Literatura científica selecionada sobre o tema "Particules de polymère"

Initially, this review presents the fundamentals of corrosion-resistant polymer/fullerene nanocomposites. Then, the potential of polymer/fullerene nanocomposites for corrosion resistance in biomedical applications is presented. In particular, anticorrosion biomedical applications of fullerene-based nanomaterials are proposed for antimicrobial applications, drug delivery, bioimaging, etc. According to the literature, due to the low conductivity/anticorrosion features of pristine thermoplastic polymers, conjugated polymers (polyaniline, polypyrrole, polythiophene, etc.) with high corrosion resistance performance were used. Subsequently, thermoplastic/thermosetting polymers were filled with nanoparticles to enhance their anticorrosion properties relative to those of neat polymers. Accordingly, fullerene-derived nanocomposites were found to be effective for corrosion protection. Polymer/fullerene nanocomposites with a fine dispersion and interactions revealed superior anticorrosion performance. The formation of a percolation network in the polymers/fullerenes facilitated their electron conductivity and, thus, corrosion resistance behavior. Consequently, the anticorrosion polymer/fullerene nanocomposites were applied in the biomedical field. However, this field needs to be further explored to see the full biomedical potential of anticorrosion polymer/fullerene nanocomposites.

Low-temperature, polymer-based fuel cells and water electrolyzers using anion conductive polymers have several potential advantages over acid-based polymer electrolyzers. However, the long-term durability of the ion conducting polymer has not been investigated to the same extent as proton conducting polymers. Further, accelerated aging test conditions with known acceleration factors have not been developed. In this study, a family of poly(norbornene) polymers used in fuel cells and electrolyzers was aged under a variety of conditions to determine the aging rate and acceleration factors. In particular, the relationship between temperature, alkalinity, and time were investigated.

Crystalline and amorphous dispersions have been the focus of academic and industrial research due to their potential role in formulating poorly water-soluble drugs. This review looks at the progress made starting with crystalline carriers in the form of eutectics moving towards more complex crystalline mixtures. It also covers using glassy polymers to maintain the drug as amorphous exhibiting higher energy and entropy. However, the amorphous form tends to recrystallize on storage, which limits the benefits of this approach. Specific interactions between the drug and the polymer may retard this spontaneous conversion of the amorphous drug. Some studies have shown that it is possible to maintain the drug in the amorphous form for extended periods of time. For the drug and the polymer to form a stable mixture they have to be miscible on a molecular basis. Another form of solid dispersions is pharmaceutical co-crystals, for which research has focused on understanding the chemistry, crystal engineering and physico-chemical properties. USFDA has issued a guidance in April 2013 suggesting that the co-crystals as a pharmaceutical product may be a reality; but just not yet! While some of the research is still oriented towards application of these carriers, understanding the mechanism by which drug-carrier miscibility occurs is also covered. Within this context is the use of thermodynamic models such as Flory-Huggins model with some examples of studies used to predict miscibility.

129 Xe NMR is a new tool for probing the morphology of polymers and polymer blends. Recent developments of the NMR of 129 Xe gas dissolved in polymers are reviewed. This technique yields information on polymer morphology via the NMR lineshape and the isotropic chemical shift and their temperature dependencies. Polymer glass transition temperatures are plainly evident. The miscibility of polymer blends is easily determined and thus phase diagrams may be mapped out. Of particular use is the potential ability to measure domain sizes in immiscible polymer blends by 2-D NMR techniques. Domain sizes from 0.1 micrometers to 25 micrometers should easily be measurable.

129 Xe NMR is a new tool for probing the morphology of polymers and polymer blends. Recent developments of the NMR of 129 Xe gas dissolved in polymers are reviewed. This technique yields information on polymer morphology via the NMR lineshape and the isotropic chemical shift and their temperature dependencies. Polymer glass transition temperatures are plainly evident. The miscibility of polymer blends is easily determined and thus phase diagrams may be mapped out. Of particular use is the potential ability to measure domain sizes in immiscible polymer blends by 2-D NMR techniques. Domain sizes from 0.1 micrometers to 25 micrometers should easily be measurable.

Pulsed UV laser beams, which are widely used in the processing of polymers, offer many advantages in the field of polymer production, primarily because their photon energy is higher than the binding energy of the polymer. In particular, the fabrication of polymers with an excimer laser process is faster and more convenient than with other processes. Nevertheless, some problems occur in the precision microprocessing of polymers, including the formation and deposition of surface debris, which is produced from the breakdown of either polymer chains or radical bonds. In the present work, a process for eliminating carbonized surface debris contamination generated by the laser ablation of a polymer was developed. The proposed approach for removing surface debris utilizes an erasable ink pasted on the polymer. The surface debris ejected from the polymer is then combined with the ink layer on the polymer. Finally, both the surface debris and the ink layer can be removed using adhesive tape.

This study investigates the treatment of surfaces with jet plasma at atmospheric pressure in the presence of acrylic acid as a resource-saving and efficient approach to joining polymers on polystyrene (PS) and polyamide 12 (PA 12) surfaces. Acrylic acid was added in order to introduce functional groups to the polymer surfaces. XPS analysis revealed a high density of oxygen-containing groups, e.g., carboxylic acid groups, on the polymer surfaces, the detailed composition depending on the polymer. The AFM measurements indicated that the modification of polyamide resulted in morphological changes and an increase in surface roughness due to polymer recrystallization. When the surface-modified polymers were brought in contact under a load, significant adhesion between the polymer surfaces was measured. In particular, PS and PA 12, which are otherwise difficult to join by gluing, could readily be connected in this way. The joint polymers could be separated intentionally by immersion in water, thus enabling the recycling of the materials. The resistance of the joint to water depends on the polymer system, with polyamide providing strikingly higher resistance than polystyrene. Accordingly, treating the joint polymers with water allows debonding on demand, particularly when PS is involved. Exposure of modified polymer surfaces to solutions of metal ions increased the resistance of joint polymers to water.

