This work expands the current understanding of materials chemistry and engineering capabilities of two synthetic platforms: 1.) bis-ortho-diynylarenes (BODA) and 2.) trifluorovinylaryl ethers (TFVE). Each platform possesses a unique chemistry which paradoxically enables the development of high-performance materials therefrom while simultaneously retaining exceptional melt and solution processability. Leveraging the apparent dichotomy in properties (performance/processability) obtainable from these two synthetics platforms, we have pursued and achieved a practical approach to high-temperature resistant materials with an immense potential for technology transfer and commercialization: 1.) BODA-derived resins (BDR) constitute a versatile platform of melt-processable resins capable of rapidly producing high performance matrix composites which include thermoset, carbon-carbon, and other specialty carbon or hybrid ceramic composite structure. BODA monomers can be synthesized via a three-step process from commercially available bisphenols and undergo a facile catalyst-free, thermal-initiated polymerization to yield polyarylene thermosets with outstanding thermal-oxidative stability, low heat release, flame resistance, and high carbon yields (>80%). The combination of melt processability, ease of cure, and high carbon yields in BDR provides an attractive quick, single-step fabrication of carbon/carbon (C/C) composites with excellent interlaminar shear strength (ILSS; ~1800 psi) after a single infusion/carbonization. Furthermore, our work in this area has shown that C/C from BDR can be prepared via a fast carbonization (10 °C/min), relative to typical 1 °C/min or 1 °C/hr industrial carbonizations, without causing undesirable shrinkage, cracking, interlaminar debonding, or detrimental changes in ILSS. 2.) Large polyaromatic hydrocarbons (PAHs) are typically known for their interesting thermal- and photo-optical properties but suffer from poor solubility and processability issues. Functionalization of these moieties with TFVE fluorocarbon groups enables melt or solution polymerization via a thermally initiated [2+2] cyclodimerization of the TFVEs towards high performance perfluorocyclobutyl (PFCB) aryl ether polymers. For example, successful fabrication of free-standing photoluminescent films with record high glass transition temperatures (Tg ~ 300 °C), exceptional thermal-oxidative stability (~250 °C, 24 h), unprecendented photostability at 250 °C in air, and excellent solubility in common organic solvents (at room temperature) have been realized via a set of triphenylene-enchained PFCB aryl ether polymers.

No description available.

Approved for public release, distribution is unlimited / Thermophotovoltaic energy conversion offers a means of efficiently converting heat into electrical power. This has potential benefits for space nuclear reactor power systems currently in development. The primary obstacle to space operation of thermophotovoltaic devices appears to be the low heat rejection temperatures which necessitate large radiator areas. A study of the tradespace between efficiency and radiator size indicates that feasible multi-junction TPV efficiencies result in substantial overall system mass reduction with manageable radiator area. The appendices introduce the endothermodynamic model of a TPV cell and briefly assess the utility of advanced carbon-carbon heat pipe radiator concepts. / Lieutenant, United States Navy

