Mesenchymale Stammzellen (MSC) werden bereits in klinischen Studien zur Behandlung verschiedener Krankheiten eingesetzt. Über deren Wirkmechanismus und Verbleib nach Applikation ist jedoch noch wenig bekannt. Die in vivo-Nachverfolgung markierter MSC mittels Magnetresonanztomographie stellt eine mögliche Methode zur Erlangung weiterer Erkenntnisse dar. Zu diesem Zweck können die MSC mittels superparamagnetischen Eisenoxid (SPIO)-Partikeln markiert werden. In dieser Arbeit wurden 3 verschiedene SPIO-Produkte zur Markierung oviner und equiner MSC verwendet: Endorem™, Resovist® und Molday ION Rhodamine B™. Die Produkte wurden hinsichtlich ihrer Einflüsse auf die biologischen Eigenschaften der MSC, ihrer Markierungseffizienz und –selektivität verglichen. Desweiteren wurde die produktspezifische magnetresonanztomographische Nachverfolgbarkeit der SPIO-markierten MSC untersucht. Weiterführendes Ziel war die Selektion des am besten geeigneten SPIO-Produktes für die Verwendung in einem in vivo-Großtierversuch zur magnetresonanztomographischen Nachverfolgung SPIO-markierter MSC nach Applikation in arthrotische Gelenke. Die MSC wurden dazu aus dem Knochenmark von je 5 gesunden Schafen und Pferden isoliert, bis zur Passage 4 (P4) expandiert und schließlich mit den verschiedenen SPIO-Produkten markiert. Unmarkierte MSC der gleichen Tiere dienten zur Kontrolle. Proliferationsvermögen sowie tripotentes Differenzierungspotential wurden in vitro untersucht. Zur Evaluierung von Markierungsselektivität und -effizienz der SPIO-Produkte wurden die MSC ab der P4 bis zur P7 wöchentlich passagiert. Ein semiquantitatives histologisches Auswertungssystem basierend auf der Preußisch Blau-Färbung sowie T2*w-GRE-Sequenzen an einem 0,5T-MRT-System wurden zur Evaluierung genutzt. Markierungsselektivität bezeichnete die intra- oder extrazelluläre Lokalisation der SPIO-Partikel. Markierungseffizienz beschrieb die Menge intrazellulär vorhandener SPIO-Partikel. Es wurde gezeigt, dass sich ovine und equine MSC mit allen 3 untersuchten SPIO-Produkten erfolgreich markieren ließen. Die Ergebnisse der in vitro-Untersuchungen ergaben keine Unterschiede zwischen SPIO-markierten und unmarkierten MSC hinsichtlich des Proliferationsvermögens, der adipogenen oder osteogenen Differenzierungsfähigkeit. Jedoch wurde eine deutliche Verminderung des chondrogenen Differenzierungspotentials SPIO-markierter MSC beobachtet, welche von der Menge intrazellulär vorhandener SPIO-Partikel und somit von der Markierungseffizienz abhängig war. Zum Zeitpunkt der initialen Markierung konnte nur Molday ION Rhodamine B™ eine selektive und effiziente Zellmarkierung gewährleisten. Mit Endorem™ konnte eine selektive, jedoch keine ausreichend effiziente Zellmarkierung erreicht werden. Resovist® dagegen bewirkte zwar eine effiziente, aber sehr unselektive initiale Zellmarkierung: Mittels Preußisch Blau-Färbung wurde gezeigt, dass große Mengen von SPIO-Partikeln nur extrazellulär anhefteten. Die 3 verschiedenen SPIO-Produkte führten weiterhin zu unterschiedlich starken hypointensen MRT-Signalen der markierten MSC, welche im Verlauf der 3-wöchigen Versuchsdauer bei allen 3 Produkten stetig abnahmen. Unmarkierte MSC waren isointens, also mittels MRT nicht darstellbar und daher nicht nachverfolgbar. Stets verursachten Resovist®-markierte MSC das stärkste hypointense MRT-Signal, gefolgt von Molday ION Rhodamine B™ und Endorem™. Resovist®-markierte MSC konnten mittels MRT bei beiden Spezies über den längsten Zeitraum nachverfolgt werden (ovine MSC bis 16 Tage, equine MSC bis 23 Tage nach Markierung). Aufgrund der exzellenten initialen Markierungseigenschaften (hohe Markierungsselektivität und –effizienz sowie gute Nachverfolgbarkeit) eignet sich Molday ION Rhodamine B™ besonders gut für die SPIO-Markierung von MSC zur Nachverfolgung mittels MRT. Molday ION Rhodamine B™ verspricht somit eine erfolgreiche Anwendung in einem in vivo-Versuch zur magnetresonsztomographischen Nachverfolgung von MSC nach Applikation in arthrotische Gelenke. / Mesenchymal stem cells (MSC) are already used in clinical studies for treatment of different diseases. However, their mechanism of action and fate after application are still not fully understood. In vivo tracking of labeled MSC via magnetic resonance imaging (MRI) is a possible method to achive further knowledge. For this purpose MSC can be labelled with superparamagnetic iron oxide (SPIO) particles. For this study 3 different SPIO products were employed for labelling of ovine and equine MSC: Endorem™, Resovist®,, and Molday ION Rhodamine B™. The products were compared in terms of their influence on biologic