Cette thèse a pour thème l'incorporation de nanoparticules d'oxyde de terre rares (Erbium et Praséodyme) dans un polymère commercial, PVC, sous forme filamentaire. Ces fils sont élaborés à l'aide d'un pilote réalisé au laboratoire permettant un filage en solvant voie humide. Les nanoparticules incorporées sont d'abord commerciales (Er203) mais elles montrent des inconvénients, ce qui entraîne l'étude sur la synthèse de nanoparticules d'oxyde d'Erbium et de Praséodyme. Une fois ces particules obtenues, elles sont dispersées dans une solution de PVC/solvant. Cette solution "chargée" est pressée à travers une filière et plongée dans un bain de coagulation afin de retirer le solvant et ainsi obtenir des filaments (mono ou multi) de PVC contenant des nanoparticules d'oxyde d'Erbium/Praséodyme. Un second thème est également étudié dans cette thèse. Il s'agit de réaliser des fibres d'oxycarbure de bore et de silicium (SiBCO). Cette étude porte sur la synthèse du poly(borosiloxane) via dissolution de l'acide borique dans le dimetyldiethoxysilane (DMDES) et du méthyltriethoxysilane (MTES). Une fois le sol de borosiloxane obtenu, il est semi-hydrolysé jusqu'à obtention d'un gel filable par extrusion à froid. Ces filaments sont enroulés sur des bobines graphite. Les bobines sont laissées à l'étuve à 60°C pour terminer l'hydrolyse avant de les pyrolysées sous argon à haute température pour afin de les transformer en fibres céramiques SiBCO
This thesis focuses on the main theme of the incorporation of nanoparticles of rare earth oxide (Erbium and Praseodymium) in a commercial polymer, PVC, shaped as filaments. These fibers are made using a apparatus developped in the laboratory. The spinning method used is a wet solvent spinning process. Embedded nanoparticles are first commercial particles (Er203) but they show disadvantages, which leads to a study of synthesis of oxide nanoparticles Erbium and Praseodymium in the laboratory. This study bings to a production a laboratory pilot (KiloLab) in order to obtain 3Kg of nanoparticles composed with 60 wt% of Erbium oxide and 40 wt% of Praseodymium xide. Once these particles obtained, it have been dispersed in a solution of PVC/solvent. This "loaded" solution of nanoparticles is presses through a spinneret for the shaping. The filaments are spun in a coagulation bath in order to remove the solvent from the solution and obtain the PVC filaments (mono or multi) containing the nanoparticles of Erbium or Praseodymium oxide.A second theme is also studied in this thesis, the realization of oxicarbide boron and silicon fibers (SiBOC). This study focuses on the synthesis and conditions to obtain a poly(borosiloxane) polymer. This polymer is obtained by the synthesis of the dimetyldiethoxysilane (DMDES), méthyltriethoxysilane (MTES) and the boric acid which bring the hetero atom of boron in the final ceramic. Once the sol of borosiloxane obtained, it is semi-hydrolysed until obtention af a gel that can be spun by extrusion at ambiant temperature. The filament are wrapped around a graphite bobbin. The shaped polymer is then leaved in a stove at 60°C for a week allowing to complete the hydrolysis.Once the hydrolysis complete and the polymer fully hydrolyses, the fibers are pyrolysed under argon at high temperature to transform the fiber into ceramic fibers of SiBOC

Pour des raisons environnementales et de santé publique, la remédiation des sites et sols pollués est impérative. Une des techniques in-situ utilisées pour dépolluer des sols présentant une pollution aux hydrocarbures, est l’utilisation de mousse liquide. Grâce à son effet bloquant, la mousse crée une barrière entre l’eau et le polluant, et facilite le pompage de celui-ci. La principale problématique de cette technique est la stabilité de la mousse face à l’huile. Des techniques de renforcement de la mousse en présence d’huile sont développées, notamment grâce à l’ajout de polymère ou de particules solides.Ce travail portera donc sur la formulation d’une mousse résistante à l’huile en milieu poreux, et ce grâce à l’utilisation de polymère ou de particules colloïdales.La première partie de ce travail présente les tests de moussabilité et de stabilité effectués hors milieu poreux, ayant permis de présélectionner les produits nécessaires à l’obtention de telles mousses. Dans une seconde partie, des essais en colonne de milieu poreux ont mené à l’optimisation des conditions d’injection, ainsi qu’au choix final des produits à utiliser. Ils ont montré comment l’ajout de polymère permet d’augmenter la résistance à l’écoulement sans augmenter la force de la mousse, et comment l’ajout de particules renforce la résistance de la mousse face à l’huile. Des essais en pilote 2D ont ensuite été réalisés dans le but de comprendre le déplacement de la mousse en milieu poreux 2D vertical. Grâce aux formulations trouvées en colonne 1D, les expériences 2D effectuées en présence d’huile ont permis de tester le renforcement face à l’huile en deux dimensions. Pour finir, la méthodologie et les contraintes à prendre en compte pour réaliser un essai de pompage 3D sont présentées en perspectives
Given the possible environmental and health issues occurring when facing a hydrocarbon polluted site, soil remediation is necessary. One of the in-situ technique to remediate a Light Non Aqueous Phase Liquid pollution is the use of foam. Because of its blocking effect, foam is able to create a water blocking barrier, to confine water beneath the floating pollutant. However, the main issue with this technique is the stability of foam facing the oily pollutant. Several options are currently under review to reinforce foam against oil, which includes polymer or particles addition.The present study thus describes the work performed to obtain an oil-resistant foam in porous media, with the use of polymer or solid colloidal particles.In the first part of the study, foamability and stability tests were performed in bulk to select a broad range of products used to formulate such foams. Then, sandpacks experiments were realized in 1D columns in order to optimize the foam injection parameters and finalize the choice of surfactant and additives. Column experiments showed how additives impacted foam strength. Polymer addition led to an increased flow resistance without improving foam strength while particles addition proved to reinforce foam resistance against oil. Those results were then applied to carry out 2D-tank experiments to study foam displacement in a vertical two dimensions’ porous medium. The 2D tank also helped to simulate a foam injection below an oily layer and observe foam behaviour. Finally, the methodology and constrains to take into account to perform a pumping test in a 3D-pilot, were presented in the outlook section

