Дисертації з теми "Composites – Matériaux nanostructurés – Nanotubes"
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Wang, Genwei. "Stabilité du nanotube de carbone : fabrication et comportement mécanique du composites à base des nanotubes." Cachan, Ecole normale supérieure, 2006. http://tel.archives-ouvertes.fr/tel-00136102.
Повний текст джерелаThe stability of carbon nanotube under self weight is analyzed by continuum method. Research results show that the critical aspect ratio can reach to 106. Double cantileveled beam model is used to study the pull in instability of two carbon nanotubes under van der waals forces. The obtained results are useful for the critical design of carbon nanotube based nanoswitch. Carbon nanotube/sic (cnt/sic) hybrid structure are fabricated by chemical vapor despositon. Different loadings of cnt/sic are added into epoxy resin to make micro/nanoscale hybrid composites. The static and dynamic compressive tests are first made to study the renforcement of different filler. Sem observation on the facture surfaces shows that both carbon nanotube and sic particle are dispersed homogeneously
Massuyeau, Florian. "Études photophysiques d'un polymère conjugué nanostructuré : du film nanocomposite à la nanofibre." Nantes, 2008. http://www.theses.fr/2008NANT2115.
Повний текст джерелаThis PhD. Thesis is aimed at the investigation of organic nanomaterials presenting original photophysical properties. We address the consequences of nanostructuration on the absorbing and emissive properties of poly(p-phenylene vinylene) (PPV), a prototypal semiconducting conjugated polymer for light emitting diode applications. On one hand we investigate quasi-two dimensional thin composite films of PPV loaded with carbon nanotubes (CNT). On the other hand, we achieve the synthesis of quasi-one dimensional PPV nanofibers exhibiting optical properties different from the bulk, which are possibly related to a near confinement regime of the photoexcited species. The PPV/NTC nanocomposite thin films are prepared by drop casting for several concentrations of PPV precursor polymer and for increasing CNT loads. The optical properties are strongly modified by these synthesis conditions. The interacting effects between polymer chains and CNT on the photoluminescence properties are discussed. The PPV nanofibers are elaborated by the wetting template method in nanoporous membranes. Depending on the synthesis conditions, we obtain either nanowires or nanotubes. These objects present different emissive characteristics. In PPV nanotubes, the quantum yield is increased and a new long-lived photoluminescence band is observed around 450 nm. We discuss the experimental results with two theoretical approaches: (i) molecular calculations of oligomers in order to find the most probable optical transition energies in short chains; (ii) a phenomenological model based on the distribution of conjugated segment lengths, allowing for a better understanding of both intrachain and interchain interactions
Do, Isabelle. "Nanocomposites nanotubes de carbone/élastomère : Propriétés rhéologiques et électriques." Pau, 2007. http://www.theses.fr/2007PAUU3005.
Повний текст джерелаSince carbon nanotubes (CNT) tend to remain as entangled agglomerates, homogeneous dispersed states within a polymer is not easily obtained, which reduces the interest of nanotubes as reinforcements. Many of the solutions proposed to address this issue rely on the modification of the interface between carbon nanotubes and the polymer matrix. The aim of the study is to establish the relationship between the nature of the CNT/polymethylacrylate (PMA) interface and the spatial organization of the CNTs in the matrix, on the one hand, and rheological and electrical properties of the nanocomposites, on the other hand. The interface is controlled by using polyacrylic acid (PAA), either by grafting it on the nanotubes surface, or by using it as a surfactant. The study of the morphology of the composites by electronic microscopy showed the importance of distinguishing the distribution of CNTs in the matrix (i. E. The repartition of the nanotubes clusters in the whole sample), from their dispersion (i. E. Their individualization within the clusters). This distinction is central as it allows explaining the physical properties of the nanocomposites. The studies of the linear viscoelastic and electrical properties of the composites highlighted the existence of percolation phenomena. We also showed that the electrical properties of the composites are sensitive to the CNTs dispersion, whereas the rheological ones are sensitive to the quality of distribution. The use of PAA, either grafted or adsorbed on nanotubes, allows an increase in electrical conductivity as well as a better dispersion of the nanotubes, thus lowering the electrical percolation thresholds
Lanfant, Briac. "Élaboration et étude des propriétés thermomécaniques de composites à matrice SiC nanostructurée renforcée par des nanotubes de carbone." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112275/document.
Повний текст джерелаCeramic carbides materials such as SiC, due to their refractory nature and their low neutron absorption are believed to be promising candidates for high temperature nuclear or aerospace applications. However, SiC brittleness has limited its structural application. In this context this work examines in a first part the possibilities to perform dense nanostructured SiC matrix by SPS without the use of sintering additive. Indeed a reduction of grain size (below 100 nm) accompanied by a high final density seem to be the solutions to counteract the brittleness and thus to improve mechanical properties. Dense (95%) and nanostructured (grain size around 100 nm) SiC samples were obtained thanks to the realization of an effective dispersion technique and the study on the sintering parameters effect. High hardness (2200 Hv) and decent fracture toughness (3.0 MPa.m1/2) were achieved. This first work also showed the preponderant influence of recurrent pollutants (oxygen and carbon) found in SiC powders on the final microstructure and mechanical properties of sintered samples. The oxygen as silica or silicon oxycarbide seems to promote densification mechanisms while free carbon (3.5%wt) causes lower grain size and densification state. Mechanical properties with carbon are also negatively impacted (950 Hv and 2.4 MPa.m1/2). Such degradation is due by the specific localization of carbon structure between the grains. In return of the expected mechanical properties improvement by reducing the grain size, the thermal conductivity is drastically decrease of due to the phonon scattering at the grain boundaries. With the aim of reducing this effect, a second study was initiated by introducing multiwalled carbon nanotubes (MWCNTs) into the SiC matrix. The MWCNTs by exhibiting a high toughness could also help to enhance the mechanical properties. Green bodies with different amounts of well dispersed MWCNTs (0%wt to 5%wt) were realized. Like free carbon, MWCNTs are located between the grains and induce a reduction of grain size. However the appearance of CNTs percolation for an amount above 1%wt, with the SPS sintering technique, allows an improvement of densification up to 97%. Hardness (up to 2550 Hv) and fracture toughness (4.0 MPa.m1/2) are also achieved with the SiC/NTC composites. Despite the good thermal properties of MWCNTs, the increase of grain boundary decreases the thermal conductivity of these composites
Bardash, Liubov. "Synthesis and investigation of nanostructured polymer composites based on heterocyclic esters and carbon nanotubes." Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10174/document.
Повний текст джерелаThe thesis relates to synthesis and investigation of nanostructured polymer composites based on oligomers of cyanate esters of bisphenol a (DCBA) or cyclic butylene terephthalate (CBT) and multiwalled carbon nanotubes (MWCNTS). Catalytic effect of mwcnts in process of DCBA polycyclotrimerization as well as in cbt polymerization has been observed. Significant increase in crystallization temperature of nanocomposites based on polybutylene terephthalate (cPBT) with adding of MWCNTS is observed. The effect of processing method of cpbt/mwcnts nanocomposites on its electrical properties has been found. It has been established that the additional heating of the samples (annealing) at temperatures above melting of cPBT leads to reagglomeration of MWCNTS in the system. It is established that reagglomeration of MWCNTS results in increase of conductivity values of nanocomposites due to formation of percolation pathways of MWCNTS through polymer matrix. In the case of polycyanurate matrix (PCN), it is found that addition of small mwcnts contents (0.03-0.06 weight percents) provides increasing tensile strength by 62-94 percents. It has been found that addition of even 0.01 weight percents of MWCNTS provides significant increase in storage modulus of cPBT matrix. This is explained by effective dispersing of small amount of the nanofiller during in situ synthesis of pcn or cpbt matrix that is confirmed by microscopy techniques. It has been established that the properties of the nanocomposites based on heterocyclic esters and MWCNTS can be varied from isolator to conductor and has low percolation thresholds (0.22 and 0.38 weight percents for cPBT and PCN nanocomposites respectively). The conductivity of samples is particularly stable on a very large range of temperature from 300 to 10 degrees Kelvin that make these materials perspective for practical applications in microelectronics, as parts of aircraft and space constructions
Oubenali, Mustapha. "Synthèse par dépôt chimique en phase vapeur catalytique (C-CVD) de nanostructures de carbone et leurs applications en catalyse et pour des matériaux composites." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0058/document.