behaviour of the MSC, their labelling efficiency, and selectivity. Furthermore, product specific magnetic resonance traceability of SPIO labelled MSC was evaluated. Final aim was the selection of the most suitable SPIO product to be used in an in vivo large animal study employing MRI tracking of SPIO labelled MSC after application into osteoarthritic joints. MSC therefore, were isolated from bone marrow of each 5 healthy sheep and horses, expanded up to passage 4 (p4), and labelled by the different SPIO products. Unlabelled MSC from the same animals served as control. Proliferation potential and tripotent differentiation capacities were assessed in vitro. For evaluation of labelling selectivity and efficiency of the SPIO products MSC were passaged weekly from p4 up to p7. Semiquantitative histological scoring based on Prussian blue staining and images using T2*w GRE sequences in a 0.5T MRI system were used. Labelling selectivity describes the intra- or extracellular localisation of the SPIO particles. Labelling efficiency describes the amount of intracellular SPIO particles. It was shown that ovine and equine MSC could be successfully labelled by all 3 evaluated SPIO products. The results of the in vitro experiments did not show differences between labelled and unlabelled MSC in terms of proliferation potential, adipogenic or osteogenic differentiation capacities. However, an inhibited chondrogenic differentiation capacity of SPIO labelled MSC was observed, which was dependend on the amount of intracellular SPIO particles and therefore, also on labelling efficiency. At the time of initial labelling, only Molday ION Rhodamine B™ showed selective and efficient cell labelling. With Endorem™ selective, but not efficient cell labelling was achieved. Resovist®, in contrast, caused efficient but very unselective initial cell labelling: By Prussian blue staining it was shown that large amounts of SPIO particles were attached extracellularly. These 3 different SPIO products led to variable hypointense MRI signals of the labelled MSC which decreased in all 3 products during the 3 week study period. Unlabelled MSC were isointense, thus not visible, and therefore, not traceable using MRI. At every point of time, Resovist® labelled MSC resulted in the most hypointense MR signals, followed by Molday ION Rhodamine B™ and Endorem™. Resovist® labelled MSC were traced over the longest time span (ovine MSC until 16 days, equine MSC until 23 days post labelling). Due to excellent initial labelling properties (high labelling efficiency and selectivity, good traceability) Molday ION Rhodamine B™ suits best for SPIO labelling of MSC to be tracked by MRI. Molday ION Rhodamine B™ therefore, promises a successful use in an in vivo study using MRI for MSC tracking after application into osteoarthritic joints.

There is a demand for new straightforward approaches for stabilization and solubilization of various nanoparticulate materials in their colloidal form, that pave way for fabrication of materials possessing compatibility with wide range of dispersing media. Therefore in this thesis a new general method to form stable nanocrystals in water and organics using amphiphilic polymers generated through simple and low cost techniques is presented and discussed. Amphiphilic coating agents are formed using thiolated or carboxylated polyethylene glycol methyl ether (mPEG-SH) as a starting material. These materials are available with a wide variety of chain lengths. The method of obtaining of amphiphilic NPs is quite general and applicable for semiconductor CdTe nanocrystals as well as nanoscale noble metal (Au) and magnetic (Fe3O4) particles. This approach is based on anchoring PEG segment to the surface of a nanoparticle to form an amphiphilic palisade. Anchoring is realized via interaction of –SH (for CdTe and Au) or –COOH (in the case of magnetite) functional groups with particle’s surface. The resulting amphiphilicity of the nanocrystals is an inherent property of their surface and it is preserved also after careful washing out of solution of any excess of the ligand. The nanocrystals reversibly transfer between different phases spontaneously, i.e. without any adjustment of ionic strength, pH or composition of the phases. Such reversible and spontaneous phase transfer of nanocrystals between solvents of different chemical nature has a great potential for many applications as it constitutes a large degree of control of nanocrystals compatibility with technological processes or with bio-environments such as water, various buffers and cell media as well as their assembly and self-assembly capabilities.

