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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Procédés d'ignifugation du poly(éthylène téréphtalate) - application textile : synergie entre OMPOSS et retardateur de flamme phosphoré / Ignifugation of poly(ethylene terephtalate) for textile application : synergy between OMPOSS and a phosphorous based flame retardant

Vannier, Aurore 07 July 2008 (has links)
Cette étude propose un procédé d'ignifugation en masse du PET basé sur l'incorporation de retardateur de flamme phosphoré (OP950) et de nanoparticules (LDH, MWNT, OMPOSS). Si les LDH synthétisés entrainent la dégradation du PET, les MWNT et les OMPOSS apportent une amélioration des propriétés feu. Un effet de synergie est observé lors de l'incorporation simultanée d'OP950 (source d'intumescence) et d'OMPOSS. Cet effet est attribué à des phénomènes physiques tels que la sublimation des OMPOSS. L'étude de la dégradation des différents composants du mélange a révélé la formation d'espèces à base de phosphates ou de silice qui ne réagissent pas entre elles ou avec le polymère. L'amélioration des propriétés feu est donc due à la formation de composés phosphorés jouant le rôle de barrière entre la flamme et le polymère, et de silice issue de la dégradation de l'OMPOSS améliorant la résistance du char. L'émission de composés gazeux contribuerait également au développement de l'intumescence. La faisabilité du filage de la formulation intumescente a été étudiée et des fibres élaborées, malgré la faible dispersion des additifs au sein de la matrice polymère. Un masterbatch a été conçu industriellement à partir de cette étude par des partenaires industriels. Les non-tissés fabriqués montrent une résistance au feu améliorée comparée au polyester seul et passent de nombreux tests métier. Ce masterbatch est actuellement commercialisé / This study proposes to f1ame retard PET by the incorporation of a phosphorous based fia me retardant (OP950) and nanoparticles (LDH, MWNT, OMPOSS). Whereas the synthesized LDH lead to the degradation of PET, MWNT and OMPOSS bring an improvement in the f1ame retarding properties. A synergistic effect is observed when OMPOSS are added simultaneously with OP950 (bringing intumescence). This effect is due to physical phenomena such as the sublimation of the POSS. The study of the degradation of the different components of the blend revealed the formation of phosphate based species or silica, that do not react with each other or with the polymer. The improvement of the fire properties is then attributed to the formation of phosphorous components acting as a barrier between the polymer and the f1ame. It is proposed that silica reinforce the mechanical properties of the char, and that the gaseous components act as blowing agent. The feasibility of the spinning has been studied and fibres elaborated in spite of the poor dispersion of the additives into the polymer matrix. A masterbatch has been industrially prOOuced from this study by industrial partner. The non-wovens manufactured with those fibres show goOO fire retarding properties. They pass a number of normalized tests. This masterbatch is now commercialized.
2

Amélioration du comportement au feu du polyamide 6,6 par traitement de surface et en masse / Improvement of fire behavior of polyamide 6,6 by surface and mass treatment

