The purity of the disulfonated monomer, such as 3,3"-disulfonated-4,4"-dichlorodiphenyl sulfone (SDCDPS), was very important for obtaining high molecular weight copolymers and accurate control of the oligomer's molecular weight. A novel method to characterize the purity of disulfonated monomer, SDCDPS, was developed by using UV-visible spectroscopy. This allowed for utiliziation of the crude SDCDPS directly in the copolymerization to save money, energy, and time. Three series of tert-butylphenyl terminated disulfonated poly(arylene ether sulfone) copolymers (BPSH35, 6FSH35, and 6FSH48) with controlled molecular weightsï¼ Mnï¼ , 20 to 50 kg·mol-1, were successfully prepared by the direct copolymerization method. The molecular weight of the copolymer was controlled by a monofunctional monomer tert-butylphenyl, and characterized by the combination of 1H NMR spectra and modified intrinsic viscosity measurements in NMP with 0.05 M LiBr, which was added to suppress the polyelectrolyte effect. The mechanical properties of the membranes, such as the modulus, strength and elongation at break, were improved by increasing the molecular weights, but water uptake and proton conductivities found insensitive to copolymers" molecular weights. Three series of disulfonated poly(arylene ether ketone) random copolymers have been synthesized and comparatively studied, according to their different chemical structures, for use as proton exchange membranes. The copolymers containing more flexible molecular structures had higher water uptake and proton conductivity than the rigid structures at the same ion exchange capacity. This may be due to the more flexible chemical structures being able to form better phase separated morphology and higher hydration levels. A new hydrophobic-hydrophilic multiblock copolymer has been successfully synthesized based on the careful coupling of a fluorine terminated poly(arylene ether ketone) (6FK) hydrophobic oligomer and a phenoxide terminated disulfonated poly(arylene ether sulfone) (BPSH) hydrophilic oligomer. AFM images and the water diffusion coefficient results confirmed that the multiblock copolymer formed better proton transport channels. This multiblock copolymer showed comparable proton conductivity and fuel cell performance to the Nafion® control and had much better proton transport properties than random ketone copolymers under partially hydrated conditions. This suggested that the multiblock copolymers are promising candidates for proton exchange membranes especially for applications at high temperatures and low relative humidity. / Ph. D.

The objectives of this research were to study the gas transport properties of proton exchange membranes (PEM), namely disulfonated poly(arylene ether sulfone) (BPSH-35), post sulfonated diels-alder poly(phenylene) (SDAPP), and poly(perfluoro sulfonic acid) (Nafion). The O2 gas permeabilities were found to be lower in BPSH and SDAPP as compared to poly(perfluoro sulfonic acid) because of difference in Tg (TgBSPH= 250 oC, TgSDAPP= 330 oC versus TgNafion=150 oC). Higher Tg polymers have a more rigid, inflexible polymer segments causing a reduction in gas permeability. In comparison to SDAPP, BPSH has a lower O2 gas permeability because of the bulky side groups in the SDAPP backbone. O2 sorption measurements were carried out both under non-humidified and humidified conditions as a function of relative humidity and temperature at a normal PEM operating pressure of 1 atm. Under non-humidified conditions, BPSH, SDAPP, and Nafion 112 exhibited Henry's Law sorption, consistent with dilute dissolution of O2 into the polymer matrix. The enthalpies of sorption were calculated to determine the interaction of O2 with each membrane. The sorption enthalpies in BPSH and SDAPP increased with increasing pressure indicating the formation of more O2-O2 interactions. The enthalpies in Nafion 112 were relatively constant with increasing pressure. In the presence of moisture, the sorption behavior changed from Henry's Law to Type IV sorption behavior, which is common in hydrophilic polymers. The SDAPP membrane was found to have the highest percent wet O2 mass uptake because of a higher number of sulfonic acid groups interacting with the water/O2 system. Finally the O2 sorption for various porous catalyst powders, consisting of platinum supported on carbon was measured in the non-humidified and humidified state. The catalysts were found to have Knudsen diffusion in the non-humidified state with 20 wt% Pt-C having the largest O2 sorption. In the humidified state, the highest O2 mass uptake was achieved with 40 wt% Pt-C. These results are explained in terms of the trade-off between catalyst dispersion and catalyst size. Furthermore, O2 sorption measurements were utilized for membrane electrode assemblies containing 40 wt% Pt-C and hot pressed at 210 oC for BPSH-35 (25 and 80K) and Nafion 112 membranes. The same sorption behavior occurred in the MEAs as in the neat membrane, but at a lower capacity. This is because the electrode introduces a more tortuous path to the gas molecules permeating across the membrane. / Ph. D.

