Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-12T18:36:46Z No. of bitstreams: 1 rafaelcarvalhaesmachado.pdf: 15330554 bytes, checksum: b28797a7ed7a97cc333b801efe362c9b (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:30:09Z (GMT) No. of bitstreams: 1 rafaelcarvalhaesmachado.pdf: 15330554 bytes, checksum: b28797a7ed7a97cc333b801efe362c9b (MD5) / Made available in DSpace on 2016-04-24T03:30:09Z (GMT). No. of bitstreams: 1 rafaelcarvalhaesmachado.pdf: 15330554 bytes, checksum: b28797a7ed7a97cc333b801efe362c9b (MD5) Previous issue date: 2016-01-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A presente tese, intitulada "Síntese, caracterização e avaliações biológicas de 4-piridinil, 7-cloro-4-quinolinil e 9-acridinil, semicarbazidas e tiossemicarbazidas" descreve a preparação, caracterização e avaliação do potencial biológico de compostos sintéticos híbridos contendo uma porção heterocíclica (núcleo piridínico, quinolínico ou acridínico) associada a uma subunidade tiossemicarbazida ou semicarbazida N-4 substituída. Os compostos almejados foram preparados por duas rotas sintéticas distintas: 1) via reação de substituição nucleofílica aromática entre os derivados halo-heterocíclicos (4-cloropiridina, 4,7-dicloroquinolina e 9-cloroacridina) e as tiossemicarbazidas e semicarbazidas N-4 substituídas e 2) via reação de adição dos derivados heterocíclicos de hidrazina (4-hidrazinopiridina, 7-cloro-4-hidrazinoquinolina e 9-hidrazinoacridina) aos isotiocianatos e isocianatos. As estruturas químicas dos produtos obtidos, bem como as dos intermediários sintéticos, foram caracterizadas por faixa de fusão, espectroscopia no infravermelho, de ressonância magnética nuclear de hidrogênio e de carbono-13 e por espectrometria de massas. Os compostos sintetizados foram avaliados como potenciais agentes antibacterianos (S. aureus, E. coli, P. aeruginosa e S. typhimurium), antituberculares (M. tuberculosis) e antitumorais. Enquanto alguns dos compostos avaliados apresentaram atividade antibacteriana promissora, nenhum dos compostos sintéticos pode ser considerado candidato a agente anti-TB. Em relação a atividade antitumoral, a maioria dos compostos avaliados exibiu elevada citotoxicidade. / The present thesis, entitled “Synthesis, characterization and biological evaluation of 4-pyridinyl, 7-chloro-4-quinolinyl, 9-acridinyl, semicarbazides and thiossemicarbazides”, describes the preparation, characterization and evaluation of the biological potential of synthetic hybrid compounds containing a heterocyclic moiety (pyridine, quinoline or acridine ring) associated with an N-4 substituted semicarbazide or thiosemicarbazide subunit. The desired compounds were prepared by two different synthetic routes: 1) via nucleophilic aromatic substitution reaction between the halo-heterocyclic derivatives (4-chloropyridine, 4,7-dichloroquinoline and 9-chloroacridine) and N-4 substituted thiosemicarbazides and semicarbazides and 2) via addition reaction of the heterocyclic hydrazine derivatives (4-hydrazinopyridine, 7-chloro-4-hydrazinoquinoline and 9-hydrazinoacridine) to isothiocyanates and isocyanates. The chemical structures of the products obtained, as well as synthetic intermediates, were characterized by their melting points, infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopies and by mass spectrometry. The compounds synthesized were evaluated as potential antibacterial (S. aureus, E. coli, P. aeruginosa e S. typhimurium), antituberculosis (M. tuberculosis) and antitumor agents. While some of the evaluated compounds showed promising antibacterial activity, none of the compounds synthesized may be considered a candidate as an anti-TB agent. With respect to antitumor activity, the majority of the evaluated compounds exhibited high cytotoxicity.