Gallou, Hélène 01 April 2010 (has links)
L’objectif principal de ce travail concerne le développement de formulations afin d’ignifuger le Polyamide-6,6 renforcé ou non par des fibres de verre pour des applications axées sur le matériel électrique. La compréhension des mécanismes d’ignifugation mis en jeu a mis en évidence un effet de protection du à la formation d’une couche barrière limitant les transferts de matière et de chaleur. Les performances feu évaluées à l’aide des tests de l’indice limite d’oxygène (LOI), de l’UL94, du fil incandescent et du calorimètre à cône ont permis de satisfaire tous les critères retenus pour l’évaluation des matériaux contenant un phosphinate d’aluminium. L’utilisation des traitements de surface pour apporter des propriétés d’ignifugation aux matériaux a permis de concentrer les propriétés ignifuges en surface, et de préserver les propriétés mécaniques et physiques du polymère. Des dépôts en couches minces utilisant la technique de polymérisation assistée par plasma froid ont favorisé l’amélioration des performances feu du PA66-25% FV en termes de LOI, mais n’ont apporté aucun changement au calorimètre à cône. L’application d’un enduit ignifuge sur le PA66-25% FV après activation de sa surface par flammage a révélé une amélioration du comportement ignifuge. La combinaison des deux procédés d’ignifugation, à savoir le traitement en surface d’une formulation contenant une faible quantité d’ignifugeant, a été étudiée. Ainsi, l’application d’un revêtement ignifugeant sur un substrat contenant une quantité minimale d’OP1230 (5 %) a permis de satisfaire à l’ensemble du cahier des charges. / The main objective of this study concerns the development of fire retardant PA66 formulations, reinforced or not with glass fibers, uses for electrical material. The experimental approaches studies the influence of non-halogenous organophosphorous flame retardant, such as melamine polyphosphate, phosphinate, or melamine cyanurate on the fire performance of the PA66 in order to understand the fireproofing mechanisms. The efficiency in terms of fire protection defines the OP1230 as optimal flame retardant. The attention was related more particularly to the formulation with the minimal amount of additive so that the product present to the fire conditions for electric applications. The thermal degradation study shows that no new species are identified during the degradation which indicates that no chemical reaction appears. This means that only physical interactions could explain the improved fire behavior of the heated formulation. The evolution of the intermediate structures has been investigated and mechanisms have been proposed according to the conclusions made. The second axis of the study concerns the use of surface treatments to fireproof the polymer surface. Thin layer deposits using cold plasma assisted polymerization technique or thicker layer by intumescent coating applications were carried out on the PA66-25 % FV after surface activation. Both processes allows to preserve the mechanical and physical properties of the polymer. The last step of the work was to apply the surface treatment on PA66 containing 5 % OP1230 which gives very satisfying results in terms of fire protection, the OP1230 showed the best efficiency in terms of fire protection.
3

Synthesis of novel phosphinate salts and development of formulations for the flame retardancy of glass fiber reinforced PolyButylene Terephthalate (PBT) / Synthèse de nouveaux sels de phosphinate et développement de formulations pour l’ignifugation du PolybutyleneTerephthalate renforcé par des fibres de verre

Louisy, Jérémie 12 October 2012 (has links)
Cette étude s’intéresse aux procédés d’ignifugation d’un thermoplastique, le PolyButylène Téréphthalate (PBT), et plus particulièrement à l’ajout en masse de retardateurs de flamme à base de phosphore. L’objectif de ce projet consiste à mettre au point une formulation PBT renforcée avec des fibres de verre et ignifugée en vue d’application dans le domaine électrique et électronique. Dans un premier temps, les propriétés au feu de différents additifs combinés à un sel de diethylphosphinate d’aluminium commercial sont évaluées. Différents sels de phosphinate dérivés de l’acide carboxyethyl(methyl)phosphinique ont par ailleurs été synthétisés puis testés, soit seuls ou combinés à des additifs retardateurs de flamme. Deux systèmes retardateurs de flamme, l’un consistant en un mélange RDP bentonite - diethylphosphinate d’aluminium, l’autre en un mélange RDP bentonite - phenyl amide carboxyethyl(methyl)phosphinate d’aluminium, se sont avérés particulièrement efficaces en terme d’amélioration du comportement au feu du PBT renforcé. Les mécanismes d’ignifugation de ces systèmes ont été étudiés et comparés. Il a été démontré que les deux sels de phosphinate présentaient un mode d’action essentiellement en phase gaz, en libérant des espèces acides phosphiniques agissant comme inhibiteurs des réactions de combustion. Concernant le sel de phosphinate commercial, la libération d’acides phosphiniques s’effectue par interaction chimique entre l’additif et le PBT. A l’inverse, le sel de phosphinate synthétisé au laboratoire semble n’interagir que modérément avec le polymère. / This study deals with the formulation of an innovative flame retardant material based on glass fiber reinforced PolyButylene Terephthalate (PBT/GF) used in Electronic and Electrical Equipments (EEE). In a first approach, the flame retardant properties of various additives in combination with the commercial aluminium diethylphosphinate are evaluated in PBT/GF. In a second approach, a variety of phosphinate salts derived from carboxyethyl(methyl)phosphinic acids are synthesized and then tested alone or in combination with FR additives. Two innovative flame retardant systems, namely the combination of Resorcinol bis-Diphenyl Phosphate (RDP) modified bentonite clay with either the aluminium diethylphosphinate or the aluminium phenyl amide of carboxyethyl(methyl)phosphinate, were found to greatly improve the fire behavior of PBT/GF. The FR mechanism of flame retardants were investigated and compared. Both phosphinate salts from the innovative systems mainly act through a gas phase mode of action by releasing phosphinic acids. Regarding the commercial product, the release of phosphinic acid occurs due to chemical interaction between the phosphinate salt and the PBT matrix while the synthesized product only moderately interacts with the polymer.
4

