Poly(ether-b-amide) (Pebax® grade 1074) is a waterproof breathable block copolymer containing soft poly(ethylene oxide) and rigid polyamide 12 segments. Its intrinsic gas permeabilities to nitrogen, oxygen, methane, helium, hydrogen, and carbon dioxide were tested under different feed pressures (0.3 – 2.5 MPa) and temperatures (20 – 80 °C). This helps to obtain a comprehensive understanding of the polymer, because prior work reported in the literature addressed only a few gases and used inconsistent membrane preparation and test methods. Relatively high polar (or quadrupolar)/nonpolar gas selectivity were observed. CO2/N2 selectivity was demonstrated to be as high as 105±0.4 in Pebax®1074, with CO2 permeability coefficient of approximately 180±1 Barrer at room temperature. Additionally, the effects of solvent used in membrane preparation, heat treatment, membrane thickness, and polymer solution concentration on the membrane permeability were evaluated. Pebax® is a highly breathable material, thus its application as breathable chemically-resistant protective clothing was studied. Dimethyl methylphosphonate (DMMP) – a sarin simulant – was selected as the challenge agent. The liquid pervaporation of pure water (simulating perspiration) and pure DMMP were measured for Pebax®1074, Pebax®2533, nitrile, latex, poly(vinyl chloride), low density polyethylene, silicone, and silicone-polycarbonate copolymer under pervaporation mode. Pebax®1074 was not only the most water permeable material but also the most selective of all the tested materials for water/DMMP – making it a very promising material for this application.

Poly(ether-b-amide) (Pebax® grade 1074) is a waterproof breathable block copolymer containing soft poly(ethylene oxide) and rigid polyamide 12 segments. Its intrinsic gas permeabilities to nitrogen, oxygen, methane, helium, hydrogen, and carbon dioxide were tested under different feed pressures (0.3 – 2.5 MPa) and temperatures (20 – 80 °C). This helps to obtain a comprehensive understanding of the polymer, because prior work reported in the literature addressed only a few gases and used inconsistent membrane preparation and test methods. Relatively high polar (or quadrupolar)/nonpolar gas selectivity were observed. CO2/N2 selectivity was demonstrated to be as high as 105±0.4 in Pebax®1074, with CO2 permeability coefficient of approximately 180±1 Barrer at room temperature. Additionally, the effects of solvent used in membrane preparation, heat treatment, membrane thickness, and polymer solution concentration on the membrane permeability were evaluated. Pebax® is a highly breathable material, thus its application as breathable chemically-resistant protective clothing was studied. Dimethyl methylphosphonate (DMMP) – a sarin simulant – was selected as the challenge agent. The liquid pervaporation of pure water (simulating perspiration) and pure DMMP were measured for Pebax®1074, Pebax®2533, nitrile, latex, poly(vinyl chloride), low density polyethylene, silicone, and silicone-polycarbonate copolymer under pervaporation mode. Pebax®1074 was not only the most water permeable material but also the most selective of all the tested materials for water/DMMP – making it a very promising material for this application.

