Polymeric and Polymer/Inorganic Composite Membranes for Proton Exchange Membrane Fuel Cells

dc.contributor.authorHill, Melinda Louen
dc.contributor.committeechairMcGrath, James E.en
dc.contributor.committeememberRiffle, Judy S.en
dc.contributor.committeememberDavis, Richey M.en
dc.contributor.committeememberDillard, John G.en
dc.contributor.committeememberWard, Thomas C.en
dc.contributor.departmentMacromolecular Science and Engineeringen
dc.date.accessioned2014-03-14T21:10:26Zen
dc.date.adate2006-04-18en
dc.date.available2014-03-14T21:10:26Zen
dc.date.issued2006-03-31en
dc.date.rdate2007-04-18en
dc.date.sdate2006-04-11en
dc.description.abstractSeveral types of novel proton exchange membranes which could be used for both direct methanol fuel cells (DMFCs) and hydrogen/air fuel cells were investigated in this work. One of the main challenges for DMFC membranes is high methanol crossover. Nafion, the current perfluorosulfonic acid copolymer benchmark membrane for both DMFCs and hydrogen/air fuel cells, shows very high methanol crossover. Directly copolymerized disulfonated poly(arylene ether sulfone)s copolymers doped with zirconium phosphates and phenyl phosphonates were synthesized and showed a significant reduction in methanol permeability. These copolymer/inorganic nanocomposite hybrid membranes show lower water uptake and conductivity than Nafion and neat poly(arylene ether sulfone)s copolymers, but in some cases have similar or even slightly improved DMFC performance due to the lower methanol permeability. These membranes also show advantages for high temperature applications because of the reinforcing effect of the filler, which helps to maintain the modulus of the membrane, allowing the membrane to maintain proton conductivity even above the hydrated glass transition temperature (Tg) of the copolymer. Sulfonated zirconium phenyl phosphonate additives were also synthesized, and membranes incorporating these materials and disulfonated poly(arylene ether sulfone)s showed promising proton conductivity over a wide range of relative humidities. Single-Tg polymer blend membranes were studied, which incorporated disulfonated poly(arylene ether sulfone) with varied amounts of polybenzimidazole. The polybenzimidazole served to decrease the water uptake and methanol permeability of the membranes, resulting in promising DMFC and hydrogen/air fuel cell performance.en
dc.description.degreePh. D.en
dc.identifier.otheretd-04112006-125700en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04112006-125700/en
dc.identifier.urihttp://hdl.handle.net/10919/37597en
dc.publisherVirginia Techen
dc.relation.haspartMelindaHillDissertation.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectdisulfonated copolymeren
dc.subjectzirconium phosphateen
dc.subjectpoly(arylene ether sulfone)en
dc.subjectpolymer blenden
dc.subjectproton exchange membraneen
dc.subjectfuel cellen
dc.titlePolymeric and Polymer/Inorganic Composite Membranes for Proton Exchange Membrane Fuel Cellsen
dc.typeDissertationen
thesis.degree.disciplineMacromolecular Science and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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