Master of Science (MS), Wright State University, 2014, Chemistry

Two monomers, 4',3,5-trifluorodiphenylsulfone, 1, and 4',3,5-trifluorobenzophenone, 2, have been investigated for their potential use as special BB'B''type monomers to synthesize functionalized, linear PAEs via a process called reactivity ratio controlled polycondensation (RRCP). A model study with monomer 1 resulted in a mixture of unreacted starting material, two mono-substitution products (para-and meta-F substitution) and a significant amount of di-substitution products as evidenced by the GC/MS and 13C DEPT-90 NMR spectroscopy. Conversely, subjecting monomer 2 to similar conditions, using 3-aminophenol (3f) as the nucleophile, afforded mono-substitution exclusively. A series of functionalized, linear PAEs polymers were prepared by reaction of compound 2 with selected phenols to generate functional B2 type monomers in situ, followed by reaction with Bisphenol-A to afford the corresponding linear poly(arylene ether)s. Molecular weight analysis of the polymers showed relatively high molecular weights with broad molecular weight distributions. The polymerization process was accompanied by the formation cyclic oligomers, which could not be removed via re-precipitation. Thermal analysis of the polymers indicated relatively high thermal stability, under a nitrogen atmosphere, with 5 % weight loss temperatures ranging from 380 °C to 459 °C. All the polymers were completely amorphous displaying only glass transition temperatures ranging from 108 °C to 136 °C.

Committee: Eric Fossum Ph.D (Advisor); Kenneth Turnbull Ph.D (Committee Member); William Feld Ph.D (Committee Member) Subjects: Chemistry

Master of Science (MS), Wright State University, 2020, Chemistry

The synthesis of poly(arylene ether)s, with a pendent aryl iodide, was achieved via nucleophilic aromatic substitution (NAS) polycondensation of DI-DFDPS monomer. The platform diiodo-difluorodiphenyl sulfone monomer, DFDPS-DI (3), was prepared in one-step, via EAS chemistry. Structural characterization was provided by NMR spectroscopy, GC/MS, and elemental analysis. As “pre” approach didn't work here, so “post” approach was used to synthesize N-heterocycle functionalized copolymers. The DI-copolymers were subjected to copper-catalyzed C-N coupling reaction with carbazole, phenoxazine, and indole and the syntheses of chromophore based copolymer were successfully carried out. A series of PAEs containing carbazole, phenoxazine, and indole substituents were synthesized and characterized. The copolymers were characterized by a combination of NMR spectroscopy, UV/Vis spectroscopy. DI-copolymers displayed had sufficient molecular weight (Mn) and thermal stability with 5% weight loss temperature (Tg) above 388 0C and glass transition temperature, Tg, value above 193 0C. Optical analyses provided that all modified copolymer materials emitted in the light blue region.

Committee: Eric Fossum Ph.D. (Advisor); Daniel Ketcha Ph.D. (Committee Member); Ioana Pavel Ph.D. (Committee Member) Subjects: Chemistry

Master of Science (MS), Wright State University, 2018, Chemistry

The synthesis of N-heterocycle functionalized triphenylphosphine oxide based PAEs, utilizing 3,5 difluorinated diphenyl sulfone systems was achieved. 3'-Iodo 3,5-difluorodiphenylsulfone was subjected to copper and palladium catalyzed coupling reactions with carbazole, phenothiazine, and indole. The syntheses of 3'-(9-carbazole) 3,5-difluorodiphenylsulfone, 3'-(9-phenothiazine) 3,5-difluorodiphenylsulfone, and 3'-(9-indole) 3,5-difluorodiphenylsulfone were successfully carried out. Copolymers with 4,4' difluorotriphenylphosphine oxide, as well as 4,4' dihydroxydiphenyl ether (DPE), as the nucleophilic partner, were prepared via standard nucleophilic aromatic substitution (NAS) polycondensataion reactions. Incorporation of the monomers containing N-heterocycle units was determined by NMR spectroscopy. All polymers displayed sufficient molecular weights (Mn) to allow for films to be cast from THF solution. Polymers in the series displayed excellent thermal stability with 5% weight loss temperatures (Td-5%) above 375 ⁰C, under a nitrogen atmosphere, and relatively high glass transition temperatures (Tg) ranging from 181 ⁰C for the DPS-PTZ based copolymers to 194 ⁰C for the indole-based copolymer.

Committee: Eric Fossum Ph.D. (Advisor); David Dolson Ph.D. (Committee Member); Kuppuswamy Arumugam Ph.D. (Committee Member) Subjects: Chemistry

Master of Science (MS), Wright State University, 2016, Chemistry

A series of poly(arylene ether)s were synthesized by nucleophilic aromatic substitution reaction (NAS) polycondensation of N,N-dialkyl-2,4-difluorobenzenesulfonamides. The aim of the project was to determine the thermal properties of poly(arylene ether)s by varying pendent sulfonamide activating group. The sulfonamide-activated monomers were synthesized by reacting 2,4-difluorobenzenesulfonyl chloride with a series of n-alkyl, iso-alkyl and cycloalkyl amines, ranging from n-propyl to n-octyl. Their poly(arylene ether)s were prepared with bisphenol-A as the nucleophilic reaction partner. The 4'-bromo-2,4-difluorodiphenylsulfone monomer, was utilized to synthesized copolymer with 4,4'-difluorodiphenylsulfone and bisphenol-A. The polymers were characterized by 1H and 13C NMR spectroscopy, TGA, DSC and SEC. Sulfonamide based polymers, exhibited moderate thermal stability with 5% weight loss temperature ranging from 372 oC to 405 oC. The influence of the alkyl group on glass transition temperature was examined, it was found that as the length of alkyl group length increases glass transition temperature decreased, which ranged from 34 oC to 179 oC.