Повний текст джерелаIn this work, we describe the different forms, the catalytic growth, the structure and properties of carbon nanotubes and nanofibres (Chapter I). Hydroxyapatite was used as catalyst support for the synthesis of multi-walled carbon nanotubes (MWCNTs) and nanofibres (CNFs) by catalytic chemical vapour deposition (C-CVD) in a fluidized bed reactor (Chapter II). After support removal by washing with diluted hydrochloric acid, a theoretical and experimental study of surface oxidation of carbon nanotubes by nitric acid treatment has been performed. It allows to identify and quantify the groups formed on the surface of carbon nanostructures and also to propose a mechanism for the formation of these groups (Chapter III). The functionalized nanotubes and nanofibers have been used as supports for heterogeneous catalysis. The hydrogenation of p-halonitrobenzene was used as model reaction to compare the catalytic performances of ruthenium supported on MWCNTs or CNFs-H catalysts. The influence of experimental parameters such as temperature, nature of the substrate and prior heat treatment (activation) of the catalyst on the catalytic activity and selectivity is presented. The catalytic performances have been correlated to the structure of the catalyst as determined from TEM, TPD, TPR and PZC analysis (Chapter IV). The carbon nanostructures produced have also been used as reinforcement fillers for hydroxyapatite-nanotube composites. We have studied in particular, the germination of octacalcium phosphate crystals under conditions of constant solution composition on the surface of the composite (Chapter V)
Cayla, Aurélie. "Élaboration de détecteurs souples de température : mise en oeuvre et caractérisation de multifilaments à base de polymères immiscibles chargés en nanotubes de carbone." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10086/document.
Повний текст джерелаThis study is a part of the European research project INTELTEX (“Intelligent multireactive textiles Integrating nano-filler based CPC-fiber”) of the Sixth Framework Programme for Research and Technological Development. The elaboration of a textile sensors is ensured by the incorporation of carbon nanotubes (CNT) in one or more polymers. The final goal of this work is to integrate in Personal Protective Equipment (PPE) for fire-fighters, a new textile composite based on the use of innovative nanofillers enables them to be alerted at a critical elevation of the surrounding temperature. The realisation of this sensor requires the preparation of a biphasic Conductive Polymer Composite (CPC), where the two polymers have farther melting temperatures and one of which corresponds to the wished detection temperature. The CNT are introduced in the phase which is sensible to the temperature elevation (Polycaprolactone (PCL)) and protected by the second polymer whose melting temperature is higher (Polypropylene (PP)). For our application, an interpenetration of two phases (co-continuous morphology) and a selective localization of CNT in the PCL are privileged to obtain a good electrical conductivity. Once the development step of the biphasic conductive multifilament (by melt spinning) reached, the yarn is embedded in an instrumented woven structure, which permits to record the electrical signal. The presence of an effect of Positive Temperature Coefficient (PTC) allows the detection at the melting temperature of PCL (58°C). The firsts prototypes studied under conditions closer to the reality show the reproducibility so that very promising results
Chihi, Manel. "Étude des performances d’un composite carbone/époxy dopé par des nanocharges sous des sollicitations sévères." Electronic Thesis or Diss., Brest, École nationale supérieure de techniques avancées Bretagne, 2021. http://www.theses.fr/2021ENTA0017.
Повний текст джерелаThis thesis work was carried out in a context of valorization of composite materials based on nanofillers. The knowledge of the mechanical behavior of nanocomposites doped by nanofillers submitted to high dynamic loading is an important data for the designers of composite structures dedicated to civil and military applications. This behavior must be characterized in a wide range of deformation; for strain rates in the range of 10² to 10⁵s⁻¹. Particular attention is devoted to the Hopkinson pressure bar system (SHPB) because of its frequent use in such a wide range of deformation which corresponds to the strain rate deformation range of most industrial applications. In this context, we first conducted a study focused on the effect of nanofillers on the dynamic behavior and damage kinetics of a carbon/epoxy composite. We have chosen two types of nanofillers with similar chemical compositions (based on pure carbon) but two different geometries (quasi-1D for carbon nanotubes (CNT) and 2D for graphene nanoplatelets (GNP). The two series of nanocomposites CNT and GNP were prepared under the same conditions while using common mass fractions (0.5%, 1% and 2%) in order to conduct a comparative study of the two nanocomposite systems. A dynamic compression test (in-plane (IP) and out-of-plane (OP)) and a numerical study were conducted. It has been shown that the dynamic behavior and damage kinetics of the materials are very sensitive to the strain rate and the direction of solicitation. The results of these tests also allowed us to understand the influence of the addition of nanofillers on the response of the materials. The percentage of 1% GNP shows optimal performances in stiffness, maximum stress and resistance to damage. However, nanocomposites can be very sensitive to environmental conditions, in particular to hygrothermal aging that can reduce the mechanical performances. Therefore, the effect of hygrothermal aging (60°C/80%RH) on the lifetime of nanocomposites is studied experimentally (in-plane loading). Decreases of different mechanical properties as a function of time (15, 40 and 100 days) and absorbed water content are highlighted for each mass fraction. However, it was shown that the introduction of nanofillers, except in the case of 0.5% CNT, leads to a more significant degradation of the reference composite
Daon, Joffrey. "Matériaux d'Interface Thermique Nanostructurés." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC082/document.
Повний текст джерелаWith progress in microelectronics, the miniaturization of devices is a current issue and the component density on a device follows Moore’s law. As a consequence the power density reaches levels that challenge device reliability. New heat dissipation strategies are needed to efficiently drain heat.Thermal interface materials (TIMs) are used to transfer heat across interfaces, for example between the device and its packaging. However, to meet microelectronics requirement, commercials TIMs still need to be highly thermally conductive.In order to achieve these requirements, this work is focused on the use of vertically aligned carbon nanotubes (VACNTs) and functional polymers. All thermal contact resistances existing in TIMs, from VACNTs / Polymer / to substrate are studied.Interaction optimizations are based on the study of different polymers which are specially designed to develop covalent bonding with the CNTs sidewalls and/or metallic surface. The interest of these covalent bondings is to improve the thermal transfer by phonons. Finally, the increase of the intrinsic thermal conductivity of the polymer is considered.Regarding the results, a decrease of all thermal contact resistances is shown. In order to have a better understanding of these results, the thermal interfaces obtained are analyzed in situ
Axel, Salinier. "Préparation d’un composite hybride par co-malaxeur : influence des paramètres de mise en oeuvre sur les propriétés." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3047/document.
Повний текст джерелаThis PhD work deals with the relationship between the processing parameters at the melt state and the polymer matrix hybrid composite material’s properties. The fillers studied are short glass fibres (micrometric scale) and carbon nanotubes (CNT) (nanometric scale) dispersed in a high temperature polymer matrix, the poly(etherimide) (PEI). We showed that glass fibres strongly participate in the CNT network structuration and that electrical conductivity of multiscale composite materials is higher than the one of nanocomposite materials. The combination of the two fillers allows obtaining a synergy effect for the mechanical properties especially for the elongation at break which is due to a preferential localization of CNT at the PEI/glass fibres interfaces. The study of the influence of processing parameters on the properties of nanocomposite materials and hybrid composite materials showed that Specific Mechanical Energy (SME) has a strong influence on the hybrid composite material properties and especially on the electrical conductivity. These variations are the consequences of CNT network modifications. Glass fibres concentration has also a strong influence on the electrical conductivity of the hybrid composite materials. It is possible to adjust the electrical conductivity with modifying the concentration of glass fibres especially for the CNT amount closed to the electrical percolation threshold
Jourdain, Vincent. "Croissance catalytique séquentielle de nanotubes de carbone." Montpellier 2, 2003. http://www.theses.fr/2003MON20146.
Повний текст джерелаFranchini, Elsa. "Structuration of nano-objects in epoxy-based polymer systems : nanoparticles & nanoclusters for improved fire retardant properties." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0006/these.pdf.
Повний текст джерелаIl a été montré récemment que l’ajout de particules nanométriques au sein d’un matériau polymère pouvait conduire à une meilleure résistance au feu, tout en préservant les propriétés mécaniques du matériau de base. Cette nouvelle voie d’ignifugation constituerait par ailleurs une approche plus respectueuse de l’environnement, et une bonne alternative à l’utilisation traditionnelle d’additifs bromés très toxiques. Un des paramètres clé dans de tels matériaux, afin d’obtenir d’intéressantes propriétés feu, semble être l’état de dispersion et l’organisation des nano-objects au sein de la matrice. L’objectif de cette thèse est donc d’introduire dans une matrice epoxy différents types de nano-objets. L’idée générale est de contrôler l’état de dispersion de différents nano-objects au sein d’une matrice epoxy et d’étudier l’influence de ce paramètre sur les morphologies et propriétés générées. Deux types de nanoparticules à haut facteurs de forme ont été étudiées: la sépiolite et les nanotubes de carbone. Un deuxième type de nano-objet a aussi été étudié : les clusters POSS qui ont une structure hybride organique/inorganique. Le premier travail de cette thèse a été de comprendre les phénomènes qui peuvent intervenir lors de la mise en œuvre de tels matériaux, afin de faire ressortir les paramètres clé qui permettent le contrôle de l’état de dispersion des nano-objets au sein de la matrice, et ce, afin de contrôler la nanostructuration développée. Dans une deuxième partie, les morphologies générées ont été étudiées et mises en relation avec les propriétés générales des matériaux ainsi structurés et plus particulièrement avec les propriétés de résistance au feu des matériaux
Dudek, Christophe. "Étude de matériaux hyperfréquences innovants : des microfils nanocristallisés aux composites magnétiques artificiels." Tours, 2006. http://www.theses.fr/2006TOUR4011.
