Materiais nanoestruturados têm recebido destaque na comunidade científica, destacando-se, dentre eles, os nanocompósitos à base de polímeros e argila. Quando esses materiais são obtidos no estado líquido, ressalta-se também o uso de água em substituição a solventes orgânicos, devido a questões ambientais. Neste trabalho foram sintetizadas dispersões aquosas à base de poliuretanos (WPUs) e argila hidrofílica do tipo montimorilonita (MMT) de natureza sódica, com o objetivo de avaliar as propriedades de barreira a gases conferidas pela presença de argila e pela variação nas proporções entre os segmentos flexíveis poli(glicol propilênico) (PPG) e o copolímero em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG). Os monômeros empregados na síntese foram: poli(glicol propilênico) (PPG); copolímero em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), com teor de 7% de EG; ácido dimetilolpropiônico (DMPA), diisocianato de isoforona (IPDI) e etilenodiamina (EDA), como extensor de cadeia. Foram sintetizadas dispersões aquosas com e sem a presença de argila, fixando-se a razão entre o número de equivalentes-grama de grupos diisocianato e hidroxila (razão NCO/OH) em 1,5. Nas formulações foi variado também o teor de argila em relação à massa de prepolímero em 0,5% e 1%. Foi adicionada uma etapa de agitação adicional com dispersor Turrax em algumas formulações. A argila foi previamente deslaminada em água deionizada e incorporada à formulação na etapa da dispersão do prepolímero. As dispersões foram avaliadas, quanto ao teor de sólidos totais, tamanho médio de partícula e viscosidade aparente. Os filmes vazados a partir das dispersões foram caracterizados por espectrometria na região do infravermelho (FTIR) e permeabilidade ao CO2. A resistência térmica dos filmes foi determinada por termogravimetria (TG). Foram observadas modificações nas propriedades dos filmes obtidos com a inserção da argila e com a variação no teor de segmentos à base de poli(glicol etilênico). A inserção da argila promoveu uma melhoria na resistência térmica das membranas bem como uma redução na permeabilidade das mesmas. Foi observado um aumento na permeabilidade das membranas obtidas a partir das formulações com maior percentual de copolímero (EG-b-PG), com e sem argila. / Nanostructured materials have been receiving increasing attention of scientific community, especially systems of nanocomposites based on polymer and clay. These materials can be obtained in aqueous state and the use of water, replacing organic solvents, is an important line of research due to environmental issues. In this work, dispersions based on waterbone polyurethanes and sodic hydrophilic clay montmorillonite (MMT) were synthesized, in order to evaluate the possible formation of nanocomposites (NWPUs). The monomers employed in the synthesis were: poly (propylene glycol) (PPG), block copolymer based on poly (ethylene glycol) and poly (propylene glycol) (EG-b-PG), containing 7% ethylene glycol; dimethylolpropionic acid (DMPA); isophorone diisocyanate (IPDI); and ethylenediamine (EDA) as chain extender. Aqueous dispersions with and without clay were synthesized by fixing the ratio between the equivalent-grams of diisocyanate and hydroxyl groups (NCO/OH ratio) in 1.5. The clay content also varied from 0.5% to 1% related to prepolymer initial mass. An additional stirring step with Turrax disperser was made in some formulations. The clay was previously delaminated in deionized water and incorporated at prepolymer dispersion in water-addition step. The dispersions were then evaluated in terms of solids content, particle size and apparent viscosity. The films cast from dispersions were characterized by infrared spectrometry (FTIR), thermogravimetry (TG) and permeability to CO2. Cast films were obtained and the gas barrier properties imparted by the clay were analyzed as well as the influence of poly (ethylene glycol) segments content. The insertion of clay imparted an improvement in thermal resistance properties and a decrease in membrane permeability. It was also observed an increase in permeability to CO2 of membranes obtained from formulations containing the higher amount of copolymer (EG-b-PG), independent of clay content.