The Organization for Economic Cooperation and Development (OECD) under Base Erosion and Profit Shifting (BEPS) Action 2 indicated that tax arbitrage via hybrid mismatch arrangements "result in a substantial erosion of the taxable bases of the countries concerned" and "have an overall negative impact on competition, efficiency, transparency and fairness." The relevant action allowing for neutralising the effects of hybrid mismatch arrangements is therefore needed and justified. To achieve that purpose, the OECD developed different anti-hybrid rules under BEPS Action 2. In that regard, however, one may ask whether addressing tax arbitrage via hybrid mismatches as proposed by the OECD is of interest and relevance for developing countries. This paper aims to map that unexplored research area by means of a comparative analysis in four developing countries - Uruguay, Colombia, Brazil, and South Africa. / Series: WU International Taxation Research Paper Series

Les études de la relation entre les humains et les animaux prennent petit à petit leur place en anthropologie. Depuis plusieurs points d’observation, l’anthropologie interprète et explique les relations établies entre les humains et les animaux au fil de l’histoire. Petit à petit ces études s’engagent à observer les animaux plus proches de nous et plus communs, comme les animaux domestiques (Dalla Bernardina, 2006). Nous essaierons dans cette étude de comprendre comment cet animal domestique interagit socialement et ce qu’il signifie dans un contexte social indigène. Mon objectif est d’ethnographier cette relation entre sujets humains et canins, dont la coexistence et l’histoire font sens. En ce qui concerne les Indiens et les animaux, l’anthropologie nous présente plusieurs travaux, Erikson (1988 ; 1998 ; 2000, 2012), Descola (1986 ; 2005), Viveiros de Castro (1998, 2002 ; 2009), Vander Velden (2009 ; 2011, 2012), Kohler (2011, 2012), qui me serviront de base pour entamer cette recherche. En partant du principe que les êtres humains maintiennent une relation objective et subjective avec les animaux je prétends mener une ethnographie des liens entre les Pitaguary et leurs chiens. J’utiliserai le concept de « communauté hybride » du philosophe Dominique Lestel (1996, 2001, 2004, 2007, 2013) pour définir une société où la relation de collaboration entre humains et animaux se superpose à celle d’autorité. Il s’agit de mettre en lumière les liens interspécifiques au centre des rapports sociaux, où tant l’humain que l’animal ont statut de sujet. Pour mener cette étude, l’immersion dans les terres Pitaguary et l’observation participante de la relation entre ce peuple et ses chiens a été la méthodologie appliquée. Nous évoquons d’abord l’histoire des Pitaguary dans le contexte de la « renaissance » des Indiens du Nordeste, puis la place des animaux, et des chiens en particulier, dans leurs mythes, rituels et pratiques (chasse, soins) et l’interprétation subjective des comportements canins par les Pitaguary eux-mêmes. Nous nous centrons enfin sur les chiens, dans leur quotidien, dans leur histoire de vie, et dans leur relation sociale avec les humains. / The study of the relations between humans and animals gradually increases in importance in anthropology. Originating from different approaches, the anthropological studies have sought to interpret the relations established between human and animals in historical senses. Researches have more and more concentrated efforts on the observation of the closest and more common animals (Dalla Bernardina, 2006), such as the domestic species. This research will seek to understand how the domestic animal interacts with human, Erickson (1988 ; 1998 ; 2000, 2012), Descola (1986 ; 2005), Viveiros de Castro (1998, 2002 ; 2009), Vander Velden (2009 ; 2011, 2012), Kohler (2011, 2012), beings in a native (Indian) community, analyzing the day-to-day life of the Pitaguary tribe in the State of Ceará, Brazil, with their pet dogs. The goal is an ethnographic study of the relation among human and canine individuals, whose long story of coexistence has led to the creation of a special bond among many of those. Starting from the general idea that humans keep objective and subjective relations with animals, the proposal is an anthropological research based on the ethnography of the relations between the Pitaguary and their pet dogs, based on