Дисертації з теми "Membranes (technologie) – Matériaux"
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Courtois, Thierry. "Etude de la formation de la couche de polarisation de concentration en microfiltration tangentielle." Toulouse, INPT, 1992. http://www.theses.fr/1992INPT019G.
Tazi, Bouchra. "Élaboration et caractérisation d'une nouvelle membrane minérale conductrice ionique à structures dense et microporeuse." Montpellier 2, 1988. http://www.theses.fr/1988MON20138.
Broussous, Lucile. "Elaboration de nouvelles géométries tubulaires de membranes céramiques : application à la réduction du colmatage." Montpellier 2, 1999. http://www.theses.fr/1999MON20008.
Boissière, Cédric. "Elaboration de silices mésoporeuses MSU-X : applications en chromatographie HPLC et membranes d'ultrafiltration." Montpellier 2, 2001. http://www.theses.fr/2001MON20085.
Moise, Cazach Nicoleta-Adinela. "Récepteurs macrocycliques fonctionnalisés comme transporteurs membranaires et réactifs analytiques." Montpellier 2, 2007. http://www.theses.fr/2007MON20106.
Thomas, Michel. "Transport de l'eau à travers une membrane perfluorosulfonique Nafion : relations avec la microstructure : développement de membranes composites à haute perméabilité aux gaz." Lyon 1, 1989. http://www.theses.fr/1989LYO10174.
Uzio, Denis. "Préparation et caractérisation de membranes catalytiques méso et microporeuses : systèmes à base de platine." Lyon 1, 1994. http://www.theses.fr/1994LYO10055.
Mo, Yayuan. "Elaboration et mise en oeuvre de membranes alginate, polyethylenimine à haut pouvoir de percolation : application en tant que matériaux adsorbants ou catalyseurs supportés." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTG014.
Alginate is a hydrophilic and biocompatible polymer with abundant free carboxyl and hydroxyl groups. This work developed and optimized the process for the fabrication of highly-percolating membranes based on alginate. The simple process has been designed by mixing alginate and polyethyleneimine (PEI) to obtain a structured hydrogel and subsequently improved stability by crosslinking between glutaraldehyde (GA) and amine groups of PEI. This double interaction (PEI/alginate, PEI/GA) makes it possible to produce macroporous membranes, after air-drying (without energy-consuming and sophisticated drying procedure), allowing natural drainage. The prepared membranes have been used for two applications: (a) sorption of metal ions (cationic and anionic), and (b) hydrogenation of nitrophenolic compounds by heterogeneous catalysis. The membranes and their interactions with metal ions were analyzed by FTIR, SEM, and XPS. The adsorbent was characterized by the presence of carboxylic groups and amino functions, which offers numerous possibilities for interacting with metal ions by complexation (i.e., carboxylates, free amines) and ion exchange/electrostatic attraction (i.e., protonated amine groups) depending on the pH of solution and metal speciation. These different possibilities have been illustrated by a series of experiments on metal ions such as Hg(II), Cu(II), Se(VI), Cr(VI), As(V). These various studies illustrate the particular affinity of membranes for metal anions (preferentially to cations) due in particular to the greater availability of protonated amino functions. Furthermore, an additional study was conducted on PEI crosslinked with GA (as a powder) for exploring the effect of the crosslinking of PEI on the binding of metal ions. The study demonstrated that the crosslinking rate has a moderate effect on the sorption of Se(VI) ions. At last, after briefly studying the sorption of Pd(II) on the membranes, a reduction was made of Pd(II) loaded on the support (partially converted to Pd(0)) in order to synthesize catalysis for the hydrogenation of 3-NP to 3-AP. This demonstrates the feasibility of applying these supports for heterogeneous catalysis
Grasset, Frédéric. "Augmentation de la température de fonctionnement d'une pile à combustible par synthèse de nouveaux matériaux conducteurs protoniques." Montpellier 2, 2005. http://www.theses.fr/2005MON20025.
Mosadegh, Sedghi Sanaz. "Fabrication and characterization of new and highly hydrophobic hollow fiber membranes for CO₂ capture in membrane contactors." Doctoral thesis, Université Laval, 2013. http://hdl.handle.net/20.500.11794/24658.