In den durchgeführten Versuchsreihen wurden die Wasserabsorption sowie die Gas- und Wasserpermeabilität sowohl an gerissenen als auch rissfreien Prüfkörpern aus textilbewehrtem Beton (TRC) untersucht. Eine deutliche Steigerung der Wasseraufnahme bei Proben mit unbeschichteten Textilien konnte mit Zunahme der Garnfeinheit beobachtet werden. Bei den gerissenen Proben besteht eine ausgeprägte Abhängigkeit der Transportraten von Flüssigkeiten und Gasen zu den relevanten Risscharakteristika (kumulative Risslänge, Rissbreite). Weiterhin sind Selbstheilungseffekte von feinen Rissen infolge einer zyklischen Wasserbeaufschlagung beobachtet worden. Hierbei kam es zu einer deutlichen Reduzierung der Transportraten sowohl für Wasser als auch für Gase. Eine speziell entwickelte Permeabilitätsmesskammer zur Durchführung von In- Situ-Messungen ermöglicht Untersuchungen zum Stofftransport unter axialer Zugbelastung bei verschiedenen Dehnungszuständen.

Materiais nanoestruturados têm recebido destaque na comunidade científica, destacando-se, dentre eles, os nanocompósitos à base de polímeros e argila. Quando esses materiais são obtidos no estado líquido, ressalta-se também o uso de água em substituição a solventes orgânicos, devido a questões ambientais. Neste trabalho foram sintetizadas dispersões aquosas à base de poliuretanos (WPUs) e argila hidrofílica do tipo montimorilonita (MMT) de natureza sódica, com o objetivo de avaliar as propriedades de barreira a gases conferidas pela presença de argila e pela variação nas proporções entre os segmentos flexíveis poli(glicol propilênico) (PPG) e o copolímero em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG). Os monômeros empregados na síntese foram: poli(glicol propilênico) (PPG); copolímero em bloco à base de poli(glicol etilênico) e poli(glicol propilênico) (EG-b-PG), com teor de 7% de EG; ácido dimetilolpropiônico (DMPA), diisocianato de isoforona (IPDI) e etilenodiamina (EDA), como extensor de cadeia. Foram sintetizadas dispersões aquosas com e sem a presença de argila, fixando-se a razão entre o número de equivalentes-grama de grupos diisocianato e hidroxila (razão NCO/OH) em 1,5. Nas formulações foi variado também o teor de argila em relação à massa de prepolímero em 0,5% e 1%. Foi adicionada uma etapa de agitação adicional com dispersor Turrax em algumas formulações. A argila foi previamente deslaminada em água deionizada e incorporada à formulação na etapa da dispersão do prepolímero. As dispersões foram avaliadas, quanto ao teor de sólidos totais, tamanho médio de partícula e viscosidade aparente. Os filmes vazados a partir das dispersões foram caracterizados por espectrometria na região do infravermelho (FTIR) e permeabilidade ao CO2. A resistência térmica dos filmes foi determinada por termogravimetria (TG). Foram observadas modificações nas propriedades dos filmes obtidos com a inserção da argila e com a variação no teor de segmentos à base de poli(glicol etilênico). A inserção da argila promoveu uma melhoria na resistência térmica das membranas bem como uma redução na permeabilidade das mesmas. Foi observado um aumento na permeabilidade das membranas obtidas a partir das formulações com maior percentual de copolímero (EG-b-PG), com e sem argila. / Nanostructured materials have been receiving increasing attention of scientific community, especially systems of nanocomposites based on polymer and clay. These materials can be obtained in aqueous state and the use of water, replacing organic solvents, is an important line of research due to environmental issues. In this work, dispersions based on waterbone polyurethanes and sodic hydrophilic clay montmorillonite (MMT) were synthesized, in order to evaluate the possible formation of nanocomposites (NWPUs). The monomers employed in the synthesis were: poly (propylene glycol) (PPG), block copolymer based on poly (ethylene glycol) and poly (propylene glycol) (EG-b-PG), containing 7% ethylene glycol; dimethylolpropionic acid (DMPA); isophorone