the concept of a “hybrid society”, such as the defined by the philosopher Dominique Lestel (1996, 2001, 2004, 2007, 2013) in order to define a society in which the relation of collaboration between men and animals overcomes the dominative relation (understood as determining on the process of domesticization/familiarization). It comes down to seek to understand the interespecific connections on the community life, in which both the humans as much as the animals have a leading role. Intensive field research on the Pitaguary landings to assess the relation between this people and their pet dogs (along with other wild animals, domestic e familiarized) will be the methodology to be employed. It must be pointed out the history of the Pitaguary in the context of the “reemergence” of the Indians in Northeastern Brazil, next the importance of their pet animals and dogs, especially on mythical, rites and daily habits (such as hunting and cures) just as the subjective interpretation of the canine behavior by the own Pitaguary. We’ll focus at last on the pet dogs on day-to-day matters, their life stories, and within their social relations with humans. / O estudo das relações entre humanos e animais ganha paulatinamente espaço na Antropologia. Partindo de diferentes abordagens teóricas e metodológicas, os estudos antropológicos têm buscado interpretar as relações estabelecidas entre animais humanos e não humanos etnográfica e historicamente. Cada vez mais as investigações empenham-se na observação de animais, mais próximos e comuns (Dalla Bernardina, 2006), como as espécies domésticas ou domesticadas. A pesquisa aqui proposta tenta compreender como o animal doméstico interage socialmente com seres humanos em uma população indígena, Erikson (1988 ; 1998 ; 2000, 2012), Descola (1986 ; 2005), Viveiros de Castro (1998, 2002 ; 2009), Vander Velden (2009 ; 2011, 2012), Kohler (2011, 2012). O objetivo foi etnografar a relação entre sujeitos humanos e caninos, cuja longa história de convivência levou à criação de um nexo especial entre uns e outros. Partindo do princípio de que os seres humanos mantêm relações objetivas e subjetivas com os animais, fiz esta pesquisa antropológica baseada na etnografia das relações entre os Pitaguary e seus cachorros, a partir do conceito de “sociedade híbrida”, tal como definido pelo filósofo Dominique Lestel (1996, 2001, 2004, 2007, 2013) para definir uma sociedade em que a relação de colaboração entre homens e animais se sobrepõe à relação de dominação (entendida como determinante no processo de domesticação/familiarização). Trata-se de buscar compreender os laços interespecíficos no seio do convívio social, no qual tanto o humano quanto o animal ocupam o estatuto de sujeito. Pesquisa de campo intensiva nas terras Pitaguary para a observação da relação entre esse povo e seus cães (além de outros animais selvagens, domésticos e familiarizados) foi a metodologia aplicada. Evocamos primeiramente a história dos Pitaguary no contexto do « ressurgimento » dos índios do Nordeste, em seguida o lugar dos animais e dos cães, em particular nos mitos, rituais e práticas (caça, curas) assim como a interpretação subjetiva dos comportamentos caninos pelos próprios Pitaguary. Nos centraremos finalmente sobre os cachorros no quotidiano, suas histórias de vida, e dentro de suas relações sociais com os humanos.

This thesis explores the working lives of British Born South Asian Ethnic Minorities (BB SAEMs), critiquing the homogenous identities ascribed to them in previous research. Its methodology is life-story interviews analysed using Nvivo. This identified four hybrid categories emerging from two cultures. I fitted myself neatly into just one. However the reflexive analysis required in good qualitative research led me to realise that I fitted into not one, but all four categories, and into others not yet recognised. At this point, my thesis had to take a new turn. An auto-ethnographic, moment-by-moment study led to an ‘unhybrid categorisation of hybridities’ acknowledging ‘fuzziness and mélange, cut ‘n’ mix, and criss and crossover’ where identity is a complex-mix, always in flux. I conclude not only with this new theory of identity formation in the working lives of BB SAEMs, but also by arguing that by imposing the requirement to categorise, research methods lead to over-simplification and misunderstanding.