Au cours des dernières décennies, la technologie membranaire a montré de grandes performances dans les séparations en phase liquide telles que la production d’eau potable à partir d’eau de mer. Beaucoup d’efforts ont été faits pour étendre son application aux séparations de gaz. La séparation des composants de l’air, des gaz industriels de raffineries, la séparation et la récupération du CO2 du biogaz et du gaz naturel sont des exemples dans lesquels la technologie membranaire est appliquée au niveau industriel. La séparation par membranes a été substituée ou interfacée avec les méthodes conventionnelles telles que la distillation cryogénique pour produire de l’air enrichi en oxygène (fraction molaire >- 30%) qui est injecté dans les brûleurs industriels pour obtenir une température plus élevée, avec moins de consommation de gaz. Il est également possible d’utiliser la technologie membranaire pour capturer et recycler le CO2 émis par les gaz de combustion des centrales électriques et les aciéries pour résoudre le problème des gaz à effet de serre. Les membranes pour la séparation des gaz peuvent être classées en deux catégories principales, basées sur le matériau, polymère et inorganique, dans lesquelles les membranes polymériques sont plus populaires. Par rapport aux matériaux inorganiques, les membranes polymères présentent une meilleure facilité de traitement, une résistance mécanique et une densité de remplissage plus élevée, ce qui les rend appropriées pour des applications à grande échelle. Elles ne peuvent cependant pas supporter des températures élevées ou des agents chimiques agressifs. Leurs propriétés de séparation (perméabilité et sélectivité) peuvent être sévèrement compromises par les hydrocarbures condensables (C2+) lorsqu’elles sont appliquées dans les usines pétrochimiques, les raffineries et le traitement du gaz naturel. Pour améliorer les performances des membranes polymères, le nouveau concept, de membrane à matrice mixte (MMM), a été réalisé en dispersant des particules nanométriques ou microscopiques de matériaux inorganiques dans une matrice polymère. Dans ce travail, nous avons préparé de nouvelles MMMs en utilisant des polymères et des matériaux organo-métalliques (MOF) en tant que phases continue et dispersée, respectivement. Nous avons développé plusieurs techniques pour surmonter la faible adhérence interfaciale entre les deux phases qui diminue typiquement l’efficacité de séparation des MMM. Pour ce faire, dans la première partie de cette thèse (Chapitre 3), nous avons synthétisé des particules de MOF comportant des fonctions -NH2 et une série de polymères décorés de -OH pour la préparation de MMMs. La liaison physique entre les deux groupes fonctionnels s’est avérée améliorer nettement l’adhérence polymère/charge des MMMs obtenues ainsi que leur performance de séparation des gaz. Dans la partie suivante (Chapitre 4), nous avons introduit une modification post-synthétique pour former une liaison chimique entre le polymère et la charge dans les MMMs. Dans des conditions optimisées, un MOF fonctionnalisé portant des groupes réticulables a été amené à réagir avec un polymère déjà synthétisé contenant des extrémités de chaînes réactives pour produire, pour la première fois, des MMMs réticulées. Dans la dernière partie (Chapitre 5), nous avons décrit une nouvelle technique pour obtenir in-situ la liaison chimique polymère-charge pendant la synthèse du polymère. Dans cette technique, les particules de MOF ont été directement introduites dans le milieu de polymérisation. L’importance des liens polymère-charge a été étudiée en fonction du temps de polymérisation. Cette étude a montré une forte relation entre la qualité de l’interaction polymère-charge et les propriétés de séparation des gaz des MMMs.
Au cours des dernières décennies, la technologie membranaire a montré de grandes performances dans les séparations en phase liquide telles que la production d’eau potable à partir d’eau de mer. Beaucoup d’efforts ont été faits pour étendre son application aux séparations de gaz. La séparation des composants de l’air, des gaz industriels de raffineries, la séparation et la récupération du CO2 du biogaz et du gaz naturel sont des exemples dans lesquels la technologie membranaire est appliquée au niveau industriel. La séparation par membranes a été substituée ou interfacée avec les méthodes conventionnelles telles que la distillation cryogénique pour produire de l’air enrichi en oxygène (fraction molaire >- 30%) qui est injecté dans les brûleurs industriels pour obtenir une température plus élevée, avec moins de consommation de gaz. Il est également possible d’utiliser la technologie membranaire pour capturer et recycler le CO2 émis par les gaz de combustion des centrales électriques et les aciéries pour résoudre le problème des gaz à effet de serre. Les membranes pour la séparation des gaz peuvent être classées en deux catégories principales, basées sur le matériau, polymère et inorganique, dans lesquelles les membranes polymériques sont plus populaires. Par rapport aux matériaux inorganiques, les membranes polymères présentent une meilleure facilité de traitement, une résistance mécanique et une densité de remplissage plus élevée, ce qui les rend appropriées pour des applications à grande échelle. Elles ne peuvent cependant pas supporter des températures élevées ou des agents chimiques agressifs. Leurs propriétés de séparation (perméabilité et sélectivité) peuvent être sévèrement compromises par les hydrocarbures condensables (C2+) lorsqu’elles sont appliquées dans les usines pétrochimiques, les raffineries et le traitement du gaz naturel. Pour améliorer les performances des membranes polymères, le nouveau concept, de membrane à matrice mixte (MMM), a été réalisé en dispersant des particules nanométriques ou microscopiques de matériaux inorganiques dans une matrice polymère. Dans ce travail, nous avons préparé de nouvelles MMMs en utilisant des polymères et des matériaux organo-métalliques (MOF) en tant que phases continue et dispersée, respectivement. Nous avons développé plusieurs techniques pour surmonter la faible adhérence interfaciale entre les deux phases qui diminue typiquement l’efficacité de séparation des MMM. Pour ce faire, dans la première partie de cette thèse (Chapitre 3), nous avons synthétisé des particules de MOF comportant des fonctions -NH2 et une série de polymères décorés de -OH pour la préparation de MMMs. La liaison physique entre les deux groupes fonctionnels s’est avérée améliorer nettement l’adhérence polymère/charge des MMMs obtenues ainsi que leur performance de séparation des gaz. Dans la partie suivante (Chapitre 4), nous avons introduit une modification post-synthétique pour former une liaison chimique entre le polymère et la charge dans les MMMs. Dans des conditions optimisées, un MOF fonctionnalisé portant des groupes réticulables a été amené à réagir avec un polymère déjà synthétisé contenant des extrémités de chaînes réactives pour produire, pour la première fois, des MMMs réticulées. Dans la dernière partie (Chapitre 5), nous avons décrit une nouvelle technique pour obtenir in-situ la liaison chimique polymère-charge pendant la synthèse du polymère. Dans cette technique, les particules de MOF ont été directement introduites dans le milieu de polymérisation. L’importance des liens polymère-charge a été étudiée en fonction du temps de polymérisation. Cette étude a montré une forte relation entre la qualité de l’interaction polymère-charge et les propriétés de séparation des gaz des MMMs.
In recent decades, membrane technology has shown its great performance in liquid phase separations such as production of drinking water from seawater. It has now attracted much scientific attention to expand its application to gas separations. Separation of air components, H2 from refinery industrial gases, separation and recovery of CO2 from biogas and natural gas are some examples in which the membrane technology is potentially applied at industrial level. The membrane based separation was either partially substituted or integrated with conventional methods like cryogenic distillation to product oxygen-enriched air (mole fraction 30% ) that is injected into industrial burners to obtain higher temperature with less gas consumption. It is also possible to use membrane technology to capture and recycle CO2 emitted from flue gas streams of power plants and steel mills in solving the greenhouse effect. The membranes for gas separation can be classified in two main categories, based on material, polymeric and inorganic, in which polymeric membranes are more popular. Compared to the inorganic, the polymer membranes show better processability, mechanical strength and higher packing density, hence, being suitable for large-scale applications. They cannot, however, withstand high temperatures or aggressive chemical agents. Their separation properties (permeability and selectivity) may be severely affected by condensable hydrocarbons (C2+) when they are applied in petrochemical plants, refineries and natural gas treatment. To enhance the performance of polymer membranes, a new concept, mixed matrix membrane (MMM), has been proposed by dispersing nano- or micro-sized particles of inorganic materials into a polymer matrix. In this work, we have prepared novel MMMs using polymers and metal organic framework (MOF) as the continuous and dispersed phases, respectively. We have developed several techniques to overcome the weak interfacial adhesion between the two phases that typically decreases the separation efficiency of MMMs. To do so, in the first part of this thesis (Chapter 3), we have synthesized a -NH2 included MOF particle and a series of -OH decorated polymers for MMM preparation. The physical bonding between the two functional groups was found to clearly improve the polymer/filler adhesion of the obtained MMMs as well as their gas separation performance. Then, in the following part (Chapter 4), we have introduced a post-synthetic modification to form chemical bonding between the polymer and filler within MMMs. Under optimized conditions, a functionalized MOF bearing crosslinkable groups was reacted with an as-synthesized polymer containing reactive chain-ends to produce, for the first time, crosslinked MMMs. In the final part (Chapter 5), we have described a novel technique to obtain in-situ the polymer-filler chemical bonding during the polymer synthesis. In this technique, the MOF particles were directly introduced into the polymerization medium. The extent of the polymer-filler link was studied as a function of polymerization time. This study has shown a strong relationship between the quality of polymer-filler interaction and the gas separation properties of the MMMs.
In recent decades, membrane technology has shown its great performance in liquid phase separations such as production of drinking water from seawater. It has now attracted much scientific attention to expand its application to gas separations. Separation of air components, H2 from refinery industrial gases, separation and recovery of CO2 from biogas and natural gas are some examples in which the membrane technology is potentially applied at industrial level. The membrane based separation was either partially substituted or integrated with conventional methods like cryogenic distillation to product oxygen-enriched air (mole fraction 30% ) that is injected into industrial burners to obtain higher temperature with less gas consumption. It is also possible to use membrane technology to capture and recycle CO2 emitted from flue gas streams of power plants and steel mills in solving the greenhouse effect. The membranes for gas separation can be classified in two main categories, based on material, polymeric and inorganic, in which polymeric membranes are more popular. Compared to the inorganic, the polymer membranes show better processability, mechanical strength and higher packing density, hence, being suitable for large-scale applications. They cannot, however, withstand high temperatures or aggressive chemical agents. Their separation properties (permeability and selectivity) may be severely affected by condensable hydrocarbons (C2+) when they are applied in petrochemical plants, refineries and natural gas treatment. To enhance the performance of polymer membranes, a new concept, mixed matrix membrane (MMM), has been proposed by dispersing nano- or micro-sized particles of inorganic materials into a polymer matrix. In this work, we have prepared novel MMMs using polymers and metal organic framework (MOF) as the continuous and dispersed phases, respectively. We have developed several techniques to overcome the weak interfacial adhesion between the two phases that typically decreases the separation efficiency of MMMs. To do so, in the first part of this thesis (Chapter 3), we have synthesized a -NH2 included MOF particle and a series of -OH decorated polymers for MMM preparation. The physical bonding between the two functional groups was found to clearly improve the polymer/filler adhesion of the obtained MMMs as well as their gas separation performance. Then, in the following part (Chapter 4), we have introduced a post-synthetic modification to form chemical bonding between the polymer and filler within MMMs. Under optimized conditions, a functionalized MOF bearing crosslinkable groups was reacted with an as-synthesized polymer containing reactive chain-ends to produce, for the first time, crosslinked MMMs. In the final part (Chapter 5), we have described a novel technique to obtain in-situ the polymer-filler chemical bonding during the polymer synthesis. In this technique, the MOF particles were directly introduced into the polymerization medium. The extent of the polymer-filler link was studied as a function of polymerization time. This study has shown a strong relationship between the quality of polymer-filler interaction and the gas separation properties of the MMMs.