L’étude est focalisée sur l’activation d’alcynes fonctionnalisés par des complexes hétérobimétalliques [(OC)3Fe(µ-CO)(µ-Ph2PXPPh2)Pt(PPh3)] (X = CH2, NH) et [(OC)3Fe(Si(OMe)3)(µ-dppm)Pt(H)(PPh3)] conduisant à la formation de composés de type dimétallacyclopenténone et µ-vinylidène dont la réactivité a été exploitée. En particulier, un travail systématique a été mené avec divers alcynols et les données cristallographiques ont révélé l’existence de liaisons hydrogènes variées, intra ou intermoléculaires ; par ailleurs, la déshydratation de ces composés par HBF4 a généré des espèces de type allènylidène cationiques. Egalement, les réactions de diynes aliphatiques et aromatiques terminaux conduisent à des complexes Fe‒Pt [(OC)2Fe(µ-dppm)(µ-C(=O)CH=C{E-C≡CH}Pt(PPh3)] (E = espaceur) portant un alcyne libre, permettant la construction de systèmes tétranucléaires Fe‒Pt symétriques et asymétriques ou des assemblages hétéropolynucléaires Fe‒Pt-Co‒Co. La réaction de cycloaddition a été aussi réalisée sur la triple liaison libre avec des azotures R-N3 pour former des 1,2,3-triazoles organométalliques. Finalement, des études préliminaires concernant l’immobilisation des composés hétérobimétalliques Fe‒Pt sur des particules de silice Aerosil 200 ont été initiées. / The study deals on the heterobimetallic activation of functionalized alkynes by the complexes [(OC)3Fe(µ-CO)(µ-Ph2PXPPh2)Pt(PPh3)] (X = CH2, NH) and [(OC)3Fe(Si(OMe)3)(µ-dppm)Pt(H)(PPh3)] leading to the formation of various species such as dimetallacyclopentenones and μ-vinylidenes, whose reactivity has been investigated. In particular, a detailed study was carried using divers alkynols as substrates. X-ray crystallographic data reveal the occurrence of intra- and intermolecular hydrogen bonding; dehydratation of these compounds by HBF4 leads to formation of cationic allenylidene species. The reactions of aliphatic and aromatic diynes affords Fe‒Pt complexes [(OC)2Fe(µ-dppm)(µ-C(=O)CH=C{E-C≡CH}Pt(PPh3)] (E = spacer) bearing a second alkyne unit, allowing the construction of tetranuclear symmetric and asymmetric Fe‒Pt or heteropolynuclear Fe‒Pt-Co‒Co assemblies. Cycloaddition reactions using azides R-N3 were also performed on the pendant alkyne unit to form a series of organometallic 1,2,3-triazoles. Finally, preliminary studies have been undertaken to immobilize heterobimetallic Fe‒Pt compounds on the surface of Aerosil 200 silica particles.

This study develops a reliable intelligent non-destructive evaluation (NDE) expert system for carbon-carbon (C/C) composites based on thermography, ultrasonic, computed tomography and post processing by means of fuzzy expert system technique. Data features and NDE expert knowledge are seamlessly combined in the intelligent system to provide the best possible diagnosis of the potential defects and problems. As a result, this research help ensure C/C composites' integrity and reliability. Four types of orthotropic aerospace composite material groups, which include 2-D pitched based commercial aircraft disc brakes and asmolds, 3-D PAN based C/C composites, and carbon fiber reinforced plastic (CFRP) panels, were tested. Based on the performance testing results of thermography, air-coupled ultrasonic, and x-ray computed tomography, the testing data pattern corresponding to feature and quantification of defects were found. This NDE knowledge databases were transformed to fuzzy logic expert system models. The models succeefully classified and indicated the defect's size and distribution and the intelligent systems perform NDE better than human operators. These fuzzy expert systems not only eliminate human errors in defect detection but also function as NDE experts. In addition, fuzzy expert systems improve the defect detection by incorporating fuzzy expert rules to remove noises and to measure defect size more accurately. In the future, the expert system model could be continuously updated and modified to quantify the size and distribution of defects. The systems developed here can be adapted and applied to build an intelligent NDE expert system for better quality control as well as automatic defect and porosity detection in C/C composite production process.