Cette thèse vise à développer des nanoparticules de PLGA pour la vectorisation et à étudier l’interaction de ces nanoparticules avec des bicouches phospholipidiques imitant les membranes cellulaires. Pour la vectorisation passive, les changements physico-chimiques ont été contrôlés en incubant les NPs de PLGA (50:50) dans différentes conditions de pH tamponné à des intervalles de temps accrus. Le PLGA a montré plusieurs comportements de dégradation différant selon le pH. La formation de pores a été observée à pH élevé (conditions basiques) tout en préservant le volume des particules mais en modifiant la densité. Par opposition, à faible pH, une érosion superficielle des particules conduisant à une diminution de leur taille a été démontrée. Cette étude a été réalisée à l'aide de la DLS, l’ESEM et la spectrophotométrie. Pour la vectorisation active, les parois des capsules de PLGA (75:25) ont été modifiées par addition de phospholipides. La libération de la sonde fluorescente hydrophile, la calcéine, a été contrôlée en augmentant la température. On a observé qu'avec le DOPC (0,31 mM), la vectorisation peut être déclenchée à l'aide de détergents ou d'une enzyme (PLA2). Dans le cadre de cette étude, nous avons proposé la formation d'un complexe lipide-polymère ayant lieu à l'intérieur de la matrice, ce qui le rend vulnérable aux enzymes ou détergents induisant sa libération. L'effet des NPs de PLGA sur les bicouches phospholipidiques imitant la membrane cellulaire a été réalisé à l'aide de sondes fluorescentes moléculaires (Prodan et Laurdan). L'étude a été effectuée en calculant la polarisation généralisée (GP) sous l'influence des NPs de PLGA (50:50 et 75:25). L'interaction ayant lieu s’avérait être un phénomène de surface et aucune effet des NPs sur la perméabilité des membranes modèles LUVs et SUVs n’a été souligné. La valeur de Tm des phospholipides est également maintenue lorsque l’étude est menée avec le Laurdan. Les études de GP mené avec la sonde Prodan fournissent la première méthode originale pour déterminer la Tg de PLGA dans des conditions aqueuses. C'est une méthode rapide et facile qui détermine la valeur de Tg de PLGA en temps réel et en utilisant une très petite quantité de l'échantillon. Cette interaction n'est pas affectée par la composition des membranes cellulaires imitant les bicouches. / This thesis aims at developing PLGA nanoparticles for controlled release and investigating its interaction with phospholipid bilayers mimicking cell membranes. For passive controlled release the physiochemical changes were monitored by incubating the PLGA (50:50) NPs in different buffered pH conditions at increased time intervals. PLGA exhibited dissimilar degradation behavior with pore formation for high pH (basic conditions) maintaining the volume of the particles but change in the density, while at low pH it showed surface erosion. There is decrease in the particle size upon incubating in low pH. This study was carried out using DLS, ESEM and spectrophotometry. For active release the walls of PLGA (75:25) capsules were modulated using phospholipids. The release of hydrophilic fluorescent probe Calcein was monitored with increasing the temperature. It was observed that with DOPC (0.31mM) the release can be triggered using detergents or an enzyme (PLA2). We propose the formation of a lipid-polymer complex within the polymer matrix forming plugs which are vulnerable to enzymes/detergents inducing release. The effect of PLGA NPs over the phospholipid bilayers mimicking cell membrane was carried out using molecular fluorescent probes (Prodan and Laurdan). The study was carried out by calculating the generalised polarisation (GP) under the influence of PLGA NPs (50:50 and 75:25). It is found that the interaction is a surface phenomenon and there is no influence of NPs over the permeability of model membranes LUVs and SUVs. The Tm value of the phospholipids is also maintained when studied with Laurdan. Prodan probe GP studies provide first original method to determine the Tg of PLGA in complete aqueous conditions. It is a rapid and easy method which determines the Tg value of PLGA in real time using very small quantity of the sample. This interaction is not affected by the composition of the bilayer mimicking cell membranes.