Ces travaux décrivent l'élaboration de latex hybrides de polymère / nanotubes d'Imogolite et polymère / nanofeuillets d'hydroxydes doubles lamellaires (HDL) en milieu aqueux dispersé. Les deux charges inorganiques ont été choisies pour leurs propriétés thermiques, mécaniques et pour leur anisotropie de forme, ce qui pourrait permettre l'élaboration de films nanostructurés. Les latex ont été synthétisés par une stratégie originale basée sur le procédé de polymérisation RAFT en émulsion. Cette stratégie consiste à utiliser des copolymères hydrophiles (macroRAFT), comportant à la fois des unités d'acide acrylique et un groupe trithiocarbonate terminal, comme agents de couplage et stabilisants. Dans un premier temps, ces macroRAFTs ont été adsorbés à la surface des nanoparticules inorganiques, puis l'extension de ces chaînes a été réalisée par la polymérisation d'un monomère hydrophobe selon un procédé semi-batch. Des nanotubes d'Imogolite décorés de particules de latex ou des nanotubes d'Imogolite encapsulés ont été obtenus, selon les conditions de synthèse adoptées. L'effet de différents paramètres sur la morphologie finale des particules hybrides a été étudié. La nature de l'agent macroRAFT s'est avérée être un paramètre clé pour le succès de l'encapsulation. La même stratégie a été utilisée en vue de l'encapsulation des HDL. Quelles que soient les conditions investiguées, des latex stables contenant des particules d'HDL encapsulées par du polymère ont été formés. Dans tous les cas, la morphologie des latex nanocomposites a été caractérisée par MET et cryo-MET et reliée à la méthode de modification de la surface et aux conditions de polymérisation. Enfin, les propriétés mécaniques ainsi que la microstructure des films hybrides de polymère / nanotubes d'Imogolite ont été étudiées par DMA et MET, respectivement, et reliées à la morphologie des particules de latex

L'objectif de ce travail est de caractériser le comportement Théologique des suspensions de dioxyde de titane dans les solutions de polymère. Le premier chapitre est consacré à la caractérisation des suspensions étudiées. Les résultats obtenus en cisaillement permanent ainsi qu'en oscillation sont consignés dans le chapitre deux. Ces comportements sont expliqués par l'étude des interactions particule-particule et particule-polymère de la phase continue. Le troisième chapitre est ainsi consacré à la mise en place les outils d'analyse d'image nécessaires pour étudier les images obtenues sous cisaillement. Dans un quatrième chapitre, nous avons étudié l'influence de la géométrie des agrégats de dioxyde de titane sur les propriétés Théologiques de l'échantillon sous cisaillement. Enfin, le dernier chapitre de cette thèse est consacré à l'étude de l'instabilité de Saffman- Taylor et aux figures de digitation visqueuse obtenues avec une suspension de dioxyde de titane
This study deals with rheological properties of titanium dioxyde suspensions in polymer solutions. Rheological behaviour is strongly dépendent on particle-particle interactions and also on particle-polymer interactions in the continuons phase. These interactions really undergoes shape modification of aggregates. Consequently, we have developped tools to Observe titanium dioxyde aggregates under shear. The shape of aggregates is caracterised by a fractal dimension Df in two or three dimensions. This parameter can be correlated with the évolution of suspension viscosity. The last part of this work deals with flow instabilities obtained with glass beads dispersed in a solution of polyisobutylene. Saffman- Taylor instability appeared when cone and plate of the rheometer are removed from each other. In the case of titanium dioxyde suspensions, fractal shape can be observed and can be related to viscous fingering in hele-Shaw cells