diisocyanate (IPDI); and ethylenediamine (EDA) as chain extender. Aqueous dispersions with and without clay were synthesized by fixing the ratio between the equivalent-grams of diisocyanate and hydroxyl groups (NCO/OH ratio) in 1.5. The clay content also varied from 0.5% to 1% related to prepolymer initial mass. An additional stirring step with Turrax disperser was made in some formulations. The clay was previously delaminated in deionized water and incorporated at prepolymer dispersion in water-addition step. The dispersions were then evaluated in terms of solids content, particle size and apparent viscosity. The films cast from dispersions were characterized by infrared spectrometry (FTIR), thermogravimetry (TG) and permeability to CO2. Cast films were obtained and the gas barrier properties imparted by the clay were analyzed as well as the influence of poly (ethylene glycol) segments content. The insertion of clay imparted an improvement in thermal resistance properties and a decrease in membrane permeability. It was also observed an increase in permeability to CO2 of membranes obtained from formulations containing the higher amount of copolymer (EG-b-PG), independent of clay content.

En France, le système de stockage profond de déchets radioactifs envisagé est constitué d’une barrière naturelle (roche hôte argileuse, argilite) et de barrières artificielles, comprenant des bouchons d’argile gonflante (bentonite)-sable pour son scellement. L'objectif de cette thèse est d’étudier l’efficacité du gonflement et du scellement des bouchons placés dans l’argilite, sous l’effet, à la fois, d’une pression d’eau et d’une pression de gaz (tel que formé dans le tunnel). Pour évaluer la capacité de scellement du bouchon bentonite/sable partiellement saturé en eau, on a évalué sa perméabilité au gaz Kgaz sous pression de confinement variable (jusqu’à 12MPa). L'étanchéité au gaz (Kgaz < 10-20m2) est obtenue sous confinement Pc≥9MPa si la saturation est d’au moins 86-91%. Par ailleurs, nous avons évalué le gonflement et l'étanchéité du bouchon de bentonite-sable imbibé d’eau dans un tube d’argilite ou de Plexiglas-aluminium lisse ou rugueux. La présence de gaz diminue la pression effective de gonflement (et la pression de percée de gaz) à partir d’une pression Pgaz= 4 MPa. Après saturation complète en eau, l’écoulement continu de gaz au travers du bouchon seul se fait à Pgaz=7-8MPa s’il dispose d’une interface lisse avec un autre matériau (tube métallique), alors que celui au travers de l’ensemble bouchon/argilite a lieu à Pgaz=7-7,5MPa. Le passage à travers le bouchon gonflé au contact d’une interface rugueuse se fait à une pression de gaz bien supérieure à la pression de gonflement du bouchon. Les essais de percée de gaz montrent que l'interface et l'argilite sont deux voies possibles de migration de gaz lorsque l’ensemble bouchon/roche hôte est complètement saturé / In France, the deep underground nuclear waste repository consists of a natural barrier (in an argillaceous rock named argillite), associated to artificial barriers, including plugs of swelling clay (bentonite)-sand for tunnel sealing purposes. The main objective of this thesis is to assess the sealing efficiency of the bentonite-sand plug in contact with argillite, in presence of both water and gas pressures. To assess the sealing ability of partially water-saturated bentonite/sand plugs, their gas permeability is measured under varying confining pressure (up to 12MPa). It is observed that tightness to gas is achieved under confinement greater than 9MPafor saturation levels of at least 86-91%. We than assess the sealing efficiency of the bentonite-sand plug placed in a tube of argillite or of Plexiglas-aluminium (with a smooth or a rough interface). The presence of pressurized gas affects the effective swelling pressure at values Pgas from 4MPa. Continuous gas breakthrough of fully water-saturated bentonite-sand plugs is obtained for gas pressures on the order of full swelling pressure (7-8MPa), whenever the plug is applied along a smooth interface. Whenever a rough interface is used in contact with the bentonite-sand plug, a gas pressure significantly greater than its swelling pressure is needed for gas to pass continuously. Gas breakthrough tests show that the interface between plug/argillite or the argillite itself are two preferential pathways for gas migration, when the assembly is fully saturated