Ces travaux ont porté sur l’intérêt de l’utilisation d’une membrane composite zéolite (CHA SSZ-13) accessible à l’échelle commerciale au travers de la technologie membranaire de perméation de gaz et de vapeurs. L’applicabilité de cette technologie séparative s’est principalement focalisée sur la récupération du méthane, propane et d’isobutène issus de flux produits à des échelles industrielles par des procédés durables. La mise au point d’un banc expérimental pour la mesure de données de perméation de gaz et de vapeur a été réalisé. En se basant sur des mesures expérimentales de perméation menées avec la membrane zéolite de l’étude, un premier cas d’application pratique a été de simuler les performances séparatives d’un procédé hybride associant un module membranaire zéolite avec une condensation cryogénique à partir d’un cahier des charges industriel pour la récupération d’isobutène. Le procédé hybride étudié est toujours plus performant que le procédé de condensation cryogénique seul de référence en termes de pureté du produit condensé obtenu et de consommation énergétique. Des cartographies ont été dressées afin de situer les performances de séparation simulées en fonction de l’objectif de récupération d’isobutène souhaité. Un second cas théorique de récupération du propane à partir d’évents de purge à l’azote avec un procédé hybride de séparation cryogénique couplée à une membrane permsélective a été étudié. Une cartographie des performances de séparation membranaire relative au couple propane/diazote selon les données de la littérature ouverte actuelles a été présentée. La membrane la plus permsélective au diazote et au propane (respectivement CHA SSZ-13 et PEBAX 2533) a été sélectionné afin de simuler des procédés hybrides dont les performances séparatives ont été comparées à celles de la condensation cryogénique seule de référence. Pour de faibles teneurs en propane, il a été constaté que le procédé le plus performant (besoin énergétique et qualité du produit condensé) impliquait un module membranaire polymère de type PEBAX 2533 avec un système de mise sous vide du perméat. / This work focused on the interest of using a zeolite composite membrane (CHA SSZ-13) accessible on a commercial scale through the membrane technology of gas and vapor permeation. The applicability of this separation technology has mainly focused on the recovery of methane, propane and isobutene from fluxes produced at industrial scales by sustainable processes. The development of an experimental lab scale pilot for gas and vapor permeation data measurements is detailed. Based on experimental permeation measurements carried out with the zeolite membrane of the study, a first case of practical application was to simulate the separation performance of a hybrid process associating a zeolite membrane module with a cryogenic condensation from an industrial specification for the recovery of isobutene. The hybrid process studied is always more efficient than the only cryogenic condensation process taken as reference in terms of purity of the condensed product obtained and energy consumption. A chart was generated to locate the simulated separation performance based on the desired isobutene recovery objective. A second theoretical case of propane recovery from nitrogen purging vents with hybrid membrane cryogenic separation process was studied. This study presented a chart of the membrane separation performance of propane over nitrogen according to data from the open literature. The most nitrogen- and propane-selective membrane (CHA SSZ-13 and PEBAX 2533 respectively) was then selected and used in order to simulate hybrid processes where separation performances were compared to a baseline cryogenic standalone process. For low propane contents in the nitrogen feed mixture, it was found that the most efficient process (energy need and quality of the condensed product) involved a PEBAX 2533 polymer membrane module with a vacuum system for the permeate.

Produced water (PW) is an oil and gas extraction byproduct that contains a variety of contaminants. PW was traditionally disposed of in deep injection wells or released into the environment. However, these practices may have environmental consequences. The reuse of PW for power water injection (PWI) can help to reduce these impacts by providing a renewable source of water that can be used to maintain production pressure and increase oil recovery. Additionally, the reuse of PW can save oil companies money on water treatment, transporting and disposal costs. Ultrafiltration membranes are used to separate oil from water in produced water. However, ultrafiltration membranes are susceptible to severe fouling by oil molecules, which can reduce their performance. This research investigated the use of Pebax® coating to improve the performance of ultrafiltration membranes for oily-water mixture. The results showed that Pebax® coating can enhance the resistance of membranes to fouling to fouling. The optimal balance between fouling resistance and water flux was found to be achieved by applying very thin coating layers and using appropriate solvents (e.g., n-Butanol). The Pebax® coating creates an essentially defect-free layer on the membrane surface, as seen by the SEM images. Additionally, the coated membranes outperformed the untreated membranes in terms of fouling resistance. This result demonstrated that oil molecules showed less adhesion on the surface and penetration inside membrane pores, thus reducing fouling. Overall, the findings of this research point to PEBAX® coating as a potential means of enhancing the ability of ultrafiltration membranes to resist fouling in the process of separating oil from water. To analyze the long-term performance of coated membranes and to optimize the coating procedure, additional research is required.

[pt] A implementação de medidas que reduzam as emissões de gases de efeito estufa ganha importância no cenário atual. Um importante método para captura de CO2 consiste nos processos de separação por membranas. Visando melhorar a eficiência seletiva na separação de gases, este trabalho estudou a síntese de membranas poliméricas de matrizes mistas a fim de aumentar os valores de permeabilidade, utilizando líquidos iônicos em sua estrutura, que apresentam elevada solubilidade de CO2 e seletividade. A síntese do líquido iônico foi realizada a partir do cátion imidazólico e do ânion NTf2(-) , em reações de 3 etapas. Os filmes poliméricos de matrizes mistas foram sintetizados por diferentes tipos de polímeros comerciais, PEBAX 1657, PEBAX2533 e PU 1185A10; com concentrações de 0 por cento, 20 por cento e 60 por cento (m/m) do líquido iônico. A técnica de ressonância magnética nuclear (RMN) de (1)H e (13)C foi utilizada para validar a composição do líquido iônico. As caracterizações de membranas compósitas se deram pelas técnicas de microscopia eletrônica de varredura (MEV), análise termogravimétrica (TGA) e espectroscopia de infravermelho com transformada de Fourier (FTIR). Na presença do líquido iônico, a seletividade relativa de CO2/N2 apresentou um aumento considerável para as membranas de PU e PEBAX2533, enquanto a permeabilidade de CO2 aumentou nas membranas de PU e PEBAX1657. / [en] The measures to reduce greenhouse gas emissions, gains more importance in the current scenario. Processes involving membrane separation are an important method for CO2 capture which are widely used. In order to improve the selective efficient in the gas separation this paper studies the development and synthesis of composite polymeric membranes that will be able to increase the permeability using ionic liquids in your structure, which have high CO2 solubility and selectivity. The ionic liquid synthesis was obtained using imidazolium cation and the NTf2(-) anion, on 3 steps reactions. The composite polymeric membranes were synthesized by different types of commercial polymers, PEBAX1657, PEBAX2533 and PU 1185A10; with 0 percent, 20 percent and 60 percent (wt.) concentrations of ionic liquid. The nuclear magnetic resonance (NMR) technique for 1H and 13C was used to validate the ionic liquid structure. The composite membrane characterizations were obtained by those techniques: scanning electron microscope (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR). In the presence of ionic liquid, the selectivity of CO2/N2 increased for the PU and PEBAX2533 membranes, and the permeability of CO2 increased for the PU and PEBAX1657 membranes.