Ce travail de thèse porte sur l'élaboration de particules de polymère magnétiques capables de capter et relarguer différents microorganismes par des interactions électrostatiques non spécifiques. Des nanoparticules d'oxyde de fer cationiques stabilisées par des contre-ions nitrate ont été synthétisées par coprécipitation de sels de fer. La surface de la maghémite obtenue a été modifiée par voie sol-gel avec un organosilane présentant une fonction méthacrylate pour permettre son incorporation covalente dans des particules de latex par des réactions de copolymérisation. Ces particules ont été obtenues par polymérisation radicalaire en dispersion, en émulsion ou en miniémulsion du méthacrylate de méthyle ou du styrène, conduite en présence de maghémite. Les interactions entre celle-ci et le stabilisant rendent difficile la formation de latex magnétiques par polymérisation en dispersion. En revanche, la polymérisation en (mini-)émulsion permet, selon la technique de dispersion des oxydes de fer utilisée avant polymérisation, l'obtention de particules de latex de 140 à 650 nm, dont la fraction magnétique varie entre 2 et 37 % et contient jusqu'à 91 % de maghémite. La distribution de taille est toutefois large. Les particules magnétiques ainsi obtenues ont été ensuite fonctionnalisées directement au cours de la polymérisation en émulsion par l'introduction de co-monomères chargés, de polyélectrolytes ou de polyamphotères réamorçables. Ces deux derniers types de polymère sont obtenus par polymérisation RAFT. Leur capacité de capture/relargage a été évaluée sur des systèmes modèles à base de silice. Les polyamphotères donnent de bons résultats sur de nombreux microorganismes
This thesis describes the synthesis of magnetic latexes which are able to capture and release various microorganisms via non-specific and electrostatic interactions. Cationic iron oxide nanoparticles stabilized by nitrate counterions were synthesized by the co-precipitation of iron salts in water. The surface of the asobtained maghemite was then modified by a sol-gel process using a methacrylate-functionalized organosilane, in order to incorporate the iron oxide nanoparticles into latex particles by copolymerization reactions. Magnetic particles were obtained by dispersion, emulsion or miniemulsion polymerization of styrene or methyl methacrylate, performed in the presence of iron oxide. Due to the interaction between the stabilizers and iron oxides, dispersion polymerization was not a suitable approach. On the other hand, (mini-)emulsion polymerization led to a large range of particle diameters (140 – 650 nm), according to the process used to disperse iron oxides prior to the polymerization. These latexes contained between 2 and 37 % of magnetic particles, incorporating up to 91% of iron oxide. But the size distribution remained quite broad in all cases. The functionalization of the as-prepared magnetic particles was then undertaken by the introduction of either a charged co-monomer or polyelectrolytes or polyampholytes reactivable during the polymerization process. These kinds of polymers were synthesized by RAFT polymerization. Their ability to capture and release microorganisms was tested on silica-based model systems. Polyampholytes displayed good results on several microorganisms

Cette etude est consacree a la granulation de particules solides en lit fluidise discontinu par la pulverisation de solutions aqueuses de liants (polymeres ou sels mineraux). Outre la comprehension des phenomenes qui se produisent a l'echelle globale, l'objectif essentiel de ce travail est de mieux comprendre l'influence des phenomenes qui se produisent a l'echelle locale sur la cinetique de croissance et sur la resistance mecanique des agglomerats formes. Nous avons donc etudie l'influence des parametres lies au procede (vitesse de l'air de fluidisation, debit de la solution liante, concentration en liant), des proprietes des particules solides (taille, forme, porosite et solubilite) et la viscosite de la solution liante (entre 1 et 185 cp) sur la cinetique de croissance de taille des agglomerats formes. Afin d'etudier l'influence des parametres lies a la mouillabilite de la surface des particules, la tension superficielle des solutions a ete modifiee entre 72 a 33 mn/m, en utilisant des tensio-actifs et l'angle de contact a ete modifie entre 38\ et des valeurs superieures a 90\ par un traitement chimique conduisant a l'hydrophobisation partielle ou totale de la surface des particules. Nos resultats ont montre qu'une augmentation de la tension superficielle, une diminution de l'angle de contact et de la taille des particules favorisent l'agglomeration des particules, tandis que la viscosite de la solution n'a pas un effet significatif sur la croissance. Ainsi l'agglomeration des poudres en lit fluidise est essentiellement dominee par les forces capillaires (forces statiques) et non pas par la force de dissipation visqueuse. De plus, nos resultats ont montre que la cinetique de sechage des solutions peut aussi avoir un effet

Ce travail concerne les proprietes physiques des melanges silice-siloxane. Ces systemes sont formes d'agregats de silice interconnectes par des chaines polydimethylsiloxane adsorbees. La loi d'adsorption observee est caracteristique de l'adsorption en polymere fondu propre a ces systemes. Cette loi d'adsorption est aussi bien verifiee par la microanalyse du taux de polymere adsorbe, que par la mesure rmn du taux de monomeres fixes. La saturation de la surface est assimilee a un processus de diffusion macromoleculaire au voisinage d'un plan adsorbant. La formation du reseau silice-siloxane est decrite dans le cadre theorique de la percolation. Le gonflement des reseaux obtenus est decrit dans l'approche en champ moyen de flory. Nous proposons une methode d'analyse de la fonction de relaxation de l'aimantation transversale d'un echantillon semi-cristallin permettant une estimation par rmn du taux de cristallinite. Une etude comparative de la cinetique de cristallisation des polymeres purs et dans les systemes extraits est presentee. On etudie l'influence des parametres temperature et fraction volumique de silice sur la vitesse de cristallisation globale