Повний текст джерелаThis thesis concerns the development of new concepts in the microwave's magnetic materials field. Based on a multiple approach of the dynamic permeability, several attempts have been carried out. On the one hand, the study of nanocrystallized ferromagnetic glass-coated microwires has led, for the first time, to significant permeability levels up to 4 GHz at 350°C. On the other hand, a new type of metamaterial made of ferromagnetic core combined with copper helices has exhibited a large band microwave permeability. Eventually, the analysis of the magnetic response of magnets as part of mechanical systems has evidenced the concept of vibrating inductor in a magnetic field. This new technology seems to offer great potential gains
Saba, Johan. "Electrodéposition de polymère conducteur électronique sur des fibres de carbone greffées de nanotubes de carbone." Thesis, Cachan, Ecole normale supérieure, 2012. http://www.theses.fr/2012DENS0073.
Повний текст джерелаThis thesis is part of the ANR project “PROCOM” from the Mat&Pro program whose coordinator is EADS IW. The aim of the project is the development of a process likely to be scaled up industrially to produce fibrous reinforcements for high performance composites. The project incorporates new concepts in nano / micro-scale and an electrochemical surface treatment. This PhD work presents the synthesis of an electronically conductive polymer (polypyrrole) by an electrochemical route, on the surface of hybrid reinforcements which are carbon fibers grafted by carbon nanotubes (CNTs). At first, the polymer synthesis has been optimized and the influence of different electrochemical parameters on the doping level and the thickness of the polymer layer was investigated. The parameters studied were the applied potential, the polymerization time, the nature of the electrolyte and the dopant. Then, the influence of polymer deposition on three very important parameters was considered. These parameters are the electrical conductivity, the mechanical properties and the adhesion of CNTs on the surface of the carbon fibers. The electrical properties are important because these composites are intended to be used for the fuselage of aircraft that must be able to dissipate the current from lightning. Good intrinsic electrical properties of CNTs and the use of a conductive polymer have improved the conductive properties of reinforcements. The polymer, which is at the interface between the reinforcing hybrid fibers and the matrix, is expected to improve the mechanical properties of the final material. However, to improve this interface different pre-treatments were carried out, such as heat treatment, plasma surface functionalization and incorporation of a grafting layer. Finally, the polymer plays a protective role in the dissemination of CNTs in the atmosphere in order to avoid any health risk. In a second step, a system for the electropolymerization of hybrid fibers in continuous was implemented with the aim of developing an industrially scalable process
Ben-Abdallah, Philippe. "Transferts de chaleur par rayonnement dans les matériaux composites micro et nanostructurés." Habilitation à diriger des recherches, Université de Nantes, 2008. http://tel.archives-ouvertes.fr/tel-00289689.
Повний текст джерелаLes développements réalisés ces dernières années dans le domaine des nanotechnologies autorisent désormais la structuration de la matière à une échelle sub-longueur d'onde jusque dans le domaine visible ce qui permet de sculpter à macro échelle les propriétés radiatives des matériaux composites et de contrôler les échanges radiatifs en champ proche dans ces milieux..
La première partie de mon HDR portera sur les transferts radiatifs dans les matériaux nanocomposites à gradient de permittivité diélectrique dans l'approximation de l'optique géométrique. Des avancées spectaculaires ont récemment été faites sur ce sujet grâce aux progrès technologiques réalisés dans le domaine de la nanofabrication. Il est désormais possible de concevoir des matériaux composites complexes pour générer artificiellement une variation spatiale de la permittivité diélectrique et de la perméabilité magnétique . Nous montrerons que cette structuration permet de modeler les trajets optiques et de contrôler le flot d'énergie radiative dans ces milieux. Nous verrons qu'il existe une analogie forte entre la théorie de la relativité générale et l'électrodynamique classique dans un nanocomposite à gradient de permittivité diélectrique (i.e. la lumière expérimente la matière comme un champ gravitationnel effectif). Nous montrerons comment le transfert radiatif peut-être modélisé dans ces milieux, quels sont les effets induits par la courbure de l'espace temps sur le champ de luminance, sur l'absorption, le processus diffusion et le champ de température. Nous verrons en particulier que la courbure de l'espace temps permet dans certaines conditions d'amplifier la luminance monochromatique directionnelle dans un milieu absorbant. Enfin, nous montrerons que ces matériaux permettent de concevoir des sources thermiques cohérentes en champ lointain.
Dans une seconde partie nous nous intéresserons aux propriétés de cohérence du champ rayonné par des matériaux stratifiés micro et nanostructurés et à la mise au point de sources thermiques cohérentes à partir de ces matériaux. Nous commencerons par décrire le comportement émissif en champ lointain des films fins et montrerons que ces milieux peuvent se comporter comme des antennes thermiques. Nous verrons ensuite comment les structures composites planes peuvent servir à mettre au point des sources thermiques à haut de degré de cohérence spectrale simultanément pour les deux états de polarisation du champ électromagnétique. Enfin, nous montrerons qu'il est possible, pour concevoir une source thermique cohérente, d'abandonner la démarche heuristique usuelle basée sur une approche de type essai-erreur au profit d'une démarche ab-initio plus rationnelle.
Dans la troisième et dernière partie de ce mémoire nous présenterons nos travaux sur les transferts de chaleurs en champ proche dans les matériaux composites. Une fois de plus, on commencera par décrire le comportement des films minces. Nous verrons que lorsqu'un film supporte des ondes de surface, l'hybridation de ces modes de part et d'autre du film lui confère un comportement radicalement différent de celui des matériaux massifs. On étudiera ensuite les transferts de chaleur par interactions d'ondes de surface dans des réseaux de nanoparticules immergés dans des matrices diélectrique solides. Nous montrerons que lorsque les nanoparticules sont séparées par des distances plus grandes que leur diamètre, chaque particule peut-être considérée comme un simple dipôle en interaction avec ces voisins. Dans ce cas, nous verrons que le transfert de chaleur par interaction des polaritons de surface à travers le réseau est négligeable. En revanche, nous montrerons qu'à courtes distances de séparation (typiquement pour des distances inférieures au diamètre des particules) les interactions multipolaires peuvent devenir très importantes et augmenter significativement le transfert de chaleur. Enfin, nous étudierons le transport de chaleur dans les réseaux monodimensionnels en régime balistique et en régime diffusif .
Gaudon, Alexandre. "Matériaux composites nanostructurés par séparation de phases dans le système silice - zircone." Limoges, 2005. http://aurore.unilim.fr/theses/nxfile/default/04090e61-c42c-4fa5-a005-6843abcb42da/blobholder:0/2005LIMO0033.pdf.
Повний текст джерелаThis work is devoted to the synthesis of nanocomposite via a sol-gel process. We have more specifically focused our attention to the silica – zirconia system. Microstructural properties of these materials were investigated by small angle X-ray scattering, X-ray diffraction and transmission electron microscopy. After 600°C heat treatments, a nanoscaled amorphous phase separation consisting in silicon-rich and zirconium-rich interconnected domains was shown to be present. For higher heat treatments the crystallization of zirconia nanocrystals occurs in the previously formed zirconium-rich region. The size and spatial distribution of crystalline particles, dispersed in the amorphous silica-rich matrix, are controlled by the annealing conditions. Finally we have extended this study to silica – zirconia thin coatings and to potentially luminescent materials in the ZrO2 – Eu2O3 – SiO2 and ZnO – SiO2 systems
Bouizi, Younes. "Micro-composites formés d'une couche continue de zéolithe recouvrant un cœur de zéolithe – Etude des processus de formation." Mulhouse, 2005. http://www.theses.fr/2005MULH0810.
