Orientador: José Fernando Durigan / Banca: Ben-Hur Mattiuz / Banca: Mário Sérgio Carvalho Dias / Resumo: Este trabalho objetivou testar o uso de tratamento químico combinado ou não com tratamento hidrotérmico, na conservação e qualidade pós-colheita de mangas 'Tommy Atkins' e 'Palmer', bem como avaliar o efeito da modificação da atmosfera de armazenamento por filmes plásticos e cera de carnaúba no prolongamento da vida útil pós-colheita de mangas 'Palmer'. Utilizou-se mangas provenientes de pomar comercial de Taquaritinga-SP, safra 2006/2007, que foram colhidas no estádio de maturação "de vez" e imediatamente transportados para o laboratório de Tecnologia dos Produtos Agrícolas da FCAV, Jaboticabal, onde foram selecionadas, visando padronizá-las quanto a coloração, tamanho e ausência de injúrias. Na primeira fase os frutos foram submetidos a tratamento com os fungicidas Sporekill® (cloreto de dodecil dimetil amônio a 12%) e Magnate 500 EC® (imazalil a 50%), associados ou não com tratamento hidrotérmico a 53°C/5 min ('Tommy Atkins') e 53°C/10 min ('Palmer'). Após secagem, eles foram armazenados sob condição de ambiente (23°C, 65% UR), e eram analisados a cada três ('Palmer') ou quatro dias ('Tommy Atkins'), quanto a ocorrência de podridões, aparência, perda de massa e firmeza, assim como quanto ao pH e teores de sólidos solúveis, acidez titulável e ácido ascórbico da polpa. Na segunda fase, o melhor tratamento para a manga 'Palmer' foi combinado com diferentes proteções e armazenamento sob condição ambiente (23°C, 65% UR) ou refrigerada (12°C, 65% UR). Os frutos armazenados sob refrigeração, após 28 dias foram levados ao ambiente, para avaliação da evolução do amadurecimento, aos 3 e 6 dias. Utilizou-se os seguintes tratamentos: Testemunha (sem tratamento); Testemunha com tratamento fitossanitário; Filme de polietileno de baixa densidade (PEBD), com espessura de 0,050mm; Polifilme multicamada; ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work was undertaken to test the use of chemical control in combination or not with hydrothermal treatment on the preservation and post harvest quality of 'Tommy Atkins' and 'Palmer' mangoes. Also, we evaluated the effect of modifying the storage atmosphere by the use of plastic film and carnauba wax on the shelf life of 'Palmer' fruits. Mangoes from a commercial orchard in Taquaritinga-SP were harvested in the season 2006/2007 at the breaker ripening stage, immediately transported to the laboratory of Technology of Agricultural Products, FCAV, Jaboticabal, and selected by color, size and absence of injuries. In the first stage, fruit were treated with the fungicides Sporekill® (12% dodecyl dimethyl ammonium) and Magnate 500 EC® (50% imazalil), associated or not with hydrothermal treatment at 53°C for 5 min ('Tommy Atkins') and 53°C for 10 min ('Palmer'). After drying, fruits were stored at room temperature (23°C, 65% RH), and analyzed every three ('Palmer') or four days ('Tommy Atkins') for the occurrence of rots, appearance, weight loss and firmness, as well as pH and the levels of soluble solids, titable acidity and ascorbic acid in the pulp. In the second phase, the best treatment for 'Palmer' mangoes was combined with different protections and storage at room conditions (23°C, 65% RH) or refrigerated (12°C, 65% RH). Fruits stored with refrigeration were transferred to room conditions after 28 days for ripening evaluations 3 and 6 days later. The following treatments were used: untreated control, fungicide-treated control, low-density polyethylene film (0.050mm), multilayer polyfilm, polyvinyl chloride (PVC) film (0.017mm), and 18% carnauba wax. In the first stage, fruits from the cultivars Palmer and Tommy Atkins submitted to different treatments showed no wilting symptoms until the sixth and eighth day, respectively ...(Complete abstract / Mestre