Cross-bridged cyklamy jako ligandy dvojmocného manganu / Cross-bridged cyclams as manganese(II) chelators

Míka, Luděk January 2013 (has links)
Title: Cross-bridged cyclams as manganese(II) chelators Autor: Bc. Luděk Míka Department: Department of Inorganic Chemistry, Faculty of Science Supervisor: doc. RNDr. Jan Kotek, Ph.D. Supervisor's e-mail address: modrej@natur.cuni.cz Abstract: The aim of this project was to synthesize a new kind of Mn(II) complexes with ligands derived from cross-bridged cyclam. These complexes may be potentially used as contrast agents in magnetic resonance imaging. Six macrobicyclic ligands with various pendant arm were synthesized, three complexes were sucesfully prepared. Electrochemical properties of prepared manganese(II) complexes with synthesized ligands were studied using cyclic voltammetry. Relaxivity of prepared complexes was determined by 1 H NMR spectroscopy. Keywords: cross-bridged cyclam, phosphonate, phosphinate, pendant arms, manganese
5

Příprava nových porézních koordinačních polymerů, jejich charakterizace a solvotermální stabilita / Synthesis of novel porous coordination polymers, their characterization and solvothermal stability

Ondrušová, Soňa January 2019 (has links)
This diploma thesis builds on the already published work, in which phosphinate analogs of terephthalic acid were used to prepare new stable metal-organic frameworks (MOFs) Fe-ICR- 2 and Fe-ICR-4. With the use of analogous biphenylene linkers, two new Fe-MOFs were prepared - Fe-ICR-6 and Fe-ICR-7. Isoreticular MOFs were also prepared using Al3+ metal centers. These materials were characterized by X-ray powder diffraction and adsorption isotherm measurements. Their solvothermal stability was measured after shaking and refluxing in water, ethanol, and toluene and activation from water. Furthermore, their thermal stability and the disintegration mechanism in air were determined by thermal analysis. Keywords: coordination polymer, metal-organic framework, stability, phosphinate
6

Avaliação de inibidores de corrosão em meios agressivos que simulam os de produção de petróleo. / Corrosion inhibitors evaluation in aggressive media that simulate those in the oil gas prodution.

