William Feld (Committee Member), Eric Fossum (Advisor), Kenneth Turnbull (Committee Member)
Master of Science (MS)
A series of poly(arylene ether)s, containing a pendant mono sulfonic acid group, was synthesized using 3-sulfonated-3', 5'-difluorodiphenyl sulfone and a variety of bisphenols for use in proton exchange membranes (PEM). Nucleophilic aromatic substitution was utilized for homo and copolymerizations. In addition, the relationship between perfectly alternating and random copolymers and their effects on overall properties was studied. Polymerization reactions yielded linear sulfonated poly(arylene ether)s, sPAEs, with molecular weights ranging from 15,400 to 212,000 g/mol. All of the polymers were characterized by gel permeation chromatography (GPC), 13C NMR spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). All polymers exhibited excellent thermal stability in excess of 300 °C. The proton conductivity of several samples rival that of Nafion® under similar conditions while the water uptake values, in the acid form, were 26, 23 and 32%, respectively. A relationship exists between order and thermal properties of sPAES as the more closely alternating structures exhibited higher Tg's as well as higher Td5% than their more random analogues. Pendant sulfonated systems do offer relatively low WU values and high conductivity, coupled with excellent thermal stability, making them attractive candidates for new PEMs.
Department or Program
Department of Chemistry
Year Degree Awarded
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