Made available in DSpace on 2014-12-17T14:57:52Z (GMT). No. of bitstreams: 1 JeanCSA.pdf: 2642121 bytes, checksum: ee65334424753f93878bcb16392de432 (MD5) Previous issue date: 2009-03-24 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The types of products manufactured calcium silicate blocks are very diversified in its characteristics. They include accessory bricks, blocks, products in dense material, with or without reinforcements of hardware, great units in cellular material, and thermal insulating products. The elements calcium silicate are of great use in the prefabricated construction, being formed for dense masses and hardened by autoclaving. This work has for objective develop formulations that make possible the obtaining of calcium silicate blocks with characteristics that correspond the specifications technical, in the State of the Rio Grande of the North, in finality of obtaining technical viability for use in the civil construction. The work studied the availability raw materials from convenient for the production of calcium silicate blocks, and the effect of variations of the productive process on the developed products. The studied raw materials were: the quartz sand from the city of S?o Gon?alo do Amarante/RN, and two lime, a hydrated lime and a pure lime from the city of Governador Dix-Sept Rosado/RN. The raw materials collected were submitted a testes to particle size distribution, fluorescence of X rays, diffraction of X rays. Then were produced 8 formulations and made body-of-test by uniaxial pressing at 36 MPa, and cured for 7 hours at about 18 kgf/cm2 pressing and temperature of approximately 180 ?C. The cure technological properties evaluated were: lineal shrinkage, apparent density, apparent porosity, water absorption, modulus of rupture flexural (3 points), resistance compression, phase analysis (XRD) and micromorphological analysis (SEM). From the results presented the technological properties, was possible say that utilization of hydrated lime becomes more viable its utilization in mass limestone silica, for manufacture of calcium silicate blocks / Os tipos de produtos s?lico-calc?rios fabricados s?o muito diversificados em suas caracter?sticas. Eles incluem tijolos, blocos, produtos acess?rios em material denso, com ou sem refor?os de ferragem, grandes unidades em material celular, e produtos isolantes t?rmicos. Os elementos s?lico-calc?rios s?o de grande utiliza??o na constru??o pr?-fabricada, sendo formados por massas densas e endurecidos em autoclave. Este trabalho teve como objetivo desenvolver formula??es que possibilitem a obten??o de blocos s?lico-calc?rios com caracter?sticas que correspondem ?s especifica??es t?cnicas, no Estado do Rio Grande do Norte, na finalidade de obter viabilidade t?cnica para uso na constru??o civil. O trabalho estudou a disponibilidade de mat?rias-primas convenientes para a produ??o de blocos s?lico-calc?rios, e o efeito das varia??es do processo produtivo sobre os produtos desenvolvidos. As mat?rias-primas estudadas foram: uma areia quartzosa oriunda do munic?pio de S?o Gon?alo do Amarante/RN, e duas cal, uma cal hidratada e uma cal virgem oriundas do munic?pio de Governador Dix-Sept Rosado/RN. As mat?rias-primas coletadas foram submetidas a ensaios de distribui??o de tamanho de part?cula, fluoresc?ncia de raios X, difra??o de raios X. Em seguida foram produzidas 8 formula??es e confeccionados corpos-de-prova por prensagem uniaxial a 36 MPa, e curados durante 7 horas em press?o de aproximadamente 18 kgf/cm2, e temperatura de aproximadamente 180?C. As propriedades tecnol?gicas de cura avaliadas foram: retra??o linear, massa espec?fica aparente, porosidade aparente, absor??o de ?gua, m?dulo de ruptura ? flex?o em 3 pontos, resist?ncia a compress?o, an?lise fases (DRX) e an?lise micromorfol?gica (MEV). A partir dos resultados apresentados das propriedades tecnol?gicas, foi poss?vel afirmar que a utiliza??o da cal hidratada torna-se mais vi?vel sua utiliza??o em massas s?lico-calc?rias, para fabrica??o de blocos s?lico-calc?rios

Estruturas de sílica mesoporosa cúbica em forma de gaiola (originalmente identificadas como FDU-1) altamente ordenadas, estáveis térmica e hidrotermicamente, com tamanhos de poros da ordem de 12 nm, foram sintetizadas a partir de TEOS e como molde utilizou-se o copolímero tribloco poli(óxido de etileno)-poli(óxido de butileno)-poli(óxido de etileno) 850-6600 (EO39BO47EO39), em meio ácido. Foi desenvolvido um procedimento de síntese, empregando um forno de microondas no tratamento hidrotérmico para obtenção da sílica FDU-1. Após tratamento hidrotérmico, as amostras foram calcinadas a 540°C, em duas etapas, empregando atmosferas de N2 e ar. Os materiais foram caracterizados por análise elementar, FTIR, TG, SAXS e Isotermas de adsorção de N2 a 77 K. Os dados de SAXS, associados aos das Isotermas de adsorção de