In this work, highly hydrophobic low density polyethylene (LDPE) hollow fiber membranes aiming to be used for CO2 capture in gas-liquid membrane contactors (GLMC) were fabricated using a simple, novel method, without solvent or diluents, economic and environmentally friendly, which does not require any mechanical or thermal post-treatments. In order to produce hollow fibers and control their porosity, the process combines melt extrusion and template-leaching techniques. A mixture of LDPE and NaCl particles first produce blends with different salt contents. A microporous structure and a rough highly hydrophobic surface can then be produced by leaching the salt particles from the hollow fiber matrix via immersion in water. The new method represents a very promising alternative to conventional membrane fabrication approaches which are mainly based on phase inversion process that involves toxic and expensive solvents. The fabricated membranes were characterized in terms of morphology, density, porosity and pore size distribution, hydrophobicity, breakthrough pressure and mechanical properties. Since the phenomenon of membrane wetting by liquid absorbents is the major cause of the reduction of long-term efficiency of GLMC, a comprehensive study on the compatibility between membrane and absorbent liquid was performed. Morphological, chemical and thermal stability of LDPE membranes in contact with different aqueous alkanolamine solutions including monoethanolamine (MEA) and 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD), as well as blends of MEA/PZ (piperazine) and AHPD/PZ, was investigated in detail.
Gazagnes, Laetitia. "Modification de la surface de membranes céramiques par greffage, application au dessalement et à la séparation d'émulsions." Montpellier 2, 2005. http://www.theses.fr/2005MON20074.
Pagès, Xavier. "Décharge luminescente transportée pour la synthèse de membranes a-SiCx:H à l'intérieur d'un support céramique tubulaire." Montpellier 2, 2001. http://www.theses.fr/2001MON20034.
Combe, Corine. "Estimation de la sélectivité en nanofiltration à partir des propriétés du matériau membranaire : Modèles de transport." Toulouse 3, 1996. http://www.theses.fr/1996TOU30201.
Maïsterrena, Bernard. "Compartiments asymétriques séparés par des membranes artificielles perméables porteuses d'enzymes immobilisés : approche expérimentale et théorique des étapes de diffusion-réaction-séparation des réactants." Lyon 1, 1989. http://www.theses.fr/1989LYO10015.
Boye, Anne. "Synthèse et caractérisation d'une membrane de nanofiltration en polyphosphazène." Montpellier 2, 1992. http://www.theses.fr/1992MON20018.
Vacassy, Robert. "Synthèse et caractérisations de membranes minérales de nanofiltration : Modélisations du transport de matière et de la perméabilité à l'eau." Montpellier 2, 1996. http://www.theses.fr/1996MON20082.
Fillaudeau, Luc. "Microfiltration tangentielle de la bière de garde sur des membranes céramiques multicanaux." Compiègne, 1998. http://www.theses.fr/1998COMP1146.
Barbar, Reine. "Contribution à la mise au point de nouveaux matériaux membranaires pour la filtration de milieux complexes : étude physico-chimique de membranes d'acétate de cellulose et de méthylcellulose partiellement alkylée obtenues par immersion-précipitation." Vandoeuvre-les-Nancy, INPL, 2006. http://docnum.univ-lorraine.fr/public/INPL/2006_BARBAR_R.pdf.
In response to today's consumer seeking for high quality oil with an authentic stamp, membrane processing are part of the "mild technologies" looked for, both economically and quality wise. In the present study hydrophobicity is considered as the key for the separation. In the present work, a fractionation device having four compartments allowed the separation of an oil-in-water model emulsion through two commercial membranes of different hydrophobicity. A theoretical model of a hydrophilic/hydrophobic junction was proposed which allows the one way flow of molecules compatible with the barrier surface. In order to create an hydrophobicity scale between the two commercial membranes, new membrane materials must be synthesized. A third membrane was then synthesized from the ternary system of cellulose acetate/acetone/water by the immersion precipitation process. Small angle light scattering measurements defined a nucleation and growth mechanism ruling the phase separation. Further modification of the membranes was conducted by the incorporation of hydrophobically modified methylcellulose through its bond with epoxydodecane aliphatic chains. Membrane surface analysis by ATR-FTIR revealed an absorbance amplification in the alkyl stretching region. XPS high resolution spectra confirmed these observations by the increase of the carbon percentage in alkyl function C-(C,H). Membranes need further hydrophobic modifications in order to obtain better filtration results
Daoudi, Meriem. "Performances et durabilité des membranes alternatives aux membranes PFSA." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0011.