Vespa, Alfredo Sahade 24 February 2017 (has links)
Através de técnicas eletroquímicas (espectroscopia de impedância eletroquímica, resistência à polarização linear e curvas de polarização potenciodinâmica), gravimétrica e analítica, compostos orgânicos foram estudados para avaliar suas possibilidades de emprego como inibidores de corrosão. Poliglicerol hiper-ramificado puro, modificado com dicloro-fosfato, funcionalizado com grupo tiol, funcionalizado com grupo sulfeto e com grupo sulfonato de potássio - foram os compostos sintetizados e testados. Além desses, compostos comerciais, um contendo a função fosfinato e outro a função imidazolina quaternária foram testados com o mesmo intuito. Isotermas de adsorção foram ajustadas aos dados obtidos para imidazolina quaternária. Para simular condições próximas às encontradas na produção de petróleo, água do mar sintética acidificada com ácido clorídrico até pH 3 foi o meio utilizado, tendo o aço carbono 1020 empregado como substrato metálico. O Poliglicerol hiper-ramificado gerou resultados eletroquímicos e gravimétricos que mostraram que em concentrações de até 600 ppm desse composto o processo corrosivo é incentivado ao invés de ser desacelerado, indicando que tal composto não deve ser usado como inibidor de corrosão. O Poliglicerol hiper-ramificado modificado com dicloro-fosfato apresentou resultados insatisfatórios para as condições testadas tanto nos ensaios eletroquímicos como nos gravimétricos. Nas concentrações de 200, 400 e 600 ppm desse composto, a concentração intermediária é a única que diminui ligeiramente a taxa de corrosão, e para as demais concentrações a corrosão é incentivada. Os ensaios eletroquímicos das outras três moléculas obtidas por funcionalização do poliglicerol hiper-ramificado com grupos tiol, sulfonato e sulfeto indicaram aumento da deterioração do substrato. Os resultados de impedância eletroquímica indicaram que o composto à base de fosfinato e na concentração de 2000 ppm e maiores tempos de imersão resultaram em melhores resultados protetores. O ajuste dos dados às isotermas de adsorção para a imidazolina quaternária apresentou melhores resultados para o modelo de Flory-Huggins, porém, os elevados valores de coeficiente de determinação R2 das isotermas de Langmuir e Temkin também permitem dizer que tais modelos de adsorção são seguidos. / Organic compounds were studied by lectrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potenciodynamic polarization curves), analytical and gravimetric techniques, to analyze the possibilities of their use as corrosion inhibitors. Hyper branched polyglycerol only and modified with dichloro-phosphate, functionalized with thiol group, functionalized with sulfide and also with sulphonate group were synthesized and tested as corrosion inhibitors. Furthermore, commercial compounds, one based on phosphinate and a quaternary imidazoline were tested with the same objective. Adsorption isotherms were adjusted to the data obtained for quaternary imidazoline. To simulate the conditions close to those found in petroleum production, synthetic sea water acidified with hydrochloric acid up to pH 3 was the medium used, with 1020 carbon steel used as a metal substrate. The hyper branched polyglycerol generated electrochemical and gravimetric results which showed that, in concentrations up to 600 ppm of this compound, the corrosive process is favored rather than decelerated, indicating that this compound should not be used as a corrosion inhibitor. The hyper branched polyglycerol modified with dichloro-phosphate presented unsatisfactory results for the tested conditions for both electrochemical and gravimetric measurements. At concentrations of 200, 400 and 600 ppm of this compound, the intermediate concentration is the only one that slightly decreases the corrosion rate, and for the other concentrations corrosion is favored. The electrochemical measurements for the other three molecules obtained by functionalization of the hyper branched polyglycerol with thiol, sulphonate and sulfide groups indicated an increase on the substrate deterioration. The electrochemical impedance results showed that the compound based on phosphinate at 2000 ppm concentration and for higher immersion times resulted in better protective results. The adjustment of the data of the adsorption isotherms for quaternary imidazoline presented better results for the Flory-Huggins model. However, the high values of correlation factor R2 of Langmuir and Temkin isotherms show that these adsorption models are also followed.
7

Avaliação de inibidores de corrosão em meios agressivos que simulam os de produção de petróleo. / Corrosion inhibitors evaluation in aggressive media that simulate those in the oil gas prodution.