La thèse est consacrée aux matériaux électro-actifs, qui sont développés et conçus pour faire de la conversion entre énergie électrique et énergie mécanique. Avec les nouvelles technologies émergentes de transduction électromécanique, les polymères électro-actifs (EAP) ont gagné une attention considérable. Ils présentent de grandes déformations quand ils sont soumis à un champ électrique. Cependant, ces matériaux présentent de faibles permittivités et exigent pour fonctionner l’application de forts champs électriques. Les recherches entreprises dans la thèse traitent de différentes méthodes ayant pour but d'augmenter la permittivité des polymères et par conséquent d’améliorer les propriétés électromécaniques sous des champs électriques modérés. Les différentes approches consistent à la mise au point de nouveaux matériaux, par la méthode de mélange de polymères ou en utilisant un nouveau type de polymère, et par l'incorporation de nano-charges spéciales dans la matrice polymère. Un mélange de polyuréthane (PU) et PEMG obtenu à partir d'un procédé en solution conduit à des valeurs plus basses de module de Young, mais aussi à de plus faibles permittivités diélectriques. Il est cependant mis en évidence une amélioration des propriétés électromécaniques, par exemple, à le gain à des champs électriques modérés est d’un facteur 2, avec seulement 9% en poids de PEMG. Deux types de Pebax sont testés comme matrice polymère. Des valeurs très élevées de permittivités sont obtenus plus particulièrement pour le Pebax1657 mais liés pour ce matériau à des valeurs élevées de conductivité. En dépit de ces permittivités élevées, seule une légère amélioration de la conversion électromécanique est observée par rapport au polyurethane. Nous nous sommes également intéressés aux nanocomposites de polyuréthane basés sur desnanoparticules d'argent recouvertes de polymère polyvinylpyrrolidone (PVP). Un fin revêtement de polymère sur les nanoparticules d'argent conduit à une meilleure dispersion des charges dans les films de polyuréthane, et des valeurs plus élevées de permittivité. Différentes quantités d'Ag-PVP sont testées jusqu'au seuil de percolation proche de 45% en poids de charges. À partir des mesures par interférométrie laser et du nouveau dispositif de caractérisation croisée, les propriétés électromécaniques optimales sont obtenues pour 20% en poids de Ag-PVP, avecun gain de 2 à 6 par rapport au polyuréthane pur. Afin d'expliquer la différence entre les résultats expérimentaux et attendus, et par conséquent pour parvenir à une meilleure compréhension du comportement électromécanique de ces différents matériaux, certaines hypothèses ont été discutées et testées. Nous avons montré notamment une baisse des permittivités diélectriques sous champs électriques pour les Pebax et les nanocomposites, des problèmes d'absorption d'eau pour les Pebax et une diminution de cristallinité dans le cas des nanocomposites PU-Ag. / The thesis is devoted to electroactive materials, which are developed and designed to make conversion between the electricity and the mechanical form. With newer emerging electromechanical transduction technologies, electroactive polymers (EAP) have gained a considerable attention. The polymers are competitive in many applications such as actuators, sensors, robotic system and biological mimics since they are cheap, light, easy to process, and they present large electric field-induced strains. However, these materials suffer from the low permittivity and high voltage requirement to drive the actuations. The research undertaken for the thesis intends then to provide different methods in order to enhance the polymer permittivity and consequently the electromechanical activities at moderate electric fields. The different approaches consist on the development of new materials by polymer blend method or by using new kind of polymer, and on the incorporation of special nano-fillers in the polymer matrix. A blend of polyurethane (PU) and poly [ethylene-co-(methyl acrylate)-co-(glycidyl methacrylate) (PEMG) obtained from a simple solution method leads to lower values of Young modulus but also lower dielectric permittivities. The PU-PEMG blend presents however an improvement of the electromechanical capabilities, for example it is obtained a two fold increase of the strain at moderate fields with only 9%wt of PEMG.Two types of Polyetherblockamide (Pebax) are tested as polymer matrix. Very high values of permittivities are obtained particulary for Pebax1657 but accompanied for this material by high values of conductivity. Despite these high permittivities (more than 200000 for Pebax 1657 and 500 for Pebax 2533 at 0.1 Hz), only a moderate improvement of the electromechanical capability is observed compared to PU. We are also intererested on polyurethane nanocomposites based on silver nanoparticles coverered by PolyVinylPyrrolidone (PVP) polymer. A little polymer coating of the nanosilver leads to a better dispersion into the polyurethane films and higher values of permittivity. Different amounts of Ag-PVP are tested up to the percolation threshold close to 45%wt of fillers. Based on laser interferometer measurements and new cross characterization device, the optimal electromechanical properties are obtained for 20 %wt of Ag-PVP and a gain of 2 to 6 is obtained compared to pure polyurethane. In order to explain the difference between experimental and expected results and consequently to achieve a better understanding of the electromechanical behaviour of these different materials, some hypotheses were discussed and tested. We have shown particularly a drop of dielectric permittivities under electric fields for Pebax and nanocomposites, some problems of water absorption for Pebax and a decrease of crystallinity for the PU-Ag nanocomposites.

