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Contrôle des mécanismes d'interactions nanocharge/polymère en milieu solvant : application aux revêtements à base de PVC et de PAIAugry, Ludivine 24 March 2011 (has links) (PDF)
Ce travail de thèse a consisté à améliorer certaines propriétés de revêtements fonctionnels à base de polychlorure de vinyle (PVC) plastifié et de polyamide-imide (PAI) par incorporation de nanocharges inorganiques préformées, lamellaires ou divisées. La compatibilisation des nanocharges avec la matrice dans laquelle elles ont été incorporées s'est avérée indispensable pour obtenir des films nanocomposites avec une distribution homogène et un état de dispersion le plus fin possible. Différentes stratégies de compatibilisation ont été étudiées, comme la physisorption, la chimisorption, l'intercalation ou encore la chélation d'agents compatibilisants judicieusement choisis et adaptés à chacun des systèmes. Les nouvelles nanocharges ainsi modifiées ont été caractérisées en vue de leur introduction dans la matrice. Les films nanocomposites " compatibilisés " ont été élaborés en voie solvant et/ou par polymérisation in-situ, suivie d'une gélification physique pour le PVC ou d'une réticulation chimique pour le PAI. La caractérisation morphologique des films, réalisée par DRX et MEB/MET, ainsi que les propriétés thermiques et thermomécaniques des films, évaluées par ATG, DSC et DMA, mettent en évidence l'importance de deux paramètres : la chimie de surface des nanocharges, à l'origine des interactions interfaciales nanocharge/polymère, et le procédé d'élaboration du nanocomposite.
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Síntese caracterização de materiais híbridos de poliamida-imida (PAI) e copolissilsesquioxanos de 3-aminopropiltrietoxissilano (APES) e feniltrietoxissilano (PTES) / Synthesis and characterization of hybrid organic-inorganic materials of polyamide-imide (PAI) and copolisilsesquioxanes of 3-aminopropyltriethoxisilane (APES) and phenyltriethoxysilane (PTES).Demarchi, Angelita de Araujo 25 February 2011 (has links)
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Previous issue date: 2011-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Polyamide-imide (PAI) is a polymer widely used in magnet wires for electrical applications due to combination of their mechanical, electrical and thermal properties. This polymer can be improved by the addition of inorganic moieties, among them silsesquioxanes, forming organic/inorganic hybrids. This dissertation presents the preparation of hybrid polymers PAI/copolysilsesquioxane (PAI/coPSQ), where the matrix of polyamide-imide (PAI) is prepared from the condensation of trimellitic anhydride (TMA) and diphenylmethane-4 ,4-diisocyanate (MDI), and the copolysilsesquioxane is prepared by the sol-gel method from alkoxide precursors, in this case, 3-aminopropyltriethoxysilane (APES) and phenyltrietoxisilane (PTES). The methods for obtaining the hybrid PAI/coPSQ by simple mixing and in situ reaction were evaluated. The hybrid polymers were characterized by their spectroscopic characteristics, morphology, electrical, mechanical and thermal properties. The PAI/coPSQs coatings prepared with APES-rich coPSQ presented gelatinization due to high crosslinking generated by the polymer chains of PAI and the amine groups of PSQ. The method of in situ reaction mixture was more efficient in the generation of hybrid PAI/coPSQ, minimizing the occurrence of gelatinization. The SEM and AFM confirmed the absence of separation between the organic and inorganic phases and the FTIR and NMR 13C and 29Si analysis confirmed the formation of a Si-O-Si network. PAI/coPSQ hybrid samples showed no significant changes of Tg, while PAI/PTES hybrid obtained by polycondensation of PTES presented a decrease of Tg. PAI/PSQs hybrids were analyzed by thermogravimetry and showed a small improvement in thermal resistance. The results of nanoindentation tests confirmed the influence of adding coPSQ to increase hardness and elastic modulus of PAI films, while the average performance of dielectric strength showed trends of increasement. / O polímero poliamida-imida (PAI) é amplamente utilizado em fios esmaltados para aplicações elétricas devido ao balanço de suas propriedades mecânicas, elétricas e térmicas. Este polímero pode ser melhorado pela adição de cargas inorgânicas em sua matriz, dentre elas os silsesquioxanos, formando híbridos