Alfredo Sahade Vespa 24 February 2017 (has links)
Através de técnicas eletroquímicas (espectroscopia de impedância eletroquímica, resistência à polarização linear e curvas de polarização potenciodinâmica), gravimétrica e analítica, compostos orgânicos foram estudados para avaliar suas possibilidades de emprego como inibidores de corrosão. Poliglicerol hiper-ramificado puro, modificado com dicloro-fosfato, funcionalizado com grupo tiol, funcionalizado com grupo sulfeto e com grupo sulfonato de potássio - foram os compostos sintetizados e testados. Além desses, compostos comerciais, um contendo a função fosfinato e outro a função imidazolina quaternária foram testados com o mesmo intuito. Isotermas de adsorção foram ajustadas aos dados obtidos para imidazolina quaternária. Para simular condições próximas às encontradas na produção de petróleo, água do mar sintética acidificada com ácido clorídrico até pH 3 foi o meio utilizado, tendo o aço carbono 1020 empregado como substrato metálico. O Poliglicerol hiper-ramificado gerou resultados eletroquímicos e gravimétricos que mostraram que em concentrações de até 600 ppm desse composto o processo corrosivo é incentivado ao invés de ser desacelerado, indicando que tal composto não deve ser usado como inibidor de corrosão. O Poliglicerol hiper-ramificado modificado com dicloro-fosfato apresentou resultados insatisfatórios para as condições testadas tanto nos ensaios eletroquímicos como nos gravimétricos. Nas concentrações de 200, 400 e 600 ppm desse composto, a concentração intermediária é a única que diminui ligeiramente a taxa de corrosão, e para as demais concentrações a corrosão é incentivada. Os ensaios eletroquímicos das outras três moléculas obtidas por funcionalização do poliglicerol hiper-ramificado com grupos tiol, sulfonato e sulfeto indicaram aumento da deterioração do substrato. Os resultados de impedância eletroquímica indicaram que o composto à base de fosfinato e na concentração de 2000 ppm e maiores tempos de imersão resultaram em melhores resultados protetores. O ajuste dos dados às isotermas de adsorção para a imidazolina quaternária apresentou melhores resultados para o modelo de Flory-Huggins, porém, os elevados valores de coeficiente de determinação R2 das isotermas de Langmuir e Temkin também permitem dizer que tais modelos de adsorção são seguidos. / Organic compounds were studied by lectrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potenciodynamic polarization curves), analytical and gravimetric techniques, to analyze the possibilities of their use as corrosion inhibitors. Hyper branched polyglycerol only and modified with dichloro-phosphate, functionalized with thiol group, functionalized with sulfide and also with sulphonate group were synthesized and tested as corrosion inhibitors. Furthermore, commercial compounds, one based on phosphinate and a quaternary imidazoline were tested with the same objective. Adsorption isotherms were adjusted to the data obtained for quaternary imidazoline. To simulate the conditions close to those found in petroleum production, synthetic sea water acidified with hydrochloric acid up to pH 3 was the medium used, with 1020 carbon steel used as a metal substrate. The hyper branched polyglycerol generated electrochemical and gravimetric results which showed that, in concentrations up to 600 ppm of this compound, the corrosive process is favored rather than decelerated, indicating that this compound should not be used as a corrosion inhibitor. The hyper branched polyglycerol modified with dichloro-phosphate presented unsatisfactory results for the tested conditions for both electrochemical and gravimetric measurements. At concentrations of 200, 400 and 600 ppm of this compound, the intermediate concentration is the only one that slightly decreases the corrosion rate, and for the other concentrations corrosion is favored. The electrochemical measurements for the other three molecules obtained by functionalization of the hyper branched polyglycerol with thiol, sulphonate and sulfide groups indicated an increase on the substrate deterioration. The electrochemical impedance results showed that the compound based on phosphinate at 2000 ppm concentration and for higher immersion times resulted in better protective results. The adjustment of the data of the adsorption isotherms for quaternary imidazoline presented better results for the Flory-Huggins model. However, the high values of correlation factor R2 of Langmuir and Temkin isotherms show that these adsorption models are also followed.
8

Bifunkční chelatanty pro selektivní komplexaci mědi / Bifunctional chelators for selective copper(II) binding

Paúrová, Monika January 2012 (has links)
Title: Bifunctional chelators for selective copper(II) binding Autor: Bc. Monika Paúrová Department: Department of Inorganic Chemistry, Faculty of Science Supervisor: doc. RNDr. Jan Kotek, Ph.D. Supervisor's e-mail: modrej@natur.cuni.cz Abstract: In this Master thesis, cyclam bifunctional derivatives bearing pendant phosphinate groups (4-methyl-11-p-aminobenzyl-1,4,8,11-tetraazacyclotetradecane-1,8- bis(methylenephosphinic acid)) and phosphonate groups (4-methyl-11-p-aminobenzyl- 1,4,8,11-tetraazacyclotetradecane-1,8-bis(methylenephosphonic acid)), were prepared and studied as potential ligands for complexation of divalent copper. These ligands are suitable for binding to a macromolecular carrier. Keywords: radiomedicine, copper, cyclam, chelating agent, phosphinate, phosphonate, kinetic inertness, kinetic lability, thermodynamic stability
9

