WorldCat Identities

Dantras, Eric

Overview
Works: 41 works in 63 publications in 2 languages and 68 library holdings
Roles: Thesis advisor, Other, Opponent, 958, Author, Contributor
Publication Timeline
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Most widely held works by Eric Dantras
Élaboration de composites polymère ferroélectrique-fils submicroniques ferromagnétiques : analyse des propriétés magnétoélectriques by Thanh Hoai Lucie Nguyen( Book )

3 editions published between 2014 and 2015 in French and held by 3 WorldCat member libraries worldwide

The purpose of this work is to elaborate magnetoelectric polymer matrix composites. An electrodeposition process was used to prepare original magnetic submicron wires with different chemical compositions. Magnetic particles were dispersed in a P(VDF-TrFE) ferroelectric polymer matrix. The study of electrical properties of composites filled with cobalt wires shows a percolation mechanism with a threshold at 1.15 vol%. This low value demonstrates a homogenous dispersion. This homogeneity is confirmed by mechanical strength. For magnetoelectric properties, composites are filled with 0.3 vol% i.e. below the percolation threshold: particles with different chemical compositions and aspect ratio have been used. After poling, composites keep the polymeric matrix piezoelectricity. Upon magnetic field, ferromagnetic properties are exhibited by a hysteresis loop. A magnetoelectric coefficient of the same magnitude order than the one of ceramics has been measured on these composites remarkable for their low density and ductility
Liaison structurale par collage de composite fibre carbone - PEEK : élaboration et analyse des propriétés physiques by Aurélie Leonardi( Book )

3 editions published between 2013 and 2014 in French and held by 3 WorldCat member libraries worldwide

The aim of this PhD work is the development of a structural bonding for thermostable thermoplastic composites (Carbon Fiber / PolyEtherEtherKetone) in view of aerospace applications. Several adhesion mechanisms have been combined : mechanical anchoring, surface activation by reduction and adhesion promoter association. The influence of PEEK surface functionalization was characterized by surface spectroscopies, thermal, mechanical and dielectric analyses. The reference structural bonding was created by a thermoset adhesive. A thermostable thermoplastic adhesive was formulated and developed to promote interdiffusion and create a thermoplastic structural bonding. Dynamic dielectric spectroscopy has been applied to the analysis of structural modifications in the assemblies. The surface functionalization efficiency was evaluated by single lap shear tests. The ultimate stress was multiplied by a factor five, upon optimization of adhesion properties
Mechanical and thermal behaviour of bamboo flour-reinforced XLPE composites by Geoffrey Haddou( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

Evaluation de la compacité des enrobés bitumineux et caractérisation large bande des propriétés diélectriques des roches. by Steven Araujo( )

2 editions published in 2017 in English and held by 2 WorldCat member libraries worldwide

Le contrôle des chaussées neuves en génie civil est primordial pour assurer sa bonne miseen oeuvre et lui conférer une durée de vie optimale. Dans cet objectif, divers paramètresphysiques nécessitent d'être scrupuleusement calibrés et contrôlés afin d'éviter une dégradation précoce de la chaussée et des problèmes de sécurité pour les conducteurs qui l'empruntent. De plus, les coûts associés à la mise en place et à la maintenance des chaussées sont considérables. Parmi les propriétés qui requièrent une attention particulière, la compacité, qui est indicative de la quantité d'air en volume dans la chaussée, est celle qui nous intéresse dans cette étude. Actuellement, seulement deux méthodes en laboratoire (en Europe) sont considérées comme des méthodes normalisées pour déterminer la compacité. Néanmoins, ces techniques sont destructives et/ou nucléaires ce qui est un frein majeur à leur utilisation. Durant ces deux dernières décennies, de nouvelles techniques électromagnétiques (non nucléaires et non destructives) ont émergé et ont prouvé leur forte utilité dans le domaine de la géophysique et du génie civil et plus particulièrement pour la détermination de la compacité. Cependant, ces nouvelles techniques nécessitent de prendre un certain nombre de précautions pour déterminer la compacité. Tout d'abord, elles permettent de mesurer la permittivité diélectrique du matériau en question. Ainsi pour déterminer la compacité, il est nécessaire d'utiliser des lois de mélange électromagnétiques. L'utilisation de ces modèles requiert une connaissance précise des constituants qui composent la chaussée ainsi que de leurs propriétés (masse volumique et permittivité diélectrique). La première partie de ce travail démontre la pertinence d'utiliser un radar à sauts de fréquences pour déterminer la compacité. L'étude de plusieurs lois de mélange électromagnétiques a été réalisée et les modèles présentant les meilleurs résultats ont été sélectionnés. Cependant, ces techniques font face de nos jours à un problème majeur. En effet, l'utilisation de matériaux recyclés est de plus en plus fréquente pour la construction de nouvelles chaussées ce qui rend la détermination de la compacité encore plus difficile par des méthodes électromagnétiques. Par conséquent, plusieurs méthodologies ont été développées, et sont proposées pour déterminer la compacité d'une nouvelle autoroute qui comporte des matériaux recyclés. La seconde partie de ces travaux de recherche porte sur la caractérisation diélectrique de plusieurs roches qui sont les éléments principaux d'une chaussée. Cette caractérisation est validée de basses à hautes fréquences mais aussi en fonction de la température. Les résultats montrent que à haute fréquence, la permittivité est principalement dépendante de la densité et de la composition chimique de la roche. En revanche, lorsque la fréquence d'investigation diminue et que la température varie, d'autres phénomènes apparaissent et changent dramatiquement le comportement diélectrique de la roche. Il a également été montré que l'eau joue un rôle majeur dans le comportement diélectrique à basse fréquence de la roche. Ces phénomènes se répercutent à "haute fréquence" par de très faibles variations qui pourraient expliquer les déviations obtenues par les méthodes électromagnétiques capacitives qui fonctionnent dans la région du MHz et qui sont également utilisées pour le contrôle de la compacité des chaussées neuves
Conductivité, diffusivité, émissivité thermiques de composites poly (EtherKetoneKetone) - charges carbonées : fibres continues et particules by MiKe Coulson( Book )

