Dissertations / Theses on the topic 'Polymères – Propriétés électriques – Propriétés mécaniques'
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Probst, Nicolaus. "Etude des propriétés électriques et diélectriques des composites polymères - noirs de carbone : parallélisme entre propriétés électriques et mécaniques." Mulhouse, 1991. http://www.theses.fr/1991MULH0180.
Full textChailan, Jean-François. "Contribution des spectrométries mécanique et diélectrique à l'étude du vieillissement d'élastomères en ambiance nucléaire." Lyon 1, 1993. http://www.theses.fr/1993LYO10236.
Full textDalmas, Florent. "Composites à matrice polymère et nano-renforts flexibles : propriétés mécaniques et électriques." Phd thesis, Grenoble INPG, 2005. http://tel.archives-ouvertes.fr/tel-00012111.
Full textLecoublet, Morgan. "Ρrοpriétés Diélectriques des Μatériaux Biοsοurcés." Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMR027.
Full textIn a context of sustainable development and public awareness of environmental issues, biobased polymers represent a promising niche in the industrial sector, with a strong growth potential. This is a favorable context for the development of new biobased and/or biodegradable structures suitable for a wide range of dielectric applications, but many limitations still exist to fully benefit from the dielectric performance of biobased polymers. This thesis is part of a broader effort to promote the use of biobased materials in the dielectric field, proposing an advanced study of the multiphysical properties, particularly dielectric properties, of biobased polymers to identify applications in dielectric fields suitable for such materials. In the first phase of the thesis, an advanced literature review identified three biobased polymers with high potential for the dielectric field, i.e. polylactic acid (PLA), polyhydroxybutyrate-co-valerate (PHBV) and cellulose acetate (CA). Their dielectric performance were comparable to conventional synthetic polymers used in electrical insulation, such as polyethylene, polypropylene and epoxy resin. In addition, the literature review also identified three potential strategies to encourage the use of bio-based polymers in electrical insulation, i.e. the development of polymer blends, the creation of bio(nano)composites based on cellulosic fillers, and the use of new processing techniques such as 3D printing. The second phase of the thesis proposes the creation of polymer blends and 3D printing to obtain 3D-printed PLA-based materials for application in electrical insulation. Preliminary results showed that PLA : CA blends were the most promising for the continuation of the project and were therefore chosen for the 3D printing step. The addition of CA improved the mechanical stability of PLA in a rubbery state, but also slightly reduced their electrical insulation capacity. An optimization step using a Taguchi design resulted in 3D-printed polymer blends samples with mechanical rigidity and electrical insulation capacity comparable to low-density polyethylene. The final phase of the thesis proposes to combine the use of cellulose-based bio(nano)composites and 3D printing to obtain PLA-based materials for application in electrical insulation. Two different fillers were used and compared: cellulose microcrystals (MCC) and cellulose nanocrystals (NCC). The results showed that the addition of cellulose fillers improved the mechanical rigidity of the materials, but also slightly reduced their electrical insulation capacity. A factorial design optimization step produced cellulose-reinforced biocomposites with superior mechanical properties to polypropylene, while offering comparable electrical insulation properties. This thesis therefore proposes biobased and even compostable alternatives to polyethylene and polypropylene in the electrical insulation field, through the combined use of different strategies easily applicable on an industrial scale, in line with a sustainable development approach
Capsal, Jean-Fabien. "Elaboration et analyse des propriétés physiques de nanocomposites hybrides ferroélectriques." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/835/.
Full textThe piezoelectric activity of a hybrid ferroelectric nanocomposite, i. E. Polyamide 11/ Barium Titanate (BT), has been investigated for different loadings of BT particles. The BT volume fraction (phi) was ranging from 0. 024 to 0. 4 with a particle size of 50 nm, 100 nm, 300 nm and 700 nm. The influence of polarization mode on the piezoelectric behaviour has been studied. The magnitude of the poling field used in this study is in the same order of magnitude of the one used for bulk BT i. E. Significantly lower than for piezoelectric polymers. The optimum piezoelectric coefficient is reached when the amorphous phase of the polymeric matrix is in the liquid state i. E. ; for a polarization temperature higher than the glass transition and for time constant allowing macromolecular mobility. The composite piezoelectric activity decreases for particles size lower than 300 nm due to the loss of the tetragonal phase. The nanotexture of these particles has been investigated by TEM and HRTEM. A core shell structure has been observed. An increase of the longitudinal piezoelectric strain coefficient d33 with the raising of BT volume fraction was shown. Contrary to inorganic piezoelectric ceramics, the dielectric permittivity of hybrid composites remains moderate although the piezoelectric voltage coefficient of composites is bigger than ceramics
Cârlescu, Vlad. "Caracterizarea statică și dinamică a polimerilor electroactivi dielectrici pentru aplicații mecatronice." Thesis, Artois, 2013. http://www.theses.fr/2013ARTO0204/document.
Full textThe concept of biomimetism, or bionics, published since 1969, are studying structural and functional patterns of living to transfer them to technics. In nature, the movements are produced by muscles, while the technique uses the engines. Despite the advanced state of conventional actuation technologies such as hydraulic, pneumatic and electric motors, there is a growing demand in the field like mechatronics, robotics and bioengineering for electromechanical actuators with high performance and deformations, flexible, lightweight, high reliability and low cost. The diversity of physical phenomena in smart materials (piezoelectric, electromagnetic and magnetostrictive, shape-memory alloys, electro and magneto-rheological fluids, ferromagnetic shape memory alloys and electroactive polymers) open new opportunities in the design and development unconventional actuators. Due to their high adaptability, the polymers are used increasingly used in many areas. Sensors and actuators based polymers is a promising field of intelligent polymers and are more associated with artificial sensors and actuators in living organisms. Thus, after ’90, a considerable attention in the unconventional actuators based on smart materials was attract by electroactive polymers (EAPs). These materials have a high electromechanical coupling and are also very flexible and very light They deform when they are subjected to an electric field and can generate a current or a field when subjected to a mechanical deformation. Thus, they can be used either as a flexible sensors ans actuators, or generator. The thesis is divided into seven sections and involve the determination of the dielectric, mechanical and electromechanical properties of some silicone based polydiméthylsiloxane (PDMS) with inclusions of SiO2 and TiO2 for use as actuators in mechatronic applications. The dielectric parameters such as dielectric constant loss were determined by dielectric spectroscopy and showed to be similar to those reported in literature. The elastic properties were studied by several mechanical tests, such as uniaxial tension, uniaxial compression and indentation tests of free-standfing circular films. Electromechanical properties of PDMS-SiO2-TiO2 elastomers excited by CD and AC voltages were evaluated by non-destructive methods, such as scanning laser vibrometry. Also, the thesis presents the personal contributions on the implementation of the finite element analysis (FEA) to simulate the deformation of the PDMS-SiO2-TiO2 elastomers subjected to uniaxial tension and compression
Périé, Thomas. "Dispersion de nanotubes de carbone dans les polymères : de la nanostructuration aux composites hautes performances." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://pastel.archives-ouvertes.fr/pastel-00634552.