orgânicos/inorgânicos. O presente trabalho apresenta o preparo de polímeros híbridos PAI/copolissilsesquioxano (PAI/coPSQ), onde a matriz de poliamida-imida (PAI) é preparada a partir da reação de condensação entre o anidrido trimelitico (TMA) e o difenilmetano-4,4-diisocianato (MDI), e o copolissilsesquioxano é preparado pelo método sol-gel a partir de precursores alcóxidos, neste caso o 3-aminopropiltrietoxissilano (APES) e o feniltrietoxissilano (PTES). Foram avaliadas as metodologias de obtenção do híbrido PAI/coPSQ por mistura simples e por reação in situ. Os polímeros híbridos foram caracterizados quanto às suas características espectroscópicas e morfológicas, propriedades elétricas, mecânicas e térmicas. Os vernizes de PAI preparados com coPSQs ricos em APES apresentaram gelatinização devido ao alto grau de reticulação gerado pelas ligações cruzadas entre as cadeias poliméricas do PAI e os grupos amínicos. O método de mistura por reação in situ mostrou-se mais eficiente na geração do híbrido PAI/coPSQ, minimizando a ocorrência de gelatinização. As análises morfológicas confirmaram a ausência de separação entre as fases orgânica e inorgânica e as análises de FTIR e NMR 13C e 29Si confirmaram formação da rede Si-O-Si. As amostras híbridas PAI/coPSQ não apresentaram alterações significativas de Tg, enquanto que o híbrido PAI/PTES obtido pela policondensação somente do PTES apresentou grande diminuição de Tg. Os híbridos PAI/PSQs apresentaram uma pequena melhoria na estabilidade térmica analisada por termogravimetria. Os resultados do ensaio de nanoindentação confirmaram a influência da adição do coPSQ para o aumento da dureza e do módulo de elasticidade dos filmes de PAI, enquanto que os resultados médios da propriedade de rigidez dielétrica apresentaram tendência de aumento.
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Desenvolvimento de membranas de poli(éter imida) sultonada para a permeacão de gases / Development of sulfonated poly(ether imide) membranes for gas permeationMichelle Silva Vila Chã 21 December 2009 (has links)
A busca por membranas com propriedades adequadas a separação de gases em escala industrial tem levado a modificação e sIntese de polImeros de engenharia, com objetivo de obter membranas com propriedades adequadas. Uma das modificaçoes que tem se apresentado promissora é a inserção de grupos sulfônicos em polImeros comerciais. Espera-se que o polImero sulfonado apresente um aumento na permeação de gases polares, em relação a gases apolares, devido a sua estrutura mais polar e flexIvel. Neste contexto, o objetivo do presente trabalho é a sIntese e caracterização de membranas de poli(éter imida) sulfonada para a permeação de gases. Um planejamento experimental foi desenvolvido, em diferentes condiçoes reacionais de temperatura, tempo e excesso de um dos reagentes (ácido acético), para a sIntese de poli(éter imida) sulfonada (SPEI). Através deste planejamento, constatou-se que as variáveis que mais influenciam o grau de sulfonação são a temperatura e o tempo. O polImero com o maior grau de sulfonação, determinado por capacidade de troca iônica (IEC= 92 mEq H+/g), foi utilizado para o preparo da membrana de SPEI, obtida pela técnica de inversão de fase por evaporação do solvente, utilizando-se clorofórmio como solvente. Este filme foi caracterizado a partir das seguintes análises: espectroscopia de infravermelho (FTIR), calorimetria diferencial de varredura (DSC), análise termogravimétrica (TGA) e microscopia eletrônica de varredura (MEV), a fim de avaliar a influência da inserção do grupo sulfônico na matriz polimérica. O espectro de infravermelho de
SPEI apresentou bandas relacionadas as vibraçoes assimétricas em 1240 cm-1
(ligação O=S=O), ligação simétrica em 1171 cm-1 (O=S=O) e ligação S-O entre
1010-1024 cm-1. Isto indica a presença de grupos sulfônicos. A análise de DSC foi realizada entre 150-250C. Nesta faixa, não foram observadas alteraçoes na temperatura de transição vItrea (Tg) do polImero modificado (217C). Acredita-se que a decomposição do grupo sulfona aconteça antes da temperatura atingir o Tg do polImero. Esta suposição é confirmada na análise de TGA. As imagens de MEV
