No description available.

The synthesis of polyesters and copolyesters containing the bicycl o[2. 2.2]octane ring and 1,4-cycl ohexanedi acetic acid and 1,4-cyclohexanedimethanol spacers are discussed. The following homopolyesters were synthesized: poly[oxy(2-methyll, 4-phenylene)oxycarbonyl-l,4-bicyclo[2.2.2]octylenecarbonyl] I; and poly[oxy(2-chloro-l,4-phenylene)oxycarbonyl-l,4-bicyclo[2.2.2]octy-1 enecarbonyl] II. The following copolyesters were synthesized: poly[oxy (2-chl oro- 1,4-phenyl ene )oxycarbonyl-l ,4-bi cycl o[2. 2. 2]octyl enecarbonyl-co-oxy- (2-chloro-1,4-phenylene)oxysebacoyl] III; poly[oxy(2-methyl-l,4- phenylene)oxycarbonyl-l,4-bicyclo[2.2.2]octylene-co-oxy(2-methyl-l,4- phenyl ene)oxysebacoyl] IV; poly[oxy(2-methyl-l,4-phenylene)oxyterephthaloyl- co-oxy(2-methyl-l,4-phenylene)oxy-l,4-cyclohexanediacetoyl] V; poly[oxy(2-methyl-1,4-phenylene)oxyterephthaloyl-co-oxymethylene-1,4 cyclohexylenemethyleneoxyterephthaloyl] VI; and poly[oxy(2-chloro-1,4 phenylene)oxyterephthaloyl-co-oxymethylene-1,4 cyclohexylenemethyleneoxyterephthaloyl]VII. The resulting homopolyesters and copolyesters were characterized by proton NMR, DSC, TGA, IR, solution viscosity, and polarizing optical microscopy.

No description available.

Catalisadores de óxido de vanádio suportados sobre titânia foram preparados pelo processo sol-gel. A secagem do material foi efetuada em condições supercríticas (aerogel) e pelo método convencional (xerogel). As características texturais foram determinadas por adsorção de N2 à 77K para obtenção de isotermas de adsorção, área superficial BET, distribuição, forma e tamanho de poros. A morfologia do material foi verificada por microscopia eletrônica de varredura. A estrutura e a identificação dos grupos superficiais foram determinadas por difratometria de raios-X e espectroscopia de infravermelho. Obteve-se sólidos com áreas superficiais ate três vezes superiores que os valores médios encontrados na literatura. Porosidade de ate 300 cm3g-1 para os aerogéis. Três tipos de espécies vanádio foram identificados nos catalisadores: grupos superficiais vanadis monoméricos, grupos vanadatos poliméricos e cristalitos de V2O5. O suporte e formado por TiO2 nas formas anatásio e rutilo com predominância da primeira forma nos aerogeis. A análise de microscopia mostrou urna granulometria ligeiramente esférica com partículas em torno de 6OMEGAm e boa dispersão do óxido de vanádio sobre a titânia. / In this work, catalysts of V2O5/ TiO2 were obtained by sol-gel method, and dried under two different conditions: supercritical (aerogel) and conventional one (xerogel). The textural characterization was carried out by adsorption of N2 at 77K, determining the adsorption isotherm, BET surface area and size, shape and distribution of porous structure. The morphology of synthesized material was studied by SEM, the structure and surface groups were characterized by XDR and FTIR, respectively. The surface area was about three time of reported in the literature. The porosity achieves values of 300 cm3g-1for aerogels. Three surface species were identified for vanadium: monomeric vanadyl, polymeric vanadates groups and V2O5 in crystallites forms. Two different forms of crystallization, rutile and anatase, were found for TiO2 support, being the first of them predominant for aerogels. The analysis of SEM micrographies exhibited a spheric granulation of particles of about 6OMEGAm and showed a good dispersion of vanadium oxide on titanium.

Recent studies of new metal complexes for antitumor properties have focused on the speeding up of the treatment process in chemotherapy. In this study, focus was put on the two new metal complexes, copper (LCu(OAc)2) and iron {LFeCl2[FeCl4]}complexes that have been synthesized. Both new complexes have been characterized by FT-IR and UV-Vis. In addition, the structures of two complexes have been established by the X-ray crystallography. The molecular structures of (LCu(OAc)2) and LFeCl2[FeCl4] have been determined confirming that the ligand is bidentate (N,N) imidazopyridine and adopted octahedral configurations. The two complexes and ligand L have been tested for biological activity against prostate cancer cell line LNCaP. The complexes have shown promising results for the anti-proliferative activity. Although the ligand displayed high cytotoxicity toward prostate cancer cell line, the complexes have shown far better cytotoxicity property than the ligand.