Повний текст джерелаThe present thesis deals with the preparation and the mechanism of formation of core-shell zeolite micro-composites comprising a single crystal core and a polycrystalline shell. Several framework types (BEA, FAU, LTA, MFI, MOR, SOD) covering a broad range of chemical compositions were combined in the course of this study in order to determine the factors controlling the formation of the composites. Two approaches, a direct synthesis and a secondary growth after seeding of the core surface, were employed. The reactivity of the core surface and structural similarities of the zeolites building the composite were found to be of paramount importance for the direct unseeded synthesis. The factors controlling the composite formation via secondary growth were found to be: (i) the composition of the two counterparts; (ii) the stability of the core crystals in the synthesis media; and (iii) the rapid crystal growth kinetics of the shell. The synthesized core-shell composites are expected to show improved performance in the existing petrochemical processes and to open routes for new applications for zeolite materials
Porcher, Marina. "Matériaux nanostructurés polymères conjugués/nanotubes de carbone verticalement alignés pour la réalisation de supercondensateurs." Thesis, Tours, 2016. http://www.theses.fr/2016TOUR4025/document.
Повний текст джерелаThis thesis focused on the elaboration of nanostructured composite materials based on vertically aligned carbon nanotubes (aligned CNT) and π-conjugated polymers and their use as electrode materials in supercapacitor-type energy storage devices. The first part focused on aligned CNT growth by aerosol-assisted CVD on stainless steel substrates and the deposition of a SiOx ceramic sublayer. Thanks to the optimization of this growth process, long, dense, and aligned CNT carpets which can directly act as support for the electrodeposition of π-conjugated polymers were obtained. The second part focused on the electrodeposition of poly (3-methylthiophene) (P3MT) in EMITFSI ionic liquid medium on aligned CNT carpets using a “pulsed” chronopotentiometric method to produce homogeneous deposits in the depth of the carpets. An optimal P3MT mass composition of 70 %, which helped achieve a specific capacitance of 170 F.g-1 of polymer while maintaining high charge-discharge kinetics, compared with NTC/P3MT entangled composites, was determined. NTC/P3MT // P3MT/NTC symmetrical devices and CA // P3MT/NTC hybrid devices were assembled using the optimized composite materials. The hybrid device reached a voltage of 2.7 V and a system capacitance of 26 F.g-1 in EMITFSI at 25 ° C. Furthermore, a maximum energy of 23 Wh.kg-1 and a maximum power of 6.9 kW.kg-1 were obtained with only a 7 % loss after 4000 cycles. Finally, the electrodeposition of polypyrrole (Ppy) was investigated in different protic and aprotic ionic liquids. After quartz crystal microbalance studies in order to better understand the insertion mechanisms of ionic species during conjugated polymer growth and during its reversible positive doping, the electrodeposition of Ppy within the deepness of the aligned CNT carpets was optimized. Aligned CNT/Ppy nanocomposites with specific capacitances ranging between 100 and 130 F.g-1 were obtained
Semaan, Chantal. "Polymères nanostructurés à base de nanotubes de carbone." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14187/document.
Повний текст джерелаThis work is concerned with the study of carbon nanotubes (CNT) dispersions in a polymer matrix in order to obtain nanocomposite with unique properties. In the first part, we investigated the CNT wrapping by amphiphilic block copolymers to facilitate their suspension in aqueous solution. Based on the results, we could assess the effect on CNT dispersion quality of the molar mass of copolymers, the nature of the hydrophobic block and the length of hydrophilic block. In the second part, the incorporation of CNTs in polymer matrix was developed. Water or melt processing were chosen to control the distribution of CNTs in various polymer matrices (Polyethylene oxide, polyethylene and polymethyl methacrylate) through a prior wrapping of CNT. The studies of physical properties, including rheological and electrical properties, of nanocomposites were undertaken. Relationships between the state of dispersion, the nature of the coating and the method of preparation of composites were established
Timperman, Laure. "Matériaux electrocatalytiques nanostructurés pour la réduction de l'oxygène moléculaire et tolérants aux polluants." Poitiers, 2010. http://theses.edel.univ-poitiers.fr/theses/2010/Timperman-Laure/2010-Timperman-Laure-These.pdf.
Повний текст джерелаOxide/carbon composites (TiO2/C and WO3/C) were prepared by sol-gel method to be used as catalysts substrates. The synthesis of TiO2 in the carbon matrix allows for a more important oxidation of carbon because of a strong “chemical” interaction. The catalysts activity was evaluated for the cathodic oxygen reduction reaction. Metallic nanoparticles were deposited onto oxide/carbon supports by photo-deposition using UV light to generate electrons at the oxide surface in order to reduce the metallic salt, allowing a selective deposition of the metal onto the oxide by this way of synthesis, leading a strong interaction between the metal end the metal of the oxide of the composite. Furthermore, the electrocatalytic activity of these materials was improved as compared to carbon supported catalysts. The catalysts stability and tolerance towards organic molecules, as methanol or formic acid (for alcohol fuel cells, or membrane less fuel cells) were also studied
El, Moussawi Zeinab. "Matériaux composites nano-architecturés à base de nanotubes de carbone pour application photovoltaïque." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI095.
Повний текст джерелаControlled modulation of intrinsic functional (absorption, band gap, conductivity) and physico-chemical properties (dispersability, solvent-processability) of CNTs could broaden up their application potential in nanotechnology. However, it has been an ambitious synthetic goal for more than a decade. In this work, we developed an efficient methodology to do so in a mastered manner on single-walled carbon nanotubes (SWNT). It involves the meticulous functionalization based on gradual formation of covalent aryl bonds. It was proven that, the intrinsic electrical conductivity, optical and electrochemical properties of the functionalized SWNTs could be gradually modulated in two steps depending on the functionalization degree. The so- controlled covalent functionalization was the basic synthetic technique to make SWNT easier to manipulate and tolerably soluble, with modulated electrical and electrochemical properties, so that the performances in photovoltaic cells were unusually appreciated. Unsorted functionalized SWNTs were employed in organic photovoltaic (OPV) cells as electron acceptors or dopants with commercial polymer (P3HT) and novel, synthesized low bandgap copolymer, respectively
Basov, Sergey. "Nouvelles approches pour le design de composites multiferroïques nanostructurés de type (1-3)." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0007/document.
Повний текст джерелаMultiferroic materials including magnetoelectric materials that combine magnetic and ferroelectric orders have attracted great attention due to a possible strain-mediated coupling leading to potential applications in memories, sensors, detectors, spintronic and microwave devices. The number of single-phase multiferroic materials operating at room temperature being limited, we are exploring artificially designed multiferroic nanostructures consisting of ferroelectric and ferrimagnetic oxides. Current work is focused on strain-mediated magnetoelectric effect, which allows to generate a spontaneous polarization or magnetization by an applied magnetic field (direct ME effect) and electric field (converse ME effect) respectively. ME effects can be observed at room temperature through interface and strain interaction in two-phase multiferroic nanocomposites. The combination of piezoelectric materials PbZr0.52Ti0.48O3 (PZT), Ba0.7Sr0.3TiO3 (BSTO), BaTiO3 (BTO) and magnetostrictive CoFe2O4 (CFO) materials have been intensively studied in multiferroic nanocomposites. The community has been able to demonstrate large magnetoelectric coupling at room temperature in epitaxial thin films, so called 2-2 connectivity system, but a key limitation in epitaxially grown thin films is a substrate imposed clamping effect limiting thin film’s strain. Designing innovative architectures is a challenge in the field of multiferroic nanocomposites. Our work is focused on vertically aligned multiferroic nanostructures, so called (1-3) connectivity nanocomposites, where one-dimensional ferrimagnetic CoFe2O4 nanostructures (1) are embedded into three-dimensional PZT, BTO and BSTO layers (3). New routes were considered to design three kinds of materials: i) vertically aligned CFO nanowire arrays surrounded by PZT nanotubes embedded into alumina membranes; ii) vertically aligned CFO nanopillar arrays embedded in thin BTO, BSTO and PZT layers supported on Si substrates; ii) 3-D interconnected CFO nanowire networks embedded in a thick PZT matrix. The objectives of the present work are to control the oxidation of metallic CoFe2 nanowires and nanopillars to control the morphology and density of CFO nanostructures, to control the resistivity and dielectric losses of the nanocomposites at the interface region, and to increase the magnetoelectric coupling of the multiferroic nanocomposites by increasing the interfacial surface area between the two ferroic phases.The first geometry we are developing is a deposition by sol-gel dip impregnation of PZT nanotube arrays into self-supported porous alumina membranes, followed by an electrodeposition and thermal oxidation of CoFe2 nanowire arrays within PZT nanotubes. The second architecture we are focusing on is a deposition by RF magnetron sputtering of BSTO and BTO layers and by sol-gel dip coating of PZT layers onto vertically aligned CoFe2 and CoFe2O4 nanopillar arrays supported on Si substrates. The CoFe2 oxidation is conducted in-situ during the BSTO and BTO sputter deposition. Free-standing CoFe2 nanopillar arrays are obtained by electrodeposition into anodized alumina nanoporous structures and chemical dissolution of alumina templates. The last geometry is prepared using a combination of electrodeposition into self-supported porous polymer membranes and sol-gel processes. The PZT-CFO nanostructures are prepared using impregnation of thick PZT layers into self-supported CoFe2 3D nanowire networks on Si substrates by sol-gel method and their simultaneous oxidation during PZT layers crystallization. Specific attention was focused on interfaces through microstructural and morphological evaluations of nanocomposites using XRD, HRSEM, TEM and EDS characterizations. The performances of the nanocomposites were evaluated using magnetic, dielectric, ferroelectric and ME measurements, an alternating gradient magnetometer, impedance analyser, PFM and the ME susceptometer operated inside PPMS were utilized, respectively
Mallégol, Stéphane. "Caractérisation et application de matériaux composites nanostructurés à la réalisation de dispositifs hyperfréquences non réciproques." Phd thesis, Université de Bretagne occidentale - Brest, 2003. http://tel.archives-ouvertes.fr/tel-00004319.