N2, demonstraram que os materiais obtidos com 45 e 60 min de exposição a microondas, apresentaram propriedades texturais compatíveis com aquelas do material obtido pelo método convencional. Os ensaios de termogravimetria evidenciam a faixa de temperatura em que ocorrem as decomposições térmicas do copolímero no material como sintetizado e conduziram a uma otimização das melhores condições para calcinação. As curvas TG/DTG indicaram que no aquecimento dos materiais até 1200ºC, há a transformação completa dos grupos silanóis em siloxanos a partir da eliminação de água. Esse fato é confirmado a partir dos espectros de absorção na região do IV e possibilitou estimar que a quantidade dos grupos Si-OH na superfície do material varia com o tempo de tratamento hidrotérmico na etapa de síntese. / Highly ordered, thermally and hidrotermally stable, with large pore size of 12 nm, caged-like cubic mesoporous silica structures (originally denoted FDU-1) were synthesized from TEOS and poly(ethylene oxide)-poly(butylene oxide)poly(ethylene oxide) B50-6600 triblock copolymer template (EO39BO47EO39) under acidic conditions.The synthesis procedure was developed using microwave oven for hydrothermal treatment to obtain FDU-1 silica. After hydrothermal treatment, the samples were calcined to 540 ºC, in two stages, using N2 and air atmospheres. The materials characterized by elementary analysis, FTIR, TG, DRX and nitrogen adsorption isothermal at 77 K. The data association of SAXS and the nitrogen adsorption isothermal demonstrated that the material isolated with 45 and 60 minutes of the exposition to the microwaves in the hydrothermal treatment showed testure properties compatible to that one of material obtained by the conventional method. Thermogravimetric experiments evidenced the temperature range where occur copolymer thermal decomposition according to the synthesis, as synthesized materials. This information was important to optimize the material calcination conditions. The TG/DTG curves indicated that, in the material heated up to 1200 ºC, occurs complete transformation of silanol in to siloxane groups with water elimination. This fact is confirmed through the IR spectra and enabled to calculate the quantity of the Si-OH groups in the material surface which vary hydrothermal treatment time in the syntesis stage.

Orientadora: Profa. Dra. Marcia Tsuyama Escote / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, Santo André, 2017. / Neste trabalho foram estudados os efeitos da substituição do Bi por um elemento terra-rara (R = Pr, Dy) e da adição de polímeros nas propriedades físicas de compostos de BiFeO3 (BFO) sintetizados pelo método hidrotermal assistido por micro-ondas. Inicialmente, amostras de BFO foram preparadas em diferentes condições de síntese (tempo, temperatura e concentração de KOH) e com este estudo escolheu-se os parâmetros de síntese utilizados neste trabalho para síntese de todas as amostras. As sínteses hidrotermais foram realizadas a 200 °C por 120 min com concentração de KOH de 4 M. Os compostos preparados foram avaliados por meio de medidas de difração de raios X (DRX) e de imagens de microscopia eletrônica de varredura (MEV). Na segunda etapa, o efeito da substituição de bismuto (Bi) por praseodímio (Pr) ou disprósio (Dy) foi investigado por meio de medidas das propriedades físicas caracterizadas por medidas de DRX e análise pelo método de refinamento de Rietveld, imagens de MEV, espec-tros de absorção na região UV-Vis, medidas de constante dielétrica em função da frequência e medidas de magnetização em função do campo magnético aplicado (MxH) e da temperatura (MxT). Por meio das análises de DRX das amostras de Bi1-xRxFeO3, foi observado que com a substituição de Bi por R as amostras tendem a cristalizar-se de forma polimórfica, apresentando duas simetrias: uma romboédrica (R3c) e outra monoclínica (Cc), sendo que a proporção da simetria monoclínica tende a aumentar com o aumento de x. Este polimorfismo, em geral, está associado a presença de Fe2+ na estrutura do Bi1-xRxFeO3, que exerce forte influência nas pro-priedades magnéticas destes compostos. As medidas elétricas mostraram uma melhora dos va-lores da constante dielétrica destas amostras quando comparadas a amostras sem substituição e com resultados listados na literatura para compostos BiFeO3 dopados preparados por outras