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dc.contributor.advisorHerring, Andrew M.
dc.contributor.authorPage-Belknap, Zachary Stephan Glenn
dc.contributor.committeememberPivovar, Bryan S.
dc.contributor.committeememberLiberatore, Matthew W.
dc.date.accessioned2015-09-23T20:43:58Z
dc.date.available2015-09-23T20:43:58Z
dc.date.submitted2015
dc.description2015 Fall
dc.descriptionIncludes illustrations (some color)
dc.descriptionIncludes bibliographical references.
dc.description.abstractPolymer electrolytes have been developed for use in anion exchange membrane fuel cells for years. However, due to the highly corrosive environment within these fuel cells, poor chemical stability of the polymers and low ion conductivity have led to high development costs and thus prevention from widespread commercialization. The work in this study aims to provide a solution to these problems through the synthesis and characterization of a novel polymer electrolyte. The 800 EW 3M PFSA sulfonyl fluoride precursor was aminated with 3-(dimethylamino)-1-propylamine to yield a functional polymer electrolyte following quaternization, referred to in this work as PFSa-PTMa. 1 M solutions of LiPF6, HCL, KOH, NaOH, CsOH, NaHCO3 and Na2CO3 were used to exchange the polymer to alternate counterion forms. Chemical structure analysis was performed using both FT and ATR infrared spectroscopy to confirm sulfonyl fluoride replacement and the absence of sulfonic acid sites. Mechanical testing of the polymer, following counterion exchange with KOH, at saturated conditions and 60 ºC exhibited a tensile strength of 13 ± 2.0 MPa, a Young’s modulus of 87 ± 16 MPa and a degree of elongation reaching 75% ± 9.1%, which indicated no mechanical degradation following exposure to a highly basic environment. Conductivities of the polymer in the Cl- and OH- counterion forms at saturated conditions and 90 ºC were observed at 26 ± 8.0 mS cm-1 and 1.1 ± 0.1 mS cm-1, respectively. OH- conductivities were slightly above those observed for CO32- and HCO3- counterions at the same conditions, 0.63 ± 0.18 and 0.66 ± 0.21 mS cm-1 respectively. The ion exchange capacity (IEC) of the polymer in the Cl- counterion form was measured via titration at 0.57 meq g-1 which correlated to 11.2 ± 0.10 water molecules per ion site when at 60ºC and 95% relative humidity. The IEC of the polymer in the OH- counterion form following titration expressed nearly negligible charge density, less than 0.01 meq g-1. The low OH- conductivities and IEC were attributed to the formation of a predominately zwitterionic polymer when exposed to a strong base. Removal of the sulfonamide proton following counterion exchange with a strong base and formation of a zwitterion was confirmed by FTIR with the absence of a primary amine stretch between 3000-3600 cm-1. 1H NMR analysis of small molecule analogues established that the sulfonamide site was not methylated during quaternization as evident by the exclusion of a strong singlet around 2.9 ppm. pH indication tests with Thymolphthalein illuminated the slight presence of free OH- ions within the polymer following counterion exchange thus validating the low IEC and formation of a predominately zwitterionic polymer. Recommended future work with this polymer electrolyte consists of fine tuning the polymer to be less or completely zwitterionic, pKa analysis of the sulfonamide linkage with small molecule analogues, implementation into microbial fuel cell and biological separation processes for pH regulation, and development as a support infrastructure for ionic liquids.
dc.identifierT 7863
dc.identifier.urihttp://hdl.handle.net/11124/18052
dc.languageEnglish
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.rightsCopyright of the original work is retained by the author.
dc.subjectExchange
dc.subjectMembrane
dc.subjectZwitterion
dc.subjectFuel Cell
dc.subjectAnion
dc.subjectPolymer
dc.titleSynthesis and characterization of aminated perfluoro polymer electrolytes
dc.typeThesis
thesis.degree.disciplineChemical and Biological Engineering
thesis.degree.grantorColorado School of Mines
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)


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