This work details the synthesis and growth mechanisms of 1D magnetic and semiconducting nanostructures. Specifically, magnetic iron oxide and ZnS-SiO2 nanowires are examined. These materials are chosen due to their promise for biomedical and electronic applications and the perceived need to both create these structures as tools for these applications and to understand their formation processes so that they can be manufactured at a scale and efficiency suitable for commercialization. The current state and impact of nanotechnology is discussed through the lens of continuing technological advances and environmental factors, and the term is defined according to a specific set of criterion involving size, utility, and uniqueness. Details of synthesis and characterization of Fe3O4, ε-Fe2O3, and ZnS-SiO2 core-shell nanowires are presented. Observations regarding the growth of these structures are paired with additional experiments, simple simulations, and other literature to discuss the classical VLS growth process in general, and its applicability to these structures in particular. Finally, some exciting future applications are discussed, with details for initial experimental work presented in the appendix.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-18T15:52:41Z No. of bitstreams: 1 THIBÉRIO MUNDIM FERREIRA PIRES - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2711001 bytes, checksum: 1f8649d213d5e99a5e386e92ea63aa59 (MD5) / Made available in DSpace on 2018-04-18T15:52:41Z (GMT). No. of bitstreams: 1 THIBÉRIO MUNDIM FERREIRA PIRES - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2711001 bytes, checksum: 1f8649d213d5e99a5e386e92ea63aa59 (MD5) Previous issue date: 2014-07-18 / Agentes de contraste são materiais de grande relevância para a qualidade das imagens obtidas por ressonância magnética, acentuando o contraste das imagens e facilitando o diagnóstico de patologias. As nanopartículas têm sido bastante utilizadas como agentes de contraste para ressonância magnética, sendo que as mais utilizadas são as nanopartículas de óxido de ferro. A segurança e toxicidade das nanopartículas tem sido objeto de uma preocupação cada vez maior, pois o conhecimento sobre os efeitos biológicos de materiais deste tipo ainda não é suficiente. As propriedades das nanopartículas, por sua vez, dependem do tamanho, microestrutura e revestimento da superfície, controlados pelas condições de síntese e processamento das nanopartículas. O objetivo deste trabalho foi obter óxido de ferro pelo Método Pechini, para utilização como agentes de contraste para uso em ressonância magnética, de modo a caracterizá-los. Nanopartículas de óxido de ferro foram sintetizadas pelo Método Pechini, com razão entre o ácido cítrico em relação aos cátions metálicos de 3:1, sendo posteriormente calcinadas em temperaturas de 400ºC e 900ºC, pelos períodos de 1h ou 2h. Logo após foram caracterizadas por Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva de Raios-X (EDS), Difração de Raios X - (DRX), Análise de Calorimetria Exploratória Diferencial (DSC), Termogravimetria (TG) e Espectroscopia de Infravermelho com Transformada de Fourier (FTIR). Também foi realizado Ensaio de Citotoxicidade – Viabilidade Celular. Os resultados de DRX revelaram a formação da fase hematita e presença de segunda fase magnetita. A morfologia é constituída de aglomerados de aspecto rígido com partículas de formato irregular, com tamanho menor e maior que 10 µm. A temperatura de calcinação de 400ºC não foi suficiente para se obter nanopartículas de óxido de ferro estáveis termicamente. Os pós obtidos pelo Método Pechini não apresentaram viabilidade celular. / Contrast agents are materials of great relevance to the quality of the images obtained by magnetic resonance imaging, accentuating the contrast of images and facilitating the diagnosis of pathologies. Nanoparticles have been widely used as contrast agents for magnetic resonance imaging, and the most used are nanoparticles of iron oxide. The safety and toxicity of nanoparticles has been the subject of increasing concern, because knowledge about the biological effects of such materials is not enough. The properties of the nanoparticles, in turn, depend on the size, microstructure and surface coating, all of them controlled by the conditions of synthesis and processing of nanoparticles. The aim of this study was to obtain iron oxide by Pechini method, for use as contrast agents in diagnostic magnetic resonance imaging, in order to characterize them. Iron oxide nanoparticles were synthesized by Pechini method with ratio of citric acid to metal cations in relation 3:1, subsequently calcined at temperatures of 400 º C and 900 º C, for periods of 1h or 2h. Soon after were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy Xray (EDS), X-Ray Diffraction - (XRD), Differential Scanning Calorimetry analysis (DSC) , Thermogravimetry (TG), and Fourier Transform Infrared Spectroscopy (FTIR). Was also performed Cytotoxicity Assay - Cell Viability. The XRD showed the formation of phase of hematite and presence of second phase of magnetite. The morphology consists of rigid aspect of agglomerates with particles of irregular shape and with a smaller size greater than 10 µm. The calcination temperature of 400 ° C was not sufficient to obtain iron oxide nanoparticles thermally stable. The powders obtained by the Pechini method showed no cell viability.