mostraram que foram obtidos filmes livres de poros e defeitos. A membrana da SPEI foi utilizada no ensaio de permeaçao dos gases 02, N2 e C02, a fim de determinar a permeabilidade e seletividade da membrana. As permeabilidades encontradas para o gas oxigênio foram de 0,76 barrer para a PEI e 0,46 barrer para a SPEI. A seletividade do dióxido de carbono em relaçao ao oxigênio aumentou de 3,5, na membrana de PEI, para 4,83, na membrana de SPEI. Em relaçao ao nitrogênio, as permeabilidades medidas foram 0,064 barrer e 0,043 barrer, para a PEI e para a SPEI, respectivamente, enquanto a seletividade em relaçao ao C02 aumentou de
41,1 para 55,5. Estes resultados indicam que o efeito de sorçao predominou devido
ao aumento das interaçöes moleculares, reduzindo assim o volume livre, o que tornou a membrana sulfonada mais compacta, com permeabilidade menor e maior seletividade. Estes resultados corroboram com a premissa de que a sulfonaçao é um processo promissor para o desenvolvimento de membranas mais eficientes. / The search for membranes with suitable properties for gas separation in industrial scale has led to the modification and synthesis of engineering polymers with the purpose of obtaining membranes with superior properties. 0ne of the modifications that have been considered promising is the insertion of sulfonic groups in commercial polymers. Due to its structure more polar and flexible, it is expected that the sulfonated polymer present an increase in polar gas permeation in relation to nonpolar gases. In this context, the objective of this work is the synthesis and characterization of membranes of poly (ether imide) sulfonated for the permeation of gases. An experimental design was developed in different reaction conditions of temperature, time and an excess of one of the reagents (acetic acid), for the synthesis of poly (ether imide) sulfonated, SPEI. Through this planning, it was found that the variables that most influenced the degree of sulfonation are temperature and time. The polymer with the highest degree of sulfonation, by ion exchange capacity
(IEC = 92 mEq H+ I g), was used to prepare SPEI membrane obtained by the
technique of solvent evaporation, using chloroform. This film was characterized from the following analysis: infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) to evaluate the influence of insertion of the sulfonic group in the polymer matrix. The infrared spectrum showed bands of SPEI related to asymmetric vibrations at 1240cm-
1 (S = 0 = 0), in symmetric stretch at 1171 cm-1 (0 = S = 0) and S0 stretch between
1010-1024cm-1. This indicates the presence of sulfonic groups. The DSC analysis was carried out between 150-250C. In this range, there are no significant changes in glass transition temperature of the modified polymer (217C). It is believed that the decomposition of the sulfone group occurs before the temperature reaches the Tg of the polymer. This assumption is confirmed in the TGA analysis. The images of SEM showed that films were obtained free of pores and defects. The membrane SPEI obtained by the technique of solvent evaporation, was used for testing permeation of gases 02, N2 and C02 in order to determine the permeability and selectivity of the membrane. The permeabilities found for oxygen were 0.76 barrer for PEI and 0.46 barrer for SPEI. The selectivity of carbon dioxide relative to oxygen increased from
3.5 to 4.83. Regarding nitrogen, the permeability measurements were 0.064 barrer
and 0.043 barrer for the PEI and the SPEI, respectively, while the selectivity relative to C02 increased from 41.1 to 55.5. These results indicate that the predominant effect of sorption due to increased molecular interactions, thus reducing the free volume, made the membrane sulfonated more compact with lower permeability and higher selectivity. These results agree with the premise that the sulfonation is a promising process for the development of more efficient membranes.
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Studies towards Developing Diastereoselective SN1 Reactions of α-Keto CarbocationsDubland, Joshua 06 April 2010 (has links)
Although α-keto carbocations have been demonstrated to be viable intermediates in solvolysis reactions, their applications in synthesis are scarce. These species can be considered to be equivalent to “reversed polarity” enolates and, as such, could be useful for the asymmetric formation of carbon-carbon and carbon-heteroatom bonds. In principle, facial selectivity in additions to α-keto carbocations may be induced using easily removed ester, amide, or imide chiral auxiliaries. Efforts to achieve such diastereoselective SN1 reactions of α-keto carbocations are described herein.