La maintenance de la méthylation ADN sur les sites CG joue un rôle crucial dans le silencing des éléments transposables (TE) et l’expression correcte des gènes. Chez Arabidopsis thaliana, on observe, dans le mutant met1-3 déficient en méthylation CG, une apparition ectopique de méthylation CHG sur de nombreux gènes, ainsi qu’une relocalisation de la diméthylation de la lysine 9 de l’histone H3 (H3K9me2) de l’hétérochromatine vers l’euchromatine. Nous avons démontré que ceci est lié à un défaut de transcription au niveau du grand intron du gène codant la déméthylase H3K9me2 IBM1. Nous avons également constaté que dans les épihybrides F1 issus du croisement de plantes met1-3 avec une plante sauvage la méthylation CHG présente dans l’intron de l’allèle IBM1 hérité du parent mutant était perdue. Afin de définir si la perte de méthylation affecte également d’autres loci génomiques, et plus globalement à l’échelle du génome entier l’impact de la rencontre de deux épigénomes différents, nous avons analysé les profils de méthylation, de siRNAs et de transcription des épihybrides F1. Nos données révèlent que l’union de deux méthylomes distincts au sein d’un même génome provoque une restructuration considérable des profils épigénétiques et transcriptionnels. La méthylation CHG apparaissant sur de nombreux gènes dans met1 tend à persister, créant ainsi de nouveaux épiallèles pouvant être hérités. Du côté des TE, nombre d’entre eux sont déméthylés et réactivés, tandis que d’autres sont immédiatement reméthylés et resilencés. Ainsi, ces résultats contribuent à la compréhension de la stabilité de la méthylation ADN et de son rôle dans le contrôle différentiel des gènes et des TE. / Maintenance of DNA methylation at CG sites is crucial for silencing of transposable element (TE) and proper expression of genes. In Arabidopsis thaliana, met1-3 mutant, deficient in CG methylation, shows ectopic appearance of CHG methylation at numerous genes, as well as relocation of H3K9me2, from heterochromatin towards euchromatin. We have shown that this is due to a defect of the transcription of the large intron of the gene encoding the IBM1 H3K9me2 demethylase. We also found that, in the F1 epihybrids from the cross between met1 and WT plants, CHG methylation at the intron of the met1-derived IBM1 allele is lost. In order to define whether the loss of methylation at IBM1 also affects other genomic loci, and the impact of the union of two different epigenomes on methylation and transcription genome-wide, we analyzed the methylation, siRNA and transcription patterns of F1 epihybrids. Our data reveal that the union of two distinct methylomes within the same genome triggers considerable restructuring of epigenetic and transcriptional patterns. CHG methylation appearing in the mutant parent tends to persist in F1, creating new epialleles that can be inherited. On the TE side, lots of them are demethylated and reactivated while others are immediately remethylated and resilenced. Thus, our results provide new insights to the understanding of DNA methylation stability and its role in the differential control of genes and TEs.

Dans les générateurs de vapeurs (GV), les tubes du circuit primaire sont sujets aux chocs et aux forces de couplage auto-excitatrices nommées forces fluides élastiques.Il est crucial, lors du dimensionnement des GV, de maîtriser la dynamique de ces tubes, ainsi que d'estimer au mieux les efforts mécaniques auxquels ils sont soumis.En effet, cela permet aux ingénieurs d'optimiser la durée de vie des installations et d’augmenter le rendement des centrales électriques.Le but de la présente thèse est de trouver une technique d'essai hybride, basée sur le contrôle actif des vibrations, pour reproduire la contribution modale des forces de couplage sur un tube. En effet, les expériences en milieu réel, dans les conditions que l'on trouve dans les GV, sont hors de prix et très difficiles à reproduire. Dans ces travaux de recherche, une structure de test interagit avec un modèle numérique, qui modélise le fluide, à travers un système de contrôle actif en temps réel. Dans un premier temps les efforts mécaniques appliqués sur le tube sont caractérisés, puis un système de contrôle, constitué de transducteurs et de la carte de contrôle, est conçu pour générer les forces de couplage sur le tube, en prenant en considération les non-linéarités dues aux impacts. / In steam generators, the primary loop tubes are subjected to fluid-elastic couplingforces and impacts. Understanding the dynamic of these tubes is crucial when designingsteam generators. Mastering coupling and impacts forces would allow engineers toimprove the design of structure components and would optimize the tube lifetime, whileimproving the overall performances of power plant.The aim of the current research is to provide a hybrid test technique reproducingthe modal coupling forces on a tube, since experiments on fluid are expensive anddifficult to set up. In this work, the experimental structure interacts with a numericalmodel (which models the fluid-elastic coupling forces) via a real time controller and aset of transducers. First, we characterize the coupling and impact forces, and then, anactive vibration control approach is set up to reproduce the modal contribution of fluidelasticforces on the tube, taking in consideration the non-linearities due to the impacts.