Poly(arylene ether sulfone)s (PAES) are important commercial polymers and have been extensively studied due to their excellent thermal and mechanical properties. However, some applications are still limited when good solvent resistance and low thermal expansion coefficient are required. There has been a continuous interest in developing new PAES based on new monomers or polymer modifications to obtain new properties or to enhance existing properties. In this dissertation, the synthesis, characterization and structure-property relationship of new 1,4-cyclohexylene ring containing PAESs were comprehensively studied. Different polymerization techniques were used to synthesize polymers with different segmental lengths. The monomer, 4,4'-[trans-1,4-cyclohexanebis(methylene)] bisphenol (CMB), was synthesized and fully characterized. Based on 4,4′-dihydroxy-p-terphenyl (DHTP), 4,4′-dihydroxybiphenyl (DHBP) and the CMB monomer, homopolymer and random copolymers of PAES were prepared with high molecular weights and high glass transition temperatures. Dynamic mechanical analysis (DMA) on these polymers showed multiple sub-Tg relaxations. A large increase in the ultimate elongation was obtained with the CMB and DHTP containing sample, which could be due to the strong sub-Tg relaxations observed from the DMA results. A series of four acid chloride monomers were synthesized and polymerized with phenol terminated PAES oligomers. Solution polymerization and pseudo-interfacial polymerization techniques were used to prepare both bisphenol-A (bis-A) based and DHBP based PAES oligomers. With the incorporation of the trans-1,4-cyclohexylene units, decreases in the glass transition temperatures were observed from both the bis-A based and the DHBP based polymers. However, melting transitions were only observed in the DHBP based trans-1,4-cyclohexylene containing PAESs. Crystallinity was confirmed by differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). A mechanical property study of the high molecular weight trans-1,4-cyclohexylene containing polymer samples showed moderate ultimate elongation enhancements. A series of PAES-polyester multiblock copolymers were synthesized with both solution method and melt polymerization. In the solution method, phenol terminated PAES oligomers and the acid chloride terminated poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) oligomers were presynthesized and coupled in solution. The molecular weights of the polymer products obtained from the solution method were limited by solubility issues. Melt phase polymerization was employed to obtain high molecular weight polymers. Hydroxy ethoxy terminated PAES oligomers were synthesized and polymerized with 1,4-cyclohexanedimethanol (CHDM) and dimethyl terephthalate (DMT) in the melt. Polymers with high molecular weights were obtained. Tensile test results suggested that the mechanical properties of these polymers were dominated by the PAES components with polyester contents up to 20 wt%. Melting transitions were observed from polymers with higher polyester contents, and these polymers exhibited limited solubility in common organic solvents. / Ph. D.

Poly(arylene ether sulfone)s with dendritic terminal groups were synthesized by step-growth polymerization of two difunctional monomers in the presence of preformed dendritic end-cappers. These polymers were characterized by NMR, SEC, DSC, TGA, melt rheology and tensile tests. The melt viscosities of these polymers in the high frequency region were lower than the control while the stress-strain properties were comparable to those of the control, suggesting that it is possible to reduce the high shear melt viscosities of this type of polymers without affecting the stress-strain properties by introducing bulky dendritic terminal groups. Poly(arylene ether sulfone)s with hyperbranched terminal groups were also synthesized. These polymers were synthesized by reacting fluoro-terminated poly(arylene ether sulfone) chains with an arylene ether ketone AB2 monomer. The terminal groups of these polymers were capped by tert-butylphenol. The results from NMR and SEC showed that multiple tert-butyl units were successfully introduced onto the polymer chains, suggesting that this synthetic method could be useful for introducing multiple functional groups onto the polymer chain ends in fewer synthetic steps than an analogous method using preformed dendritic end-cappers. It was also demonstrated that multiple sulfonated phenols were attached to the terminal groups of polysulfones by this method. A novel cyclohexyl-containing difunctional monomer was prepared and successfully incorporated into poly(arylene ether sulfone) backbones. These polymers were characterized by NMR, SEC, DSC, TGA, DMA and tensile tests and compared to terephthaloyl analogs. Tensile tests and DMA showed the cyclohexyl units impart a higher magnitude of secondary relaxation than the terephthaloyl units while maintaining high modulus, suggesting that these polymers may have higher impact strength than the ones with no cyclohexyl units. / Ph. D.

