel cells
Electrochimica Acta, 2004
Nafion ® /montmorillonite (MMT) nanocomposite membranes were prepared to reduce methanol crossover while maintaining essential proton conductivity. When the loading of MMT clay was less than 20 wt.%, the X-ray diffraction patterns of Nafion ® /MMT nanocomposite membranes were featureless, indicative of the disordered and exfoliated structure of clay. It was observed that both tensile strength and elongation at break were improved by the nanodispersed clay particles. In addition, the thermal decomposition temperature of Nafion ® backbones shifted to higher temperature region due to the strong interaction of polymer main chains with organo-clays. Refractive index (RI) measurement showed that methanol permeability of unmodified Nafion ® was ca. 2.3 × 10 −6 cm 3 cm/cm 2 s while that of 1 wt.% Nafion ® /MMT nanocomposite membrane decreased down to 1.6 × 10 −7 cm 3 cm/cm 2 s without apparent conductivity loss. As a result, 1 wt.% Nafion ® /MMT nanocomposite membranes delivered much higher power density than unmodified Nafion ® membrane at concentrated methanol feed up to 10 M.
Asia-Pacific Journal of Chemical Engineering, 2017
Sulfonated polyvinylalcohol‐mordenite (SPVA‐MOR) membranes for direct methanol fuel cell use were synthesized and characterized. It had earlier been found out that polyvinylalcohol‐mordenite (PVA‐MOR) membranes, while having excellent methanol permeability and modest proton conductivity values, had inferior direct methanol fuel cell performances than Nafion™. Sulfonating the polyvinylalcohol matrix had been suggested to improve the proton conductivity. In this work, polyvinylalcohol powder was sulfonated by using propane sultone as the sulfonating agent prior to the membrane synthesis. Morphological analyses revealed that the zeolite particles mixed homogeneously within the polymer matrix. Sulfonating the polymer slightly decreased both water and methanol uptakes. Both in PVA‐MOR and SPVA‐MOR membranes, water uptake turned out to be higher than the methanol uptake. SPVA‐MOR membranes were found to have an average proton conductivity of 0.052 S·cm−1 when compared with the 0.036 S·cm−...
Journal of Applied Polymer Science, 2007
Sulfonated poly(vinyl alcohol) (PVA) for use as a proton conductive membrane in a direct methanol fuel cell (DMFC) was prepared by reacting the PVA with sulfoacetic acid and poly(acrylic acid). The effects of the amount of sulfoacetic acid and poly(acrylic acid) on proton conductivity, methanol permeability, water uptake, and ion exchange capacity (IEC) of the sulfonated PVA membranes were investigated by using impedance analysis, gas chromatography, gravimetric analysis, and titration techniques, respectively. The water uptake of the membranes decreased with the amount of the sulfoacetic acid and the amount of poly(acrylic acid) used. The proton conductivity and the IEC values of the membranes initially increased and then decreased with the amount of the sulfoacetic acid. The methanol permeability of the sulfonated PVA membranes decreased continuously with the amount of the sulfoacetic acid.
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019
In this work, polymer electrolyte membranes were synthesized by polyvinyl alcohol and Sulfosuccinic acid by phase inversion technique. Also, prepared polyvinyl alcohol with Sulfosuccinic acid by adding Montmorillonite (MMT) nanoparticles. The effect of different concentrations of (0,5,15,20,25 wt%) nanoparticles in the membranes was studied with respect to proton conductivity and methanol permeability. The characterization studies for the synthesized membranes were done by Fourier transform infrared spectroscopy (FTIR), Universal testing machine (UTM) and Thermogravimetric analysis (TGA). The result shows that the incorporation of the montmorillonite organoclay upon sulfonated PVA membrane strongly affected the properties of the membranes. FTIR spectrum confirms sulfonation. Mechanical stability was evaluated using UTM. Proton conductivity and methanol permeability of the membrane changed with the contents of Montmorillonite in a nonlinear fashion. The optimum concentration of Montmorillonite within the sulfonated membrane, corresponding to maximum proton conductivity to methanol permeability ratio was 15wt%. The novel Polyvinyl alcohol membrane showed excellent proton conductivity; less methanol permeability as compared to Nafion membrane.