Catalisadores de óxido de vanádio suportados sobre titânia foram preparados pelo processo sol-gel. A secagem do material foi efetuada em condições supercríticas (aerogel) e pelo método convencional (xerogel). As características texturais foram determinadas por adsorção de N2 à 77K para obtenção de isotermas de adsorção, área superficial BET, distribuição, forma e tamanho de poros. A morfologia do material foi verificada por microscopia eletrônica de varredura. A estrutura e a identificação dos grupos superficiais foram determinadas por difratometria de raios-X e espectroscopia de infravermelho. Obteve-se sólidos com áreas superficiais ate três vezes superiores que os valores médios encontrados na literatura. Porosidade de ate 300 cm3g-1 para os aerogéis. Três tipos de espécies vanádio foram identificados nos catalisadores: grupos superficiais vanadis monoméricos, grupos vanadatos poliméricos e cristalitos de V2O5. O suporte e formado por TiO2 nas formas anatásio e rutilo com predominância da primeira forma nos aerogeis. A análise de microscopia mostrou urna granulometria ligeiramente esférica com partículas em torno de 6OMEGAm e boa dispersão do óxido de vanádio sobre a titânia. / In this work, catalysts of V2O5/ TiO2 were obtained by sol-gel method, and dried under two different conditions: supercritical (aerogel) and conventional one (xerogel). The textural characterization was carried out by adsorption of N2 at 77K, determining the adsorption isotherm, BET surface area and size, shape and distribution of porous structure. The morphology of synthesized material was studied by SEM, the structure and surface groups were characterized by XDR and FTIR, respectively. The surface area was about three time of reported in the literature. The porosity achieves values of 300 cm3g-1for aerogels. Three surface species were identified for vanadium: monomeric vanadyl, polymeric vanadates groups and V2O5 in crystallites forms. Two different forms of crystallization, rutile and anatase, were found for TiO2 support, being the first of them predominant for aerogels. The analysis of SEM micrographies exhibited a spheric granulation of particles of about 6OMEGAm and showed a good dispersion of vanadium oxide on titanium.

A obtenção de compósitos poliméricos condutores de eletricidade tem sido alvo de pesquisa com o objetivo de combinar as propriedades de diferentes materiais poliméricos. Neste trabalho foram preparados compósitos de filmes de poli(tereftalato de etileno) (PET) com camadas superficiais do polímero condutor polianilina (PANI). Para obter a camada condutora o filme de PET foi imerso no meio reacional da síntese da PANI, realizada em solução método este freqüentemente empregado para a produção de PANI. Foram otimizados os parâmetros da síntese (temperatura, concentração dos reagentes, tempo de polimerização, etc..) com o objetivo de se obter uma camada de PANI com espessura adequada, condutividade superficial elevada e com boa adesão no substrato de PET. O processo da reação de polimerização foi monitorada pela medida do potencial de circuito aberto e também diretamente pela camada de PANI depositada no PET, através de medidas de espectrocospia UV-Vis-NIR, condutividade elétrica e adesão da camada de PANI. Em condições otimizadas da síntese, realizada a temperatura ambiente durante o tempo de 20 minutos, pode-se obter camadas de PANI com condutividade da ordem de 10 S/em, boa adesão ao substrato de PET e com razoável transparência óptica. Os compósitos obtidos nas condições otimizadas foram caracterizados usando-se microscopia por SEM, microscopia óptica, microscopia AFM, difratogramas de raios-X, DSC, análise DMTA, análise TGA, correntes termo estimuladas, medidas de ruptura elétrica, medidas de adesão e solubilidade da camada de PANI. Verificou-se também que o tratamento térmico dos compósitos melhora a adesão da camada de PANI ao substrato de PET. Foi descoberto um novo método para dopar as camadas condutoras de PANI no qual o compósito desdopado é tratado por descarga corona. O processo é realizado totalmente a seco e pode-se obter uma condutividade da camada de PANI da ordem de 0,3 S/em com boa adesão. Observou-se que a eficiência do processo é dependente da umidade relativa do ar na câmara de tratamento e que a estabilidade da condutividade elétrica é melhor que nas amostras dopadas em solução / Composites with conductive properties have been proposed as materiais in which different physical properties of polymers are combined. In this work a composite consisting of surface layers of polyaniline, PANI, deposited on films of poly(ethylene terephtalate), PET, were prepared. In order to deposit the PANI the PET film were immersed in the solution in which the synthesis reaction is carried out. The parameters of the synthesis usually optimized in order to obtain a layer of PANI with enough thickness, high electric conductivity and good adhesion to the PET substrate. The synthesis was monitored by means of open circuit potential and also using UV-Vis-NIR spectroscopy and the electric conductivity of the PANI layer on PET. Using the optimized conditions, at room temperature and polymerization time of 20 minutes, a composite with a surface conductivity of the order of 10 S/em, good adhesion and a reasonable optical transparence can be obtained. Such composite were characterized employing electron scanning microscope, atomic force microscope, optic microscope, X-rays diffractometry, differential scanning calorimeter, thermal dynamic analysis, thermogravimetric analysis, thermally stimulated depolarization current, electric thermal stability of the conductivity, electric breakdown measurements, adhesion measurements and solubility of the PANI layer. It was also found that the thermal treatment leads to an improvement of the adhesion properties of the PANllayer. It was found that a corona discharge could be used to dope the PANI layer of a dedoped composite, leading to a new method for doping polymeric materiais. Such process is performed under dry conditions and gave a conductivity of the order 0.3 S/em. The process efficiency is dependent of the relative air humidity of the corona chamber and the thermal stability of the electric conductivity is betler when compared with the composites obtained by doping in solution.