D-Aminoacylases and Dipeptidases within the Amidohydrolase Superfamily: Relationship Between Enzyme Structure and Substrate Specificity

Cummings, Jennifer Ann 2010 December 1900 (has links)
Approximately one third of the genes for the completely sequenced bacterial genomes have an unknown, uncertain, or incorrect functional annotation. Approximately 11,000 putative proteins identified from the fully-sequenced microbial genomes are members of the catalytically diverse Amidohydrolase Superfamily. Members of the Amidohydrolase Superfamily separate into 24 Clusters of Orthologous Groups (cogs). Cog3653 includes proteins annotated as N-acyl-D-amino acid deacetylases (DAAs), and proteins within cog2355 are homologues to the human renal dipeptidase. The substrate profiles of three DAAs (Bb3285, Gox1177 and Sco4986) and six microbial dipeptidase (Sco3058, Gox2272, Cc2746, LmoDP, Rsp0802 and Bh2271) were examined with N-acyl-L-, N-acyl-D-, L-Xaa-L-Xaa, L-Xaa-D-Xaa and D-Xaa-L-Xaa substrate libraries. The rates of hydrolysis of the library components were determined by separating the amino acids by HPLC and quantitating the products. Gox1177 and Sco4986 hydrolyzed several N-acyl-D-amino acids, especially those where the amino acid was a hydrophobic residue. Gox1177 hydrolyzed L-Xaa-D-Xaa and N-acetyl-D-amino acids with similar catalytic efficiencies (~10⁴ M⁻¹s⁻¹). The best substrates identified for Gox1177 and Sco4986 were N-acetyl-D-Trp and N-acetyl-D-Phe, respectively. Conversely, Bb3285 hydrolyzed N-acyl-D-Glu substrates (kcat/Km ⁹́⁸ 5 x 10⁶M⁻¹s⁻¹) and, to a lesser extent, L-Xaa-D-Glu dipeptides. The structure of a DAA from A. faecalis did not help explain the substrate specificity of Bb3285. N-methylphosphonate derivatives of D-amino acids were inhibitors of the DAAs examined. The structure of Bb3285 was solved in complex with the N-methylphosphonate derivative of D-Glu or acetate/formate. The specificity of Bb3285 was due to an arginine located on a loop which varied in conformation from the A. faecalis enzyme. In a similar manner, six microbial renal dipeptidase-like proteins were screened with 55 dipeptide libraries. These enzymes hydrolyzed many dipeptides but favored L-D dipeptides. Respectable substrates were identified for proteins Bh2271 (L-Leu-D-Ala, kcat/Km = 7.4 x 10⁴ M⁻¹s⁻¹), Sco3058 (L-Arg-D-Asp, kcat/Km = 7.6 x 10⁵ M⁻¹s⁻¹), Gox2272 (L-Asn-D-Glu, kcat/Km = 4.7 x 10⁵ M⁻¹s⁻¹), Cc2746 (L-Met-D-Leu, kcat/Km = 4.6 x 10⁵ M⁻¹s⁻¹), LmoDP (L-Leu-D-Ala, kcat/Km = 1.1 x 10⁵ M⁻¹s⁻¹), Rsp0802 (L-Met-D-Leu, kcat/Km = 1.1 x 10⁵ M⁻¹s⁻¹). Phosphinate mimics of dipeptides were inhibitors of the dipeptidases. The structures of Sco3058, LmoDP and Rsp0802 were solved in complex with the pseudodipeptide mimics of L-Ala-D-Asp, L-Leu-D-Ala and L-Ala-D-Ala, respectively. The structures were used to assist in the identification of the structural determinants of substrate specificity.

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