Full textKechaou, Borhane. "Corrélation entre propriétés diélectriques et mécaniques de composites à matrice époxyde renforcée par des fibres de verres E." Ecully, Ecole centrale de Lyon, 2003. http://bibli.ec-lyon.fr/exl-doc/bkechaou.pdf.
Full textTwo unidirectional glass fiber reinforced polymers composite materials, being different only by the nature of the fiber/matrix interface (sizing), were studied. The approach is based on the fact that any stress, whatever its nature (electric, mechanical, radiative, thermal. . . ), applied to a dielectric material led to an injection of electric charges. These charges can diffuse or be trapped. To simulate these phenomena, the "mirror method" (Scanning Electron Microscopy Mirror Effect SEMME) were used. It is shown that the fiber/matrix interfaces impose a greater instability of the charges, with a double role of motion but also of trapping of the charges along the interface. A composite which has a sizing allowing the diffusion, therefore limiting the localization of the polarization energy, is consequently preferable from the mechanical or tribological point of view
Louis, Christel. "Mélanges de polysulfones avec un élastomère acrylate : caractérisation morphologique et thermo-mécanique." Toulon, 2001. http://www.theses.fr/2001TOUL0002.
Full textZhao, Hang. "Comportement multifonctionnel des composites comportant des nano/micro renforts." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLC020/document.
Full textDue to the outstanding mechanical electrical and thermal properties, carbon nanotubes (CNTs) received worldwide attentions and intensive investigations in last decades. CNTs are greatly potential in applications such as energy storage and microelectronics. The one dimensional structure, high aspect ratio and low density, promote CNTs serving as the excellent fillers in composites field. However, due to the strong interactions, CNTs are usually difficult to be dispersed and aligned in a polymer matrix. Designing the CNTs construction reasonably is an effective way to ameliorate the dispersion states of CNTs in matrix. These specific hybrid constructions allowed CNTs arrays synthesized vertically onto the substrates through catalyst chemical vapor deposition method. These CNT arrays effectively overcome the problem of CNTs aggregation and promote the interconnection among CNTs, leading to a considerable improvement of multi-functional properties of composites. Graphite nanoplatelets (GNPs) served as substrate make their synthesizing products-GNP-CNTs hybrids (GCHs) possess distinct merits of all-carbon composition, totally-conductive coupling structure and the low intrinsic density. These GCHs constructions provide a great improvement in the dielectric and electrical properties of composites. However, the relationship between GCHs organization and synthesizing conditions during CVD process and the influence of the addition of GCHs to internal conductive networks have not been reported in detail. These mentioned issues will be investigated and discussed in this thesis, which is divided into four chapters:The first chapter makes a general review of the structure, properties, application and synthesis of CNTs and GNP substrates, and the main procedures of fabricating composites and surface functionalization of CNTs. Moreover, a short introduction of the development of micro-nano hybrids applied to the functional composites is made. Most importantly, the developing electrical states and (di) electrical characteristics of composites with ever-increasing conducting filler loading are reviewed in detail at the last part.The second chapter discusses firstly the synthesis process through the CCVD approach and the relationship between CVD parameters and the corresponding construction of GCHs, where the temperature, gas composition and reaction time were controlled. The constructions CNT arrays are dependent on the synthesis conditions. Furthermore, the results obtained from analysis can provide a structural foundation for the huge application potential of GCHs constructions. The third chapter introduces the poly(vinylidene fluoride)-based nanocomposites containing GCH particles, the dielectric properties of which are improved more greatly than the ternary composites loading equivalent mixture of GNPs and CNTs. The composites achieved by dispersing GCH particles into matrix using the mechanical melt-mixing process, showing a strongly reduced percolation threshold (5.53 vol %) and the relatively high thermal stability. Their improved dielectric properties can be attributed to the formed microcapacitor networks and the change of crystalline formation of matrix, caused by well-designed CNT arrays constructions. The fourth chapter investigates the advanced GCHs/ polydimethylsilicone (PDMS) composites with high piezo-resistive performance at wide temperature range. The synthesized GCHs can be well dispersed in the matrix through the mechanical blending process. The flexible composite shows an ultra-low percolation threshold (0.64 vol%) and high piezo-resistive sensitivity (gauge factor ~103 and pressure sensitivity ~ 0.6 kPa-1). Particularly, the much improvements of electrical properties achieved in GCHs/PDMS composites compared with composites filled with equivalent CNT, GNP or mixture of CNTs/GNPs. Slight motions of finger can be detected and distinguished accurately using the composites film as typical wearable sensor
Fournier, Jérôme. "Contribution à l'étude des matériaux composites conducteurs à matrice époxyde : application à la non linéarité électrique." Lyon 1, 1997. http://www.theses.fr/1997LYO10336.
Full textLonjon, Antoine. "Nanocomposite conducteur polymère - nanofils métalliques : élaboration et analyse des propriétés physiques." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1346/.
