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Proton Conducting Membranes (proton + conducting_membrane)
Selected AbstractsHybrid Polymer Electrolyte Fuel Cells: Alkaline Electrodes with Proton Conducting MembraneANGEWANDTE CHEMIE, Issue 7 2010Murat Ünlü Dr. Kluges Management: Eine neuartige Brennstoffzellenarchitektur vereint die Stabilität und hohe Ionenleitfähigkeit von Protonenaustauschmaterialien (PEM) mit dem überlegenen elektrochemischen Verhalten von Anionenaustauschmembran(AEM)-Elektroden. Das Wassermanagement ist gegenüber klassischen Polymerelektrolytmembran-Brennstoffzellen deutlich verbessert, wobei eine Selbstbefeuchtung der Zelle erreicht wird. [source] Proton conducting membranes based on poly(vinyl chloride) graft copolymer electrolytesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2008Jin Kyu Choi Abstract The direct preparation of proton conducting poly(vinyl chloride) (PVC) graft copolymer electrolyte membranes using atom transfer radical polymerization (ATRP) is demonstrated. Here, direct initiation of the secondary chlorines of PVC facilitates grafting of a sulfonated monomer. A series of proton conducting graft copolymer electrolyte membranes, i.e. poly(vinyl chloride)- g -poly(styrene sulfonic acid) (PVC- g -PSSA) were prepared by ATRP using direct initiation of the secondary chlorines of PVC. The successful syntheses of graft copolymers were confirmed by 1H-NMR and FT-IR spectroscopy. The images of transmission electron microscopy (TEM) presented the well-defined microphase-separated structure of the graft copolymer electrolyte membranes. All the properties of ion exchange capacity (IEC), water uptake, and proton conductivity for the membranes continuously increased with increasing PSSA contents. The characterization of the membranes by thermal gravimetric analysis (TGA) also demonstrated their high thermal stability up to 200°C. The membranes were further crosslinked using UV irradiation after converting chlorine atoms to azide groups, as revealed by FT-IR spectroscopy. After crosslinking, water uptake significantly decreased from 207% to 84% and the tensile strength increased from 45.2 to 71.5,MPa with a marginal change of proton conductivity from 0.093 to 0.083,S,cm,1, which indicates that the crosslinked PVC- g -PSSA membranes are promising candidates for proton conducting materials for fuel cell applications. Copyright © 2008 John Wiley & Sons, Ltd. [source] Highly Fluorinated Comb-Shaped Copolymers as Proton Exchange Membranes (PEMs): Improving PEM Properties Through Rational Design,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2006B. Norsten Abstract A new class of comb-shaped polymers for use as a proton conducting membrane is presented. The polymer is designed to combine the beneficial physical, chemical, and structural attributes of fluorinated Nafion-like materials with higher-temperature, polyaromatic-based polymer backbones. The comb-shaped polymer unites a rigid, polyaromatic, hydrophobic backbone with lengthy hydrophilic polymer side chains; this combination affords direct control over the polymer nanostructure within the membrane and results in distinct microphase separation between the opposing domains. The microphase separation serves to compartmentalize water into the hydrophilic polymer side chain domains, resulting in effective membrane water management and excellent proton conductivities. [source] Evolution of Permanent Deformations (or Memory) in Nafion 117 Membranes with Changes in Temperature, Relative Humidity and Time, and Its Importance in the Development of Medium Temperature PEMFCs,FUEL CELLS, Issue 4 2009G. Alberti Abstract An important problem for medium temperature polymer electrolyte fuel cells (MT PEMFCs) operating in the temperature range 90,140,°C is the short time-life of proton conducting membranes. To shed some light on the empirical annealing treatments used for increasing the membrane durability, a systematic research on the effects of thermal treatments of Nafion 117 membranes was undertaken with the hope that the information obtained could be useful for a better understanding of the real limits for MT PEMFCs. Kinetic experiments showed that, for each couple of T,RH values, the water taken up from the membrane reaches a constant value only after long times of equilibration (,200,h). Taking into account that the enlargements provoked by the water-uptake remain as permanent deformations when the samples are cooled, it was found that the evolution of the deformations provoked by changes in temperature and RH can be conveniently estimated at 20,°C by determining the water taken up after equilibration in liquid water. By relating the counter-elastic index of the matrix (nc(m)) to the extent of these deformations, a set of equations were obtained which allowed us to predict their evolution with changes of temperature and relative humidity. A good agreement with experimental values was found. The importance of this discovery for the development of MT PEMFCs is discussed. [source] Physicochemical and electrochemical characterizations of organic montmorillonite (OMMT)/sulfonated poly(ether ether ketone) (SPEEK) composite membranesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010R. Gosalawit Abstract Physicochemical and electrochemical properties of the organic montmorillonite (OMMT)/sulfonated poly(ether ether ketone) (SPEEK) composite membranes are considered for their use as proton conducting membranes. The paper presents the preparation and characterization of SPEEK and its composite membranes with OMMT as well as their comparison to the reference Nafion® 117 membrane. Water uptake and thermal property (Td1) are improved when the OMMT loading content increases. Methanol permeability decreases as OMMT loading content increases up to as high as 53% (5 wt% OMMT/SPEEK composite membrane). For proton conductivity, all membranes show improvement when the operating temperature increases from 25 to 90 °C. The proton conductivity at 100 °C of 3 wt% OMMT/SPEEK composite membrane (5.6 × 10,2 S/cm) is one order of magnitude higher than that of Nafion® 117 (2 × 10,3 S/cm). Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. 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