The main objective of this thesis is to find a compromise between durability, cost, and eventually the ability to sustain high temperatures ionomer membranes used in PEMFC (Proton Exchange Membrane Fuel Cell). This work focused on sulfonated poly (ether ether ketone) membranes (sPEEK), which were chosen because of their good mechanical properties and high temperature resistance. However, sPEEK membranes suffer from a poor chemical stability, compared to the reference PFSA (PerFluoroSulfonic Acid) membranes. In order to overcome this problem, two approaches have been developed: pretreatment and/or hybridization of sPEEK membranes.The impact of sulfonated poly (ether ether ketone) membranes pretreatments on their functional properties, chemical structure and fuel cell performances was studied. Several physico-chemical characterization techniques as well as electrochemical diagnostic tools were used to correlate the cell performance with the sorption and transport properties of tested membranes.Subsequently, the durability of the best of these samples was studied via ex-situ and in-situ approaches. The ex-situ approach provided a first insight into the chemical stability of the membranes. In addition, the in-situ degradation tests allowed to evaluate the durability of the membranes under chemical and mechanical stresses very close from those encountered during fuel cell cells operation. For this purpose, an accelerated aging test was developed, combining potential cycling, humidity cycling and open-circuit prolonged hold.Finally, the second approach consists, in addition to the application of a pretreatment, in the hybridization of the membranes by sol-gel processes. Several precursors with sacrificial or redox functions were impregnated into the sulfonated poly (ether ether ketone) membranes. The analysis of fuel cell performances and membrane durability after applying the accelerated stress test have highlighted the efficiency of this approach: the performance and durability of some hybrid membranes even exceeded those of the reference PFSA membranes
Maurin, Bernard. "Morphogénèse des membranes textiles architecturales." Montpellier 2, 1998. http://www.theses.fr/1998MON20028.
Thoraval, Valérie. "Elaboration et caractérisation d'un élément de microfiltration et d'ultrafiltration en céramique." Montpellier 2, 1990. http://www.theses.fr/1990MON20132.
Tchicaya-Bouckary, Lydie. "Membranes pour pile à combustible moyenne température : évaluation des propriétés du polyéthercétone sulfoné et de matériaux hybrides organiques-inorganiques." Montpellier 2, 2000. http://www.theses.fr/2000MON20066.
Schrotter, Jean-Christophe. "Elaboration et caractérisation de matériaux mixtes polyimide-silice : application à la séparation de gaz et corrélations structure-propriétés." Montpellier 2, 1996. http://www.theses.fr/1996MON20130.
Papet, Sébastien. "Etude de la synthèse de matériaux inorganiques en milieu CO2 supercritique. Application à l'élaboration de membranes minérales de filtration tangentielle." Montpellier 2, 2000. http://www.theses.fr/2000MON20116.
Guironnet, Laure. "Compréhension de l'influence des paramètres micro et nano structuraux sur les performances électrochimiques de conducteurs mixtes." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0077.
The technology of ceramic membranes for oxygen separation knows a great interest due to high energetic efficiency in comparison with the cryogenic distillation process. However, for now, the oxygen fluxes produced by the membrane technology are not high enough for industrial applications. It is therefore necessary to improve the performances of the membranes. The results obtained in this work, using an original device, allowed us to a better understanding of the influence of architectural parameters on the oxygen flux and on the mechanisms limiting the transport of oxygen through the membrane. As a result, it is possible to investigate new architectures of membrane of which the oxygen flux could be close to industrial targets
Hanafia, Amira. "Étude des mécanismes interdépendants d’élaboration d’une membrane polymère sans solvant organique par une méthode originale de séparation de phase (TIPS-LCST), à partir d’un polymère biosourcé : l’hydroxypropylcellulose." Electronic Thesis or Diss., Montpellier 2, 2014. http://www.theses.fr/2014MON20045.