Повний текст джерелаBarguet, Laurianne. "Contrôle acoustique et vibratoire de la mécano-synthèse des matériaux composites à matrice métallique nanostructurés." Thesis, Le Mans, 2015. http://www.theses.fr/2015LEMA1027/document.
Повний текст джерелаDuring the ODS steel (Oxide Dispersion Strengthened) synthesis, the first stage consists in an active milling between original materials, which are metallic powder and oxide to obtain reinforced micro/nanoscale dispersions. This process, known as mechanical alloying, could be realized by balls milling composed by a cylindrical tank rotating around its main axis, within which steel beads are introduced. The grinding results from different combinations of collisions between beads and powders on the tank walls, that lead to morphological grain powder evolution (grain size and shape). The first part of this thesis proposes an ultrasonic method to characterize the metallic powder. An experimental method, which consists in acoustic probing for measuring linear acoustic parameters (longitudinal wave velocity and elastic modulus) of a slab of powder sample, appears to be suitable to follow different mechanical alloying stages. A dependence of the acoustic parameters on the morphological characteristics of metallic powder (grain shape and grain size distribution) is shown with the same sample preparation and the same confining pressure. In the second part, optimization process by identification of ball milling optimal rotation speed is researched in a first step. Correlation between acoustic or vibration signals and bead motion versus rotation speed, shows that acoustic and vibration energy are good indicators that can be used to find the optimal rotation speed. In a second step, acoustic and vibration measures are used to follow grain material properties evolution during a grinding (for a period of 176hrs) and to identify powder clogging mechanism on a milling tank
Diebold, Morgane. "Systèmes composites organogélateurs/polymères semi-conducteurs : de la preuve conceptuelle aux matériaux nanostructurés pour l'électronique plastique." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAE002.
Повний текст джерелаImproving the performances of organic photovoltaic devices requires morphology control of the active layers. Highly nanostructured donor-acceptor bulk heterojunctions were prepared by heterogeneous nucleation of poly (3-hexylthiophene) (P3HT, donor) on naphthalene diimide organogelators fibers (NDI, acceptor). The first part of this work was dedicated to the self-assembly of NDI-core organogelators substituted by amide groups and trialkoxyphenyls dendrons. We evaluated the influence of the flexible chain between the naphthalene core and the amide groups (2 C-C bonds for NDI2 and 4 for NDI4) on the physico-chemical properties of the organogelators.The second part of this work focused on the polymorphism of NDI2 with identification of four different polymorphs with their optical, spectroscopic and structural signatures. A phase diagram of NDI2 in the solid state was determined. The last part of this manuscript concerns the fabrication of donor-acceptor nano-composites between NDI organogelators and P3HT. The formation process in solution of these nano-composites was analyzed by following the crystallization kinetics of P3HT by UV-Vis absorption spectroscopy and the thin film morphology (shish-kebab structures) by transmission electron microscopy. The nucleating effect of various organogelators on P3HT was demonstrated. Solar cells were made from the composites P3HT:PCBM : organogelator and their energetic conversion yield was shown to be increased in the presence of organogelators
Patel, Stéphanie. "Nanotubes de carbone alignés sur supports carbonés : de la synthèse aux matériaux composites." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112296.
Повний текст джерелаBecause of their properties, composite materials have attracted considerable interests in advanced technology such as in aeronautic field because of their properties. In the case of organic composite reinforced with long fibres, the properties depend not only on the reinforcements and the matrix but also on the interface between the fibre and the matrix (F/M). This thesis deals with the work led to integrate securely aligned carbon nanotubes (CNT) directly on carbon fibres (CF) in order to assess their effects on electrical and mechanical properties at the F/M interface in thermosetting and thermoplastic composite. To include aligned CNT directly on carbon substrates, the catalytic chemical vapour deposition synthesis method of CNT has been developed which consists in carrying out the synthesis in two steps in the same synthesis equipment avoiding intermediate handling. First, a deposition of oxide ceramic layer based on SiO2 is performed followed by the growth of CNT. The process has been adjusted in order to achieve a homogeneous growth of aligned CNT along the carbon fibre cloth compatible with industrial requirement for composite elaboration. Each material obtained from the different steps has been characterized with complementary physical and chemical analysis techniques in order to understand the ceramic sub-layer role on the growth of CNT. In particular, it has been pointed out that during the growth of CNT the sub-layer is modified by the incorporation of iron in the ceramic layer based SiO2, leading to the formation of mixed oxide which plays the role of diffusion barrier layer resulting in the growth of aligned, dense and long CNT on carbon substrates (glassy carbon, carbon fibre cloth). Besides, to avoid the dispersion of CNT in the atmosphere during the handling step for the elaboration of composite, a surface functionalization of CNT has been performed to encapsulate them. Finally, electrical and mechanical properties have been measured on carbon clothes exposed to different treatments and on composites reinforced with these clothes
Marcourt, Marjorie. "Étude de l’évolution de la conductivité électrique de matériaux composites sous déformations élongationnelles : application au thermoformage." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1097/document.
Повний текст джерелаIn this work we present a complete study of the electrical conductivity evolution of molten nano-composites under extensional deformation. The conductive polymer composites are a pure Polystyrene matrix filled with Carbon Nanotubes. The conductivity properties of the composites rely on the formation of a percolated network through the material. When the composite flows, the filler network can be disrupted, altering the conductivity of the composite. Thus, after a small deformation a moderately conductive composite can turn into an insulating material. From an applied viewpoint, for instance, the thermoforming of a composite sheet with good electrical properties can lead to an insulating finished part. In the literature, the studies mainly focus on the conductivity variation of molten composites under small shear deformation at low shear rates.This study aims at analyzing the microstructure evolution when the molten composite undergoes large deformation and especially in elongation. That is why we developed a new experiment that gives the possibility to monitor the specimen conductivity during its extensional deformation all the while recording the elongation stress. On the one hand, we highlighted a close relationship between the extensional conditions that are the specimen temperature and the extensional rate with the conductivity variation. Indeed, the conductivity variations can be described by means of the Weissenberg number that takes into account the polymer dynamics and the extensional rate. On the other hand, we have shown that the volume confinement of the filler, here achieved by the presence of polybutadiene nodules, gives the possibility to decrease the filler amount without impacting the process-ability of the composites. Finally, we propose a model that describes the conductivity evolution of CPC under extensional and planar flow. It links the structural evolution of the filler network to the macroscopic properties of the composite
Berciaud, Stéphane. "Détection photothermique et spectroscopie d'absorption de nano-objets individuels : nanoparticules métalliques, nanocristaux semiconducteurs, et nanotubes de carbone." Bordeaux 1, 2006. http://www.theses.fr/2006BOR13278.
Повний текст джерелаCombessis, Anthony. "Appport des nanotubes de carbone à la conduction électrique de matériaux organiques." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENI062.
Повний текст джерелаThe present thesis proposes a multi-scale understanding of some mechanisms that govern the genesis of percolating networks constituted with carbon nanotubes in thermoplastic polymers. The effect of "dynamic percolation" on the d.c. and a.c. electrical properties of the resulting nanocomposites was studied by means of the identification of the relationships between the filler organization and the use properties. The consequences of this controlled self-organization on the statistic percolation law d.c. critical parameters are discussed. Two possible origins of the dynamic percolation are proposed. From an applicative point of view, thermal treatments were applied to design new materials. The range of accessible permittivity and conductivity values is also discussed
Sahraoui, Yosra. "Électrodes modifiées par des matériaux composites fonctionnalisés pour application capteurs et biocapteurs." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10071.