Proton exchange membrane fuel cells (PEMFCs) have been extensively studied as clean, sustainable and efficient power sources for electric vehicles, and portable and residential power sources. As one of the key components in PEMFC system, proton exchange membranes (PEMs) act as the electrolyte that transfers protons from the anode to the cathode. The state-of-art commercial PEM materials are typically based on perfluorinated sulfonic acid containing ionomers (PFSAs), represented by DuPont's Nafion®. Despite their good chemical stability and proton conductivity at high relative humidity (RH) and low temperature, several major drawbacks have been observed on PFSAs, such as high cost, high fuel permeability, insufficient thermo-mechanical properties above 80°C, and low proton conductivity at low RH levels. Therefore the challenge lies in developing alternative PEMs which feature associated ionic domains at low hydration levels. Nanophase separated hydrophilic-hydrophobic block copolymer ionomers are believed to be desirable for this purpose Three series of hydrophobic/hydrophillic, partially fluorinated/sulfonated multiblock copolymers were synthesized and characterized in this thesis. The hydrophilic blocks were based upon the nucleophilic step polymerization of 3, 3′-disulfonated, 4, 4′-dichlorodiphenyl sulfone (SDCDPS) with an excess 4, 4′-biphenol (BP) to afford phenoxide endgroups. The partially fluorinated hydrophobic blocks were largely based on 4, 4′-hexafluoroisopropylidenediphenol (6F-BPA) and various difluoro monomers (excess). These copolymers were obtained through moderate temperature (~130-150°C) coupling reactions, which minimize the ether-ether interchanges between hydrophobic and hydrophilic telechelic oligomers via a nucleophilic aromatic substitution mechanism. The copolymers were obtained in high molecular weights and were solvent cast into tough membranes, which had nanophase separated hydrophilic and hydrophobic regions. The performance and structure-property relationships of these materials were studied and compared to random copolymer systems. NMR results supported that the multiblock sequence had been achieved. They displayed superior proton conductivity, due to ionic, proton conducting channels formed through the self-assembly of the sulfonated blocks. The nano-phase separated morphologies of the copolymer membranes were studied and confirmed by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). Through control of a variety of parameters, including ion exchange capacity and sequence lengths, performances as high, or even higher than those of the state-of-the-art PEM, Nafion®, were achieved. Another series of semi-crystalline hydrophobic poly(ether ether ketone)-hydrophilic sulfonated poly(arylene ether sulfone) (PEEK-BPSH100) multiblock copolymers was first synthesized and characterized. However due to their semi-crystalline structure, PEEK blocks are insoluble in most organic solvents at relatively low reaction temperatures, which prevents the coupling reaction between PEEK and BPS100. In order to facilitate the synthesis and processing, removable bulky ketimine was introduced to synthesize amorphous pre-oligomers poly(ether ether ketimine) (PEEKt). The synthetic procedure first involves the synthesis of hydrophobic poly(ether ether ketimine)-hydrophilic sulfonated poly(arylene ether sulfone) (PEEKt-BPS100) multiblock pre-copolymers via coupling reactions between phenoxide terminated hydrophilic BPS100 and fluorine terminated hydrophobic PEEKt blocks. The membranes cast from PEEKt-BPS100 were boiled in 0.5M sulfuric acid water solution to hydrolyze the amorphous PEEKt blocks to semi-crystalline PEEK blocks and acidify BPS100 blocks to BPSH100 blocks simultaneously. FT-IR spectra clearly showed the successful hydrolysis and acidification. The proton conductivity, water uptake and other membrane properties of the acidified semi-crystalline PEEK-BPSH100 membranes were then evaluated and compared with those of the state-of-the-art PEM, Nafion®. / Ph. D.