Submitted by ANA CAROLINA DE TOLEDO SANTANA null (actoledo@iq.unesp.br) on 2016-03-17T17:25:32Z No. of bitstreams: 1 Dissertação Carol Final.pdf: 7825510 bytes, checksum: 921c29706ed56e5ef489712bae28fc30 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-03-21T20:10:04Z (GMT) No. of bitstreams: 1 santana_act_me_iq_par.pdf: 4512361 bytes, checksum: 07a7dc911b2bdd27db8608948a16848b (MD5) / Made available in DSpace on 2016-03-21T20:10:04Z (GMT). No. of bitstreams: 1 santana_act_me_iq_par.pdf: 4512361 bytes, checksum: 07a7dc911b2bdd27db8608948a16848b (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho teve como principal objetivo estudar a atividade catalítica de soroalbumina bovina (BSA) em reações formadoras de uma nova ligação C-C: Reações aldólica, de Henry e Morita-Baylis-Hillman (MBH). Em todos os casos a BSA atuou como catalisador, visto que quando as reações foram realizadas sem sua presença, não houve formação dos produtos desejados. Os rendimentos obtidos para as reações aldólica (37%), Henry (80%) e MBH (73%), variaram de bons a moderados e não foi observada enantiosseletividade para nenhuma das reações estudadas. As soroalbuminas são proteínas que formam muita emulsão dificultando os processos downstream na separação dos produtos e materiais de partida. Visando minimizar este inconveniente, a BSA foi submetida à imobilização em MCLEA (magnetic cross-linking enzyme aggregates) utilizando nanopartículas magnéticas de óxido de ferro. Nestes casos, o biocatalisador pôde ser facilmente retirado do meio reacional com aplicação de um campo magnético externo. Esta metodologia afetou diretamente no rendimento da reação de Henry, passando de 80% para 89%. Porém, para as outras reações a melhoria no rendimento não foi tão expressiva. A imobilização também não foi eficaz para o aumento dos excessos enantioméricos. Até o momento para a reação de MBH com os substratos utilizados, não há relatos na literatura para a síntese do aduto desejado catalisado pela BSA. Sendo assim, optamos por realizar um planejamento fatorial completo dessa reação visando otimizar as condições reacionais bem como os rendimentos. As variáveis estudadas foram: temperatura, concentração do biocatalisador e condição do biocatalisador (livre ou imobilizado). Os resultados obtidos mostraram que a variável com maior influência na reação, é a concentração do biocatalisador. A conversão obtida passou de 30% para 40% utilizando 2,2 μmol de BSA. Em seguida, realizamos um estudo de ascendência da concentração do catalisador visando otimizar este parâmetro. A conversão obtida passou para 73% quando foram utilizadas 3,7 μmol de biocatalisador imobilizado. Realizamos um estudo de reciclagem do biocatalisador imobilizado. Foi possível reutiliza-lo porém com diminuição da conversão a partir do segundo ciclo. Os resultados obtidos nesta dissertação evidenciam o potencial biocatalítico da BSA em reações para a formação de ligação C-C. / This work aimed to study the catalytic activity of bovine serum albumin (BSA) in reactions that form a new C-C bond: aldol reactions, Henry and Morita-Baylis-Hillman (MBH). In all cases BSA served as the catalyst, whereas when the reactions were carried out without their presence there was no formation of the desired products. The yields obtained for aldol reactions (37%), Henry (80%) and MBH (73%), ranged from good to moderate enantioselectivity and was not observed for any of the studied reactions. The serum albumins are proteins that form the much emulsion difficulting downstream processes in separation of the products and starting materials. To minimize this inconvenience, the BSA was subjected to immobilization in M-CLEA (magnetic cross-linking enzyme aggregates) using magnetic nanoparticles of iron oxide. In these cases the biocatalyst could be easily removed from the reaction medium by applying an external magnetic field. This methodology directly affect the yield of the Henry reaction, from 80% to 89%. However, for other reactions the improvement of yields was less pronounced. The immobilization was also not effective for improving the enantiomeric excess. So far for the MBH reaction with the worked substrates, there are no reports in the literature for the synthesis of the desired adduct catalyzed by BSA. So we decided to study a full factorial design of this reaction to optimize the reaction conditions and yields. The variables studied were: temperature, the biocatalyst concentration and biocatalyst conditions (free and immobilized). The concentration of biocatalyst was the major factor with interference in all reactions. The conversion increased from 30% to 40% using 2.2 μmol of BSA. Then we perform a study of catalyst concentration to optimize this parameter. The conversion increased to 73% when they were used 3.7 μmol immobilized biocatalyst. To evaluate the retention of catalytic activity of BSA immobilized, it was performed a study of the immobilized biocatalyst recycling. It was possible the reuse but with reduced conversion from the second cycle. The results obtained in this work demonstrated the potential of BSA in C-C bond formation reactions.