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Studies towards Developing Diastereoselective SN1 Reactions of α-Keto CarbocationsDubland, Joshua 06 April 2010 (has links)
Although α-keto carbocations have been demonstrated to be viable intermediates in solvolysis reactions, their applications in synthesis are scarce. These species can be considered to be equivalent to “reversed polarity” enolates and, as such, could be useful for the asymmetric formation of carbon-carbon and carbon-heteroatom bonds. In principle, facial selectivity in additions to α-keto carbocations may be induced using easily removed ester, amide, or imide chiral auxiliaries. Efforts to achieve such diastereoselective SN1 reactions of α-keto carbocations are described herein.
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[en] DEVELOPMENT AND CHARACTERIZATION OF FLEXIBLE COMPOSITE SUBSTRATES FOR ORGANIC DEVICES APPLICATIONS / [pt] DESENVOLVIMENTO E CARACTERIZAÇÃO DE SUBSTRATOS COMPÓSITOS FLEXÍVEIS PARA APLICAÇÃO EM DISPOSITIVOS ORGÂNICOSVANESSA LUZ E CALIL 20 July 2015 (has links)
[pt] Nas últimas décadas a tecnologia de displays e células solares evoluiu consideravelmente. Há menos de cinco décadas atrás a tecnologia de volume (bulk) era a mais amplamente utilizada no mundo. Com o surgimento das tecnologias de dispositivos planos ocorreu uma grande revolução e, nos dias atuais, é a tecnologia dominante na área de displays e de células solares. Já a tecnologia do futuro surgiu com a descoberta dos materiais orgânicos semicondutores tornando possível a substituição dos convencionais substratos de vidro por substratos flexíveis, como os substratos poliméricos ou metálicos. Nesta tese foram desenvolvidos diferentes tipos de substratos compósitos poliméricos baseados no termoplástico comercial de alto desempenho, poli(éter imida) (PEI), e na celulose bacteriana (CB), um polímero natural e biocompatível comumente utilizado como pele artificial. Os nanocompósitos foram idealizados para aplicação como substratos flexíveis em dispositivos orgânicos. Três tipos de substratos foram estudados: nanocompósito PEI/nanotubos de carbono (CNTs); nanocompósito CB/PEI; e CB modificada por camada de dióxido de titânio dopado com alumínio (AlTiO2). Os dois primeiros substratos foram utilizados na produção de dispositivos orgânicos emissores de luz (OLEDs), enquanto o último na produção de um dispositivo fotodetector em meio aquoso – implante de retina. Os novos materiais foram caracterizados, principalmente, por suas propriedades ópticas e morfológicas, e os resultados foram utilizados para determinar suas possíveis aplicações. O nanocompósito PEI/CNT apresentou propriedades similares ao polímero puro quando produzido com baixas concentrações de CNTs. Para maiores concentrações os resultados obtidos mostraram-se inferiores aos do polímero puro. Já o nanocompósito CB/PEI apresentou propriedades comparáveis ou melhores que dos polímeros puros. Podemos destacar a grande melhoria em sua transparência óptica na região do visível, além de ter sido possível a obtenção de uma rugosidade superficial comparável à encontrada para substratos de vidro e com maior homogeneidade em relação aos substratos de PEI. Ambos substratos foram funcionalizados pela deposição de uma camada de óxido de índio-estanho (ITO), que foi utilizado como eletrodo transparente na produção dos OLEDs. A análise da funcionalização da superfície mostrou que os filmes de ITO sobre os compósitos apresentou propriedades elétricas também comparáveis aos obtidos para substratos de vidro e PEI. No caso do substrato de CB/PEI foi verificada melhor estabilidade do filme de ITO nos testes de flexão, não sendo observado variações no valor de sua resistividade mesmo após sofrer flexão de 5mm de diâmetro. Os dispositivos produzidos no substrato compósito PEI/CNT também apresentaram propriedades semelhantes às obtidas pela utilização do polímero puro. A maior eficiência atingida por ambos dispositivos flexíveis chegou a 1,45 cd/m2, ainda abaixo dos valores obtidos para os substratos de vidro – 2,15 cd/m2 no caso do substrato com ITO comercial e 2,00 cd/m2 no caso do substrato com ITO depositado. Já os dispositivos produzidos no nanocompósito CB/PEI apresentou excelente eficiência (2,50 cd/m2), sendo maior que o obtido para subtratos revestidos com ITO comercial. O substrato de CB/AlTiO2 foi idealizado para melhorar a aderência do ITO no filme de CB quando em contato com a água. O resultado obtido foi bastante satisfatório, pois, além de manter a camada de ITO aderido ao substrato, melhorou em 46 porcento sua rugosidade superficial. Essa modificação na morfologia da superfície acarretou em uma melhora significativa da resistividade elétrica do filme de ITO sobre o substrato flexível, uma redução de aproximadamente 63 porcento. Os substratos modificados foram utilizados para a produção de um dispositivo fotodetector. Os resultados obtidos