Les réservoirs dits « tight gas » sont constitués de grès de faible perméabilité ayant des propriétés petro-physiques susceptibles de nuire à la productivité du gisement. Une importante zone de transition est observée in situ dans laquelle ni l’eau ni le gaz ne sont suffisamment mobiles pour permettre une extraction industrielle : c’est ce que l’on appellera le « permeability jail ». Cette étude vise principalement à caractériser l’influence du chargement mécanique (via l’utilisation de différentes pressions de confinement) et de la nature des roches (roches provenant de différents puits et prélevées à différentes profondeurs) sur les courbes de perméabilité relative au gaz et les caractéristiques poro-mécaniques de ces roches. La porosité accessible à l’eau mesurée est de 2 à 12%. La perméabilité intrinsèque au gaz a mis en évidence de fortes disparités sans lien avec la porosité des échantillons. Une grande sensibilité de la perméabilité relative au confinement a été observée dès l’application de pressions de confinement de 15 à 30 MPa. Deux familles d’échantillons ont ainsi été identifiées. Les échantillons les plus perméables (perméabilité compris entre 100 – 1000 μD), sont peu sensibles au confinement et leur perméabilité relative ne chute qu’à partir de saturations de l’ordre de 50%. Les échantillons les moins perméables apparaissent beaucoup plus sensibles à la fois au confinement et à la saturation.Des méthodes classiquement utilisées dans le domaine pétrolier reposant sur l’interprétation d’essais de porosimétrie par intrusion mercure, ont également été mise en œuvre pour évaluer les perméabilités relatives et les comparer aux mesures expérimentales / So-called tight gas reservoirs are constituted of low permeability sandstones, which petro-physical properties may interfere with proper gas recovery. They have a low absolute permeability (below 0.1 mD under ambient conditions), a porosity lower than 10%, and a strong sensitivity to in situ stresses as compared to conventional reservoirs. Moreover, an important transition zone is observed in situ, where partial water saturation is present, and which may extend over several hundred meters over the free water table. In such zone, where water saturation is on the order of 40-50%, neither gas nor water seems sufficiently mobile for industrial extraction: this is the permeability jail. Our aim is to assess their actual petro-physical properties, namely porosity, gas permeability under varying hydrostatic stress and water saturation level, in relation with sandstone microstructure. Accessible water porosity measured is between 2 to 12%. The intrinsic permeability to gas did not appeared related to the porosity of samples. A high sensitivity of gas permeability to confinement was observed. Two families of samples were identified. The more permeable samples (permeability between 100-1000 μD), are relatively insensitive to confinement and their relative permeability decrease for water saturation higher than 50%. Less permeable samples appear much more sensitive to mechanical loading and saturation.Methods classically used in oil and gas industry based on the interpretation of mercury intrusion porosimetry tests have also been used to evaluate relative permeability and compared with experimental measurements