In this thesis, a comprehensive study of the electrical properties of carbon-hydrogen (CH) complexes in silicon (Si) and silicon-germanium (SiGe) alloys is presented. These complexes form by the reaction of residual carbon impurities with hydrogen that is introduced either by wet chemical etching or a dc hydrogen plasma. The complexes were detected and characterized by the deep level transient spectroscopy (DLTS), Laplace DLTS, and minority carrier transient spectroscopy (MCTS) technique. With this approach, properties like the activation enthalpy for carrier emission, the capture cross section, the charge state, and the thermal stability of the complexes were determined. The composition of the complexes was derived from the analysis of their depth profiles in samples with different impurity concentrations. Using these methods, eight carbon-hydrogen related defect levels (E42, E65, E75, E90, E90', E262, H50, H180) and one hydrogen related level (E150) were detected in Si, SiGe alloys and Ge. Hydrogen plasma treatment at temperatures around 373 K introduces four dominant traps in Si at about Ec-0.06 eV (E42), Ec-0.52 eV (E262), Ev+0.33 eV (H180), and Ev+0.08 eV (H50). E42 and E262 are shown to be two charge states of the same defect. The characteristic field dependence of their emission rate links E42 with the double acceptor level and E262 with the single acceptor level of a CH complex. By comparison of their properties with calculations they are assigned to the anti-bonding configuration of the CH complex (CH_1AB). H180 was previously suggested to be the donor state of the CH_1AB configuration. This hypothesis could not be confirmed. Instead, it is shown that H180 exhibits a barrier for hole capture of about 53 meV, which hinders the reliable determination of its charge state from the field dependence of the emission rate. However, its activation enthalpy is in reasonable agreement with the predicted level position of the acceptor state of the CH_T configuration of CH, where H sits on the tetrahedral interstitial (T) position next to carbon. Therefore, H180 is tentatively assigned to CH_T. H50 is reported for the first time and it appears with concentrations close to the detection limit of the DLTS technique (~1E11 cm^-3). This complicates the determination of its charge state. Nevertheless, theory predicts the acceptor level of the CH_2AB configuration at about Ev+0.07 eV, which is remarkably close to the experimental value of H50. Therefore, H50 is tentatively assigned to the acceptor level of CH_2AB. In contrast, hydrogenation of silicon by wet chemical etching introduces three dominant levels at Ec-0.11 eV (E65), Ec-0.13 eV (E75), and Ec-0.16 eV (E90). Previously, E90 was contradictorily assigned by different authors to the donor and to the acceptor state of the bond-centered configuration of the CH complex (CH_1BC). In this work, this contradiction is resolved. It is shown that two different defect levels (E90 and E90') appear in the DLTS spectra at about 90 K in samples with a low oxygen concentration (< 1E17 cm^-3). The acceptor state of the CH_1BC configuration (E90) can be observed directly after hydrogenation by wet chemical etching or a dc hydrogen plasma treatment at temperatures below 373 K. In contrast, the donor state of a CH_n complex (E90', Ec-0.14 eV), that involves more than one hydrogen atom, is formed by a reverse bias annealing of samples with a net donor concentration of Nd > 1E15 cm^-3. By comparison with theory it is concluded that n > 2. In samples with a high oxygen concentration (> 1E17 cm^-3) E65 and E75 are dominant. Both levels belong to the CH_1BC configuration disturbed by a nearby oxygen atom. The appearance of two levels is the result of two inequivalent positions of the oxygen atom in respect to the CH bond. E42, E90, E262, and H180 are also investigated in diluted SiGe alloys to analyze the influence of alloying on their electrical properties. The presence of Ge atoms in the closest environment of the defects leads to the appearance of additional defect levels close to those observed in pure Si. The relative concentration