2 editions published in 2018 in French and held by 2 WorldCat member libraries worldwide

L'objectif de ces recherches est l'amélioration du procédé de placement de fibre par dépose laser, appliqué à des composites Poly(EtherKetoneKetone) / fibre carbone continue. L'optimisation des paramètres de dépose implique l'étude de la stabilité de la matrice, ainsi que l'analyse du comportement thermique des composites. La conductivité et diffusivité thermiques, ainsi que l'émissivité sont les paramètres clés pour comprendre le comportement des transferts volumiques et surfacique dans ces matériaux. Des composites PEKK/particules de carbone ont été élaborés afin d'étudier l'effet de la morphologie du carbone sur les paramètres thermiques. L'émissivité des composites PEKK / fibres continues a été mesurée en comparant les radiations émises par le matériau et celle émises par un corps noir à la même température. La conductivité et la diffusivité thermiques, qui sont des paramètres intrinsèques au composite, augmentent avec le taux de charge et la température. Ces deux paramètres ont été étudiés en fonction de la Température, dans le cas de composite PEKK / fibre carbone continue et PEKK / particules de carbone pour plusieurs taux de charge
Élaboration d'ensimages thermoplastiques thermostables : influence sur le comportement mécanique des composites PEEK / fibres de carbone by Isabelle Giraud( Book )

2 editions published in 2011 in French and held by 2 WorldCat member libraries worldwide

Ce travail présente l'élaboration de nouveaux ensimages de fibres de carbone compatibles avec des matrices polymères thermoplastiques thermostables, telles que le PEEK, dont la température de mise en œuvre est supérieure à 300°C. Premièrement, deux solutions ont été envisagées, une à base d'oligomères de PolyEtherKetoneKetone (PEKK) synthétisés, et l'autre à base de PolyEtherImide (PEI). Ces deux composés étant solides, un travail de formulation a été nécessaire afin d'obtenir des dispersions aqueuses stables idéales pour un ensimage industriel. Dans une deuxième partie, des composites modèles PEEK/FC ont été élaborées avec des fibres ensimées et non ensimées. Dans la dernière partie, l'influence de l'ensimage sur les propriétés mécaniques des composites a été mise en évidence par microscopie électronique à balayage et par une analyse mécanique dynamique en cisaillement avant et après immersion dans le kérosène. L'étude comparative des résultats obtenus met en évidence que l'ensimage tend non seulement à améliorer le transfert de contrainte entre la fibre et la matrice mais permet aussi d'éviter des infiltrations de solvant le long de la fibre
Identification et analyse des marqueurs de vieillissement pour polymères isolants sous contrainte thermique en aéronautique by Victor Henri( Book )

2 editions published in 2020 in French and held by 2 WorldCat member libraries worldwide