Full textThis work shows the elaboration of electrical conductive nanocomposites polymer/metallic nanowires, low filled to preserve the mechanical properties of the polymer matrix. Conductive metallic nanowires were performed with different kind of metals. These conductive nanowires are inserted into an electrical insulator thermoplastic matrix P(VDF-TrFE). The mechanical properties are maintained for filler content below 5 % vol. Above the percolation threshold (0. 75 % volume) the conductive nanocomposites reach a value of electrical conductivity near 10² S/m. The influence of the aspect ratio, metal, crystallinity and process are discussed to interpret the values observed
Ramachandran, Laavanya. "Comportement électrique large bande des composites polymère - fils submicroniques d'or : corrélation avec la structure et les propriétés mécaniques." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30072/document.
Full textThe aim of this work is to study the properties of a polymer-metal composite, with regards to physical, thermal, mechanical and broad band electrical analyses. High aspect ratio gold nanowires (Au NW) were prepared using a template electrodeposition method (aspect ratio of 190 determined by image analysis). The gold nanowires were dispersed in a PVDF polymer matrix to form low-filled conducting composites. The electrical conductivity of the composites exhibit electrical percolation behaviour with a critical volume fraction of 1.33%. SEM images show a slightly oriented but homogenous dispersion of AU NWs within the PVDF matrix. Mechanical analysis confirms that the homogenous dispersion Au NWs reinforces the PVDF matrix and highlights the influence of Au NWs on the physical structure of the PVDF matrix. This is confirmed by an increase in G' values and more specifically the ac relaxation process (associated with the crystallite-amorphous phase interface). Analysis of static and dynamic conductivity for low (10-2 to 106 Hz) and high frequency (106 to 109 Hz) regions reveals a thermally-activated charge transport process: tunneling being the predominant mechanism at low temperatures, the Efros and Shklovskii (ES) and Correlated Barrier Hopping (CBH) models being responsible for static and dynamic conductivity, respectively. The models were found to be coherent with the structure and mechanical properties of the composites, leading to a better understanding of charge transport mechanisms in low-filled polymer-metal composites
Ambid, Matthieu. "Evaluation de nanocomposites polypropylène/silicate pour l'isolation électrique : étude des phénomènes de polarisation, de conduction et des propriétés optiques." Toulouse 3, 2007. http://thesesups.ups-tlse.fr/795/.
Full textThis thesis focuses on polyolefin matrix nanocomposite. The goal is to provide an interpretation on their macroscopic properties. We studied electrical properties, optical and chemicophysical properties of composite materials based on iso- and syndiotactic polypropylene matrix and dispersions belong to the generic class of silicates. The means employed on measures dynamic dielectric analysis, current in the time domain, electroluminescence, photoluminescence and UV-visible spectroscopy. A method of time-frequency inversion was implemented : it allows to explain the transient currents observed from the frequency data and identify the regimes of field where nonlinear phenomena occur
Van, Durmen Pauline. "Étude de l'influence de la dispersion de nanotubes de carbone sur les propriétés électriques de composites à matrice PEEK." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2392/.
Full textThis thesis presents the processing and the characterization of electrically conductive composites for aeronautic applications. The multiwalled carbon nanotubes (MWNTs) dispersion in a thermoplastic Poly(Ether Ether Ketone) (PEEK) was realized according to a solvent way followed by hightemperature extrusion. The study of the electrical properties of PEEK/MWNT composites showed a percolation threshold at 1. 5 wt. % MWNTs and a maximum electrical conductivity of 1 S/m. The change of the composites dielectric properties with the MWNTs weight fraction reveals a percolation phenomenon in the dielectric permittivity behavior at the electrical percolation. The low filler content enables the maintenance of the structural and mechanical properties of PEEK matrix. The MWNTs dispersion state and the electrical properties of composites were studied and discussed according to the amphiphilic molecules (palmitic acid) and Poly (Ether Ketone Ketone) (PEKK) oligomers addition and MWNTs purification
Mdarhri, A. "Propriétés électromagnétiques de matériaux hétérogènes: Approche expérimentale et modélisation." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2007. http://tel.archives-ouvertes.fr/tel-00583599.
Full textReyes-Melo, Martin Edgar. "Modélisation des manifestations mécanique et diélectrique de la viscoélasticité des isolants organiques par la méthode de dérivation et d'intégration fractionnaire." Toulouse 3, 2004. http://www.theses.fr/2004TOU30086.
Full textMitov, Michel. "Action du champ électrique sur des cristaux électriques chiraux en géométrie confinée." Nice, 1993. http://www.theses.fr/1993NICE4666.
Full textWe present phase diagrams of mixtures between a cholesteric liquid crystal sidechains polymer with cholesteric or nematic low molar mass liquid crystals. We describe a new phenomenon occuring at the threshold of the cholesteric / nematic transition induced by an electric field in a confined geometry (i. E. : the celle thickness is of the order of the helicoidal pitch). It consists, in optical microscopy, in the spiral shape of filaments (bound to the cholesteric phase) embedded in the homeotropic matrix (untwisted cholesteric). We give a flexo-electric type model, based on the propagation of surface distorsions, for the spirals nucleation. A growth mechanism, linked to the intrinsic structure of filaments (exhibiting a double twist) is suggested. We show how to use of a photo-crosslinkabke polymer permits to freeze field-induced structures, as the spirals, and we give the experimental process for obtaining a film for electron microscopy studies. This gelation process via a polymeric network leads to new ways for applications as for micro-structural studies
Thevenot, Camille. "Élaboration de membranes polymères piézoélectriques souples en vue d’applications biomédicales." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0197/document.