A obtenção de compósitos poliméricos condutores de eletricidade tem sido alvo de pesquisa com o objetivo de combinar as propriedades de diferentes materiais poliméricos. Neste trabalho foram preparados compósitos de filmes de poli(tereftalato de etileno) (PET) com camadas superficiais do polímero condutor polianilina (PANI). Para obter a camada condutora o filme de PET foi imerso no meio reacional da síntese da PANI, realizada em solução método este freqüentemente empregado para a produção de PANI. Foram otimizados os parâmetros da síntese (temperatura, concentração dos reagentes, tempo de polimerização, etc..) com o objetivo de se obter uma camada de PANI com espessura adequada, condutividade superficial elevada e com boa adesão no substrato de PET. O processo da reação de polimerização foi monitorada pela medida do potencial de circuito aberto e também diretamente pela camada de PANI depositada no PET, através de medidas de espectrocospia UV-Vis-NIR, condutividade elétrica e adesão da camada de PANI. Em condições otimizadas da síntese, realizada a temperatura ambiente durante o tempo de 20 minutos, pode-se obter camadas de PANI com condutividade da ordem de 10 S/em, boa adesão ao substrato de PET e com razoável transparência óptica. Os compósitos obtidos nas condições otimizadas foram caracterizados usando-se microscopia por SEM, microscopia óptica, microscopia AFM, difratogramas de raios-X, DSC, análise DMTA, análise TGA, correntes termo estimuladas, medidas de ruptura elétrica, medidas de adesão e solubilidade da camada de PANI. Verificou-se também que o tratamento térmico dos compósitos melhora a adesão da camada de PANI ao substrato de PET. Foi descoberto um novo método para dopar as camadas condutoras de PANI no qual o compósito desdopado é tratado por descarga corona. O processo é realizado totalmente a seco e pode-se obter uma condutividade da camada de PANI da ordem de 0,3 S/em com boa adesão. Observou-se que a eficiência do processo é dependente da umidade relativa do ar na câmara de tratamento e que a estabilidade da condutividade elétrica é melhor que nas amostras dopadas em solução / Composites with conductive properties have been proposed as materiais in which different physical properties of polymers are combined. In this work a composite consisting of surface layers of polyaniline, PANI, deposited on films of poly(ethylene terephtalate), PET, were prepared. In order to deposit the PANI the PET film were immersed in the solution in which the synthesis reaction is carried out. The parameters of the synthesis usually optimized in order to obtain a layer of PANI with enough thickness, high electric conductivity and good adhesion to the PET substrate. The synthesis was monitored by means of open circuit potential and also using UV-Vis-NIR spectroscopy and the electric conductivity of the PANI layer on PET. Using the optimized conditions, at room temperature and polymerization time of 20 minutes, a composite with a surface conductivity of the order of 10 S/em, good adhesion and a reasonable optical transparence can be obtained. Such composite were characterized employing electron scanning microscope, atomic force microscope, optic microscope, X-rays diffractometry, differential scanning calorimeter, thermal dynamic analysis, thermogravimetric analysis, thermally stimulated depolarization current, electric thermal stability of the conductivity, electric breakdown measurements, adhesion measurements and solubility of the PANI layer. It was also found that the thermal treatment leads to an improvement of the adhesion properties of the PANllayer. It was found that a corona discharge could be used to dope the PANI layer of a dedoped composite, leading to a new method for doping polymeric materiais. Such process is performed under dry conditions and gave a conductivity of the order 0.3 S/em. The process efficiency is dependent of the relative air humidity of the corona chamber and the thermal stability of the electric conductivity is betler when compared with the composites obtained by doping in solution.