Le graphite est le matériau d’électrode négative utilisé actuellement dans les batteries lithium-ion commerciales. Celui-ci souffre malheureusement d’une capacité spécifique relativement faible (372 mAh.g-1) ; son remplacement par un matériau de conversion comme l’oxyde ZnFe2O4, de capacité théorique plus élevée (1001 mAh.g-1) permettrait d’augmenter la capacité de stockage des batteries lithium-ion. Travailler avec des nanoparticules de ZnFe2O4 permettrait également de limiter l’expansion volumique à laquelle est soumis le matériau en cours de cyclage tout en améliorant la cinétique des ions lithium. Des nanopoudres ZnFe2O4 ont été synthétisées au Laboratoire Edifices Nanométriques (LEDNA) du CEA par la méthode de pyrolyse laser. Cette méthode de synthèse flexible a permis d’obtenir des nanopoudres d’oxydes zinc-fer de morphologies différentes grâce à l’ajustement de différents paramètres expérimentaux (précurseurs utilisés, choix et débit des gaz). Les performances électrochimiques de ces nanomatériaux ont été évaluées en demi-cellule face à une contre-électrode de lithium métallique. Des cyclages galvanostatiques à différentes vitesses ont été réalisés à l’Université Technologique de Nanyang (NTU) à Singapour. Les mécanismes fondamentaux régissant le stockage du lithium dans l’oxyde ZnFe2O4 mais aussi dans un mélange ZnO/Fe2O3 ont été étudiés par le biais de caractérisations operando (DRX, 57Fe Mössbauer), en collaboration avec l’Institut Charles Gerhardt de l’université de Montpellier (ICGM). Ces travaux de thèse ont permis de mettre en évidence les performances électrochimiques prometteuses d’une morphologie spécifique de ZnFe2O4 consistant en une population de taille bimodale de particules, ainsi que d’identifier les réactions de lithiation et de délithiation lors des cyclages. / Graphite is currently used as negative electrode material in commercial lithium-ion batteries. Unfortunately, this material suffers from a relatively low specific capacity (372 mAh.g-1). Its substitution by a conversion material with a higher specific capacity as ZnFe2O4 (1001 mAh.g-1) would be interesting to increase the capacity of lithium-ion batteries.The use of nanomaterials can also limit the volumetric expansion of the electrode during cycling and enhance lithium ions kinetics.ZnFe2O4 nanopowders were synthesized in the Nanometric Structures Laboratory at the CEA (Atomic Energy and Alternative Energies Commission) by laser pyrolysis. This flexible synthesis method allowed the production of zinc iron oxides nanopowders with different morphologies, depending on the chosen experimental parameters (precursors, choice of gases and flow rates). Electrochemical performances were then evaluated vs. metallic lithium at the Energy Lab of Nanyang Technological University. Fundamental lithium storage mechanisms for ZnFe2O4 oxide were investigated by operando characterizations (XRD and 57Fe Mössbauer) and compared with those of a ZnO/Fe2O3 mixture. This study was realized in collaboration with the Charles Gerhardt Institute (University of Montpellier).This works highlighted the promising electrochemical performances of a specific morphology of ZnFe2O4 nanoparticles, consisting in a bimodal size population of particles, and allowed the deeper understanding of the lithiation and delithiation reactions.