Full textThe work presented here focuses on the preparation of a piezoelectric polymer material aimed to be the sensitive element of a strain sensor of biological tissues. This includes the study of the softening of the copolymer P(VDF-TrFE) necessary to be close of the mechanical properties of an artery, without reducing the piezoelectric coefficient. Plasticized P(VDF-TrFE) films with diethyl phthalate (DEP) were made according to different protocols including doctor blade technique or spin-coating and polarization under high voltage to activate the ferroelectric properties. Depending on the preparation conditions, two distinct structures were obtained with physical properties specific to each of them. For the first type of film, the study of the morphology and the hysteresis loops polarization-electric field showed a new structure of the material, with a demixing of the plasticizer in the matrix. In this case, the coercive field is strongly reduced which allows a decrease of the required high polarization voltage up to 40%, even if the film only contains 50wt% of P(VDF-TrFE). The second type of film, obtained after an annealing at lower temperature, has an almost homogeneous structure and properties close to a mixing law. The coercive field remains comparable to that of the pure P(VDF-TrFE) but the flexibility of the material is greatly increased. The study of the mechanical properties showed that the plasticizer can reduce the Young modulus to 40MPa for 30wt% of DEP in the film. In addition, the remanent polarization and the piezoelectric coefficient are also reinforced. In vitro and in vivo experiments, performed on arteries, of sensors based on these films demonstrated the high potential of the material to detect the strain of soft tissues and to function at biologic human frequencies
Henri, Victor. "Identification et analyse des marqueurs de vieillissement pour polymères isolants sous contrainte thermique en aéronautique." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30066.
Full textThis 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
Carponcin, Delphine. "Composite hybride à matrice polymère pour l'amortissement de vibrations par transduction-dissipation locale." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1763/.
Full textThis 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
Grillard, Fabienne. "Structure et propriétés de fibres composites polymère-nanotubes de carbone obtenues par voie fondu." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14577/document.
Full textThis thesis reports the study of the properties and structure of carbon nanotube / polymercomposite fibers obtained by melt spinning. By contrast to most fibers produced by thistechnology, the fibers produced in this thesis are electrically conductive. The conductivityproperties are studied as a function of various parameters including temperature andmechanical stress. It is shown that fiber drawing induced by the process leads to a relativetranslation of the nanotubes relative to each other and to a loss of electrical contacts. Ananalytical model accounts for this phenomenon and reproduces the experimental results.Polymer-nanotube fibers exhibit also particularly original thermomechanical properties suchas shape memory effects that are controllable by the programming process. Surprisingly, thefibers have a temperature memory reflected by a peak of the generated stress at thetemperature at which the materials has been programmed. These effects have beendemonstrated for various types of deformations including elongation and torsion. Althoughthese effects are governed by the properties of the polymer, it is shown that the introductionof nanotubes provides significant improvements of the thermomechanical properties
Lahoud, Nadine. "Modélisation du vieillissement des isolants organiques sous contrainte électrique : application à la fiabilité des matériaux." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/517/.
Full textThe aim of this study is to improve the description of solid organic insulators or polymers ageing under electrical stress. With this objective in view, the different ageing scenarios existing in the literature were analyzed, compared and improved. This theoretical study showed that many parameters related to their heterogeneous structure and the distribution of their properties were neglected in order to simplify the modelling. This study presents a new approach in the description of solid organic insulators ageing by taking into consideration their experimentally demonstrated structural complexity. In this approach, the polymer material has been assimilated to a set of sites representing different energy states, thereby different properties as well as ageing rates depending on each site. The principal parameters involved during the ageing process, such as the specific volume variation, the dielectric strength evolution and the local value of the electrical field have been defined. The expression of the retardation time specific to each elementary ageing process has been established. Finally, a distributed form of those retardation times has been presented. Our "phenomenological" approach is thus a multi-sites one permitting, along with an experimental study, to establish an equation relating the life time of polymer electrical insulators to the different parameters at play, all along respecting their distribution over the entire set of sites within the polymer
Yu, Zhong-Zhen. "Procédé d'extrusion réactive appliqué à l'élaboration de mélanges de polymères et de nano-composites." Vandoeuvre-les-Nancy, INPL, 2001. http://www.theses.fr/2001INPL018N.
Full textPacchini, Sébastien. "Etude des potentialités des nanotubes de carbone dans le domaine hyperfréquence : application à l'élaboration de matériaux nano-composites et contribution à la miniaturisation de composants électromécaniques (NEMS)." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/461/.
Full textThe discovery of carbon nanotubes (NTCs) by S. Iijima in 1990 allowed to explore a new world at the nanoscale. At the beginning of this decade, studies have provided a reproducibility of carbon nanotubes. Carbon nanotubes have shown exceptional stiffness, strength and remarkable thermal and electrical properties, which make them ideal candidates for the development of multifunctional materials systems. My research presents two possible uses of carbon nanotubes (CNTs) for microwave applications, exploiting their exceptional electrical and mechanical properties. The first one consist in utilizing their metallic or semiconducting properties to modify the electrical behavior of polymer (BCB) doped with carbon nanotubes. The second one aims to extend the concept of passive and reconfigurable micrometer components (MEMS)at the nanoscale to develop Nano-Electro-Mechanics Systems (NEMS). The first study consisted of an electromagnetic characterisation of polymer BenzoCycloButen (BCB) composites containing dispersed CNTs at microwave frequencies (40MHz - 40GHz) using coplanar waveguides (CPW). A new nano-composite material based on carbon nanotubes and BCB polymer is studied for shielding and electromagnetic wave absorption. For the first time to our knowledge, methods of homogenization and composite fabrication are presented, next test structures to measure microwave parameters are developed. After characterization, linear attenuation "a", complex permittivity "e*", conductivity "s" and power absorption "PA" are extracted and compared to simulation results obtained using the electromagnetic field simulator "HFSS". The electrical parameters of nano-composites are modified by DWCNTs concentration. The percolation threshold is obtained with only 0. 075wt. % of DWCNTs in BCB and the nano-composites showed 5dB of PA at 30GHz. The resulting engineerable composite gives RF-designer one more degree of freedom to to develop and optimize microwave components. .
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.
Full textThe 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
Roumy, Laurane. "Study of the Electro-Thermo-Mechanical Behaviour of a 4D Printed Actuator." Electronic Thesis or Diss., Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2024. http://www.theses.fr/2024ESMA0016.