International Journal of Electrochemistry, 2011
Electrolyte nanocomposite membranes for proton exchange membrane fuel cells and direct methanol fuel cells were prepared by carrying out a sulfonation of poly(vinyl alcohol) with sulfosuccinic acid and adding a type of organically modified montmorillonite (layered silicate nanoclay) commercially known as Cloisite 93A. The effects of the different concentrations (0, 2, 4, 6, 8 wt. %) of the organoclay in the membranes on water uptake, ion exchange capacity (IEC), proton conductivity, and methanol permeability were measured, respectively, via gravimetry, titration, impedance analysis, and gas chromatography techniques. The IEC values remained constant for all concentrations. Water uptakes and proton conductivities of the nanocomposite membranes changed with the clay content in a nonlinear fashion. While all the nanocomposite membranes had lower methanol permeability than Nafion115, the 6% concentration of Cloisite 93A in sulfonated poly(vinyl alcohol) membrane displayed the greatest proton conductivity to methanol permeability ratio.
Polymer, 2006
Sulfonated poly(arylene ether ether ketone ketone) (SPAEEKK) copolymer containing pendant sulfonic acid group (sulfonic acid content (SC) ¼ 0.67) was synthesized from commercially available monomers such as sodium 6,7-dihydroxy-2-naphthalenesulfonate (DHNS), 1,3bis(4-fluorobenzoyl)-benzene (BFBB), and hexafluorobisphenol A (6F-BPA). SPAEEKK/silica hybrid membranes were prepared using the solegel process under acidic conditions. The SPAEEKK/silica hybrid membranes were fabricated with different silica contents and the membranes were modified to achieve improved proton conductivity incorporating PeOH groups (H 3 PO 4 treatment).
Synthesis and characterization of polysulfone/clay nanocomposite membranes for fuel cell application
Journal of Applied Polymer Science, 2012
Keywords: PEM Polysulfone Layered double hydroxide Proton conductivity a b s t r a c t In the present study, sulfonated polysulfone (sPSU)/layered double hydroxide (LDH) composite membranes for use in proton exchange membrane fuel cells (PEMFCs) were investigated. Polysulfone (PSU) was sulfonated with trimethylsilyl chlorosulfonate in 1,2 dichloroethane at room temperature. Composite membranes were prepared by blending different amount (0, 1, 2, and 5%) of LDH nanoparticles with sPSU in dimethylacetamide (DMAc). The membranes were prepared by the casting method and the samples obtained were characterized by XRD, FTIR spectroscopy. The thermal behavior for all samples was evaluated by thermogravimetrical analysis (TGA). Finally electrochemical impedance spectroscopy (EIS) was used to study the membranes electrical properties. The EIS measurements were carried out with the membranes in contact with HCl solutions at different concentrations (10 À3 c 10 À1 ). Results show a clear dependence of the membrane electrical resistance with the sulfonation degree and the amount of the LDH added.
Desalination, 2002
In order to reduce the high methanol permeability of membranes in a direct methanol fuel cell application new and better materials are still required. In this paper membranes made from polybenzimidazolekulfonated polysulfone are given and compared with homopolymer membranes made from sulfonated polysulfone, blends of polyethersulfone with sulfonated polysulfone and Nafion N117. Various methods of characterization have been used such as swelling measurements, ion exchange capacity (I.E.C.), electrical resistance, permselectivity, sorption isotherms and methanol permeability which give information on the conductive properties and methanol permeability properties of the membranes. These methods were used as a first estimate to give information about what kind of material is better to be used in a direct methanol fuel cell application.