of these additional defects is in agreement with models of the proposed defect structure of E42, E90, E262, and H180. An increase of the Ge content in SiGe alloys leads to a shift of the defect levels in the band gap of SiGe. An extrapolation of this shift predicts the appearance of E90 and E262 also in pure Ge. A hydrogen related level E150 (Ec-0.31 eV) is indeed observed in hydrogenated n-type Ge. Its concentration is significantly higher after hydrogen plasma treatment than after wet chemical etching. It is shown that E150 contains a single hydrogen atom and involves an unknown impurity, most likely carbon, oxygen, or silicon. E150 represents a reasonable candidate for a CH complex in Ge. / In dieser Arbeit werden die elektrischen Eigenschaften von Kohlenstoff-Wasserstoff-Komplexen in Silizium (Si) und Silizium-Germanium-Legierungen (SiGe) studiert. Diese Komplexe bilden sich durch Reaktion von Kohlenstoff-Verunreinigungen mit Wasserstoff, welcher durch nasschemisches Ätzen oder eine Wasserstoffplasma-Behandlung eingebracht wird. Der Nachweis und die Charakterisierung der Defekte erfolgte mit den Methoden der Kapazitätstransientenspektroskopie (DLTS), Laplace DLTS und der Minoritätsladungsträgertransientenspektroskopie (MCTS). Damit wurden Eigenschaften wie die Aktivierungsenergie der Ladungsträgeremission, die Einfangquerschnitte, der Ladungszustand und die thermische Stabilität der Komplexe bestimmt. Die Zusammensetzung der Komplexe wurde durch eine Analyse der Tiefenprofile ermittelt, welche in Proben mit verschiedenen Verunreinigungskonzentrationen gemessen wurden. Mit diesen Methoden wurde acht Kohlenstoff-Wasserstoff-korrelierte Defektniveaus (E42, E65, E75, E90', E90, E262, H50, H180) in Si und SiGe und ein Wasserstoff-korreliertes Niveau in Ge nachgewiesen. Eine Wasserstoffplasma-Behandlung bei Temperaturen um 373 K erzeugt vier dominante Defektniveaus in Si bei Ec-0.06 eV (E42), Ec-0.52 eV (E262), Ev+0.33 eV (H180) und Ev+0.08 eV. Es wird gezeigt, dass E42 und E262 zwei Ladungszustände desselben Defektes sind. Die charakteristische Feldabhängigkeit der Emissionsrate zeigt, dass E42 der Doppel-Akzeptor- und E262 der Einfach-Akzeptor-Zustand eines CH-Komplexes ist. Durch Vergleich der beobachteten Eigenschaften mit theoretischen Berechnungen werden beide Niveaus der antibindenden Konfiguration des CH-Komplexes (CH_1AB) zugeordnet. Das Niveau H180 wurde in der Literatur bisher mit dem Donator-Zustand der CH_1AB-Konfiguration in Verbindung gebracht. Diese Hypothese konnte nicht bestätigt werden. Es wird gezeigt, dass H180 eine Barriere für den Löchereinfang von etwa 53 meV besitzt, was die Bestimmung des Ladungszustandes aus der Feldabhängigkeit der Emissionsrate erschwert. Die Aktivierungsenergie von H180 stimmt jedoch befriedigend mit der berechneten Aktivierungsenergie des Akzeptorzustandes der CH_T-Konfiguration überein, bei der H auf der T-Zwischengitterposition sitzt. Daher wird H180 vorläufig dem CH_T-Komplex zugeordnet. Das Niveau H50, welches zum ersten Mal hier beschrieben wird, wird nur mit sehr geringen Konzentrationen nachgewiesen. Dies erschwert die Bestimmung des Ladungszustandes. Die Aktivierungsenergie von H50 stimmt jedoch auffallend gut mit dem von der Theorie vorhergesagten Akzeptorniveau von CH_2AB (Ev+0.07 eV) überein. Daher wird H50 vorrübergehend CH_2AB zugeordnet. Das Einbringen von Wasserstoff in Silizium durch nasschemisches Ätzen führt zu drei dominanten Defektniveaus bei Ec-0.11 eV (E65), Ec-0.13 eV (E75) und Ec-0.16 eV (E90). E90 wurde bisher widersprüchlich von verschiedenen Autoren dem Donatorzustand und dem Akzeptorzustand der bindungszentrierten Konfiguration (CH_1BC) des CH-Komplexes zugeordnet. Dieser Widerspruch konnte aufgelöst werden. Es wird gezeigt, dass in Silizium mit niedrigem Sauerstoffanteil (< 1E17 cm^-3) zwei verschiedene Defektniveaus (E90 und E90') bei etwa 90 K in den DLTS-Spektren erscheinen, welche nur mit der Laplace DLTS-Technik aufgelöst werden können. Der Akzeptorzustand der CH_1BC-Konfiguration kann direkt nach nasschemischem Ätzen oder einer Wasserstoffplasma-Behandlung bei 373 K