Full textThe aim of this thesis was to develop an electro sensitive 4D printed hinge. 4D printing consists in using an additive manufacturing method coupled with an intelligent material that is sensitive to an external stimulus in order to create movement, the fourth dimension being time. For this study, the external stimulus is temperature, and heating is achieved by the Joule effect. Fused Filament Fabrication (FFF), which creates a three-dimensional structure by depositing melted polymer filaments, was chosen for its low cost, ease of use and low waste production. Polylactic acid (PLA) was used because it has excellent shape memory properties, is biosourced, is produced in Europe and is often used in FFF. To use the Joule effect, PLA reinforced with carbon black particles (CB/PLA) was considered. The result is a heat-sensitive material that can be heated remotely via an electrical circuit. An analysis of the electro-thermal and electro-mechanical couplings in this material was therefore carried out. The first step was to establish the link between the properties of the printed sample and the printing parameters. Rectangular specimens were then heated using the Joule effect and observed with a thermal camera in order to study the behaviour of the material when subjected to three different voltages. A model based on the heat equation was used to predict the temperatures reached within the material. Under electrical cycling, a change in the CB/PLA microstructure was observed, resulting in a change in electrical resistance. A study of the electro-mechanical coupling was then carried out using monotonic and cyclic tensile tests to analyse changes in electrical resistance under mechanical stress and in the context of repeated use. The advantages of a structure with a longitudinal printing angle, along the loading direction, were demonstrated by superior electrical and mechanical properties and improved durability. Other printing angles were also tested and the classical laminate theory was applied to the 3D printed specimens. Damage in the tensile specimens was monitored using acoustic emission, scanning electron microscopy and micro computed tomography. The development of crazes perpendicular to the loading direction was demonstrated. Finally, a hinge was designed and tested for a bending angle of 90°. The printing parameters were optimised to reduce the influence of residual stresses due to the manufacturing process during the programming step of the hinge. The results showed that the temperature of the plate and the printing speed had a noticeable influence. The reproducible deployment of a hinge with approximately 80% of recovery was obtained, and the force deployed and the deployment speed were measured. The repeated use of such a hinge and its durability were investigated by carrying out ten successive deployment cycles. The influence of programming and triggering temperatures was also studied. Finally, a first approach of reversible hinge was proposed. It was thus demonstrated that it is possible to create an optimised prototype of a 4D printed hinge that can be remotely triggered by Joule effect
Legorreta, Garcia Felipe. "Nanocomposites nanotubes de carbone-métal-oxyde : synthèse par CCVD et frittage par SPS." Toulouse 3, 2007. http://www.theses.fr/2007TOU30117.
Full textThe first objective was to study the preparation of CNT-metal-ZrO2 nanocomposite powders by the carbon nanotubes (CNT) in situ synthesis method. The conditions for the combustion synthesis of solid solutions between zirconia and one or several oxides of iron, cobalt, molybdenum or yttrium have been established. All solid solutions were obtained in stabilised form, either tetragonal or cubic, but yttrium incorporation was necessary to ensure a suitable thermal stability. Their selective reduction in either H2, or H2-CH4 or H2-C2H4 was studied in order to form metal-ZrO2 powders or CNT-metal-ZrO2 powders, respectively. The second objective was to study the consolidation and densification by spark-plasma-sintering of the ZrO2-matrix nanocomposite powders and of double-walled CNT-Co/Mo-MgO model powders. The mechanical properties and the electrical conductibility were measured
Lesueur, Didier. "Propriétés mécaniques des liants routiers : relations structure/propriétés." Lyon, INSA, 1996. http://www.theses.fr/1996ISAL0130.
Full textFollowing a literature review focusing on the structure of bitumens and polymer modified bitumens, linear viscoelastic properties of paving grade binders were studied versus temperature and frequency. It is shown that neat asphalt cements can be looked upon as colloidal suspensions. As a consequence, the higher the dispersed phase content, the higher the modulus of the material. Moreover, modification of a bitumen by styrene-butadiene block copolymers induces a phase separation, the polymer rich phase being the dispersed phase for the investigated polymer contents (up to 6 % mass). The Palierne emulsion model describes the rheological properties of such multiphased materials
Soulimane, Sofiane. "Conception et modélisation d'un micro-actionneur à base d'élastomère diélectrique." Phd thesis, Université Paul Sabatier - Toulouse III, 2010. http://tel.archives-ouvertes.fr/tel-00546239.
Full textHamdi, Khalil. "Fonctionnalisation de matériaux composites à renfort carbone et matrice thermoplastique par adjonction de nanocharges : élaboration et étude du comportement." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2388/document.
Full textTo extend the use of composites in more varied application (smart applications, multifunctional issues), one of the actual barrier is their poor electrical and thermal conductivities. In the case of carbon fiber reinforced composites, organic matrix are in charge of the insulating properties of the resulting composite. One of the solutions to enhance conductivities of materials is the use of conductive nanofillers. Improving the electrical and thermal properties of nanofilled polymers has been investigated in several studies. However, studiing the properties of continuous carbon fiber nano-filled composites is less approached. This work tends to fabricate and characterize carbon black and carbon nanotubes nano-filled composites. First of all, special interest was given to the delicate phase of manufacturing. As mentioned before, processing continuous fiber reinforced nanofilled polymers implies issues related to nanofillers agglomeration and inhomogeneous dispersion in the final composite. To resolve these problems, the choice of the thermoplastic (Polyamide6) matrix seemed preferable. In fact, the dispersion of nanofillers was made by twin screw extrusion which is known as one of the most effective agglomeration separation ways. Adding to this, the fabrication method based on Polyamide 6 shects called film stacking, ensure a homogeneous partition at the beginning of the process. SEM observations were performed to localize the nano-particles. It showed that particles penetrated on the fiber zone. In fact, by reaching the fiber zone, the nano-fillers created network connectivity between fibers which means an easy pathway for the current. It explains the noticed improvement of the electrical conductivity of the composites by adding carbon black and carbon nanotube. This test was performed with the 4 points electrical circuit. It shows that electrical conductivity of 'neat' matrix composite passed from 20S/cm to 80S/cm by adding 8wt% of carbon black and to 15S/cm by adding 18wt% of the same nano-filler. For carbon nanotubes, with '2.5wt% the conductivity was around 150S/cm. For the thermal properties, tests based on Joule's effect were performed. The rise of temperature was recorded using IR camera. Results obtained are in agreement with the electrical conductivity ones, showing enhancement of the thermal behavior in presence of nanofillers. Thanks to these results, the use of these composites as a damage-monitoring tool was possible. By the way, the electrical resistance change method was performed. Nanofilled materials showed better sensitivity to damage. Results were compared with classical damage monitoring tools. At the end, several 'smart' applications were tested such as graded functionalities composite and stitched nanofilled materials
Bodiguel, Hugues. "Propriétés mécaniques de films de polymères ultraminces." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2006. http://tel.archives-ouvertes.fr/tel-00114971.