This work deals with the determination of ageing markers of high-performance polymers for electrical insulation applications in aeronautics. Most of power cables are made of a successive winding of poly(tetrafluoroethylene) PTFE and poly(imide) PI. This research is focused on the effects of thermal ageing on the physico-chemical structure of these polymers in order to link them to changes in thermomechanical and electrical behaviours. For PTFE, enthalpic and mechanical relaxations are strongly impacted by changes in chemical structure associated to a depolymerisation mechanism. The values of the enthalpy of crystallization and of the amplitude of the ß mechanical relaxation associated with the crystal/crystal transition, can be used as markers of thermal ageing for PTFE. For PI, changes in the chemical structure associated to the scission - recombination mechanism, highlight the formation of heterogeneities, modifying sorption process and electrical charge transport as measured in broadband dielectric spectroscopy. The evolution of the diffusion mechanism and of the activation energy of the electrical conductivity, constitute pertinent ageing markers for PI
Composites thermoplastiques conducteurs à finalité aéronautique PEKK/fibres de carbone/fils submicroniques d'argent : de l'élaboration aux comportements électrique et mécanique by Luis Enrique Quiroga Cortes( Book )

2 editions published in 2016 in French and held by 2 WorldCat member libraries worldwide

The aim of this work is to elaborate structural composites carbon fiber/polymer/metallic nanowires with high transverse electrical conductivity. First, silver nanowires (AgNWs) with high aspect ratio were synthesized through the polyol process in presence of poly (vinyl pyrrolidone). Those nanowires were inserted in the high performance thermoplastic polymer PEKK. The influence of the chemical and physical structure on PEKK properties will be discussed. PEKK/AgNWs composites showed a very low percolation threshold (0.6 vol %) and reach high electrical conductivity values of 200 S.m-1. Influence of the content filler in PEKK matrix was studied. Then, carbon fiber reinforced composites FC/PEKK/AgNWs were performed with good quality impregnation and good dispersion of AgNWs through the composite. The conductivity of the single tape CF/PEKK was increased by 4 orders of magnitude with the presence of AgNWs
Dielectric and mechanical properties of various species of Madagascan woods by Frédéric Roig( )

1 edition published in 2017 in English and held by 2 WorldCat member libraries worldwide

Analyse thermique avancée et propriétés de transport de matériaux polylactide stéréocomplexe by Nagihan Varol( )

2 editions published in 2019 in English and held by 2 WorldCat member libraries worldwide

The originality of this work is based on analysis of physical and physicochemical properties of polylactide mixtures of different chirality (poly L-lactic acid and poly D-lactic acid) and on the influence of the chirality on the amorphous phase's properties. The materials mixtures are elaborated from two homopolymers (PLLA and PDLA) according to two methods; solution casting or extrusion. Totally amorphous and isotropically crystallized materials with more or less confined amorphous phase were studied. It is shown that a stereocomplex crystalline phase can be obtained only under certain experimental conditions. The results of the thermal and permeation analyzes showed that the PLLA / PDLA mixture improved certain properties of the material, namely higher barrier properties towards liquid water and gases were obtained compared to parent homopolymers. In order to study the molecular mobility of amorphous phases, physical aging and structural relaxation ([alpha] and [beta] relaxation), the Cooperative Rearrangement Region (CRR) concept has been applied. It has been shown that the amorphous phases of the homopolymers and the mixture have exactly the same properties at the glass transition and in the vitreous state when the materials are totally amorphous
Structure et propriétés physiques de composites à matrice biosourcée/fibres naturelles continues pour applications aéronautiques by Geoffrey Haddou( Book )

2 editions published in 2017 in French and held by 2 WorldCat member libraries worldwide

The aim of this work is to propose fully bio-based composites for a potential application in the cabin interior, and compliant with the REACh regulations. The use of vegetable fibers as reinforcement into polymeric matrices is an encouraging way to decrease the environmental impact, end the weight as well. A new bio-based polyamide matrix, synthetized by Arkema - Polyamide meta-xylylene diamine 10 - was used in this work. A preliminary study on Polyamide 11/bamboo powder showed the introduction of the fillers did not modified the physical structure of the matrix. Moreover, the optimization of the mechanical properties occurs with no coupling agent. The continuous bamboo fibers/PA mXD 10 composites, which were also processed without coupling agent, present shear moduli superior than the one of the synthetic reference glass fibers/phenolic, with a gain of weight about 50%
Vieillisement hygrothermique d'assemblages structuraux polyepoxy : analyse de la mobilité moléculaire par spectroscopie diélectrique dynamique by Mathieu Chevalier( Book )