Повний текст джерелаThe objective of the study consists in the development of modified electrodes, based on nanomaterials for electroanalytical applications. In this aim, different methods of modification of the electrodes have been proposed: chemical functionalization, adsorption and electropolymerization, using the electrostatic and covalent interactions between electrode surfaces and nanomaterials (magnetic nanoparticles, gold nanoparticles, polyoxometallates and carbon nanotubes). The prepared modified electrodes have allowed the obtaining of detection devices (sensors and biosensors) characterized for their interesting analytical performances in terms of sensitivity and detection limit. Urea biosensors, based on semi-conducting electrodes, functionalized with magnetic nanoparticles coated with urease enzyme, have allowed the sensitive detection of urea. Chemical sensors for the sensitive detection of nitrite ion have been obtained through functionalization of glassy carbon electrodes and boron doped diamond electrodes with polyoxometallates. The combination of both types of nanomaterials (carbon nanotubes and hybrid polyoxometallates) have allowed the obtaining of an original structure that presents conductive properties of nanotubes and electrocatalytic properties of polyoxometallates. These original structures have allowed the fabrication of enzymatic biosensors with a high sensitivity for the detection of glucose and catechol
Guyard, Aurélien. "Rétention d'encre par des matériaux poreux nanostructurés : interaction de surface polymère/SiO2 et structure des composites formés." Thèse, Université du Québec à Trois-Rivières, 2004. http://depot-e.uqtr.ca/1931/1/000110365.pdf.
Повний текст джерелаLaurent, Fabrice. "Croissance de nanotubes de carbone sur des fibres de carbone : application aux matériaux composites." Thesis, Mulhouse, 2016. http://www.theses.fr/2016MULH7632/document.
Повний текст джерелаThe research presented in this work aims to develop the oxyacetylene flame method for the Carbon Nanotubes (CNT) synthesis at the Laboratory of Physics and Mechanics of Textiles. The simplicity and the degree of innovation of this process make of it a serious candidate for manufacturing a pilot in order to produce new kind of tridimensional material made of CNT having grew on carbon fibres. This work consisted of:- Make a bibliographic study,- Establish a proof of concept of the growth of CNT,- Design and manufacture a device allowing process control,- Setup the process of growth on the fibres,- Identify the main parameters influencing CNT quality and quantity,- Characterize CNT,- Assume the CNT growth on carbon fibers,- Integrate these multidimensional materials into an organic matrix to realize structural composite materials,- Characterize these materials,- Describe and explain the growth mechanism in the flame.First, we focused our work on the fibres chemical treatment before flame exposition to evaluate the NTC growth conditions by varying notably, the fibres exposition temperature and the quality of the catalysts. After, the NTC syntheses on carbon fibres (CF) was done. The multidimensional product was characterized par various examinations and analyses. Composite materials were molded with epoxy resin to evaluate mechanical properties of NTC-FC. Young’s modulus was increased and tensile strength at break decreased. Transverse and longitudinal electrical properties were increased by 500 to 800 % respectively. Finally, we proposed NTC growth mechanisms. They are directly linked to the chemical and physical catalyst particles properties
Lin, Yueguo. "Comportement thermoélectrique de matériaux composites pour applications aéronautiques." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2013. http://www.theses.fr/2013ESMA0012/document.
Повний текст джерелаComposite materials – since their high specific properties – are used recently to reduce the weight of aircraftstructures and to improve the performance engine in order to reducing the emissions of CO2. Composites of Carbon FibberReinforced Polymer matrix (CFRPs) are increasingly used in civil aviation industry for the production of structural parts:fuselage panels.Integrating CFRPs in the aeronautical structures has also some difficulties: the fuselage – generally subject to pressure of airflux – would be subjected also to shocks/impacts, particularly will be damaging for exposed to the aggressive environment(temperature, humidity, liquid cooling, ...).The fuselage is the principal structure to support the charge of electric current, such as those related to the electric current returnto ground or lightning : although the secondary networks of electrical cables and wires fences are provided to support thesecharges, the action of leakage currents, probably passer through bolted and riveted joints and because of the high differences ofelectrical potential between the surface of panels thickness, can activate the thermoelectric coupling and lead to localizedheating of these structures. Phenomena related to this type of coupling may be particularly remarkable in CFRPs – since thepolymer matrices is electrically and thermally quasi-insulates, for composite the thermoelectric behaviour is highly anisotropic– and need further research and investigation. The integration of micro and nano fillers – especially carbon nanotubes (CNTs) –in the polymer resin or in interface of fibber/matrix can improve the overall behaviour, but it is a technological solution that stillrequires be explored in detail.The aim of this work is to characterize the anisotropic properties of thermoelectric behaviour of materials CFRPs – charged oruncharged in CNTs. This characterization includes:· measurement of electrical resistivity/conductivity and their evolution with temperature,· characterization of the temperature fields induced by the passage of electric current,· identification of parameters for modeling the behavior of these thermoelectric materials and interpretation oftests,· characterization of the effect of moisture aging on the values of resistivity/conductivity of the composite
Yang, Xiaofang. "Development of hybrid surface mechanical attrition treatment : formation of carbon and nitride nanomaterials." Troyes, 2009. http://www.theses.fr/2009TROY0009.
Повний текст джерелаSince the development of the new technique SMAT (Surface Mechanical Attrition Treatment), great success has been achieved. The mechanical properties and the diffusion properties of materials treated by SMAT are greatly improved. Carbon nanomaterials such as carbon nanofibers (CNFs) and carbon nanotubes (CNTs) have attracted special attention due to their unique properties and potential application. Since the diffusion properties of materials have been improved after the SMAT process, a SMAT process followed by a CVD process, i. E. Hybrid SMAT, is tailored for synthesizing carbon nanomaterials in-situ on the surface of bulk metallic materials. 316L stainless steel, pure Co, pure Ni and pure Ti plate were subjected to hybrid SMAT process to synthesize carbon nanomaterials. The effects of main parameters are discussed. The products were investigated by SEM, TEM, XRD and RAMAN characterizations. Growth mechanism was proposed. The second part of work concerns the development of SMAT machine and the formation of nitride nanomaterials on bulk metallic materials. A new SMAT system that can provide various treating conditions was developed to form a thicker nanostructured surface layer. 316 stainless steel samples were subjected to the new system, treating under traction and under thermal stress respectively. The treated samples were investigated by optical micros-copy, XRD and nanoindentation. Treated samples were submitted to the nitriding process to form nitride nanomaterials. The nitride samples were investigated by optical microscopy and microhardness tester
Livi, Sébastien. "Ionic liquids : multifunctional agents of the polymer matrices." Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0101/these.pdf.
Повний текст джерелаUne excellente stabilité thermique, une faible pression de vapeur saturante, une ininflammabilité, une bonne conductivité ionique ainsi que les différentes combinaisons cations/anions possibles font des liquides ioniques l'objet d'un engouement grandissant de la Recherche. De part ces avantages, les LI se présentent comme une nouvelle voie dans le domaine des polymères, et en particulier dans le milieu des nanocomposites où leur utilisation est essentiellement limitée à la fonction de surfactant des silicates lamellaires. Néanmoins, avant de pouvoir prétendre à un statut d'alternative, il est nécessaire de mettre en évidence les effets bénéfiques de leur utilisation sur les propriétés finales des matériaux polymères. Dans un premier temps, l’objectif de ce travail a été de synthétiser des liquides ioniques différents par la nature de leur cation et anion mais tous porteurs de longues chaînes alkyles afin de permettre une meilleure compatibilité avec la matrice. Ensuite, les excellentes propriétés intrinsèques des liquides ioniques ont motivé leur utilisation comme agents structurants dans une dispersion aqueuse fluorée. Ainsi, leur rôle d’agents ioniques sur la morphologie, les propriétés physiques, thermiques et mécaniques a été étudié. Dans une seconde partie, les liquides ioniques ont été utilisés comme agents intercalants des silicates lamellaires puis confrontés aux surfactants conventionnels dans le but de préparer des argiles thermiquement stables pour la préparation de nanocomposites thermoplastiques/argiles. Dans une dernière partie, une faible quantité de ces argiles organiquement modifiées ont été introduites par intercalation à l'état fondu dans deux matrices différentes afin de mettre en évidence les effets de ces nouveaux agents interfaciaux sur les propriétés finales du matériau
Brun, Christophe. "Carbon nanotubes based nanopackaging dedicated to innovative high frequency interconnections." Limoges, 2013. http://aurore.unilim.fr/theses/nxfile/default/c641e2f6-ac07-4af1-bef1-6f1cc829f7d0/blobholder:0/2013LIMO4042.pdf.