Polymeric membranes exhibit a trade-off between permeability and selectivity in gas separations which limits their viability as an economically feasible post-combustion carbon capture technology. One approach to improve the separation properties of polymeric membranes is the inclusion of particulate materials into the polymer matrix to create what are known as mixed matrix membranes (MMMs). By combining the polymer and particulate phases, beneficial properties of both can be seen in the resulting composite material. One of the most notable challenges in producing mixed matrix membranes is in the formation of performance-hindering defects at the polymer-filler interface. Non-selective voids or polymer chain rigidification are but two non-desirable effects which can be observed. The material selection and synthesis route are key to minimising these defects. Thin membranes are also highly desirable to achieve greater gas fluxes and improved economical separation processes. Hence smaller nano-sized particles are of particular interest to minimise the disruption to the polymer matrix. This is a challenge due to the tendency of some small particles to form agglomerations. This work involved introducing novel nanoscale filler particles into PEBAX MH1657, a commercially available block-copolymer consisting of poly(ethylene oxide) and nylon 6 chains. Poly(ether-b-amide) materials possess an inherently high selectivity for the CO2/N2 separation due to polar groups in the PEO chain but suffer from low permeabilities. Mixed matrix membranes were fabricated with PEBAX MH1657 primarily using two filler particles, nanoscale ZIF-8 and novel nanoscale MCM-41 hollow spheres. This work primarily investigated the effects of the filler loading on both the morphology and gas transport properties of the composite materials. The internal structure of the membranes was examined using scanning electron microscopy (SEM), and the gas transport properties determined using a bespoke time-lag gas permeation apparatus. ZIF-8 is a zeolitic imidazolate framework which possesses small pore windows that may favour CO2 transport over that of N2. ZIF-8-PEBAX membranes were successfully synthesised up to 7wt.%. It was found that for filler loadings below 5wt.%, the ZIF-8 was well dispersed within the polymer phase. At these loadings modest increases in the CO2 permeability coeffcient of 0-20% compared to neat PEBAX were observed. Above this 5wt.% loading large increases in both CO2, N2 and He permeability coeffcients coincided with the presence of large micron size clusters formed of hundreds of filler ZIF-8 particles. The increases in permeability were attributed to voids observed within the clusters. MCM-41 is a metal organic framework that has seen notable interest in the field of carbon capture, due to its tunable pore size and ease of functionalisation. Two types of novel MCM-41 hollow sphere (MCM-41-HS) of varying pore size were incorporated into PEBAX and successfully used to fabricate MMMs up to 10wt.%. SEM showed the MCM-41 generally interacted well with the polymer with no signs of voids and was generally well dispersed. However, some samples of intermediate loading in both cases showed highly asymmetric distribution of nanoparticles and high particle density regions near one external face of the membrane which also showed the highest CO2 permeability coeffcients. It is suspected that these high permeabilities are due to the close proximity of nanoparticles permitting these regions to act in a similar way to percolating networks. It was determined that there was no observable effect of the varying pore size which was expected given the transport in the pores should be governed by Knudsen diffusion.

No description available.