apontam substratos promissores para a produção de implantes de retinas flexíveis e biocompatíveis. / [en] Over the past decades displays and solar cells technology had substantially evolved. For less than five decades ago the bulk technology was the most widely used worldwide. With the emergence of flat device technology a great revolution has occurred and, nowadays, this is the dominant technology in the field of displays and solar cells. The future technology has begun with the discovery of the organic semiconductor material which makes possible to replace conventional glass substrates for flexible substrates such as polymeric or metallic ones. In this thesis different types of polymeric composite substrates based on commercial high performance thermoplastic polyetherimide (PEI), and a natural and biocompatible polymer commonly used as artificial skin, bacterial cellulose (BC) has been developed. The above mentioned nanocomposites were developed for application as flexible substrates in organic devices. Three types of substrates were studied: PEI/carbon nanotubes (CNTs) nanocomposite; BC/PEI nanocomposite; and BC modified with an aluminum doped titanium dioxide (AlTiO2) layer. The first two substrates were used for the production of organic emitting devices (OLEDs), while the latter one was used for the production of a photodetector device in aqueous medium – retinal prosthesis. The new materials were mainly characterized by its optical and morphological properties and the results were used to determine its possible applications. PEI/CNT nanocomposite presented similar properties to the pure polymer when produced with low CNTs contents. For higher concentrations the results were inferior to those of the pure polymer. BC/PEI nanocomposite has showed comparable or better properties when compared with pure polymers. A highlight was the great improvement in their optical transparency in the visible region of electromagnetic spectrum, and the smooth surface achieved by the nanocomposite – comparable to that found for glass substrates and with better uniformity in relation to PEI substrates. Both substrates were functionalized by depositing a layer of tin doped indium oxide (ITO), which was used as a transparent electrode in the production of OLEDs. The analysis of surface functionalization showed that electrical properties of ITO films onto composites were also comparable to those obtained for glass and PEI substrates. However, BC/PEI substrate presented better ITO film stability in bending tests, showing no changes in its resistivity value even after undergoing 5 mm diameter of bending. The devices produced in the PEI/CNT composite substrate has also similar properties to those obtained by using pure polymer. The higher efficiency achieved by both flexible devices reached 1.45 cd/m2 which is still below the values obtained for the glass substrates – 2.15 cd/m2 in the case of commercial ITO substrate and 2.00 cd/m2 in the case the substrate with deposited ITO. The devices produced onto CB/PEI composite substrates showed excellent efficiency (2.50 cd/m2), a higher value than that obtained for substrates coated with commercial ITO. The CB/AlTiO2 substrate was designed to improve the adhesion of the ITO film onto BC substrate when in contact with water. The result was quite satisfactory, because in addition to maintaining the ITO layer adhered to the substrate it has a 46 percent improvement in surface roughness. This change in surface morphology resulted in a significant improvement of ITO electrical resistivity, a reduction of approximately 63 percent was observed. The modified substrates were used for production of a photodetector device and the results showed a promising substrate for production of biocompatible and flexible retinal prosthesis.
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Exploring graphitic carbon nitrides for (opto)electronic applicationsBurmeister, David 04 December 2023 (has links)
Graphitische Karbonitride sind organische, kovalent gebundene, geschichtete und
kristalline Halbleiter mit einer hohen thermischen und chemischen Stabilität. Diese
Eigenschaften machen 2D Schichten der graphitischen Kristalle potentiell nützlich
für das Ziel, Limitationen von organischen 0D Molekularen und 1D polymerischen
Halbleitern zu überwinden. Trotz dieser interessanten Eigenschaften haben nur
wenige Publikationen erfolgreich graphitische Karbonitride in optoelektronischen
Bauteilen eingesetzt. Um die Vorteile dieser Materialien nutzbar zu machen, wurden
bessere Synthesebedingungen gesucht. Die Verwendung von einem Iod-Eutektikum
zeigt, dass Anionen mit einem größeren Radius als Bromid nicht für die Stabilisation
von graphitischen Karbonitriden geeignet sind. Das Optimieren der
Synthesebedingungen von Poly(triazin-imid)-LiBr resultiert in der Reduzierung
von einem kohlenstoffreichen Zersetzungsprodukt bei vollständiger Kondensation.