Acid Doped Polybenzimidazole Membranes for High Temperature Proton Exchange Membrane Fuel Cells Author: Ahmet &Ouml / zg&uuml / r Yurdakul One of the most popular candidates for high temperature PEMFC&rsquo / s is phosphoric acid doped polybenzimidazole (PBI) membrane due to its thermal and mechanical stability. In this study, high molecular weight PBI was synthesized by using PPA polymerization. The stirring rate of reaction solution was optimized to obtain high molecular weight. The inherent viscosity of polymer was measured at four points in 96 percent sulphuric acid solution at 30 degree centigrade by using an Ubbelohde viscometer. The highest average molecular weight was found as approximately 120,000 using the Mark-Houwink equation. The polymer was dissolved in N,N-dimethylacetamide at 70 degree centigrade with an ultrasonic stirrer. The membranes cast from this solution were doped with phosphoric acid solutions at different concentrations. The doping levels of the membranes were 6, 8, 10 and 11 moles phosphoric acid/PBI repeat unit. The mechanical strength of the acid doped membranes measured by tensile tests were found as 23, 16, 12 and 11 MPa, respectively. Conductivity measurements were made using the four probe technique. The membranes were placed in a conductivity cell and measurements were taken in humidity chamber with temperature and pressure control. The conductivity of membranes was measured at 110, 130 and 150 degree centigrade in both dry air and water vapor. The highest conductivity was 0.12 S/cm at 150 degree centigrade and 33 percent relative humidity for the membrane doped with 11 moles of H3PO4. The measurements showed that conductivity increased with increasing doping and humidity. Moreover, membranes had acceptable conductivity levels in dry air.

To achieve successful gene therapy, safe and efficient gene delivery vectors are needed. As an alternative to viral vectors, non-viral vectors, incorporating compounds such as cationic polymers and lipids have been widely studied. Much effort has been made to enhance transgene delivery efficiency, such as development of more effective cationic lipids or polymers, optimization of transfection formulations, and investigation on structural-activity of delivery vectors. Gemini surfactant, consisting of two surfactant monomers linked by a spacer group, is a thrust research area for gene therapy as non-viral vectors due to their high stability, longer storage on shelves, easiness to produce. A series of phytanyl substituted asymmetric gemini surfactants, phy-3-m (m = 12, 16, and 18) and phy-7NH-m (m = 12, 16, and 18), were rationally designed and synthesized. Due to the bulky nature and increased hydrophobicity of phytanyl branch, phy-3-m surfactants showed much lower values of critical micelle concentration (CMC) compared to their corresponding symmetric m-3-m. Particle size and transmission electron microscopy (TEM) imaging indicate that this type of gemini surfactants tends to form stacked bilayers rather than spherical or rod-like micelles which are typically observed in gemini surfactants with shorter spacers. Phy-3-m surfactants have higher degree of micelle ionization, indicating that the counter ions of the gemini surfactants can be easily replaced by other anionic ions, such as DNA, which is an advantage of phy-3-m used as transgene vectors. To evaluate transfection ability, transfection assays were carried out in OVCAR-3 cells. Transfection complexes formed by a plasmid pVGtelRL, coding enhanced green fluorescence protein (EGFP) gene, phy-3-m, and a neutral lipid, 1,2-Dioleyl-sn-glycerophosphatidylethanolamine (DOPE), at the charge ratios (+/-) of 2:1, 5:1, 10:1, and 20:1, were incubated with OVCAR-3 cells. Treated cells at all charge ratios except 20:1 showed EGFP signals under fluorescence microscopy. Meanwhile, EGFP expression and cell toxicity was quantified using fluorescence-activated cell sorting (FACS). For each gemini surfactant complex, the transfection efficiency and cytotoxicity go through a maximum, occurring at different values of the charge ratio. Considering both transfection efficiency and cytotoxicity, the optimal charge ratio to formulate the complexes containing phy-3-m was found to be 5:1 for in vitro transfection. Compared to a positive control, 16-3-16, phy-3-m showed higher transfection ability and lower cytotoxicity to OVCAR-3 cells. Initial characterization of transfection complexes was investigated by measuring particle size and zeta potential. At all charge ratios, transfection complexes were positively charged, and greater than +30 mV at 5:1 and 10:1, indicating that the complexes would be stable in solution at the ratio above 2:1. Transfection complexes were larger at lower charge ratio, but particle size dropped with increasing charge ratio (+/-). Comparing particle size and zeta potential with transfection efficiency, no correlation between size/zeta potential and transfection ability was observed. The larger particles may enter cells through caveolin-mediated pathway or phagocytosis, and smaller ones through a clathrin-mediated endocytosis. In addition, phase structures of the complexes were investigated using small angle X-ray scattering (SAXS). The complexes containing phy-3-m gemini surfactants were found to be able to adopt multiple phase structures, such as L, HII, and other highly ordered unidentified phase structures. By contrast, L structure was dominant in the transfection complexes formed by 16-3-16. The ability of phy-3-m system to adopt multiple phases appears correlated with their higher transfection efficiency in OVCAR-3 cells.