Повний текст джерелаA échelle nanométrique, les applications électroniques vont devoir faire face à des difficultés imposées par les lois physiques, les propriétés des matériaux, les caractéristiques des circuits et systèmes, l’assemblage et le conditionnement. Dans ce contexte, le packaging jouera un rôle majeur en fournissant les performances et l’efficacité nécessaires combinés aux composant nanométriques reliés à la carte mère. Les techniques d’assemblage se concentrent sur l’intégration au niveau système et de nouvelles technologies sont proposées (système 3D, packaging de substrats, intégration electro/optique). Les matériaux conventionnels utilisés pour le packaging seront ainsi inadaptés en terme de performances thermiques, mécaniques et électriques. Une des solutions actuellement à l’étude concerne l’utilisation de matériaux innovants tels que les nanotubes de carbone (NTCs), les nano-fils, les nanoparticules ou le graphène (monocouche de graphite). Dans ce manuscrit, les NTCs (feuille de graphène enroulée) vont être étudiés et vont révéler des propriétés physiques, électriques et thermiques uniques, ce qui leur apportent un certain intérêt pour le champ d’applications de l’électronique nanométrique. Ce nouveau champ de recherche concerne l’utilisation de nanomatériaux appliqués au packaging des composants électroniques et photoniques. Les applications sont diverses et variées entre les interconnections, la gestion thermique ou même mécanique. Dans ce manuscrit, nous nous concentrerons sur deux applications : les interconnections à base de nanotube de carbone utilisant la technologie flip-chip et les interconnections sans fils à base de monopoles composés de nanotubes de carbone
Jia, Zixian. "Elaboration des matériaux composites nanostructurés Ag, Au/TiO² pour la dépollution des effluents gazeux avec une activation par plasma." Thesis, Paris 13, 2013. http://www.theses.fr/2013PA132050.
Повний текст джерелаDuring this Phd work, we have developed a plasma-catalytic process of acetaldehyde removal using a diphasic process coupling a nano-structured catalyst and an atmospheric pressure plasma. The elaboration of the nanoparticulate catalyst has been firstly studied. Then its performance coupling with plasma has been investigated. The monodispersed titanium-oxo-alkoxy nanoparticles are generated in the sol-gel reactor with turbulent micromixing and deposited onto glass plates or glass balls as monolayer nanocoatings. The silver and gold deposition is achieved by the ions reduction at UV-A light illumination. The photocatalytic growth kinetics and nanoparticle morphology are studied experimentally by the TEM, SEM and AFM methods. It’s also interesting to discuss the mechanism of the nanoparticles formation and evaluate its quantum efficiency. The drawn conclusions are supported theoretically through the calculation of the absorption spectra. Then the efficiency of the process coupling a dielectric barrier discharge and a fluidized nanostructured silver and gold based bed for the degradation of a model pollutant (acetaldehyde CH₃ CHO) is studied. In the first part, the efficiency of the plasma alone process is discussed, in terms of pollutant removal and CO and CO₂ production. In the second part, CH₃ CHO removal as well as COx production is studied as a function of the photocatalytic reduction time of Ag⁺ and Au³⁺ ions, which is related to the deposited silver and gold mass. The pollutant removal pathways, including homogeneous chemistry in the plasma phase and heterogeneous chemistry on the surface, are discussed. Finally, the production of main by-products is presented and compared between Ag and Au catalysts
Rogier, Clémence. "Vers le développement d’un pseudocondensateur asymétrique avec des électrodes composites à base d’oxydes métalliques (MnO2, MoO3) et de carbones nanostructurés." Thesis, CY Cergy Paris Université, 2020. http://www.theses.fr/2020CYUN1098.
Повний текст джерелаSupercapacitors are energy storage devices for applications requiring high power densities. By developing new electrode materials with high capacitance energy densities can be enhanced. In that regard this work presents the development of composites materials associating nanostructured carbons (architectures with carbon nanotubes and/or reduced graphene oxide) and pseudocapacitive metal oxides (MnO2 and MoO3 for positive and negative electrodes respectively). Metal oxides generate high capacitances thanks to reversible redox reactions in a wide range of potentials. The nanostructured carbon matrix optimizes porosity and conductivity of the electrodes to ensure good ionic and electronic transport within the materials.First MnO2-rGO-CNTs is developed as a positive electrode using spray gun deposition of carbon nanomaterials before electrochemical growth of the oxide. The interest of these elaboration techniques lies in their easy large-scale implementation. Its maximum capacitance is measured at 265 F/g. In a similar approach MoO3-CNTs is developed as a negative electrode with a maximum capacitance of 274 F/g. The materials are characterized using different physicochemical methods (microscopy, spectroscopy, porosity analysis, XRD).These electrodes are then combined in an asymmetric hybrid pseudocapacitor in an organic electrolyte (LiTFSI/GBL) with an operating voltage window of 2V. The performances of this system in terms of energy and power densities as well as electrochemical stability were studied over several thousand cycles. The maximum energy density was found to be of 25 Wh/kg for a power density of 0.1 kW/kg
Gu, Tang. "Modélisation multi-échelles du comportement électrique et élasto-plastique de fils composites Cu-Nb nanostructurés et architecturés." Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0017/document.
Повний текст джерелаNanostructured and architectured copper niobium composite wires are excellent candidates for the generation of intense pulsed magnetic fields (>90T) as they combine both high strength and high electrical conductivity. Multi-scaled Cu-Nb wires are fabricated by accumulative drawing and bundling (a severe plastic deformation technique), leading to a multiscale, architectured and nanostructured microstructure exhibiting a strong fiber crystallographic texture and elongated grain shapes along the wire axis. This thesis presents a comprehensive study of the effective electrical and elasto-plastic behavior of this composite material. It is divided into three parts: electrical, elastic and elasto-plastic multiscale modeling. In order to investigate the link between the effective material behavior and the wire microstructure, several homogenization methods are applied which can be separated into two main types: mean-field and full-field theories. As the specimens exhibit many characteristic scales, several scale transition steps are carried out iteratively from the grain scale to the macro-scale. The general agreement among the model responses allows suggesting the best strategy to estimate reliably the effective electrical and elasto-plastic behavior of Cu-Nb wires and save computational time. The electrical models are demonstrated to predict accurately the anisotropic experimental data. Moreover, the mechanical models are also validated by the available ex-situ and in-situ X-ray/neutron diffraction experimental data with a good agreement
Palomar, Quentin. "Intégration de matériaux nanostructurés dans la conception et la réalisation de biocapteurs sans marquage pour la détection de cibles d'intérêt." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV069/document.
Повний текст джерелаThe main purpose of this work was the design and the development of biosensors by using non-marking transduction methods, such as electrochemical impedance spectroscopy (EIS), for the detection of targets of interests. To this end, various molecular architectures have been developed to allow the transduction of the signal resulting from the recognition between the bioreceptor and its substrate, and thus lead to the detection of the target.The systems developed are based on the integration of nanomaterials, such as carbon nanotubes or tungsten disulfide, to ensure the immobilization of the biospecific entity at the surface of the sensor. The advantages of these materials are multiples, since they allow a very large increase in the specific surface area and are also used in the functionalization of the surface of the electrode. Indeed, one of the major challenges encountered in the development of biosensors is the strategy involved in the immobilization of the biospecific entity on the surface of the sensor.This work was initially interested in the realization and characterization of thin films of these nanomaterials as well as their transfer to the surface of an electrode. In this context, the aim is to design porous bioarchitectures based on electrogenerated functional polymers around carbon nanostructures allowing the penetration of large biomolecules such as antibodies to develop high-performance immunosensors.The second part of the work was oriented towards the design of biosensors using these different materials. The reliability of the process has been validated by the design of immunological systems for the detection of the anti-cholera toxin antibody and dengue toxin antibody.Finally, a last enzymatic biosensor, based on the use of tungsten disulfide nano-sticks, has been developed. The latter allows the detection of two molecules of interest, catechol and dopamin, by the use of polyphenol oxidase
Girault, Baptiste. "Etude de l'effet de taille et de structure sur l'élasticité de composites W/Cu nanostructurés en couche mince." Poitiers, 2008. http://theses.edel.univ-poitiers.fr/theses/2008/Girault-Baptiste/2008-Girault-Baptiste-These.pdf.
Повний текст джерелаThe mechanical behavior of crystalline material has a high dependence on its microstructure, notably when crystallite size reaches the nanometer scale. Crystallites size is controled by the stratification of thermodynamically immiscible materials, namely tungsten and copper, isotropic and anisotropic elastically, respectively. Thin films were deposited by physical vapor deposition and their characterizations were carried out combining electron microscopy and X-ray diffraction and diffusion. In situ tensile testing combined with X-ray diffraction on supported composite W/Cu have been used to get insight into sample mechanical behavior. This work emphasises the strong complementarity between electron microscopy and X-ray diffraction analyses on microstructure characterizations, required to interpret and model tensile testing results. Theses analysis have revealed that very thin copper layers arrange as dispersoïds and that a particular crystallographic orientation distribution within tungsten layers appear as <110> and <111>. The results obtained on quasi-isotropic copper dispersoïds and laminated W/Cu composites have clearly revealed structure and size effects in tungsten sub-layers. A more detailed study of the elastic domain of laminated composite has not only revealed a strong dependence on residual stresses, but also an uppermost dislocation appearance within copper layers leading to a load transfer on tungsten layers, leading to mode II crack apparitions
Flahaut, Emmanuel. "Synthèse par voie catalytique et caractérisation de composites nanotubes de carbone - métal - oxyde. Poudres et matériaux denses." Toulouse 3, 1999. http://www.theses.fr/1999TOU30196.