Das Untersuchen der elektronischen Struktur mit ab initio Berechnungen ergibt,
dass der elektronische VB-CB-Übergang verboten ist. Dies resultiert daraus, dass die
Zustände des obersten Valenzbandes nichtbindender Natur sind. Ein Band aus
nichtbindenden Elektronen als oberstes Valenzband ist vor allem aus „lone-pair
semiconductors“ aus der sechsten Hauptgruppe bekannt. In der Welt organischer
Halbleiter wurde dieses Phänomen bisher nicht beobachtet. Die geringe
makroskopische elektrische Leitfähigkeit der PTI-Filme wurde
mit der Leitfähigkeit auf Nanoebene verglichen, woraus gefolgert
werden kann, dass der Ladungsträgertransport durch den nanokristallinen
Charakter an den Kristall-Kristall Übergängen gestört wird. Die elektronische Leitfähigkeit, Mobilität der Ladungsträger sowie die Ladungsträgerdichte wurden untersucht. Die Energie Niveaus legen nahe das Elektronentransport in der Präsenz von Sauerstoff möglich ist. Die erste Applikation eines kovalenten organischen Netzwerks in
einer organischen lichtemittierenden Diode ist gezeigt worden. / Graphitic carbon nitrides are organic covalently-bonded, layered, and crystalline
semiconductors with high thermal and oxidative stability. These properties make
2D layers of graphitic carbon nitrides potentially useful in overcoming the
limitations of 0D molecular and 1D polymer semiconductors. Only few
reports have shown them being employed in optoelectronic applications. With the
goal to find better reaction conditions that enable higher product quality from the
ionothermal synthesis the size effect of anions is studied by using an iodide eutectic
instead of bromide or chloride eutectic. The highest crystalline condensation
product obtained is melem, revealing that the large iodide anion is not capable of
stabilizing a graphitic structure. Studying the synthesis conditions of poly(triazine
imide) (PTI), the best characterized graphitic carbon nitride in literature, it is
revealed that the brown discoloration of the product is due to a carbon rich side
product. Reduction of reaction temperature and increase of reaction time allows
omittance of carbonisation. Analyzing the electronic structure with ab initio
calculations one finds that the lowest energy electronic transition in PTI is forbidden
due to a non-bonding uppermost valence band. A uppermost non-bonding valence
band is most reminiscent of lone-pair semiconductors and unknown in the world of
organic semiconductors making PTI the first organic lone-pair semiconductor. The
low electrical conductivity of PTI derivatives is compared to
nanoscale conductivity values. The results indicate that macroscopic conductivity is
hampered by the nano-crystalline character due to charge carrier trapping at crystal
interfaces. The effective mobility is in the range of amorphous organic
semiconductors with an unexpectedly high carrier density. The energy levels in PTI-LiBr potentially
enable environmentally stable n-transport. The first successful Application of a covalent organic framework in a
organic light emitting diode is presented.