Phase separation of polyer/solvent system is the most widespread industrial process to manufacture membranes. Large solvent quantity is usually used whatever the process, hence leading to environmental (coagulation and washing baths treatment) and health (industrial and plant safety) problems.This study focuses on the development of new porous membranes made from hydroxypropylcellulose (HPC), a water soluble polymer, avoiding the use of any organic solvent. Moreover, the thermo-sensitive character of this polymer, characterized by a Lower Critical Solution Temperature (LCST) in water of about 40 °C, enabled to design an original thermally induced phase separation process by temperature increase above the LCST. This study aims (i) to find the ideal polymer solution composition to produce insoluble HPC membrane, (ii) to approach and understand the link between phase separation mechanism by spinodal decomposition, crosslinkig reaction and water extraction by evaporation, (iii) characterize pure water permeability under pressure. On-line monitoring of phase sepration dynamics by phase contrast optical microscopy, crosslinking reaction by rheology and water evaporation by thermogravimetric analysis of the system HPC/water/cross-linking agent ± porogen (PEG200) allowed an understanding of simultaneous and related mechanisms occurring during elaboration (phase separation / cross-linking / water evaporation) and a correlation with HPC membrane morphologies and characteristics in relation with phase separation process parametres. Pure water permeability characterization demonstrated the efficiency of cross-linking and structural strength during several filtration cycles. Furthermore, it has been shown that water permeability of HPC membranes could be controlled in part by the temperature and the applied pressure
Levy, Caroline. "Synthèse d'oxydes nanophases conducteurs par chimie douce : mise en évidence de la mobilité de l'oxygène." Montpellier 2, 2003. http://www.theses.fr/2003MON20140.
Jouenne, Vincent. "Nanocristaux de dioxyde de titane à morphologie contrôlée : synthèse, suspensions colloïdales et dépôt par électrophorèse." Nantes, 2013. http://archive.bu.univ-nantes.fr/pollux/show.action?id=c3b26761-dabc-43ff-ab7b-2fe3f95f0dd4.
Titanium dioxide, owing unique photoactive properties, is a key material for the fabrication of a IIIrd generation photovoltaic cell. In the strategy developed in IMN, its optimal incorporation in this device requires the elaboration of a thin and dense TiO2 layer surmounted by a nanostructured and porous layer. To make these deposits, a low temperature process (< 200°C) has been developed. First of all, this work has concerned the study of a synthetic strategy based on the hydrolysis of the [Ti8O12(H2O)24]Cl8. HCl. 7H2O precursor in alcoholic media with surfactants in solvothermal conditions. Many different TiO2 anatase nanocrystal morphologies (spherical, rod-like, rhombic platelets) with a good cristallinity have been obtained with both, oleic acid and/or oleylamine, as surfactants and controlled with a judicious choice of experimental parameters, such as the molar ratio between these two surfactants. Then, the surface nanocrystals has been characterized and optimized to allow the preparation of stable colloidal solutions in appropriated solvents in order to elaborate deposits by wet or electrophoretic (EPD) routes. Dense TiO2 layers with a 25 to 60 nm thickness have been realized by spin-coating, whereas porous deposits with tunable thickness (from 70 nm to 2. 2 μm) have been performed by EPD on plane substrates. Finally, the formation of TiO2 nanopillars (diameter ~ 150-200 nm, L ~ 1–3 μm), by electrophoresis confined inside the pores of nanoporous templates, has been performed
Aubert, Marie-Cécile. "Contrainte critique d'érosion d'un dépôt superficiel de matière sur membrane de microfiltration." Compiègne, 1995. http://www.theses.fr/1995COMPD796.
Doss, Nizar. "Plaques bipolaires dans une pile à combustible à membrane : effet du design sur les performances et recherche de matériaux métalliques adaptés." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL068N/document.
This work is a contribution to the study of the role of bipolar plates on the operation of fuel cell membrane, in particular the effect of the design of these plates as a distributor of reactive gases, and the search for metallic materials that can replace conventional carbon materials .The performance of fuel cells are limited by , among other problems related to thermal hydraulics : dewatering membranes and waterlogging distribution channels gas . This performance is also limited by the type of membrane and bipolar plates used . This thesis deal primarily a comparison between membranes and bipolar plates . We also investigated problems related to moisture , especially the '' water flooding in the channels of a fuel cell by visualization tests : the evacuation of liquid water is highly dependent on the etching platesIn addition, we have searched for metallic materials candidates embodiment to replace the bipolar plates of graphite, cumbersome and costly . Two materials have been studied : 316L stainless steel and the nickel - tungsten deposited on a copper plate . The 316 L stainless steel , used as material for bipolar plates , shows good resistance to aggressive conditions within the fuel cell membrane, as shown by tests carried out over nearly 1000 hours
Dabadie, Thierry. "Synthèse et caractérisation de gels de silice dans les milieux amphiphiles organisés. Application à l'élaboration de matériaux à texture anisotrope ou à porosité ordonnée et modulable." Montpellier 2, 1994. http://www.theses.fr/1994MON20132.