Les expériences de laboratoire montrent que, même dans des solutions très diluées, l’interaction des polymères avec des écoulements fluides peut modifier considérablement les propriétés des écoulements turbulents ou, si l’écoulement est laminaire, peut déclencher un nouveau type de mouvement irrégulier appelé «turbulence élastique». Les écoulements dans un tel régime dynamique sont prometteurs pour améliorer l'efficacité du mélange dans les applications microfluidiques, qui impliquent souvent la présence d'impuretés de taille finie en suspension, telles que des particules solides petites et lourdes. La compréhension de la dispersion des particules dans les écoulements à grand nombre de Reynolds des fluides newtoniens et non newtoniens a déjà été abordée dans des études antérieures, qui ont mis en évidence des effets à la fois à grande et à petite échelle et est un sujet d'intérêt à la fois fondamental et pour des applications environnementales ou industrielles par exemple. Cependant, la dynamique des particules dans les écoulements élastiques et turbulents reste encore peu explorée. L’étude ici vise à étudier les propriétés d’agrégation de particules matérielles ponctuelles (plus lourdes que le fluide porteur) dans les fluides viscoélastiques dans des conditions de turbulence élastique (c’est-à-dire dans le cas de faible inertie du fluide et de grande élasticité). Nous effectuons des simulations numériques directes bi-dimensionelles d’écoulements périodiques avec cisaillement moyen de Kolmogorov avec des solutions de polymères dilués décrites par le modèle Oldroyd-B. Les caractéristiques à petite et grande échelle de la distribution résultante inhomogène de particules sont examinées, en se concentrant sur leur connexion avec la structure sous-jacente de l’écoulement . Notre analyse révèle que les particules sont préférentiellement regroupées dans des régions où les polymères sont instantanément maximalement étirés. L’intensité d’un tel phénomène dépend de l’interaction paramétrée par le nombre de Stokes, entre l’inertie des particules et l’échelle de temps typique associée à l’écoulement de turbulence élastique, et est la plus grande pour des valeurs intermédiaires d’inertie de particules. En particulier, il est montré que la concentration préférentielle de suspensions de particules inertielles dans de tels écoulements ressemblant à la turbulence découle de la nature dissipative de leurs dynamiques. Nous établissons une caractérisation quantitative de ce phénomène (utilisant la corrélation et la dimension de Kaplan-Yorke) qui permet de le relier à l’accumulation de particules dans des régions de l’écoulement filamenteuses fortement déformées produisant des grappes de dimension fractale faiblement supérieure à 1. À plus grande échelle, les particules subissent une ségrégation de type turbophorétique dans la direction non-homogéne de l'écoulement. En effet, nos résultats indiquent que la distribution des particules est fortement liée aux structures moyennes de l’écoulement de type turbulent. En raison de la turbophorèse, les profils de densité moyenne atteignent leur maximum dans les régions où la diffusivité turbulente est la plus faible. L'inhomogénéité à grande échelle de la distribution des particules est interprétée dans le cadre d'un modèle dérivé dans la limite d'inertie des particules, petite mais finie. Les caractéristiques qualitatives de différents observables (telles que L'écart quadratique moyen de la distribution des particules par rapport à la distribution uniforme) sont, dans une large mesure, indépendantes de l'élasticité du l’écoulement. Quand celle-ci est augmentée, on constate cependant que cette dernière diminue légèrement le degré global moyen de mélange turbophorétique
Laboratory experiments show that, even in very dilute solutions, the interaction of polymers with fluid flows can dramatically change the properties of turbulent flows or, if the flow is laminar, can trigger a new sort of irregular motion named “elastic turbulence”. Flows in such a dynamical regime are promising for enhancing mixing efficiency in microfluidic applications, which often involve the presence of suspended finite-size impurities, like small and heavy solid particles. The understanding of particle dispersion in high-Reynolds number flows of Newtonian, as well as non-Newtonian, fluids were addressed by previous investigations, and it is a subject of interest both at a fundamental level and for applications, e.g., environmental or industrial ones. However, the dynamics of particles in elastic turbulent flows are still quite unexplored.The present study aims at investigating the aggregation properties of pointlike material particles (heavier than the carrying fluid) in viscoelastic fluids in elastic turbulence conditions (i.e. in the limit of vanishing fluid inertia and large elasticity). We carry out extensive direct numerical simulations of the periodic Kolmogorov mean shear flow of two-dimensional dilute polymer solutions described by the Oldroyd-B model. Both the small- and large-scale features of the resulting inhomogeneous particle distribution are examined, focusing on their connection with the underlying flow structure. Our analysis reveals that particles are preferentially clustered in regions of instantaneously maximally stretched polymers. The intensity of such a phenomenon depends on the interplay, parametrized by the Stokes number, between the particle inertia and the typical time scale associated with the elastic turbulence flow, and is the largest for intermediate values of particle inertia.In particular, it is shown that the preferential concentration of inertial particle suspensions in such turbulent-like flows follow from the dissipative nature of their dynamics. We provide a quantitative characterization of this phenomenon (using correlation and Kaplan-Yorke dimension) that allows to relate it to the accumulation of particles in filamentary highly strained flow regions producing clusters of fractal dimension slightly above 1.At larger scales, particles are found to undergo turbophoretic-like segregation along the non-homogeneity direction of the flow. Indeed, our results indicate that the particle distribution is strongly related to the mean turbulent-like structures of the flow. As an effect of turbophoresis, average density profiles peak in the regions of lowest turbulent eddy diffusivity. The large-scale inhomogeneity of the particle distribution is interpreted in the framework of a model derived in the limit of small, but finite, particle inertia. The qualitative characteristics of different observables (such as root-mean-square deviation of the particle distribution, relative to the uniform one) are, to a good extent, independent of the flow elasticity. When increased, the latter is found, however, to slightly reduce the globally averaged degree of turbophoretic unmixing

Les propriétés macroscopiques d'un polymère peuvent être modifiées en y dispersant de petites particules inorganiques: on forme alors un composite. Récemment, une attention particulière a été portée à la réduction de la taille de ces particules vers une taille nanométrique, afin d'augmenter la surface de contact et d'amplifier les effets sur les propriétés macroscopiques du composite. Nous avons mis au point un système modèle dans lequel les charges sont des nano-billes de silice greffées de polystyrène, dispersées dans une matrice de polystyrène. Le greffage des particules est réalisé en solution colloïdale, par polymérisation contrôlée aux nitroxydes (NMP) selon une technique " grafting from ". La dispersion des particules dans la matrice va dépendre du rapport des masses de polymère greffé et libre (matriciel). Deux types de dispersion ont ainsi été observés, par des mesures complémentaires de DXPA et de MET: lorsque la masse de la matrice est suffisament proche de celle des chaînes greffées, les nanoparticules de silice sont réparties individuellement de manière homogène dans le film. A l'inverse, lorsque la masse de la matrice devient trop grande par rapport à la masse greffée, les particules se regroupent en agrégats denses. Grâce à la synthèse d'une matrice spécifique copolymère styrène H/D dont la densité de longueur de diffusion égale celle de la silice, nous avons pu réaliser une première mesure directe de la conformation de la couronne greffée dans le film, en utilisant la DNPA. La dispersion de la silice et la conformation de la couronne ont ensuite été étudiées sur des films étirés de manière uniaxiale, afin d'observer leur évolution sous déformation. Les matériaux synthétisés ont enfin été soumis à différentes sollicitations mécaniques (grandes et petites déformations), dont les réponses peuvent être corrélées à la structure locale des charges et des chaînes de polymère.

<p>The aim of the present Structural Engineering Document, a state-of-the-art report, is to review the progress made worldwide in the use of fibre rein­forced polymers as structural components in bridges until the end of the year 2000.<p> Due to their advantageous material properties such as high specific strength, a large tolerance for frost and de-icing salts and, furthermore, short installation times with minimum traffic interference, fibre reinforced polymers have matured to become valuable alternative building materials for bridge structures. Today, fibre reinforced polymers are manufactured industrially to semi-finished products and ccimplete structural components, which can be easily and quickly installed or erected on site.<p> Examples of semi-finished products and structural components available are flexible tension elements, profiles stiff in bending and sandwich panels. As tension elements, especially for the purpose of strengthening, strips and sheets are available, as weil as reinforcing bars for concrete reinforcement and prestressing members for internal prestressing or external use. Profiles are available for beams and columns, and sandwich constructions especially for bridge decks. During the manufacture of the structural components fibre-optic sensors for continuous monitoring can be integrated in the materials. Adhesives are being used more and more for joining com­ponents.<p> Fibre reinforced polymers have been used in bridge construction since the mid-1980s, mostly for the strengthening of existing structures, and increas­ingly since the mid-1990s as pilot projects for new structures. In the case of new structures, three basic types of applications can be distinguished: concrete reinforcement, new hybrid structures in combination with traditional construction materials, and all-composite applications, in which the new materials are used exclusively.<p> This Structural Engineering Document also includes application and research recommendations with particular reference to Switzerland.<p> This book is aimed at both students and practising engineers, working in the field of fibre reinforced polymers, bridge design, construction, repair and strengthening.

This article discusses the structural, electronic, magnetic, and transport properties of carbon-fullerene-based polymers. In particular, it examines the defect-induced ferromagnetism of the C60-based polymers and its analog in the case of non-traditional inorganic materials. It first reviews the computational methods currently used in the literature, highlighting the pros and cons of each one of them. It then considers the defects associated with the ferromagnetism of the C60-based polymers, namely carbon vacancies, the 2 + 2 cycloaddition bonds and impurity atoms, and their effect on the electronic structure. It also evaluates the effect of codoping and goes on to describe the electronic, magnetic and transport properties of the rhombohedral C60-polymer. Finally, it looks at the origin of magnetic coupling among the magnetic moments in the rhombohedral C60-polymer and provides further evidence for the analogy between the magnetism of the rhombohedral C60-polymer and zinc oxide.