Abstract The main objectives of this thesis are to synthesize macroscopic well-aligned multi-walled carbon nanotube films and, based on their electrical conductivity, porosity and structural uniformity, highlight potential applications for further development. In this thesis, catalytic chemical vapour deposition from ferrocene-xylene precursors is optimized to grow high quality films of long, aligned multi-walled carbon nanotubes on lithographically patterned templates in high (~800ºC) temperatures. The impacts of reaction time, temperature and precursor concentration on MWCNT film quality (film thickness, purity, density and nanotube diameter distribution) are studied. Because of the excellent control of growth selectivity and film thickness inherent to the method, several interesting applications, including solar cell and capacitor electrodes, contact brushes, coolers, particulate filters and catalyst membranes, have been developed for nanotube films in collaboration between Finnish and international research groups over the past few years. In this thesis, advanced capacitor electrodes with improved charge storage and efficient particulate filters are discussed in closer detail. As the high temperatures used for growing high quality carbon nanotubes often cause complications in cases where nanotubes need to be directly integrated with other materials, experiments were also conducted with the aim of making the growth temperature as low as possible. After testing several catalyst and precursor combinations, cobalt nanoparticles deposited on silica surfaces were found to form carbon nanotubes from vaporized cyclopentene oxide precursor already at 470°C. The results show that catalytic chemical vapour deposition is a feasible and versatile method that can be combined with photolithography to produce multi-walled carbon nanotube films with desired footprint area and thickness on various substrates. The demonstrated new applications and technical solutions are expected to contribute to further development leading to competitive practical devices based on carbon nanotubes. / Tiivistelmä Tämän väitöstyön päätavoitteina ovat makroskooppisten, yhdensuuntaisista moniseinämäisistä hiilinanoputkista koostuvien kalvojen valmistaminen ja sovellutusten esittäminen perustuen kalvojen sähkönjohtavuuteen, huokoisuuten ja rakenteelliseen yhdenmukaisuuteen. Katalyyttis-kemiallinen höyryfaasikasvatusmenetelmä on optimoitu korkealaatuisten, yhdensuuntaisista, pitkistä moniseinämäisistä hiilinanoputkista koostuvien kalvojen tuottamiseen korkeissa lämpötiloissa (~800ºC) fotolitografialla kuvioiduille kasvualustoille käyttäen ferroseeni/ksyleeni-lähtöainetta. Reaktioajan, lämpötilan ja lähtöainepitoisuuden vaikutusta nanoputkikalvon laatuun on tutkittu tarkastelemalla kalvon paksuutta, puhtautta, tiheyttä ja nanoputkien läpimittajakaumaa. Erinomaisen kasvuselektiivisyyden ja kalvon paksuuden kontrolloimisen ansiosta nanoputkikalvoja voidaan räätälöidä useisiin mielenkiintoisiin sovellutuksiin (esim. aurinkokennot ja kondensaattorin elektrodit, hiiliharjat, jäähdyttimet, partikkelisuodattimet ja katalyyttikalvot), joita olemme kehittäneet viime vuosina yhdessä suomalaisten ja kansainvälisten tutkimusryhmien kanssa. Tässä väitöstyössä on tarkasteltu lähemmin uudentyyppisiä kondensaattorielektrodeja, joilla on parantunut sähkövarauksen varastointikyky, sekä tehokkaita partikkelisuodattimia. Hiilinanoputkien kasvattaminen korkeissa lämpötiloissa aiheuttaa usein ongelmia integroitaessa nanoputkia toisiin materiaaleihin. Tästä johtuen tutkimuksessa pyrittiin saamaan nanoputkien kasvatuslämpötila mahdollisimman alhaiseksi testaamalla useita lähtöaine-katalyytti-kombinaatioita, joista koboltti-nanopartikkelit piidioksidin päällä ja syklopenteenioksidi lähtöaineena muodostivat hiilinanoputkia jo 470°C:ssa. Tulosten perusteella katalyyttis-kemiallinen höyryfaasikasvatusmenetelmä yhdistettynä fotolitografiaan on hyvin monipuolinen tapa tuottaa moniseinämäisiä hiilinanoputkia halutulla kuviolla ja kalvonpaksuudella erilaisille substraateille. Tässä väitöstyössä demonstroitujen uusien sovellutusten ja teknisten ratkaisujen odotetaan johtavan uusiin, hiilinanoputkiin perustuviin kilpailukykyisiin käytännön laitteisiin.