Romero, Figueroa Julio. "Etude des transferts sur des systèmes à membrane non-conventionnels : cas du procédé d'évaporation osmotique et de la perméation de fluides supercritiques." Montpellier 2, 2002. http://www.theses.fr/2002MON20135.
Nehache, Sabrina. "Elaboration de membranes à partir d’assemblages nano-organisés de particules polymères." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS080.
This thesis deals with the development of nano-structured thin nano-porous films from polymeric particles (ABA, AB copolymers and polymer/MOF) in perspective of developing new innovative membranes. The obtained films have been used as water filtration or gas separation membranes. Regarding the ABA triblock copolymer made of polystyrene-sodium polystyrene sulfonate-polystyrene (PS-PNaSS-PS) it was shown that nano-porous films with various structures (honeycombs, isoporous and compact), could be made. The morphologies of these nanoparticles could be tuned depending on the hydrophobic and hydrophilic block ratios, solvent composition and concentration. Concerning the study of the diblock copolymer, monodisperse spherical nanoparticles of PDMAEMA-b-PMMA were made in situ (PISA) using a coumarin functionalized RAFT chain transfer agent in ethanol. Upon UV irradiation, these particles could be connected reversibly through the dimerization of the coumarin function present on their corona. The resulting thin films had dynamic characteristic due to the establishment of the reversible formation of the cyclobutane ring under UV irradiation. This manuscript was concluded by preparation of Mix Matrix Membranes (MMMs) from mixture of polyimide (Matrimid®) and ZIF-8 nanoparticles to be used as gas permeation membrane. The employed new approach in this study led to formation of perfectly homogeneous membranes with improved cohesion between the MOF structure and the polymeric matrix. A better separation of CH4 / CO2 gas mixtures was achieved using the prepared MMM
Yacou, Christelle. "Développement de membranes céramiques multifonctionnelles à porosité hiérarchique pour le traitement et la séparation de gaz." Montpellier 2, 2009. http://www.theses.fr/2009MON20106.
This study deals with the development of a new design of multifunctional ceramic membranes with a hierarchical porosity for gas and vapour treatment or separation at low or high temperature and potential applications in the energy and environment sectors. The hierarchical porosity enables a simplification of the preparation process compared to that of conventional asymmetric ceramic membranes, by decreasing the number of required intermediate layers. Such separative layers with additional unconnected porosity and higher permeability can be thicker, thus limiting the impact of possible surface defects. Finally, incorporation and controlled location of an active solid phase, such as metal noble nanoparticles (NPs), can provide the membrane multifunctionality. An innovative sol-gel route has been developed, involving a multi-scale porogen approach combining the formation of the NPs by a microwave-assisted polyol reduction process. SiO2 or SiO2-TiO2 based membrane materials were successfully prepared exhibiting isolated macropores, mesopores, an interconnected microporosity and containing highly-dispersed Pt or Rh NPs. Structural and textural investigations were performed using X-ray spectroscopy and scattering techniques, transmission electron microscopy, and adsorption-desorption of nitrogen. Nanoindentation measurements were also carried out in order to estimate the contribution of the different types of porosity to the mechanical behaviour of the hierarchical layers. The membrane performances were studied by permeation and gas separation measurements. The catalytic properties were evaluated using two model reactions, propene oxidation and propane steam reforming
Youssef, Hicham. "Développement d'un banc de test par gonflement de membranes destiné à la caractérisation mécanique de matériaux déposés en films minces." Phd thesis, Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1629/.