Full textHammami, Saber. "Propriétés physiques et électriques de polymères électroactifs." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT033/document.
Full textElectroactive polymers known as dielectric elastomers have shown considerable promise for transducers. They are attractive for a wide range of innovative applications including softs robots, adaptive optics, haptic interface or biomedical actuation thanks to their high energy density and good efficiency. For the functioning of all these application, the electroactive polymer is subjected to high electrical field. Nevertheless, the performances of these transducers are affected by the losses and especially the ones induced by the leakage current.Mechanical pre-stretch is an effective method to improve actuation when a voltage is applied to the device made up of a dielectric elastomer sandwiched between two compliant electrodes. The overall performances of the structure (electromechanical conversion, efficiency, strain induced…) depend strongly on the electric and mechanical properties of the elastomer. Regarding electric characteristics, dielectric permittivity, dissipation factor and electric breakdown field have been deeply investigated according to various parameters such as frequency, temperature, pre-stretch, or nature of the electrodes but complete analysis of the leakage current is missing in the scientific literature.Thus, this work reports an extensive investigation on the stability of the current-time characteristics in dielectric elastomer. Particularly, we focus on the influence of the nature of the electrodes and pre-stress applied to the transducer. In order to evaluate the influence of the time duration on the behavior of the leakage current, short and long-term electrical stress times was applied during short times and up to 15 hours.Leakage current in electroactive polymers were discussed for a commercial polyacrylate (VHB4910 from 3M) currently used for soft transducers applications. This current is investigated as a function of external factors (stretching, temperature, type of material for electrodes)In order to evaluate the limitations in term of voltage and in the goal to increase the lifetime of these transducers, the second part of our study is focused on the dielectric strength of silicone rubbers for various types of electrodes (gold, Aluminum, graphene nanoplatelets, graphene : GnP). The effect of self-healing is particularly studied and a selection of electrodes for soft transducers based on dielectric elastomers is proposed
Faye, Benoît. "Polypyrroles mésomorphes conducteurs : synthèse, propriétés mécaniques et électriques." Bordeaux 1, 1999. http://www.theses.fr/1999BOR10631.
Full textSchach, Régis. "Structure et propriétés mécaniques d'interfaces entre polymères fondus." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2006. http://tel.archives-ouvertes.fr/tel-00149339.
Full textNous avons déterminé les mécanismes de formation et de rupture d'interfaces entre deux polymères identiques de masse moléculaire et microstructure contrôlées. Nous avons ainsi développé une méthode de mesure de l'adhérence adaptée aux polymères fondus.
En utilisant cette méthode, nous avons comparé les mesures d'adhérence entre polymères immiscibles à l'équilibre thermodynamique et l'épaisseur de l'interface caractérisée par réflectivité des neutrons. Nous avons montré clairement que le paramètre de Flory pilote le degré d'adhérence entre deux polymères fondus immiscibles.
Cette corrélation entre interdiffusion et adhésion nous a finalement permis d'étudier la cinétique de diffusion mutuelle de ces polymères à partir des cinétiques de montée en adhésion et de prouver expérimentalement que cette cinétique est fortement ralentie par l'immiscibilité des polymères.
Deverge, Mickaël. "Propriétés mécaniques et rhéologiques des mousses de polymères réticulés." Le Mans, 2006. http://cyberdoc.univ-lemans.fr/theses/2006/2006LEMA1008.pdf.
Full textThe use of cross-linked polymer foams gains ground more and more, particularly for acoustic absorption. This work present new approaches for the characterization of these materials, which have a behavior in hysteresis with 3 distinct zones. First the linear behavior is presented on a large frequency band with the application of the Time-temperature Superposition (TTS) principle. 2 aspects are thus shown: a weak portion of the skeleton takes part in the stress transmission, and the elastic modulus at null frequency decrease with the pore size. Then an extension of the magnetism Preisach's theory is presented for great deformations: hysteresis is thus modelled starting from a distribution of microscopic hysterons. Lastly, 2 compressive relaxation mechanisms are distinguished. Principal relaxation decreases stress by topological rearrangement of the foam beams
Deverge, Mickael. "Propriétés mécaniques et rhéologiques des mousses de polymères réticulés." Phd thesis, Université du Maine, 2006. http://tel.archives-ouvertes.fr/tel-00133963.
Full textDiverses méthodes ont été développées afin de caractériser ces matériaux, en particulier leur domaine linéaire, zone privilégiée pour l'absorption acoustique et la détermination des paramètres mécaniques courants. Cependant ces caractérisations restent souvent limitées à une faible plage fréquentielle. Une première étude présente ici le comportement linéaire sur une large gamme de fréquences grâce à l'application du principe de Superposition Temps-Température (TTS). L'utilisation du TTS sur une famille de mousses obtenues avec le même polymère, de même densité, mais dont la taille des pores est différente, met en évidence deux aspects importants: seulement 3 % du squelette solide participe à la transmission de la contrainte, et le module élastique à fréquence nulle décroît avec la taille des pores.