2 editions published in 2008 in French and held by 2 WorldCat member libraries worldwide

During spacecraft integration - in clean room - materials are used under humid and thermal controlled conditions. The characterisation and the simulation of ageing phenomena in bonding assemblies are a challenge to improve their conception and their durability. One alternative is to use accelerated testing but the link between accelerated testing and true ageing is unknown. The aim of this study was to shed some light on this correlation. This study concerned a room temperature curing epoxy-amine adhesive used in aluminium assemblies. We focused on ground ageing (also called humid ageing). The experimental protocol consisted in taking samples at different ageing times in satellite integration room. The results were compared with those obtained after 7 days of accelerated testing with different hydrothermal conditions. Dielectrical, thermal and mechanical experiments were carried out. Broadband dielectric spectroscopy gave information about molecular mobility in wide temperature and frequency range. Relaxation times and activation energy associated with molecular mobility were studied. Physicochemical processes that occur into the adhesive like the glassy transition temperature Tg were studied by differential scanning calorimetry. Mechanical test was single lap shear test. The results obtained were related to the macroscopic behaviour of assemblies as a function of accelerated testing conditions or real-time ageing. Correlation of experiments data obtained for different ageing conditions - real-time ageing, accelerated testing ageing - allowed us to understand the evolution of the studied adhesive at different scale i.e. an interpretation at a molecular level was proposed
Transitions et dynamique relaxationnelle de polymères issus de la paroi végétale by Frédéric Roig( Book )

2 editions published in 2011 in French and held by 2 WorldCat member libraries worldwide

Dans un futur proche, l'augmentation de CO2 stimulera le processus de photosynthèse et pourrait permettre un accroissement considérable de la matière végétale. Comparativement aux sources d'énergie fossile comme le pétrole ou le charbon, la matière végétale représente une ressource renouvelable chaque année. La connaissance de ses propriétés physico-chimiques est primordiale. La modification du patrimoine génétique de certaines espèces végétales permet d'identifier les gènes responsables de la synthèse des polymères constitutifs. L'objectif de ce travail de thèse est d'appliquer des techniques d'analyse thermique couplées à la spectroscopie diélectrique, à l'étude de la structure dynamique de la paroi végétale de l'Arabidopsis Thaliana. Dans une approche analytique, les principaux polymères pariétaux extraits : la cellulose et la lignine, sont étudiés. La transition vitreuse de chaque polymère ainsi que la mobilité moléculaire localisée et délocalisée ont été déterminées. La cellulose étant le constituant structural majeur de la paroi végétale, une attention particulière a été accordée à l'influence de son interaction avec l'eau sur sa structure physique. La diminution de la température de transition vitreuse quand le taux d'hygrométrie augmente, est caractéristique d'un phénomène de plastification. L'étude comparative du composite végétal naturel avec ses polymères pariétaux a montré la contribution de la cellulose et de la lignine dans la dynamique de chaîne de l'Arabidopsis Thaliana. Ces interprétations mettent en évidence l'influence des modifications génétiques sur les interactions inter et intra moléculaires des polymères pariétaux
Composite hybride à matrice polymère pour l'amortissement de vibrations par transduction-dissipation locale by Delphine Carponcin( Book )

2 editions published in 2012 in French and held by 2 WorldCat member libraries worldwide

This work deals with processing of a polymer based composite for vibration damping by transduction-local dissipation. Two preliminary steps have been performed. In a first time, a conductive composite has been elaborated. Carbon nanotubes, as conductive fillers, have allowed reaching an electrical percolation threshold for a low filler content (0,55 % vol.). In the same time, polyamide matrix became piezoelectric by dispersion of PZT particles and after a poling step. Mechanical properties are maintained until 30 % in volume for submicronic particles. An increase of the conservative and dissipative part of the mechanical modulus has been observed by dynamic mechanical analysis after a simultaneous dispersion of NTC and poled PZT. Vibration tests have highlighted the contribution of the transduction-local dissipation phenomenon to the damping factor of the polymer matrix, mainly through a sandwich configuration. The influence of various parameters on this new kind of damping has been discussed
Mise en oeuvre et optimisation d'un revêtement conducteur poly(époxy) : fils submicroniques d'argent pour la protection foudre de structures aéronautiques by Vincent Bedel( Book )

2 editions published in 2018 in French and held by 2 WorldCat member libraries worldwide