metodologias. Resultados de absorção na região UV-Vis dos compostos Bi1-xRxFeO3 eviden-ciam uma diminuição do gap de energia de 2,1 eV para a amostra com x = 0 a 1,7eV para com x = 0,3 (Pr). Por fim, no estudo do efeito da adição de polímeros ou surfactantes, foram adici-onados os seguintes materiais: polietilenoglicol (PEG), polivinilpirrolidona (PVP), carboxime-tilcelulose de sódio (NaCMC) ou brometo de cetiltrimetilamonio (CTAB) com o objetivo de verificar a influência de diferentes morfologias nas propriedades físicas do BFO. De fato, o surfactante na síntese do BiFeO3 modificou a morfologia destes compostos, sendo que o resul-tado diferencial foi a obtenção do BiFeO3 na forma de nanobastões utilizando o CTAB. Os demais surfactantes apresentaram formatos similares aqueles já descritos na literatura. As me-didas de UV-Vis revelaram que o valor do gap de energia variou de 1,7 a 2,1 eV com a variação da morfologia do BFO, sendo que este resultado já foi observado em compostos de BFO com diferentes morfologias na literatura. As medidas de constante dielétrica em função da frequên-cia apresentaram um comportamento similar àqueles observados para o BFO preparado sem surfactante. As caracterizações magnéticas revelaram modificações nas curvas de MxT e MxH na região de baixa temperatura (<50 K), o que foi atribuído a presença de fases adicionais nestas amostras. / In this work, the effects of chemical substitution and addition of polymers on the physical prop-erties of BiFeO3 (BFO) compounds synthesized by microwave-assisted hydrothermal method were studied. Firstly, samples of BFO were prepared using different synthesis conditions (time, temperature, KOH concentration), with this study we chose the synthesis parameters used in this work to produce all samples. In order to obtain the parameters that allow the production of compounds with the desired crystalline phase. Hydrothermal syntheses were performed at 200°C during 120 min with KOH concentration of 4M. The compounds were evaluated by X-ray diffraction (XRD) measurements and images of Scanning Electronic Microscopy (SEM). In the second step, the effect of bismuth (Bi) substitution by praseodymium (Pr) or dysprosium (Dy) was investigated by measurements of the physical properties characterized by XRD meas-urements, and analysis by the Rietveld method of refinement, SEM images, absorption spectra in the UV-Vis region, dielectric constant measurements as a function of frequency, and mag-netization measurements as a function of the applied magnetic field (MxH) and temperature (MxT). By means of the XRD analysis of Bi1-xRxFeO3 samples, it was observed that with Bi for R substitution these samples are likely to crystallize in a polymorphic way, which present a rhomboedric (R3c) and a monoclinic (Cc) symmetry. The proportion of monoclinic symmetry tends to increase with the increasing of x. In general, such polymorphism is related to the Fe2+ content in the Bi1-xRxFeO3 structure, which provides a strong influence in the magnetic proper-ties of these compounds. Electrical measurements of the samples show dielectric constants val-ues similar to values observed for undopped and dopped-BiFeO3 prepared by other methodologies. UV-vis absorption results of Bi1-xRxFeO3 compounds revealed a decrease of energy gap from 2.1 eV for sample with x =0 to 1.7 eV for x = 0.3 (Pr). Finally, study of the effect of polymers or surfactants addition, the following materials were added: polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), sodium carboxymethylcellulose (NaCMC) or cetyltrimethylammonium bromide (CTAB) to verify the influence of different morphologies on the physical properties of BFO. In fact, the morphology of BFO was modified through the sur-factant addition, the most remarkable results is the nanostick shape observed for BFO samples prepared with CTAB. Samples prepared using the other surfactants revealed different mor-phology than those reported in literature. UV-vis measurements revealed energy gap varying from 1.7 to 2.1 eV for BFO samples with different morphologies. Dielectric constant measure-ments as function of frequency presents similar behavior than those observed for BFO without surfactant. Magnetic characterizations revealed changes in low temperature region (<50 K), which is attributed to the presence of additional phases in these samples.