Les mousses de polymères sont certes souvent utilisées dans leur domaine linéaire, mais leur comportement mécanique diffère à de plus forts niveaux de déformation. Les courbes en contrainte-déformation présentent un comportement en hystérésis, avec trois zones de comportement distinctes (linéaire, flambement et densification). Il existe d'autres phénomènes en hystérésis qui ont été plus simplement modélisés, par exemple à l'aide de la théorie de Preisach-Krasnoselskii-Mayergoyz (PKM) issue du magnétisme. Une seconde partie de ce travail présente une nouvelle extension de cette théorie PKM aux mousses de polymères réticulés à cellules ouvertes, soumises à de grandes déformations: nous pouvons ainsi modéliser l'hystérésis observée expérimentalement, à partir d'une distribution d'hysterons microscopiques contenus dans un espace de Preisach-Mayergoyz.
Dans une troisième partie, l'influence de l'histoire passée des contraintes sur la mesure des paramètres mécaniques d'une mousse est étudiée, et plus particulièrement la rhéologie de ces mousses dans le cadre de la relaxation de compression, en distinguant deux mécanismes, l'un en zone linéaire de chargement et l'autre en dehors. Liée à l'histoire des contraintes passées, ce second mécanisme de relaxation permet la réduction des contraintes par réarrangement topologique des poutres de la mousse.
Aubert, Eddy. "Diagnostic optique du vieillisement électrique des résines époxydes sous faible champ électrique." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/340/.
Full textEpoxy resins are insulating materials widely used in electrical systems since a long time. They are made with micro-particles to improve the thermal and mechanical properties. However, problems remain regarding the possible influence of these charges on the electrical behaviour, particularly on them long-term aging under different stresses. The objective of this work is to probe the electrical activity of potential defects in analysing the optical signals under moderate alternative electrical stress (up to 9 kV). Resins with and without charges have been studied. The major obstacle of this work was to improve the collection of luminous signal, given the low level of luminescence detected, inherent to the use of low field, near the services conditions. The interpretation of the different phenomena is based on spectral analysis, imaging devices and the issue of counting photons. Two luminescent behaviours have been observed, the first shows an evolution of the luminescence with the electric field to which the sample is submitted, the second regular shows discontinuity in the same evolution with instability that we could identify as being due to non-detectable micro-cavity by DP measuring devices. Experiments were conducted to determine the evolution of this luminescence in the case of the two behaviours during ageing under different constraints (electric and humidity). Few changes were observed
Marceau, Sandrine. "Architecture multiéchelle et propriétés mécaniques de nanocomposites." Chambéry, 2003. http://www.theses.fr/2003CHAMS012.
Full textThe purpose of this study is to improve the understanding of the mechanisms leading to reinforcement effects in nanocomposite materials. To do this, "model" systems were fabricated using an amorphous polymeric matrix reinforced by colloidal silica nanoparticles. The optical, physicochemical and mechanical properties of these materials were linked to their morphology. The morphological analysis of the nanocomposites showed that the silica nanoparticles were in form of dispersed aggregates for filler fractions lower than 6 %, whereas for higher fractions a percolating network of silica was evident. The study of the molecular mobility of the polymer chains showed that the nanoparticles did not induce any variation of the global mobility of the chains. The linear viscoelastic behaviour showed that the variations with temperature of the real part of Young's modules and the damping factor tan d were connected to the underlying structure of the nanocomposites. The experimental results were then compared to those obtained using two different theoretical approaches. At the mesoscopic scale, we used an adapted micromechanical model to show that the presence of the percolating network of fillers could induce a strong reinforcement effect and a shift of the main relaxation towards lower temperatures for fractions of silica higher than the percolation threshold. At the atomic scale, we analysed a PBMA-silica system by molecular dynamics. Using this model, we could show the influence of the filler on the molecular mobility of the polymer and on the mechanical properties of the nanocomposites
Védrines, Marc. "Contribution à l'étude des propriétés mécaniques des structures en polymère injecté : Application aux propriétés élastiques locales et à la modélisation viscoélastique." Université Louis Pasteur (Strasbourg) (1971-2008), 2003. http://www.theses.fr/2003STR13160.
Full textThe thesis deals with an experimental study of local variations of mechanical properties of injection molded polymers, followed by a specific part dealing with the viscoelastic modelization of those materials (PEhD, PA, POM). The variation of microscopic parameters strongly influence mechanical characteristics, especially in areas close to the mould walls. The evolution of Young's modulus has been inquired using several experimental devices. With the aid of a vibrational flexural test rig and digital calculation and processing systems that have been developed, it was possible to measure the variation in local Young's modulus as a function of position in the thickness of the test piece The results obtained reveal a large variation in the local Young's modulus over the thickness of an injection moulded piece, in particular in the outer skin zone. The influence of the various operational parameters has been evaluated. In order to correlate those results with microstructure, several other experiments have been led :-differential scanning dilatometry, to measure the evolution of the cistallinity rate,- nanoindentation tests to measure the variation of the local Young's modulus and anisotropy. Those tests validate previous results but present a strong dispersion due to microstructure heterogeneity and viscoelastic behaviour of polymers. Therefore, a better modelization of the viscoelastic behaviour has to be taken into account : this is the point of the second part of the thesis. The classical models of linear and non linear viscoelasticity in small deformation have been identified on experimental traction test and simulated under several conditions (deformation rate jumps, unloading). It is obvious that the classical models are not sufficient to describe properly the viscoelastic behaviour : the physic of the material has to be taken into account
Dufourg, Marie-Béatrice. "Caracterisation électriques des interfaces polymère/métal dans les diodes électroluminescentes organiques." Bordeaux 1, 2002. http://www.theses.fr/2002BOR12631.
Full textVallayer, Julien. "Corrélations entre les propriétés optiques, diélectriques et mécaniques de l'alumine." Ecully, Ecole centrale de Lyon, 1999. http://www.theses.fr/1999ECDL0041.
Full textChabert, Emmanuelle. "Propriétés mécaniques de nanocomposites à matrice polymère : approche expérimentale et modélisation." Lyon, INSA, 2002. http://theses.insa-lyon.fr/publication/2002ISAL0011/these.pdf.