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

Bien que de nombreux progrès aient été réalisés dans le traitement du cancer, de nouvelles approches sont nécessaires afin de minimiser les effets secondaires délétères et d’augmenter le taux de survie des patients. Aujourd’hui de nombreux espoirs reposent sur l’utilisation de nanoparticules (NPs) d’oxyde de fer fonctionnalisées permettant de combiner, en un seul nano-objet, le diagnostic (agent de contraste en IRM) et la thérapie par hyperthermie magnétique (i.e. « theranostic »). Dans ce contexte, la stratégie développée est la synthèse de NPs à propriétés magnétiques optimisées par le contrôle de leurs taille, forme et composition, leur biofonctionnalisation et la validation de leurs propriétés théranostiques. Une démarche d’ingénierie des NPs a été mise en place allant de la synthèse du précurseur de fer et de l’étude fine de sa décomposition en passant par l’étude in situ de la formation des NPs jusqu'à leur fonctionnalisation et la détermination de leurs propriétés theranostiques. / Despite numerous advances in cancer treatment, new approaches are necessary in order to minimize the deleterious side effects and to increase patient’s survivals rate. Nowadays, many hopes rely on functionalized iron oxide nanoparticles (NPs) that combine, in a single nano-objects, diagnosis (MRI contrast agent) and magnetic hyperthermia therapy (i.e. “theranostic”). In this context, the strategy is to develop the synthesis of optimized magnetic properties NPs through the control of their size, shape, composition, biofunctionalization and the validation of their theranostic properties. A process of NPs engineering has been developed starting at the iron precursor synthesis and the fine study of its decomposition passing through the in situ formation of the NPs to their functionalization and the determination of their theranostic properties.

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No. of bitstreams: 1 TeseJVMZ.pdf: 2731888 bytes, checksum: a756e69d141b297fb91ca74654baab0d (MD5) Previous issue date: 2015-04-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / In recent decades, several studies have been conducted on the generation of materials at the nanoscale, not only by offering possible risks when inhaled, but also by the various applications that can be employed. Among the various equipment used for the generation of particles, atomizers generators have proved efficient and economical. Although many studies have used materials in solution, in which the material is dissolved in the solvent, generation of particles, it has been observed growing interest in the study of suspended nanometric materials, in which there is dispersion in the solvent. In addition, this growing interest in the suspended study materials is due to the need to generate solid aerosols from oxides, since they have high added value and important to be recaptured and intended back into production. Given the presented work aimed to disperse nanoparticles from suspensions, evaluating the time of the generation process over a period of 10 hours, for different equipment. The nanoparticles were generated by atomization of nickel and iron oxides suspensions at different concentrations and the atomization process were used three generator, a generator from TSI, model 3079, a commercial inhaler of the brand NS, model I-205 and a fluidized bed generator, model 3400. The size distribution and concentration of particles was determined by a Scanning Mobility Particle Sizer (SMPS), Model 3936 and a Aerodynamic Particle Sizer (APS), Model 3320, both from TSI, being sampled directly from the aerosol. The results relating to the dispersion of nanoparticles from the suspension of nickel and iron oxide proved effective in 10 hour period. However, TSI generator showed a dispersion of particles with a more uniform distribution, whereas the commercial inhaler dispersed a greater number of particles per cm3. In addition, the collection of particles by APS, there was the generation of micrometric particles, since the particles are already being generated aglomeradamente, which was observed in SEM and TEM images. / Nas últimas décadas, diversos estudos têm sido realizados sobre a geração de materiais na escala nanométrica, não só pelos possíveis riscos que oferecem quando inalados, mas também pelas diversas aplicações que podem ser empregados. Dentre os diversos equipamentos utilizados para a geração de partículas, os geradores atomizadores têm-se demonstrado eficientes e econômicos. Embora muitos trabalhos têm utilizado materiais em solução, na qual o material fica dissolvido no solvente, na geração de partículas, tem-se observado o crescente interesse de estudos sobre materiais nanométricos suspensos, nas quais não se dissolvem no solvente, mas sim se dispersão no meio. Em adição, este crescente interesse no estudo de materiais em suspensão é decorrente da necessidade de se gerar aerossóis sólidos provenientes de óxidos, uma vez que apresentam alto valor agregado, sendo importante ser recapturados e destinados de volta à produção. Diante do apresentado, o trabalho visou dispersar nanopartículas provenientes de suspensões, avaliando o tempo do processo de geração ao longo de um período de 10 horas, por diferentes equipamentos. As nanopartículas foram geradas através da atomização de suspensões de óxido de níquel e ferro em diferentes concentrações e no processo de atomização foram utilizados três geradores, um gerador da TSI, modelo 3079, um inalador comercial da marca NS, modelo I-205 e um gerador de leito fluidizado, modelo 3400. A distribuição de tamanho e concentração das partículas foram determinadas por meio de um Analisador de Partículas por Mobilidade Elétrica (SMPS), modelo 3936 e pelo Contador de Partículas (APS), modelo 3320, ambos da TSI, sendo a amostragem feita diretamente do aerossol. Os resultados referentes à dispersão das nanopartículas provenientes das suspensões de óxido de níquel e de ferro mostraram eficientes no período de 10 horas. No entanto, o gerador da TSI apresentou uma dispersão de partículas com uma distribuição mais uniforme, enquanto que o inalador comercial dispersou um maior número de partículas por cm3. Em adição, na coleta de partículas pelo APS, teve-se a geração de partículas micrométricas, uma vez que as partículas já estavam sendo geradas aglomeradamente, fato que foi observado nas imagens de MEV e MET.