Committee: Eric Fossum Ph.D. (Advisor); Daniel Ketcha Ph.D. (Committee Member); William Feld Ph.D. (Committee Member) Subjects: Chemistry; Polymers

Master of Science (MS), Wright State University, 2015, Chemistry

A series of functionalized poly(arylene ether)s, PAEs, based on 3,5-difluorobenzene sulfonamides with varying groups on the sulfonamide moiety were investigated. The main goal of the project was to tune the physical properties of the PAEs by altering the organic groups present on the sulfonamide nitrogen atom, including combinations of aryl iodide, alkyl, allyl, 4-ethoxycarboxylphenyl and benzyl moieties. Using 3,5-difluorobenzenesulfonyl chloride as a starting material, N-R1-N-R2-3,5-difluorobenzenesulfonamides were prepared, followed by conversion to the corresponding PAEs by reaction of 3,5-difluorobenzene sulfonamides with Bisphenol-A, via a typical NAS polycondensation. Copolymers with varying contents of the functional monomer ranging from 10 to 25 %, were prepared using 4,4`-difluorodiphenylsulphone as the comonomer. The polymers were characterized by size exclusion chromatography (SEC), NMR spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The polymers displayed moderate thermal stability in air while the glass transition temperatures depended on the structure of the R groups.

Committee: Eric Fossum Ph.D. (Advisor); William Feld Ph.D. (Committee Member); Daniel Ketcha Ph.D. (Committee Member) Subjects: Chemistry; Polymers

Master of Science (MS), Wright State University, 2014, Chemistry

A series of fluorinated poly(arylene ether)s, PAE, bearing sulfonated pendent sulfonyl groups, was prepared. A range of Ion Exchange Capacity (IEC) values were achieved by varying the ratios of sulfonated and non sulfonated monomers. Incorporation of both of the monomers was confirmed by NMR spectroscopy and characterization of the thermal properties was done using thermogravimetric analysis (TGA) and differential scanning (DSC). Polymers with these IEC values were synthesized in order to explore their use as a potential alternatives to the widely studied proton exchange membrane, Nafion, with an IEC of 0.91 meq/g. Using N-phenyl-3,5-difluorobenzene sulfonamide as the starting material a series of N-alkyl derivatives, with chain lengths of 3 to 12 carbon atoms, was prepared and characterized followed by conversion to the corresponding PAE. The polymer structure was confirmed by 1H and 13C NMR spectroscopy. Molecular weight data were obtained by size exclusion chromatography (SEC) and thermal data were acquired using TGA and DSC. The effect of alkyl chain length on the thermal stability and glass transition temperatures, Tg, values was determined. Increasing the alkyl chain length led to a decrease in the Tg values, which ranged from 111 down to 46 oC.

Committee: Eric Fossum Ph.D. (Advisor); William Feld Ph.D. (Committee Member); Daniel Ketcha Ph.D. (Committee Member) Subjects: Chemistry

Master of Science (MS), Wright State University, 2013, Chemistry

In an ongoing project involving the synthesis of functionalized poly(arylene ether)s that carry pendent phenyl sulfonyl groups, the introduction of an iodo group was desired. The effects of fluorine position on the electrophilic iodination of the 2,4-, 2,6-, and 2,5- and 3,5-isomers of difluorodiphenylsulfone, DFDPS were studied. The relative reactivity, toward EAS, was probed via 13C NMR spectroscopy and verified experimentally by iodination with N-iodosuccinimide. The product mixtures and corresponding structures indicated that intermediate stability did not always correlate to reactivity. Model studies were also conducted on DFDPS isomers that successfully carry in iodo groups in a pendent position. 2,4- and 3,5- Isomers of difluoro-N,N-diphenylbenzene sulfonamide have been synthesized for polymerization by nucleophilic aromatic substitution. Their properties were characterized by 1H, 13C, and 19F NMR spectroscopy and elemental analysis. The 2,4- and 3,5- isomers of difluoro-N,N-diphenylbenzene were polymerized with Bisphenol-A and the resultant polymers were characterized by TGA, DSC, and SEC. The isomers were successfully iodinated with N-iodosuccinimide. Model studies and polymerization reactions on the resultant 3,5-difluoro-N,N-bis(4-iodo)diphenylbenzene sulfonamide were conducted.

Committee: Eric Fossum Ph. D. (Advisor); Kenneth Turnbull Ph. D. (Committee Member); William Feld Ph. D. (Committee Member) Subjects: Chemistry