The book is a general text that shows how materials can contribute to solving problems facing nations in the 21st century. It is illustrated with diverse applications and highlights the potential of existing materials for everyday life, healthcare and the economies of nations. There are 13 chapters and a glossary of 500 materials with their descriptions, historical development, their use or potential use and a range of references. Specific areas include synthetic polymers (e.g. nylon), natural polymers (e.g. proteins, cellulose) and the role of materials in the development of digital computers and in healthcare. Solid-state lighting, energy supplies in the 21st century, disruptive technologies and intellectual property, in particular patents, are discussed. The book concludes by asking how the 21st century will be characterised. Will it be the Silicon Age, Genomic Age or New Polymer Age, as examples?

Organic chemistry is the chemistry of compounds of carbon. As well as being central to life, in the form of large molecules such as nucleic acids and proteins, organic compounds are essential to many areas of industry. Organic Chemistry: A Very Short Introduction covers the whole range of organic compounds and their roles. Beginning with the structures and properties of the basic groups of organic compounds, it goes on to consider organic compounds in the areas of pharmaceuticals, polymers, food and drink, petrochemicals, and nanotechnology. It explores how new materials, such as graphene, are opening up exciting new possibilities for applications, and also discusses the particular challenges of working with carbon compounds, many of which are colourless.

Rubber elasticity is an important sub-field of polymer science. This book is in many ways a sequel to the authors' previous, more introductory book, Rubberlike Elasticity: A Molecular Primer (Wiley-Interscience, 1988), and will in some respects replace the now classic book by L.R.G. Treloar, The Physics of Rubber Elasticity (Oxford, 1975). The present book has much in common with its predecessor, in particular its strong emphasis on molecular concepts and theories. Similarly, only equilibrium properties are covered in any detail. Though this book treats much of the same subject matter, it is a more comprehensive, more up-to-date, and somewhat more sophisticated treatment.

AbstractIn less than a century, concrete has become the most commonly used construction material worldwide. Today, it is difficult to imagine concrete entirely devoid of polymers. The implantation of polymers into concrete has taken effect in the form of Concrete Polymer Composite [C-PC = PMC + PCC + PIC + PC]. Several milestones are recognised in the development of C-PC. They are discussed here with particular emphasis on the innovative milestones that shaped the use of polymers in concrete. As the difference between polymer cement concrete and ordinary concrete diminishes, the question: “What should the paradigm of C-PC development be?” arises.

AbstractThis study investigates the effect of polymer paste content on the porosity and strength of pervious polymer concrete made of unsaturated polyester resin, fly ash filler, and crushed coarse aggregate. The porosity (total porosity and connected porosity) and strength (compressive and flexural strengths) for different polymer paste contents were investigated. The polymer paste content was chosen as an experimental variable because it determines the cost-effectiveness and has a significant impact on various material properties. The results showed that the total and connected porosity fell between 37.5–8.8% and 34.2–7.2%, respectively, when the polymer paste content increased from 7 to 19.5 wt.%. The porosity tended to decrease as the polymer paste content increased. The compressive and flexural strengths ranged from 14.5 to 41.5 MPa and 4.3 to 16.1 MPa, and the strengths increased as the paste content increased. In particular, the strengths were much higher than those of many existing studies on conventional portland cement concrete due to the enhanced adhesion of the polymer binder upon the addition of the cross-linking agent.

AbstractApproaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include tire wear, paint chips, semisynthetics (e.g., rayon), and bioplastics. Plastics commonly contain chemical additives and fillers, which may alter their toxicological potency, behavior (e.g., buoyancy), or detector response (e.g., yield fluorescence) during analysis. Field sampling methods often focus on >20 μm and even >300 μm sized particles and will thus not capture smaller microplastics (which may be most abundant and bioavailable). Analysis of a limited subgroup (selected polymer types, particle sizes, or shapes) of microplastics, while often operationally necessary, can result in an underestimation of actual sample content. These shortcomings complicate calls for toxicological studies of microplastics to be based on “environmentally relevant concentrations.” Sample matrices of interest include water (including wastewater, ice, snow), sediment (soil, dust, wastewater sludge), air, and biota. Properties of the environment, and of the particles themselves, may concentrate plastic debris in select zones (e.g., gyres, shorelines, polar ice, wastewater sludge). Sampling designs should consider such patchy distributions. Episodic releases due to weather and anthropogenic discharges should also be considered. While water grab samples and sieving are commonplace, novel techniques for microplastic isolation, such as continuous flow centrifugation, show promise. The abundance of nonplastic particulates (e.g., clay, detritus, biological material) in samples interferes with microplastic detection and characterization. Their removal is typically accomplished using a combination of gravity separation and oxidative digestion (including strong bases, peroxide, enzymes); unfortunately, aggressive treatments may damage more labile plastics. Microscope-based infrared or Raman detection is often applied to provide polymer chemistry and morphological data for individual microplastic particles. However, the sheer number of particles in many samples presents logistical hurdles. In response, instruments have been developed that employ detector arrays and rapid scanning lasers. The addition of dyes to stain particulates may facilitate spectroscopic detection of some polymer types. Most researchers provide microplastic data in the form of the abundances of polymer types within particle size, polymer, and morphology classes. Polymer mass data in samples remain rare but are essential to elucidating fate. Rather than characterizing individual particles in samples, solvent extraction (following initial sample prep, such as sediment size class sorting), combined with techniques such as thermoanalysis (e.g., pyrolysis), has been used to generate microplastic mass data. However, this may obviate the acquisition of individual particle morphology and compositional information. Alternatively, some techniques (e.g., electron and atomic force microscopy and matrix-assisted laser desorption mass spectrometry) are adept at providing highly detailed data on the size, morphology, composition, and surface chemistry of select particles. Ultimately, the analyst must select the approach best suited for their study goals. Robust quality control elements are also critical to evaluate the accuracy and precision of the sampling and analysis techniques. Further, improved efforts are required to assess and control possible sample contamination due to the ubiquitous distribution of microplastics, especially in indoor environments where samples are processed.

This chapter gives an overview of polymer-based nanocomposites (PMNC), focusing on the processing. Polymers such as condensation polymers, vinyl polymers, polyolefins, specialty polymers including biodegradable are used in production of PMNC. It is the reinforcement that is in the nanorange size in nanocomposites generally. Reinforcements used are metal powders, silica, clays, and metal oxides. The most important methods of preparing PMNC are intercalation of the polymer or pre-polymer from solution, in-situ intercalative polymerization, melt intercalation, direct mixture of polymer and particulates, template synthesis, in-situ polymerization; and sol-gel process. The structure of polymer-based nanocomposites consists of the matrix material containing the nanosized reinforcement components in the forms of whiskers, particles, nanotubes, fibers, etc. It is clear that polymer-based nanocomposites provide many benefits such as improved properties, minimization of solid wastes films, and lower and improved manufacturing capabilities.

The usage of clay polymer composites has increased in the past few decades. Due to extensive availability, wide surface areas, and good adsorption efficiency clay polymers are gaining popularity amongst researchers to remove wide range of organic as well as inorganic pollutants from effluents. This book chapter sheds light on the characteristics, occurrence, types and synthesis of clay minerals used for preparing nano-clay polymer composites. It also highlights the types, applicability and efficiencies of particular nano clay polymers for the removal of dyes, paints, nutrients, potentially toxic elements and pharmaceutical contaminants from wastewater.