Farmer-led seed systems (FSS) provide the backbone for small-scale farmers and many rural communities that use traditional methods of farming to produce seeds that grow and adapt to local conditions. FSS differ from one community and farmer to the next, depending on the methods and practices used to maintain seed varieties. Seed diversity can enhance FSS by improving livelihoods and strengthening farmers' networks, thus contributing to resilient communities. Although nuanced, the dualistic agricultural system in South Africa consists largely of subsistence (small-scale) and commercial (large-scale) farming and includes different crop management systems and post-harvest practices. In South Africa, maize (Zea mays) is a major staple grain crop with a significant role as animal and poultry feed. The North West region is one of the highest white-maize-producing provinces in South Africa. Maize seed systems include both traditional, openpollinated varieties (OPVs) and cultivars such as modern hybrids and genetically modified (GM) seed varieties, including those engineered for specific purposes. The dominant GM maize is that designated for pest resistance using Bacillus thuringienesis (Bt), a soil bacterium which produces a toxin that is fatal to a wide variety of insects such as moths and flies. Many small-scale farmers prefer their own traditional seeds for breeding, planting, selection, selling and consuming. However, FSS based on traditional varieties are threatened by modern cultivars which may be introduced in different ways including through seed exchange, purchasing at shops or by pollination from nearby commercial farms. This study was conducted in the Sespond community of the North West Province. The aim of the study was to understand how small-scale farmers in Sespond maintain traditional maize varieties through selection and storage in a complex agricultural landscape that incorporates both formal and informal seed systems. The formal system represents industrialised farms and companies that work with commercial seed. The informal system represents small-scale farmers who rely on their own seed. Qualitative methods included mapping software which was used to obtain visual agricultural data in and around Sespond. Semi-structured interviews were conducted with 30 small-scale farmers to collect information about their farming practices, including the maize varieties planted. Quantitative methods included collecting 20 maize samples from different farmers for genetic analysis. Agdia® immunostrip tests were used to detect for the presence of Crystal protein (Cry protein) produced by the Bt bacterium, engineered to improve the resistance of maize against insects. The results showed that 13 samples were negative for the protein and seven samples were positive for the protein. A key finding is that small-scale farmers are not able to detect the different maize varieties in their seed systems. This represents a threat for traditional seed varieties in the community as without this knowledge, farmers are not able to adequately manage their production and storage systems. Farmers made use of alternative storage methods such as the mill to reduce seed damage they experienced at home. However, the findings of this research showed that there was an increasing risk of farmers' traditional maize being mixed with GM maize at the mill. Farmers' rights to plant and consume traditional maize were therefore undermined. This study recommends that (a) efforts are made to increase awareness among farmers that help to distinguish transgenes from hybrids and traditional maize varieties; (b) measures are implemented at mills to both improve the transparency about the storage and processing of traditional maize and to separate traditional maize from hybrid and GM maize.

Ces travaux de thèse portent sur la synthèse de particules hybrides à partir de pigments inorganiques pour la formulation d’encres électrophorétiques colorées. Les pigments doivent répondre à un cahier des charges spécifique à ce type d’application. Ils doivent avoir une taille sub-micronique, une faible densité et un haut indice de réfraction afin d’exalter les phénomènes de diffusion. Les pigments bleus et cyan de structure spinelle CoAl2O4 et NiAl2O4 ont été synthétisés par voie Pechini. Dans les deux cas, des phénomènes de démixtion influençant la couleur ont été observés. Cependant, de par la différence de rayon ionique entre le Co2+ et le Ni2+ (rCo2+ < rNi2+), les origines en sont différentes. Dans le premier cas il a fallu éliminer les ions Co3+ stabilisés en site [6] pour obtenir une phase pure où la majorité des ions cobalt occupent les sites [4]. Dans le second cas l’ajout d’ions Al3+ a été nécessaire pour stabiliser une phase spinelle pure en présence de lacunes cationiques et d’ions Ni2+ occupant partiellement les sites [4] et [6]. Ensuite, nous avons développé des pigments magenta et jaunes de structure olivine explorant la solution solide LiCoxNi1-xPO4. Dans ces composés, l’étude des transitions électroniques corrélées à la structure et à l’environnement des ions chromophores Ni2+ et Co2+ en site [6] a permis de montrer des champs cristallins proches et un effet néphélauxétique presque identique. Finalement l’analyse de l’état de valence du chrome dans les structures de type rutile SnxCr1-xO2 a permis de synthétiser des pigments violets. Dans un second temps, la surface des pigments a été modifiée avec des chaines silanes de type n-trimethoxysilane afin de favoriser la dispersion des pigments dans un milieu apolaire. Puis les pigments modifiés ont été polymérisés dans l’Isopar G par polymérisation radicalaire