This work deals with the processing and the study of an extrinsic conductive polymer coating for the lightning strike protection of the aircraft carbon fibre reinforced polymer (CFRP) structural parts. The coating consist in a low viscosity bi component high performance poly(epoxy) matrix and silver submicronic wires with a high aspect ratio (AgNWs) obtained by a polyol process. The kinetic parameters, the physical structure and the molecular mobility of the matrix had been investigated as a function of the filler content. The surface and bulk conductivities had been measured as a function of filler content. It exhibits a percolation threshold below 1% in volume. The conduction mechanisms had been studied following an uncommon method of current density measurement as a function of the AgNWs content and the temperature. The critical electrical behaviour of each sample had been investigated through the current density method. It has permitted to understand the phenomenon responsible for the composite's degradation. Finally, lightning strike tests on representative configurations had been carried out. The ultrasonic inspections have highlighted the efficiency of the poly(epoxy)/AgNWs coating to avoid the structural delamination of the CFRP
Mise en œuvre de composites structuraux conducteurs par pulvérisation de dispersions NTC : résine époxy sur nappes fibres de carbone by Mathieu Fogel( Book )

2 editions published in 2015 in English and held by 2 WorldCat member libraries worldwide

The main goal of this work was to create multiscale Carbon Fiber-Reinforced Polymers by inserting carbon nanotubes in the matrix of the composite material to improve and homogenize the through-thickness electrical conductivity. Multiscale composites manufacturing was proposed through addition of carbon nanotubes to a standard composite conferring a nano-dimension to the material. A spray deposition technique of CNT / epoxy mixtures was developed. CNT-doped CFRP material in which the matrix came exclusively from the spraying process were successfully produced. An influence of carbon nanotubes on the transverse (Z direction) and orthogonal (Y direction) electrical conductivity could be obtained. A slight but noticeable increase of the conductivity was achieved. More than the inherent values reached, the electrical conductivity was homogenized throughout the whole laminate. This achievement could be one step in order to solve the issue of "edge-glow" on aeronautical structures
Optimisation de la conductivité électrique transverse de composites structuraux PAEK-fils submicroniques d'argent/fibres de carbone continues avec ensimage conducteur by Jérémie Audoit( Book )

2 editions published in 2017 in French and held by 2 WorldCat member libraries worldwide

This PhD thesis deals with the optimization of transverse electrical conductivity of Thermoplastic Carbon Fiber Reinforced Polymer. The influence of an electrically conductive sizing has been investigated. Silver nanoplates (AgNpts) have been successfully synthesized by a soft chemical reduction, with trisodiumcitrate (TSC) as surfactant. Silver nanoplates have been dispersed into a model matrix, percolation threshold has been determined near 5.9 % in volume fraction. This value is consistent with their moderate aspect ratio (between 12 and 28). Size and morphology of silver nanoplates are suitable for their dispersion in the sizing. Carbon fiber has been coated with conductive sizing. Carbon fiber will be further impregnated by a PAEK thermoplastic matrix. A higher conductivity level has been achieved by introducing silver nanowires in the PAEK matrix. Structural composites consisting of matrix-silver nanowires / continuous carbon fiber sized with conductive sizing have been elaborated. Their electrical conductivity reached 7 S.m-1 for a total silver volume fraction of 1 %.vol
Dynamique macromoléculaire dans la paroi végétale et ses polymères pariétaux by Golnaz Jafarpour Moghaddam( Book )

2 editions published in 2007 in French and held by 2 WorldCat member libraries worldwide

The wood has become a popular material for several industries. The wood molecular mobility and the one of three principal constitutive polymers, cellulose, hemicellulose and lignin were studied. Thermal stability and physical structure of materials were respectively obtained by Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). In parallel, macromolecular relaxation dynamics were measured by Dynamic Dielectric Spectroscopy (DDS) and Thermo Stimulated Currents (TSC). The combination of two last methods let us study the localised and delocalised molecular mobility on the extended frequency scale. The influence of the hydrogen bonds and the hydration rate on the molecular mobility was also pointed out. The analysis realised on genetically modified wood brought us the information on the inter chain interactions evolution
Thermal, mechanical and dielectric behaviour of poly(aryl ether ketone) with low melting temperature by Jérémie Audoit( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Dielectric relaxations in PEEK by combined dynamic dielectric spectroscopy and thermally stimulated current by Aurélie Leonardi( )

1 edition published in 2012 in English and held by 2 WorldCat member libraries worldwide

 
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Languages
French (28)

English (10)