The aim of this thesis is to develop and optimize a bench test for mechanical characterization of thin film. MEMS (Micro Electro Mechanical Systems) contain mechanical moving parts that must achieve performance control. These moving parts are subjected to forces, to differences in temperatures, stresses, deformations. . . The properties of their materials must be well known as in any mechanical system. The main properties are: Young's modulus, residual stresses, yield, and many others related to reliability. In the Microsystems scale, properties are different from macroscopic scale and depend greatly on the manufacturing process, so it is almost mandatory to perform measurements at each new manufacture. Among the possible tests, bulge test has decisive advantages: it gives sufficiently accurate results for the design of MEMS, it is nondestructive, it simultaneously gives the Young's modulus and residual stress. Associated to Finite Element Analysis, it can reach almost all the characteristics of elasticity, plasticity and fracture. Bulge test consists to apply a hydrostatic pressure on one side of the membrane and to measure its deflection. The measurements of pressure as a function of the deflection are used to extract the mechanical properties of the material using an appropriate numerical mathematical model. If the principle of this technique is relatively simple, its implementation is a source of great difficulty. These relate both to the establishment of a powerful and accurate apparatus, and also the interpretation of the theory itself describing the evolution of the pressure function of the deflection in the center of the membrane. We have developed a test protocol that allows to give accurate measurement with an automated process. Our research work is organized around three themes: The first is devoted to the establishment of an optimized procedure for characterizing mechanically materials deposited in thin layers. In the second we have developed techniques based on finite element analysis to characterize the membranes with any rectangular aspect ratio. The third is an application of Bulge test in certain materials used in MEMS fabrication
Lecacheux, Hélène. "Elaboration et caractérisation de matériaux membranaires fluorés par PECVD. Application à l'extraction d'ions bromure de solutions aqueuses." Montpellier 2, 1999. http://www.theses.fr/1999MON20174.
Youssef, Hicham. "Développement d'un banc de test par gonflement de membranes destiné à la caractérisation mécanique de matériaux déposés en films minces." Phd thesis, Université Paul Sabatier - Toulouse III, 2011. http://tel.archives-ouvertes.fr/tel-00720388.
Lacan, Pascale. "Synthèses et caractérisations de matériaux hybrides élaborés par voie sol-gel : application à la préparation de membranes à transport facilité et de capteurs optiques de pH." Montpellier 2, 1993. http://www.theses.fr/1993MON20112.
Lahouidak, Jamal 1er. "Etude de couches minces de TiO2 déposées par CVD et CVD assistée plasma." Montpellier 2, 1991. http://www.theses.fr/1991MON20162.
Hdach, Haddou. "Interaction liquide - solide dans les gels de silice : effet de la température." Montpellier 2, 1992. http://www.theses.fr/1992MON20229.
Rjimati, El Arbi. "Microfiltration tangentielle de suspensions particulaires : modélisation." Montpellier 2, 1990. http://www.theses.fr/1990MON20029.
Fares, Berrada Asmaa. "Compétition entre les électrotransports d'ions organiques et minéraux à travers une membrane échangeuse d'ions." Montpellier 2, 1992. http://www.theses.fr/1992MON20076.
Chaumont, Denis. "Etude structurale de la formation des sols et des gels de zircone en présence d'ultrasons." Montpellier 2, 1992. http://www.theses.fr/1992MON20087.
Madeline, Jean-Baptiste. "Filtration de dispersions agrégées de silice colloïdale : structure, consolidation et perméabilité de dépôts." Toulouse 3, 2005. http://www.theses.fr/2005TOU30155.
In coagulation/filtration processes, the separation of aggregated colloids from the liquid is a crucial step for the global operation to be effective. The problems hold in the fact that the cake formed by the accumulation of aggregates at the filter surface during filtration may collapse under the pressure applied, resulting in a lost of porosity and decrease in permeability. The aim of this study was to investigate cake restructuration mechanisms through an experimental multi-scaling approach for a better understanding and control of cake properties. For this purpose, dispersions of spherical silica colloids (Ludox and Klebosol) were aggregated by adding polycation Al137+ or divalent cation Ca2+. Structural and mechanical features of filtration cakes were investigated through SANS and TEM. Investigations have permitted to describe cake collapse through a general compression mechanism mainly controlled by the strength of interparticle bonds. Impact of floc features on cake filtration properties has been investigated and we have been able to show that cake compressibility and permeability primarily result from the breakage resistance of interparticle bonds rather than flocs initial fractal properties
Reichmann, Mickaël. "Développement de membranes céramiques à architecture optimisée pour l'oxycombustion." Thesis, Limoges, 2014. http://www.theses.fr/2014LIMO0029/document.