beobachtet werden. Im Gegensatz dazu wird durch eine Sperrspannungs-Temperung in Proben mit einer Donatorkonzentration von Nd > 1E15 cm^-3 der Donatorzustand eines CH_n-Komplexes (E90', Ec-0.14 eV), welcher mehr als ein Wasserstoffatom enthält, gebildet. Durch Vergleich mit theoretischen Berechnungen wird n > 2 geschlussfolgert. Die Niveaus E65 und E75 sind in Proben mit einem hohen Sauerstoffanteil (> 1E17 cm^-3) dominant. Beide Niveaus gehören zu einer durch ein O-Atom verzerrten CH_1BC-Konfiguration. Das Auftreten von zwei Niveaus wird durch zwei nicht-äquivalente Positionen des O-Atoms bezüglich der CH-Bindung erklärt. Die Eigenschaften von E42, E90, E262 und H180 wurden ebenfalls in verdünnten SiGe-Legierungen untersucht. Es wird gezeigt, dass Ge-Atome in der direkten Umgebung der Defekte zusätzliche Defektniveaus erzeugen, die in der Bandlücke nahe zu den Si-Defektniveaus liegen und von durch Ge-Atomen verzerrten Defekten stammen. Die beobachteten relativen Konzentrationen dieser Ge-korrelierten Niveaus kann mit Modellen der atomaren Struktur der Defekte erklärt werden. Eine Verschiebung der Defektniveaus proportional zum Ge-Anteil in der Legierung wurde beobachtet. Eine Extrapolation dieser Verschiebung legt den Schluss nahe, dass E90 und E262 auch in reinem Ge beobachtbar sein sollten. Tatsächlich wurde ein Wasserstoff-korrelierter Defekt E150 (Ec-0.31 eV) in n-Typ Germanium beobachtet. Die Konzentration von E150 ist nach einer Wasserstoffplasma-Behandlung wesentlich höher als nach nasschemischen Ätzen. Es wird gezeigt, dass E150 ein einzelnes Wasserstoffatom und ein noch unbekanntes Verunreinigungsatom enthält, höchstwahrscheinlich Kohlenstoff, Sauerstoff oder Silizium. Damit ist E150 ein sehr wahrscheinlicher Kandidat für einen CH-Komplex in Germanium.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21274号 / 工博第4502号 / 新制||工||1700(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 村上 正浩, 教授 松原 誠二郎, 教授 杉野目 道紀 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Les composites C/C sont utilisés dans les domaines du spatial et de l'aéronautique pour leurs excellentes propriétés thermomécaniques depuis la température ambiante jusqu'aux très hautes températures (> 3000°C). Ces matériaux ont une architecture complexe constituée de nappes de fibres stratifiées et aiguilletées. Leur utilisation en zones fortement sollicitées et à haute température nécessite une maîtrise des propriétés thermiques et mécaniques. Actuellement, la conception du matériau se fait de manière empirique et itérative. Pour l'accélérer, le développement d'un modèle numérique multi-échelle prédictif du comportement du composite C/C est proposé. Ce matériau a tout d'abord été caractérisé morphologiquement à ses différentes échelles caractéristiques, les propriétés thermomécaniques de ses constituants élémentaires ont également été identifiées. A l'échelle microscopique, les fils sont représentés de façon homogène et thermoélastique à partir des taux de constituants qui leurs sont associés. A l'échelle mésoscopique, deux aspects morphologiques semblent prédominants : son architecture ainsi que ses porosités et endommagements. Leur effet sur le comportement effectif du composite C/C est étudié dans le but d'évaluer leur influence relative et d'aboutir à une description suffisamment fine de leurs morphologies dans la modélisation effectuée. Un modèle de matériau idéalisé ainsi qu'un modèle basé images ont été développés. La simulation d'essais macroscopiques a révélé que ces deux aspects avaient un effet non-négligeable sur le comportement effectif du composite C/C et ont permis le développement et la validation d'un modèle prédictif multi-échelle de ce matériau, prenant en compte les caractéristiques précédentes, et permettant le lien entre l'échelle de ses constituants élémentaires et celle macroscopique. / C/C composites are used in space and aeronautics for their excellent thermomechanical properties from room temperature to very high temperatures (> 3000°C). These materials have a complex architecture consisting of layers of laminated and needled fibers. Its use in highly stressed