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Contribution à la synthèse totale de la céphalotaxine / Contribution to the total synthesis of cephalotaxineQuteishat, Laith 12 December 2013 (has links)
Depuis plus de 40 ans des chimistes se sont intéressés à l’extraction, à l’activité biologique et à la synthèse de l’homoharringtonine (HHT), un ester naturel de la céphalotaxine, qui est un puissant antileucémique utilisé pour le traitement des leucémies résistantes aux inhibiteurs de tyrosine kinase. Ces alcaloïdes sont extraits de Cephalotaxus, des conifères originaires du sud de la Chine à croissance extrêmement lente et menacés d’extinction. Leur synthèse est donc nécessaire. L’homoharringtonine utilisée en thérapeutique est obtenue à partir de (-)-céphalotaxine d’origine naturelle, par greffage d’une chaîne latérale acide suivie de purifications longues et coûteuses. L’objectif de ce travail consiste à développer une synthèse concise de la (-)-céphalotaxine, afin de s’affranchir de la ressource naturelle, de ce fait de garantir un approvisionnement d’HHT de qualité constante et de développer des analogues de seconde génération.Les stratégies développées dans ce travail ont consisté à développer une synthèse très concise de la céphalotaxine, d’une part en valorisant un synthon ABC nitrile pour y introduire les deux atomes de carbone manquant au squelette de la céphalotaxine, et d’autre part à améliorer l’accès à une synthon analogue ABC ester pour en étudier la réactivité. Ces travaux ont conduit à décrire un nouveau complexe arène chrome pentacarbonyle analogue de céphalotaxine, une méthode originale et efficace de cyclisation anionique d’imide formant un squelette 3-benzazépine à l’aide d’une nouvelle combinaison de bases, le tert-butylate de potassium et le carbonate de potassium agissant en synergie, et une nouvelle méthode de solvolyse de nitrile aliphatiques ou aromatiques sous micro-ondes qui a été exemplifiée. / For over 40 years, chemists are interested in the extraction, biological activity and synthesis Homoharringtonine (HHT ), a natural cephalotaxine ester, which is a potent antileukemic used therapeutically, especially leukemias resistant against tyrosine kinase inhibitors. These alkaloids are extracted from Cephalotaxus, evergreen trees from southern China having extremely slow growth and are in extinction. Their synthesis is thus necessary. Homoharringtonine used therapeutically is obtained from (-)-cephalotaxine of natural origin, by grafting an acidic side chain followed by lengthy and expensive purifications. The objective of this work is to develop a concise synthesis of (-)-cephalotaxine to get rid of the natural resource, thereby ensuring a supply of constant quality and develop similar second generation of HHT.The strategies developed in this work has been to develop a very concise synthesis of cephalotaxine , firstly by enhancing an ABC nitrile synthon to introduce the two carbon atoms missing to the backbone of cephalotaxine , and secondly to improve access to similar ABC ester synthon to investigate its reactivity. This work led to describe a new arena complex chromium pentacarbonyle cephalotaxine analog, an original and efficient method of anionic cyclization of imide forming a 3-benzazepine skeleton using a new combination of bases , potassium tert -butoxide and potassium carbonate acting synergistically, and a new method of aliphatic or aromatic nitrile solvolysis under microwave which was exemplified.
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Objekt pro administrativmí a logistické účely / Office and logictic buildingNavrátil, Ondřej January 2012 (has links)
Design of a steel supporting structure for one-storeyed hall based on ground plan of 60 x 80 m, clear height 10 m and total height 13,3 m. In the front part there is along the whole widht designed two-storeyed skeleton structure penetrating into the hall. From the second floor rods supported frontal part which exceeds ground plan by 2 m and on the right side is closed by pre-set cylindric structure with radius 8,6 m which covers the right frontal corner of building. The cylindric structure is around its perimeter distanced max 3,6 m from hall grand plan and is supported by posts. Both spaces had saddle roof with 8% slant, gutter edge in height 11,6 m, top line in height 12,8 m. Walls are around perimeter closed by horizontal atic in height of 13,3 m. Shape and dimensional design, load specification – stady, utility, climacic load. Calculation of imide forces and further static dimensioning of the main supporting elements and selected details. Elaboration of design documentation (dosposition, production drawing of the anchorage plan, details definited by project supervizor).
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Nové gelové elektrolyty / New gel electrolytesSumka, Martin January 2016 (has links)
This master´s thesis deals with the properties of gel polymer electrolytes, brief characteristics of other types of electrolytes and materials that are used for preparing polymer electrolytes. The thesis explains the use of the gel electrolytes in practice, the current conduction in the electrolytes and the properties of ionic liquids, and flame retardants. This thesis also focuses on methods of measurement of mechanical properties of gel polymer electrolytes. The practical part is focused on preparation of methacrylate gel electrolytes and their modifications with the use of flame retardant - triethyl phosphate (TEP) and ionic liquid - 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (Emim TFSI). In this part there are evaluations of their potential funcionality (potential window) and specific conductance conductivity using the method LSV (linear sweep voltammetry) and impedance spectroscopy. The practical part also includes a thermal analysis of selected samples by TGA, DTA and EGA methods.
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