Since few years, the study of mixed conducting materials (ionic and electronic) knows an increasing interest in the energy area, especially with the development of electrodes for Solid Oxide Fuel Cell (SOFC) or Catalytic Membrane Reactors (CMR) for the methane reforming in synthesis gas or for oxyfuel process. In this latter case, the mixed conductor membrane with La1-xAxFe1-yByO3- perovskite structure allows the separation of oxygen from air at high temperature (900°C) with a quasi-infinite selectivity without outside electric circuit, with an interesting economical cost. The oxygen transport mechanisms through the membrane are studied thanks to an original electrodes system composed of a zirconia point micro-electrode and a metallic reference electrode. This system allows the measurement of the oxygen electrochemical potential at the membrane surface. The influence of cation substitution in A-site then B-site in La0.5A0.5Fe0.7B0.3O3-(A = Ca, Sr, Ba and B = Al, Co, Cu, Ga, Mg, Mn, Ni, Sn, Ti, Zn) perovskite materials has been studied. The results obtained by this original system led us to a better understanding and a identification of the rate determining step of oxygen transport mechanism through the membrane. The influence of the microstructure on oxygen semi-permeation has been studied and an evolution model of semi-permeation properties with microstructure has been shown. The understanding of oxygen transport mechanisms led to the development and the elaboration of news architectures of membranes
Donnay, Martin. "Étude des mécanismes de déformation de membranes polymères poreuses pour applications biomédicales." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0228.
The "bioartificial pancreas" (named MAILPAN for Macro-encapsulation d’ILots PANcréatiques) developed by the startup company Defymed is an implantable device for patients diagnosed with type I diabetes. The core element of the device is a porous membrane providing molecular selectivity. The emergence of cracking in this membrane would lead to the loss of its selective properties. As a consequence, it is crucial to study and understand the mechanical behavior of this material in order to ensure its integrity during the lifetime of the device. This thesis is a part of the FUI MECABARP project, gathering together SMEs and laboratories from the Lorraine and Alsace regions. The membrane is a unique material obtained by laminating several porous polymer materials. It is made of porous “track-etched” films as well as thermal-spot bonded nonwovens. The objective is to study its deformation mechanisms using time-resolved imaging and characterization techniques during a tensile test. X-ray micro-tomography and wide- and small-angle X-ray scattering experiments were performed on high energy beamlines. These results were supplemented with time-resolved scanning electron microscopy and Raman spectroscopy experiments during a tensile test. The synergy of the chosen techniques enables a multi-scale approach (from millimeter to angström) in order to obtain the most comprehensive analysis. Solutions are suggested to improve the mechanical properties of the membrane. Besides, a mechanical testing device by inflation (“bulge test”) has been designed to provide an equibiaxial mechanical path that is closer to the actual demands
Robert, Mylène. "Impact of degradation and aging on properties of PFSA membranes for fuel cells." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0004.
Although proton-exchange membrane fuel cells (PEMFC) are nowadays considered as a safe and clean energy technology, they still suffer from durability and reliability issues restricting their widespread commercialization. Innumerable studies have already led to a better understanding of aging phenomena and highlighted membrane degradation as one of the main factors limiting PEMFC lifetime. This study aims at bringing some clarifications on the chemical and mechanical degradation mechanisms of membranes through ex-situ aging protocols as well as understanding the impact of these degradations on the membrane structure and functional properties. First, it was necessary to clarify the influence of Fenton’s reaction, an ex-situ aging protocol widely recognized in the literature, on the chemical degradation of Nafion™ membranes. The results confirmed that Fenton’s reagents concentration significantly influenced polymer chemical decomposition, both from a chemical and morphological point of view. Subsequently, we chose to monitor the evolution of pure chemical degradation of Nafion™ membranes as a function of time and to study its impact on the membrane structure, water sorption and diffusion properties, as well as operability in fuel cells. In that respect, various characterization techniques such as 19F or 1H-NMR as well as FTIR spectroscopies allowed us to correlate physico-chemical properties of the membrane to its structural characteristics and to thus highlight several indicators of chemical degradation. Finally, a custom-made device has been developed to study the impact of conjoint mechanical and chemical stress on Nafion™ membranes. The objective of this device was to replicate aging conditions close to those encountered during fuel cell operation
Cellier, Julien. "Etude et caractérisations de membranes nanocomposites hybrides pour pile à combustible du type PEMFC." Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4001/document.