Manufacturing applications for filled polymers include encapsulation of microelectronics and injection molding of composite parts. Predictive tools for simulating these manufacturing processes require knowledge of time- and temperature-dependent rheology of the polymer as well as information about local particle concentration. The overall system rheology is highly dependent on the particle concentration. The local particle concentration can change due to gravity, convection and shear-induced migration. For the epoxy systems of interest, an extent of reaction can be used to track the degree of cure. We couple the curing model with a diffusive flux suspension model [Zhang and Acrivos 1994] to determine the particle migration. This results in a generalized Newtonian model that has viscosity as a function of temperature, cure and concentration. Using this model, we examine settling of the particulate phase in both flowing and quiescent curing systems. We focus on settling in molds and flow in wide-gap counter-rotating cylinders. The heat transfer, including the exothermic polymerization reaction, must be modeled to achieve accurate results. The model is validated with temperature measurements and post-test microscopy data. Particle concentration is determined with x-ray microfocus visualization or confocal microscopy. Agreement between the simulations and experimental results is fair.

The work is devoted to the use of polymeric materials in the processing of smart glasses. In particular, polymer films such as polyethylene terephthalate (PET) and polyvinyl chloride (PVC) as well as electrochromic polymers. Polymer frequencies are widely used in window and other cases to improve their functional properties such as density, thermal insulation and UV protection. Electrochromic polymers allow you to control the transmission of light and heat in the room. These innovative materials require a wide range of applications for smart vehicles, including automobiles and electronics.

Understanding the structure/property relations in polymer/clay nanocomposites is of great importance in designing materials with desired properties. Along these lines, a critical overview is attempted on the physical and molecular origins of material properties enhancements in polymer/clay hybrid nanocomposites. A comparative discussion of mechanical, thermal, optical, and ammability properties across various polymers focuses on those properties that are universally improved. In general, such properties originate from the nature of the layered inorganic fillers and from their nano-dispersion in a polymer. In contrast, other properties are determined by the particular/distinctive interactions between a specific polymer with the filler; such attributes can not be transfered from one polymer system to another. We shall try to distinguish between these two classes of properties, and provide some insight into which properties can be improved concurrently across a wide range of polymers.

Since their development, shape memory polymers, urethanes, styrenes, and the like, have been of increasing interest in advanced material and structure design. The following is an experimental investigation into the effect polymer chain alignment has on the mechanical properties of a particular styrene shape memory polymer, Veriflex®. Aligning the polymer chains results in several material anisotropies; giving rise to the possibility of controllable, directional shape memory and modulus behavior and a basis for a multitude of prospective design concepts.

Abstract Polymer composites have generated increased interest in the development of damped structural materials because of their low density, and excellent stiffness and damping characteristics. The objectives of this paper are to study the improvement and optimization of damping in fiber reinforced structural composite materials at the micromechanical level by coating some of the fibers with special polymers which have high damping. Since shear deformation is essential for viscoelastic damping in polymers, and large shear strains are generated near the fiber/matrix interface in composites, the use of special viscoelastic polymer fiber coatings is an effective way to improve damping in such composites. Of particular interest are hybrid composites having a mixture of coated and uncoated fibers, since coating all the fibers would cause unacceptable reductions in other important properties like strength and stiffness.

Ionomeric polymers are a class of electromechanical transducer consisting of an ionomeric substrate with metal-plated electrodes. Application of a low voltage (&lt; 5 V) across the thickness of the membrane produces controllable strain. The advantage of ionomeric polymers compared to other types of electromechanical transducers (e.g. piezoelectric polymers) is low-voltage operation, high strain capability, and high sensitivity in charge mode. Two of the primary limitations of ionomeric polymers for electromechanical transducers are unstable operation in air and solvent breakdown at low voltage. This work focuses on overcoming these limitations through the development of an ionic liquid-ionomeric composite with a tailored electrode composition that maximizes strain output. It is becoming clear that charge accumulation at the polymer-electrode interface is the key to producing high strain in ionomeric polymer transducers. In this work we combine a previously developed process for incorporating ionic liquids into ionomer membranes with a new method for tailoring the electrode composition. The electrode composition is studied as a function of the surface-to-volume ratio and conductivity of the metal particulates. Results demonstrate that the surface-to-volume ratio of the metal particulate is critical to increasing the capacitance of the transducer. Increased conductivity of the metal particulates produces improved response at higher frequencies (&gt; 10 Hz) but this effect is small compared to the increase in strain produced by maximizing the capacitance. Increasing capacitance produces a transducer that is able to achieve &gt; 2% strain at voltage levels of +/- 3 V.

Abstract Drilling various depleted formations to enter the reservoir at the right location to extract the maximum gain is becoming more frequent and regular. In most cases, the overbalance reaches 1000 psi across various zones and is sometimes observed exceeding 5600 psi. Wellbore instability, deep fluid invasion, differential sticking, and mud losses are a few of the problems that need to be addressed when designing the fluid, irrespective of type of mud system (water-based or non-aqueous fluids). Also, casing isolation might not always be possible and can be very expensive. Therefore, it is necessary to identify a solution from the fluid's perspective that designs a suitable fluid mitigating the above concerns and makes the drilling easier, safer, and more efficient. With appropriate bridging, a good seal across the formation help maintain the wellbore stability and stop the fracture propagation. The seal that forms should be thin, effective, and have low permeability that can minimize the pore pressure transmission (PPT) into the formation which causes the formation to destabilize. Initially these fractures in the formation are in nano-size levels and typical products available in the market cannot bridge these properly which can lead to bigger fractures and ultimately end up in causing heavy mud loses, well control situations, and formation damage leading to lost production. Bridging software helps to predict the right combination of products required and also determines the requirement for any other, bigger particles. The latest developments in nanotechnology help in resolving the above concerns and can be used in the drilling fluids without having any adverse effect on the mud and environment. The technology features of the subject nano-sized solid particles allow them to be mixed in aqueous or non-aqueous drilling fluids and in any type of salt phase. Specific fluid design will depend on the application: whether it is to address shale stability, or overbalance or bridging requirements at the target well application with minimal material usage compared to conventional products that are presently used in the industry. The nano-sized particles are free flowing polymer particles (D50 between 100 - 200 nm) and are deformable. They can seal and mechanically plug the micro-fractures and pore throats, thus forming a semi-permeable membrane. This prevents fluid penetration and provides support to enhance hole stability. Nanotechnology helps in minimizing the overall product consumption and waste generation which can be a huge cost savings to the operator and significantly reduce the costs related to transportation movement and number of mixing hours which is indirect savings to the operator. This paper presents a detailed laboratory analysis of the product over a broad range of conditions at high overbalance pressures. Return permeability data shows the product is not damaging to reservoir, with minimal lift-off pressure and is beneficial to use for better production and improved return on investment. Due to its unique nature, it may be possible to forego breaker fluids, thus decreasing both the cost of operation and the rig time spent on each well. The product has seen great success in fields across the world and several applications were produced successfully.