Made available in DSpace on 2016-12-08T17:19:18Z (GMT). No. of bitstreams: 1 Thais de Jesus Schmitt.pdf: 2052116 bytes, checksum: d868f1a9aaf1f2eadf918c40531c8101 (MD5) Previous issue date: 2012-06-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Recently, the traditional ceramics industry has developed great interest in obtaining pigments which may have firing temperature stable, so that the action of molten glass does not interfere with the final product. In the coating industry, whose selection is strongly influenced by the visual appearance of the decorated surface, the color is an important feature. In order to search for new pigments that replace or optimize the old, new synthetic methods has being studied, as well as new systems and the incorporation of pigments alternative raw materials. Thus, this work studied the possibility of use of industrial byproducts, rich in iron, in the synthesis of pigments encapsulated in glassy matrix. The by product from the surface treatment of sheet metal was evaluated and characterized by chemical composition, crystalline phases and morphology of particles. The residue was added to the glassy matrix, homogenized using conventional milling and calcined at temperatures of 700 ° C to 900 ° C for 15 minutes. The characterization of the pigments obtained were performed using XRD and SEM. The pigments were used in ceramic and enamel porcelain paste and observed by optical microscopy and SEM. The results showed that color development becomes effective when the pigment is incorporated into porcelain paste, because it is a less aggressive. Was concluded that the developed color is influenced by oxide content employed, milling conditions and the processing temperature. The results showed that the use of the pigment developed does not interfere in the microstructural characteristics of pigmented material. / Recentemente, na indústria cerâmica tradicional, tem havido um interesse crescente na obtenção da inclusão de pigmentos na qual a temperatura de queima seja estável de tal forma que ação dos vidros fundidos não interfiram no produto final. No setor de revestimento, cuja seleção é fortemente influenciada pelo aspecto visual da superfície decorada, a cor passa a ser uma importante característica. Com o intuito de buscar novos pigmentos que substituam ou otimizem os já conhecidos, novos métodos de síntese estão sendo pesquisados, bem como novos sistemas pigmentantes e a incorporação de matérias primas alternativas. Desta forma, no presente trabalho, procurou-se estudar a possibilidade de aproveitamento de subprodutos industriais, ricos em ferro, na síntese de pigmentos encapsulados em matriz de vidro. O subproduto que é proveniente, do processo de tratamento superficial de chapas metálicas foi avaliado. O subproduto foi caracterizado quanto a sua composição química, fases cristalinas presentes e morfologia das partículas. O resíduo foi adicionado à matriz vítrea, sendo posteriormente homogeneizados, utilizando moagem convencional e seguidos de calcinação nas temperaturas de 700°C até 900°C por 15 minutos. As caracterizações dos pigmentos obtidos foram realizadas através de difratometria de raios X e microscopia eletrônica de varredura. Os pigmentos foram aplicados em esmalte cerâmico e em massa porcelânica. Posteriormente, foram realizadas análises de microscopia ótica e eletrônica de varredura. Os resultados evidenciaram que o desenvolvimento da cor torna-se efetivo quando o pigmento é incorporado em massa porcelânica, por se tratar de um meio menos agressivo. A coloração desenvolvida é influenciada por variáveis como o teor de óxido empregado, condições de moagem e temperatura de processamento. Os resultados mostraram ainda que a utilização do pigmento desenvolvido não interfere nas características microestruturais do material pigmentado.