contrôlée par les nitroxydes avec du méthacrylate de méthyle afin de diminuer la densité globale des particules hybrides et ainsi obtenir des encres stables. L’étude de l’influence des conditions expérimentales a été effectuée sur chaque pigment afin de formuler des encres colorées et chargées sans ajout de contrôleur de charge. La réalisation d’un dispositif électrophorétique à deux couleurs bleu et blanc a finalement pu être développé. / This work deals with the hybrid particles synthesis, using inorganic pigment for the coloured electrophoretic inks formulation. To comply with this type of application, pigments must have a sub-micrometer size, a low density and a high refractive index in order to exalt the diffusion phenomena. Blue and cyan spinel structure pigments CoAl2O4 and NiAl2O4 have been synthesized by Pechini process. In both these oxides, steric and electronic effects allowed stabilizing pure phases with enhanced colouring effects. In the case of CoAl2O4, we have to avoid the occurrence of Co3+ (LS) whereas for NiAl2O4, excess of Al3+ is necessary to get pure phases with nanosized crystallites. Then, magenta and yellow olivine structure pigments have been developed with the exploration of the solid solution LiCoxNi1-xPO4. In these compounds, the study of the electronic transitions combined with Ni2+ and Co2+ chromophores ions structure and environment in [6] site leads to comparable crystal field and so an almost similar nephelauxetic effect for both ions. Finally, the investigation of the valence state and the environment of chromium in rutile type structure Sn1-xCrxO2 allowed the synthesis of purple pigments. In a second part, the pigment surface has been modified with n-trimethoxysilane chains to improve the pigment dispersion in apolar media. Then, modified pigments have been polymerised in Isopar-G by nitroxyde mediated radical polymerisation with methyl methacrylate to decrease the hybrids density and to obtain stable inks. The impact of the experimental conditions has been studied on each pigments in order to formulate coloured and charged inks without any charge control agent. A two-colour electrophoretic device (blue/white) has been finally tested.

Nowadays, polymer-metal hybrids are covering a broad range of advanced applications, especially in the automotive or aerospace industries where high performance and lightweight components are highly demanded. Hybrid parts may offer additional functionality regarding strength, durability, impact and wear resistance without sacrificing size or weight of the full component. However, there are still challenges regarding improving the adhesion between dissimilar materials such as metals to polymers and its composites. There is a lack of research about the influence of a post heat treatment on adhesion and durability in polymer-metal hybrids manufactured through an overmolding processing chain. There is also a need for using adhesive promoters that may offer simultaneous corrosion protection to metallic substrates in order to extend the lifecycle of the part when subjected to diverse harsh environments. In this work, two organic coatings used as adhesive promoters on steel substrates were investigated: the first one is a polyester-based powder-coat adhesive developed in the Leibniz-Institute in Dresden. The second one is a high performance anti-corrosive electrophoretic paint that has never been reported in the literature as an intermediate adhesive layer in a thermoplastic-polyurethane (TPU) overmolding processing chain. A TPU was overmolded on both pre-coated steel substrates, and the adhesion of the polymer to the metal substrate was investigated after a heat treatment (annealing), and a subsequent hygrothermal aging at different temperature-humidity conditions. The influence of the annealing process on the adhesion and durability of the multilayered specimen was investigated in depth; similarly, failure modes and lifetimes were evaluated after the hygrothermal aging. Lifetime predictions calculated from kinetic parameters for solid decomposition -obtained from thermogravimetric analysis- were validated experimentally with polyurethane-steel hybrids commonly used as district heat pipes. Adhesion of TPU on the steel substrate using both organic coatings as adhesive promoters was successful due to the contribution of new physical-chemical and mechanical interactions at the polymer-coating interface, especially after annealing at 100 °C for 20 h. Additionally, heat treated hybrids exhibited a much better performance because of the apparent increased in the anchoring density at the polymer-metal interfaces. It is conclusive that progressive failure of the multilayered specimen is strongly dependent on water diffusion rather than thermolysis of any of the components, as it was detected by FTIR, and observed in the micrographs on the artificially-aged hybrid surfaces. Finally, accelerated aging was used to correlate lifetime predictions throughout the analysis of the kinetics of degradation using TGA experiments and mechanical tests. The calculated values of the activation energy evidence that durability of the polyurethane-based polymers is affected by temperature and humidity at the conditions described in this work. Lifecycle is directly related to kinetic parameters, and especially to the activation energy, EA. This kinetic parameter for pre-aged specimens, and particularly for those subjected to higher temperature conditions, were lower when compared to the fresh polymer; as it was demonstrated that TGA analysis is a primary tool to predict lifetime for thermoplastic and thermosetting polyurethanes.