Full textThis work aims to analyse the mechanical properties of polymer based composites reinforced by spherical nanofillers. The role of each component has been investigated: the polymer matrix, the filler and the interphase (matrix-filler, filler-filler). Firstly, the mechanical behaviour of polymer has been analysed through the molecular approach (“quasi point defect theory”) developped in GEMPPM laboratory. Based on an new formalism, a original method leading to the determination of physical parameters has been proposed. We have then validated this method for various polymers (PMMA, PET and P(S-ABu)). In a second step, the effect of grafted reactive surfactant on mechanical properties of latex films has been investigated. The comparison of self made model systems with grafted and non grafted surfactant has suggested that the grafting of surfactant affects slightly both the small and the large mechanical properties of latex films. On the contrary, the nature of the surfactant might affect the microstructure of complex latex, and in this way their mechanical properties. The last part is devoted to the effect of nanofillers. We have studied the role played by different parameters (concentration, filler nature (organic or mineral), filler/filler interactions) on the elastic mechanical properties. To model these properties, we have developped a discrete numerical approach taking into account the microstructure and the local contact (filler-filler and matrix-filler). The variation of contact caracteristics has thus enabled us to describe the different experimental results below and above the geometric percolation threshold. Finally, the analysis of tensile strain properties has suggested a rupture of the filler network from the first percent of elongation
Franbourg, Alain. "Influence d'un traitement à l'état fondu sur la structure cristalline et les propriétés mécaniques du poly(oxymethylène) et du poly(éther éther cétone) : relations : mise en oeuvre par injection/structure/propriétés." Lille 1, 1990. http://www.theses.fr/1990LIL10091.
Full textGueguen, Olivier. "Modeling and simulation of the mechanical behaviour of semi-crystalline polymers." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13073.
Full textSince the beginning of the XXth century, the plastic materials know a true development thanks to their good mechanical properties and their ease of processing. To estimate better the mechanical properties of these materials, we developed different mechanical models based on their morphology. The semi-crystalline polymer is composed of one crystalline and one amorphous phase with distinct mechanic and thermo-mechanic properties which allow us, by using homogenisation methods, to estimate the effective properties of the material such as its elasticity, its yield stress, its texture evolution… during a mechanical test. Our results are compared to experimental data at different temperatures and strain rates
Bense, Hadrien. "Croissance, compaction et adhésion de plaques minces." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC228/document.
Full textFrom a general point of view, my thesis deals with the links between the geometry and the shape of an object. It is composed of three main chapters. In the first one, we use "electro-active polymers", systems that undergo planar expansion when submitted to an electric field, to mimic a kind of biological growth. We looked at how an inhomogeneous growth can trigger buckling instability in this electro-active plate. We then tried to control locally this growth, hoping to create objects that can change shape on command. In the second chapter, we studied the opposite problem: instead of giving it a new natural shape, we force the object in adopting a non natural shape. We squashed hemispherical elastic caps. Changing a sphere into a plane is not an isometrical transformation, this operation thus creates strains in the object. We studied the mecanical instability hence produced. Finally we focused on the "contact lens" problem by wondering if it is possible to stick two spherical caps having different curvature. Here again, the mismatch of Gaussian curvature leads to patterns of instability in the elastic shell
Dang, Tan Tai. "Nanocomposites PVC/Montmorillonite : élaboration, morphologie et propriétés." Chambéry, 2005. http://www.theses.fr/2005CHAMS027.
Full textThe aim of this work is to process Poly (Vinyl Chloride)/Montmorillonite nanocomposites by new technologies developed in order to avoid any PVC therrnal degradation that is an important lirnitation of current methodologies. At first, special attention is focused on degradation of PVC/organomontmorillonite (organo-montmorillonite: quaternary aLkylamrnonium modified montmorillonite). The role of the quaternary alkylamrnonium is highlighted, and a "concerted quasi-ionic" mechanism is proposed. After this study, several methods which are supposed to avoid decomposition of PVC are explored. The parts II and IV deal with intercalation of montmorillonite and process study of nanocomposites processed by these methods. The part V deals with morphology, viscoelastic and mechanieal properties of the different familles of nanocomposites. Then a comparative study is realised between nanocomposites performed with commercial montmorillonite or with natural montmorillonite
Sakata, Hironobu. "Propriétés électriques et mécaniques de couches minces d'oxydes déposés sous vide." Bordeaux 1, 1986. http://www.theses.fr/1986BOR10530.
Full textJannot, Marion. "Polymères nanocomposites multifonctionnels. Impact sur les propriétés mécaniques de polymères à mémoire de forme." Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS549.pdf.
Full textThese works based on the developments of polymer nanocomposites illustrate the possibility of creating shape memory hybrid materials from a semi-crystalline thermoplastic elastomer copolymer, the poly(ethylene – vinyl acetate). Amongst the different approaches which exist to obtain thermo-responsive shape memory polymers, we chose to elaborate chemically crosslinked networks in attendance of an inorganic component as silicon oxo-polymer or titanium oxo-polymer. Tensile test showed that hybrid materials with titanium oxo-polymer provide an important reinforcement. At room temperature and at 100 °C, the elastic modulus of the material increase more than 3.8 times and 57 times in comparison to organic reference material crosslinked by peroxides. As the reference material, all nanocomposites display shape memory properties under appropriate conditions of time, stress and temperature. With titanium oxo-polymer, the dynamic iono-covalent nature of the hybrid interface bring news properties. Thermadapt nanocomposite materials are obtained. The use of an organic – inorganic hybrid material enable by tuning nanostructuration and nature of the hybrid interface to obtain multifunctional materials with shape memory properties, reprocessability, recyclability and thermally induced healing properties
Lafaye, Sébastien. "Propriétés mécaniques de friction et de déformation des surfaces de polymères." Phd thesis, Université Louis Pasteur - Strasbourg I, 2002. http://tel.archives-ouvertes.fr/tel-00002808.
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