The proton conductive membrane is an essential part of the operation of PEMFC. This document presents the development of a non-perfluorinated membrane based on a hybrid nanocomposite technology likely to be produced at low cost. This membrane is composed of a poly(VDF-co-HFP) matrix in which are dispersed poly(styrene sulphonic acid) (PSSA) functionalized silica nanoparticles. This work focuses on the study of the implementation of the membrane to obtain a homogeneous and dense membrane with good physicochemical and electrochemical characteristics. Fuel cell performances after running at 60 °C are extremely satisfactory with a gain, compared to Nafion NRE211, of 40% for the power density at 0.7 V. However, the durability studies showed an elution phenomenon of the functionalized silica particles which results in a high voltage decline. Different membrane modification strategies have been proposed to improve the stability of the membrane. The most interesting involve modifying the morphology of the matrix (more rigid grades of PVDF or poly(VDF-co-HFP) crosslinking by radiation) to better confine the particles or grafting functionalized silica to the matrix. This last strategy leads to a threefold decrease of the swelling and 2.5 factor of the decay rate at 80 °C
Hanafia, Amira. "Étude des mécanismes interdépendants d’élaboration d’une membrane polymère sans solvant organique par une méthode originale de séparation de phase (TIPS-LCST), à partir d’un polymère biosourcé : l’hydroxypropylcellulose." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20045.
Phase separation of polyer/solvent system is the most widespread industrial process to manufacture membranes. Large solvent quantity is usually used whatever the process, hence leading to environmental (coagulation and washing baths treatment) and health (industrial and plant safety) problems.This study focuses on the development of new porous membranes made from hydroxypropylcellulose (HPC), a water soluble polymer, avoiding the use of any organic solvent. Moreover, the thermo-sensitive character of this polymer, characterized by a Lower Critical Solution Temperature (LCST) in water of about 40 °C, enabled to design an original thermally induced phase separation process by temperature increase above the LCST. This study aims (i) to find the ideal polymer solution composition to produce insoluble HPC membrane, (ii) to approach and understand the link between phase separation mechanism by spinodal decomposition, crosslinkig reaction and water extraction by evaporation, (iii) characterize pure water permeability under pressure. On-line monitoring of phase sepration dynamics by phase contrast optical microscopy, crosslinking reaction by rheology and water evaporation by thermogravimetric analysis of the system HPC/water/cross-linking agent ± porogen (PEG200) allowed an understanding of simultaneous and related mechanisms occurring during elaboration (phase separation / cross-linking / water evaporation) and a correlation with HPC membrane morphologies and characteristics in relation with phase separation process parametres. Pure water permeability characterization demonstrated the efficiency of cross-linking and structural strength during several filtration cycles. Furthermore, it has been shown that water permeability of HPC membranes could be controlled in part by the temperature and the applied pressure
Porhel, Sabine. "Extraction liquide-liquide sur matériaux poreux. Mise en oeuvre et recherche de paramètres influents." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4709.
This study is falls within the framework of uranium mining. The step more specifically aimed is the solvent extraction during which the uranium is transferred from a lixiviation aqueous solution to an organic phase by a complexation with a tertiary amine (Alamine 336®). The study focuses on this step of separation using a liquid-liquid contact without dispersal guaranteed by an organic macroporous membrane (pertraction). This technology allows the use of phases with close densities. So, uranium and molybdenum extraction, co-extracted industrially by Alamine 336, were studied for various high extractantes molecules concentrations. For that purpose, all the influential physical chemical parameters of the chemical system (distribution curve, viscosity, density, surface tension, infinite diffusion coefficient, etc.) and of the membrane (porosity, size, tortuosity, etc.) are characterized. Pertraction essays on a single hollow fibre, developed within the framework of this study, are performed and the results are modelized by an approach of mass transfer resistances in series. A single adjustable parameter is retained: the diffusion coefficient in organic phase. This modelling allows highlighting the limitations of uranium transfer from the aqueous phase towards the organic phase during the extraction process through the membrane function of chemical system, the flows and the membrane