Повний текст джерелаEl, Sawi Ihab. "Dispersion de nanotubes de carbone et intégration de la fonction de conductivité électrique dans les matériaux composites structuraux." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/897/.
Повний текст джерелаA process of dispersion of Double-Welled Carbon Nantubes (DWCNTs) assisted with amphiphilic molecules in water then in an epoxy matrix is proposed here. The DWCNTs/Epoxy mixtures were subject to reaction kinetic and shear flow study. The electrical conductivity of the DWCNTs/epoxy composites according to the frequency and the temperature is analysed. Dynamic Mechanical Analysis of the DWCNTs/Epoxy composites shows increasing of elastic shear modulus with DWCNTs content for temperatures higher than Tg of the matrix. The last part is dedicated to the development and characterization of composite laminates DWCNTs/Carbon fibres/Epoxy resin. The electric conductivity of the laminates is increased by the presence of DWCNTs and the DWCNTs improve the (GIC) by 30% compared with laminates made without DWCNTs
Mdarhri, Ahmed. "Propriétés électromagnétiques de matériaux hétérogènes : approche expérimentale et modélisation." Bordeaux 1, 2007. http://www.theses.fr/2007BOR13372.
Повний текст джерелаLozay, Quentin. "Conception et caractérisations de matériaux composites nanostructurés à hautes propriétés barrières. Etude films multinanocouches de PE et PA6 chargés de montmorillonite." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR012.
Повний текст джерелаPolymers are used in many fields such as packaging, automotive, etc. as they have good mechanical, thermal and barrier properties. Economic and environmental challenges are driving development towards more efficient and lighter materials. The aim of this thesis work was to develop multilayer composite films based on polyethylene (PE) and polyamide (PA6) with high gas and water barrier properties. A coextrusion process with multiplier elements made it possible to carry out 100 μm thick multilayers containing up to 2049 layers. Two series of PE-binder-PA6 films of different compositions were studied. Clays (organo-modified montmorillonites) were incorporated (at 0.5 and 5 wt%) into the alternating layers of PE and PA6. The structural, thermal and mechanical properties of these multilayers have been correlated with the transport properties. We observed confinement effects on nanostratification of films and crystallinity of polymers and the impact on barrier properties. We showed the complexity of the multinanolayer structures involving interphases as well as the complexity of the transfer mechanisms. The serial model for predicting permeability highlighted significant improvements in the gas barrier properties of confined PE layers but in water. The barrier effect on all of the multilayers was, however, limited due to the “on edge” orientation of the crystalline phases and structural defects. The confinement of nanofillers (at 1% v/v) in PA6 layers has made it possible to increase the barrier properties of multilayers
Fragneaud, Benjamin. "Synthesis and characterization of polymer/carbon nanotubes composites : impact of polymer grafting on the surface of CNx MWNTs on the electrical and mechanical properties of the nanocomposites." Lyon, INSA, 2006. http://theses.insa-lyon.fr/publication/2006ISAL0124/these.pdf.
Повний текст джерелаADes nouveaux matériaux hybrides, provenant du greffage de polystyrène à la surface de nanotubes de carbone dopés azote (CNx MWNTs) ont été synthètisés et utilisés dans l’élaboration de nano-composites à matrice polymère. Dans ces travux de recherche nous avons étudiés l’impacte de ces nanotubes de carbone greffés polystyrène sur les propriétés mécaniques et électriques de matrices polystyrène (PS et poly (butadiène-co-styrène) (PSBS). Les nanotubes greffés ont une meilleure dispersion dans une matrice de polystyrène que les nanotubes sans traitement chimique. Cependant, ce type de fonctionnement ne permet pas de baisser le seuil de percolation électrique, puisque le greffage tend à isoler électriquement les nanotubes. Par ailleurs, nous avons observé une sensible augmentation de l’effet de renfort mécanique de la matrice PS quand les tubes sont greffés ; particulièrement quand les composites sont soumis à de grandes déformations. Dans le cas particulier d’une matrice nano structurée comme le PSBS, nous avons observé un effet de renfort mécanique beaucoup plus important quand les nanotubes étaient greffés. En effet, la couche de PS à la surface des CNx MWNTs connecte les domaines de PS du copolymère, permettant l’apparition d’un réseau percolant rigide avec un seuil de percolation très bas (PC <0. 05 vol%)
Charlon, Sébastien. "Elaboration et caractérisation de nouveaux systèmes nanocomposites à propriétés de transport contrôlées. Impact d'un nouveau procédé de mise en oeuvre." Rouen, 2015. http://www.theses.fr/2015ROUES011.
Повний текст джерелаDuring the last decades, a waste-reduction program, specifically for plastic packaging, was promoted due to environmental drawbacks with the development of biodegradable polymers. However, barrier properties of these biodegradable materials must be often improved to be competitive with common polyolefins (PE, PP, PET, etc. ). In this objective, the incorporation of nanofillers using industrializable processes seems to be a promising approach. Indeed, the introduction of inorganic nanofillers like clays (montmorillonite) into a polymer matrix often increased barrier properties of the polymer matrix. In this study, composites were prepared from biodegradable matrices such as Poly(Putylene Succinate) (PBS) and Poly(Butylène Succinate-co-butylène Adipate) (PBSA) loaded with Cloisite Na+ or Cloisite 30B. An extrusion process was applied with the use of liquid water injection under high pressure and high temperature into thermo-moulding or extrusion-calandaring processes. Kinetic permeation revealed changes in barrier properties as function of the elaboration process or the polymer matrix used. These results were explained from structural charectirizations (DSC, XRD) and microscopy observations (TEM) in order to correlate barrier peoperties to the dispersion and exfoliationlevels of fillers into the polymer matrices, to the degrees of cristallinity and to the rigid amorphous fractions (RAF) of the bio-polymers
Lognone, Quentin. "Optimisation des propriétés thermoélectriques des matériaux de la famille Bi2Te3-xSex pour applications en pompe à chaleur à température ambiante." Caen, 2014. http://www.theses.fr/2014CAEN2060.
Повний текст джерелаThis thesis deals with the study of Bi2Te3-xSex materials and their applications for thermoelectricity, in particular the optimization of their properties around room temperature. The thesis is composed of five chapters. The first one describes the thermoelectric effects and allows us to make a state of the art about the Bi2Te3-xSex compounds. The second chapter introduces the different techniques to make and analyze our materials. The three following chapters show the obtained results split in three different axis. First, a study about the texturation of the material is undertaken to show its influence on the material’s properties. Doping the samples to adjust its carrier concentration is the aim of the fourth chapter and finally, the nanostructuration of the material is studied in the last chapter of the thesis
Quet, Aurélie. "Composites de friction à matrice céramique : relation composition / structure / comportement tribologique." Bordeaux 1, 2007. http://www.theses.fr/2007BOR13512.
Повний текст джерелаC/C composites are nowadays the most suitable materials for needs of aircraft braking. However, they show a high wear during taxiing. SiC matrix composites are characterised by a smoothing of the wear peak noticed at low temperatures but they don't meet requirements of rejected take-off (RTO). The aim of this work is to put another carbide than SiC in the matrix of friction composites and to assess its influence on tribological properties of materials. C/C-ZrC and C/C-TiC composites were manufactured using RMI processing route (Reactive Melt Infiltration). Materials were characterised with mophological, chemical and structural analysis which reveal especially a decohesion between carbon phase and carbide phase. This gap can be limited using alloys as Zr-Si and Ti-Si alloys. Triboligical behaviour of the resulting materials was then investigated with an inertial dynamometer simulating brake stops. C/C-ZrC and C/C-TiC composites meet RTO requirements. Neverless, ZrC matrix composites have a high wear for high temperature brake stops linked to their oxidation behaviour. TiC matrix composites present moderate wear at high temperature and a lower wear at low temperature compared to C/C composites in relation to low friction coefficients
Salem, Diana. "Synthèse de nanotubes de carbone monofeuillets individuels et composites modèles polymères - nanotubes de carbone : application à l'effet photovoltaïque." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00719414.
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