Techn. Hochsch., Diss., 2002--Aachen.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2014-12-18T10:55:48Z No. of bitstreams: 1 Dissertação - Juliana Camila Lopes Cavaion - 2012.pdf: 2928983 bytes, checksum: 908363ad8b87e3a821dd54fe80dcb4ce (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-12-18T14:24:31Z (GMT) No. of bitstreams: 1 Dissertação - Juliana Camila Lopes Cavaion - 2012.pdf: 2928983 bytes, checksum: 908363ad8b87e3a821dd54fe80dcb4ce (MD5) / Made available in DSpace on 2014-12-18T14:24:32Z (GMT). No. of bitstreams: 1 Dissertação - Juliana Camila Lopes Cavaion - 2012.pdf: 2928983 bytes, checksum: 908363ad8b87e3a821dd54fe80dcb4ce (MD5) Previous issue date: 2012-06-04 / Filamentous fungi have cytochrome P450 enzyme system similar to mammals whose application allows catalyze phase I oxidative reactions of metabolism. Obtaining functionalized derivatives by these microorganisms was the main purpose of this dissertation. Studies in silico to predict metabolism in the programs MetaPrint2D and SMARTCyp indicated S-oxidation, aromatic hydroxylation and dealkylation reactions, as the most likely S-oxidation in thiomorpholine ring of 2-[4-(1,4-thiazinan-4-ylsulfonyl)phenylcarbamoyl]benzoic acid (LASSBio-596). The filamentous fungi Absidia blakesleana ATCC 26617, Aspergillus candidus ATCC 1009, Beauveria bassiana ATCC 7159, Cunninghamella echinulata ATCC 9244, Cunninghamella echinulata ATCC 9245, Cunninghamella elegans ATCC 36112, Fusarium roseum ATCC 14717 and Streptomyces vendulae ATCC 8664 were used for biotransformation of LASSBio-596. In the reaction conditions applied, substrate dissolved in methanol with concentration of 0.25 mg/mL added to liquid culture medium PDSM and incubated at 27 °C with 200 rpm for 96 hours, the fungus Beauveria bassiana ATCC 7159 performed S-oxidation in the thiomorpholine ring resulting in sulfone derivative of LASSBio-596, called LaBioCon 214, yield of 5.84 %, and it was found the hydrolysis of amide reaction obtaining the compound 4-(thiomorpholinosulfonyl)aniline, LaBioCon 202, yield of 13.8 %. It was noted the solvent used affects the biotransformation process. The monitoring of the reactions and purification of the derivatives obtained were performed by high performance liquid chromatography with ultraviolet detector at 267 nm and preparative chromatography with column Microsorb 100-5 C18 (250 x 10 mm, 5 μm). Subsequently, sulfone derivative was obtained, called LaBioCon 223, by synthesis. Structural characterization was made by classical methods such as 1H NMR and mass spectrometry. / Os fungos filamentosos possuem o sistema enzimático citocromo P450 semelhante ao de mamíferos, cuja aplicação permite catalisar reações oxidativas de fase I do metabolismo. A obtenção de derivados funcionalizados por estes microrganismos foi o objetivo principal deste trabalho. Estudos in silico de previsão do metabolismo nos programas MetaPrint2D e SMARTCyp indicaram reações de S-oxidação, hidroxilação aromática e desalquilação, sendo mais provável a S-oxidação no anel tiomorfolina do ácido 2-[4-(1,4-tiazinan-4-ilsulfonil)fenilcarbamoil]benzóico (LASSBio-596). Os fungos filamentosos Absidia blakesleana ATCC 26617, Aspergillus candidus ATCC 1009, Beauveria bassiana ATCC 7159, Cunninghamella echinulata ATCC 9244, Cunninghamella echinulata ATCC 9245, Cunninghamella elegans ATCC 36112, Fusarium roseum ATCC 14717 e Streptomyces vendulae ATCC 8664 foram empregados para biotransformação do LASSBio-596. Nas condições reacionais aplicadas, substrato solubilizado em metanol com concentração de 0,25 mg/mL adicionado ao meio de cultura líquido PDSM e incubado a 27 °C com 200 rpm por 96 horas, a Beauveria bassiana ATCC 7159 promoveu a S-oxidação no anel tiomorfolina resultando no derivado sulfona do LASSBio-596, denominado LaBioCon 214, com rendimento de 5,84 %, e constatou-se a reação de hidrólise da amida obtendo o composto 4-(tiomorfolina-sulfonil)anilina, LaBioCon 202, com rendimento de 13,8 %. Verificou-se que o solvente utilizado interfere no processo de biotransformação. O monitoramento das reações e a purificação dos derivados obtidos foram realizados por cromatografia líquida de alta eficiência com detector ultravioleta em 267 nm e cromatografia preparativa com coluna Microsorb 100-5 C18 (250 x 10 mm, 5 μm). Posteriormente, foi obtido o derivado sulfona, LaBioCon 223, por via sintética. A caracterização estrutural foi realizada por métodos clássicos como a espectroscopia de ressonância magnética nuclear de hidrogênio e espectrometria de massas.

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