areas and at high temperature requires control of thermal and mechanical properties. Currently, the design of the material is done empirically and iteratively. To accelerate it, the development of a multi-scale digital model of the C/C composite is proposed. This material was first morphologically characterized at its different characteristic scales, the thermomechanical properties of its elementary constituents were also identified. At the microscopic scale, the wires are represented homogeneously and thermoelastically from the constituent levels associated with them. At the mesoscopic scale, two morphological aspects seem to predominate: its architecture as well as its porosities and damages. Their effect on the effective behavior of the C/C composite is studied in order to evaluate their relative influence and to arrive at a sufficiently fine description of their morphologies in the modeling carried out. An idealized material model as well as an image based model have been developed. The simulation of macroscopic tests revealed that both aspects had a non-negligible effect on the effective behavior of the C/C composite and allowed the development and validation of a multi-scale predictive model of this material, taking into account the preceding characteristics, and allowing the link between the scale of its elementary constituents and the macroscopic one.

La chimie des composés à base d'iode hypervalent (i.e., iodanes) connaît un fort intérêt depuis le début des années 1990 comme en témoigne le panel de composés iodés disponibles commercialement et le nombre de transformations chimiques que ces réactifs peuvent promouvoir. Au cours de la dernière décennie,les recherches se sont essentiellement concentrées sur le développement d’iodanes chiraux et leurs applications en synthèse asymétrique. La plupart de ces iodanes sont utilisés pour la création hautement sélective de liaison carbone-hétéroatome (C–O, C–N, C–F…). La création asymétrique de liaison carbone-carbone (C–C) médiée par des iodanes chiraux a cependant été très peu étudiée jusqu'à présent. Dans ce contexte, notre groupe de recherche a décrit la synthèse de nouveaux iodanes-λ5chiraux biaryliques et de type Salen ainsi que leurs applications à la désaromatisation oxygénante asymétrique de 2-alkyl phénols avec des excès énantiomériques (ee) supérieurs à 90%. Ces travaux de thèse sont consacrés au développement de nouveaux iodanes-λ3 chiraux porteurs de ligands carbonés transférables pour la création asymétrique sans métal de liaison C–C. Sont plus particulièrement décrits la synthèse de bis(alcynyl-iodanes-λ3) biphényliques atropopurs et leur utilisation dans l’alcynylation énantiosélective de β-cétoesters (jusqu’à 68% ee) et, pour la première fois, de naphtols (jusqu’à 84% ee). / The chemistry of hypervalent organoiodine compounds (i.e., iodanes) has unarguably experienced an impressive development since the early 1990s, as evidenced by both the diversity of iodane reagents that are commercially available today and the number of chemical transformations that those reagents can promote.Over the last decade, the elaboration of new chiral iodanes and their applications in asymmetric synthesis have attracted special interests and research efforts. Most ofthem are involved in highly selective carbon-heteroatom bond-forming reactions (C–O, C–N, C–F…). However, C–C bond-forming reactions in a stereoselective fashion with chiral iodane are yet underexploited. In this context, our research group reported the synthesis of new biarylic and Salen-type chiral λ5‐iodanes and their successful application to the asymmetric hydroxylative phenol dearomatization of 2alkylphenols, with enantiomeric excesses (ee) above 90%. This thesis work is dedicated to the development of new chiral λ3‐iodanes bearing transferable carbon-basedligands for metal‐free asymmetric C–C bond construction. In particular, the synthesis of chiral biphenylic bis(alkynyl-λ3-iodanes) and their successful application to the enantioselective alkynylation of β‐ketoesters (up to 68% ee) and 2‐substituted naphthols (up to 84% ee) are described.