In den durchgeführten Versuchsreihen wurden die Wasserabsorption sowie die Gas- und Wasserpermeabilität sowohl an gerissenen als auch rissfreien Prüfkörpern aus textilbewehrtem Beton (TRC) untersucht. Eine deutliche Steigerung der Wasseraufnahme bei Proben mit unbeschichteten Textilien konnte mit Zunahme der Garnfeinheit beobachtet werden. Bei den gerissenen Proben besteht eine ausgeprägte Abhängigkeit der Transportraten von Flüssigkeiten und Gasen zu den relevanten Risscharakteristika (kumulative Risslänge, Rissbreite). Weiterhin sind Selbstheilungseffekte von feinen Rissen infolge einer zyklischen Wasserbeaufschlagung beobachtet worden. Hierbei kam es zu einer deutlichen Reduzierung der Transportraten sowohl für Wasser als auch für Gase. Eine speziell entwickelte Permeabilitätsmesskammer zur Durchführung von In- Situ-Messungen ermöglicht Untersuchungen zum Stofftransport unter axialer Zugbelastung bei verschiedenen Dehnungszuständen.

Cette thèse se concentre sur la préparation et l'étude des composites élastomères chargés avec des particules lamellaires et des liquides ioniques. Ces composites sont caractérisés par des propriétés mécaniques améliorées, une diminution du gonflement par les solvants, une faible perméabilité aux gaz ainsi que par une amélioration de la conductivité ionique. Les propriétés de structure et de surface différentes des charges lamellaires, telles que le rapport d'aspect des particules, la surface spécifique et l'activité de surface ont été analysées comme les facteurs impactant le renforcement du caoutchouc nitrile (NBR) et du caoutchouc nitrile carboxylé (XNBR). Une attention particulière a été portée aux systèmes XNBR contenant des hydroxydes doubles lamellaires (MgAI-HDL), qui varient en fonction du rapport Mg / Al et de morphologie de particules. L'application simultanée de MgAI-HDL en tant que charge et en tant qu'agent de réticulation dans XNBR ne fournit pas uniquement un produit écologique sans oxyde de zinc mais également un composite élastomère ionique avec de meilleures propriétés mécaniques, de barrière et de transparence. Cette thèse considère également les applications potentielles des liquides ioniques en tant qu'additifs multifonctionnels dans les composites élastomères afin d'obtenir une bonne dispersion des charges minérales dans une matrice polymère ainsi qu'une amélioration de la conductivité ionique des matériaux composites. La concentration optimale et le type de liquides ioniques ont été sélectionnés pour obtenir un bon compromis entre les propriétés mécaniques et la conductivité des matériaux composites de caoutchouc / This thesis focused on the preparation and the study of elastomer composites filled with layered fillers with improved mechanical properties, decreased swelling in solvents, increased UV stability and reduced gas permeability. The layered minerals were investigated not only in terms of their use as reinforcing fillers for rubbers but also as crosslinking agents, gas barrier and UV stability enhancers. The layered fillers tested belong to a class of cationic clays (natural and synthetic hectorite), anionic clays (hydrotalcites or magnesium aluminum layered double hydroxides MgAI-LDHs) and graphene-based materials. Different structural and surface properties of layered fillers were investigated as factors impacting the reinforcement of acrylonitrile-butadiene rubber (NBR) and carboxylated acrylonitrile-butadiene rubber (XNBR). Special attention has been devoted to the XNBR systems containing MgAI-LDHs varying in Mg / AI ratios, layers aspect ratios and particles morphologies. It was reported that the simultaneous application of MgAI-LDH as a filler and as a crosslinking agent in XNBR provides not only environmentally friendly, zinc-oxide free product but also ionic elastomer composite with improved mechanical, barrier and transparent properties. This thesis considers also the potential application of imidazolium ionic liquids as dispersing agents in rubber matrix, plasticizers and ionic conductivity enhancers. The optimal concentration and type of ionic liquids were selected for obtaining a good compromise between mechanical and conductivity properties of rubber composites