Estruturas de sílica mesoporosa cúbica em forma de gaiola (originalmente identificadas como FDU-1) altamente ordenadas, estáveis térmica e hidrotermicamente, com tamanhos de poros da ordem de 12 nm, foram sintetizadas a partir de TEOS e como molde utilizou-se o copolímero tribloco poli(óxido de etileno)-poli(óxido de butileno)-poli(óxido de etileno) 850-6600 (EO39BO47EO39), em meio ácido. Foi desenvolvido um procedimento de síntese, empregando um forno de microondas no tratamento hidrotérmico para obtenção da sílica FDU-1. Após tratamento hidrotérmico, as amostras foram calcinadas a 540°C, em duas etapas, empregando atmosferas de N2 e ar. Os materiais foram caracterizados por análise elementar, FTIR, TG, SAXS e Isotermas de adsorção de N2 a 77 K. Os dados de SAXS, associados aos das Isotermas de adsorção de N2, demonstraram que os materiais obtidos com 45 e 60 min de exposição a microondas, apresentaram propriedades texturais compatíveis com aquelas do material obtido pelo método convencional. Os ensaios de termogravimetria evidenciam a faixa de temperatura em que ocorrem as decomposições térmicas do copolímero no material como sintetizado e conduziram a uma otimização das melhores condições para calcinação. As curvas TG/DTG indicaram que no aquecimento dos materiais até 1200ºC, há a transformação completa dos grupos silanóis em siloxanos a partir da eliminação de água. Esse fato é confirmado a partir dos espectros de absorção na região do IV e possibilitou estimar que a quantidade dos grupos Si-OH na superfície do material varia com o tempo de tratamento hidrotérmico na etapa de síntese. / Highly ordered, thermally and hidrotermally stable, with large pore size of 12 nm, caged-like cubic mesoporous silica structures (originally denoted FDU-1) were synthesized from TEOS and poly(ethylene oxide)-poly(butylene oxide)poly(ethylene oxide) B50-6600 triblock copolymer template (EO39BO47EO39) under acidic conditions.The synthesis procedure was developed using microwave oven for hydrothermal treatment to obtain FDU-1 silica. After hydrothermal treatment, the samples were calcined to 540 ºC, in two stages, using N2 and air atmospheres. The materials characterized by elementary analysis, FTIR, TG, DRX and nitrogen adsorption isothermal at 77 K. The data association of SAXS and the nitrogen adsorption isothermal demonstrated that the material isolated with 45 and 60 minutes of the exposition to the microwaves in the hydrothermal treatment showed testure properties compatible to that one of material obtained by the conventional method. Thermogravimetric experiments evidenced the temperature range where occur copolymer thermal decomposition according to the synthesis, as synthesized materials. This information was important to optimize the material calcination conditions. The TG/DTG curves indicated that, in the material heated up to 1200 ºC, occurs complete transformation of silanol in to siloxane groups with water elimination. This fact is confirmed through the IR spectra and enabled to calculate the quantity of the Si-OH groups in the material surface which vary hydrothermal treatment time in the syntesis stage.

Este estudo teve como objetivo principal desenvolver uma técnica para síntese de um nanocompósito de Y-TZP/MWCNT-COOH (Zircônia estabilizada por 3 mol% de ítria reforçada por nanotubos de carbono funcionalizado em -COOH) com propriedades mecânicas e ópticas que permitam a sua futura utilização como infraestrutura de próteses fixas dentárias e pilares protéticos para implantes. Assim, foram avaliados a microestrutura, resistência à flexão, tenacidade à fratura, limite de fadiga e propriedades ópticas do nanocompósito e comparada àquelas medidas para Y-TZP convencional (controle). O material Y-TZP/MWCNT-COOH foi desenvolvido pelo processo de co-precipitação de hidróxidos mistos associado ao tratamento hidrotérmico/solvotérmico e prensagem uniaxial em formato de blocos para sistemas CAD/CAM. O pó de MWCNT-COOH foi caracterizado por meio de MEV-FEG, TEM, TGA, DRX e FRX previamente a sua utilização para desenvolvimento do nanocompósito. Espécimes foram obtidos a partir do material Y-TZP/MWCNT-COOH para caracterização por meio de DRX, MEV-FEG e TEM, e comparação de suas propriedades estruturais (densidade e contração), ópticas, resistência à flexão, tenacidade à fratura e limite de fadiga com a Y-TZP convencional. O MWCNT-COOH apresentou-se em feixes de nanotubos de carbono recobertos por sílica tendo comprimento médio de 5,10 ± 1,34 ?m, com 90% dos comprimentos medidos (D90) estando abaixo de 6,9 ?m. Foi verificado a não possibilidade da utilização de líquidos orgânicos em nenhum passo da fabricação dos compósito Y-TZP/MWCNT-COOH por levar ao escurecimento do compósito, inviabilizando sua futura aplicação clínica. O tratamento hidrotérmico sem uso de líquidos orgânicos mostrou-se eficaz em proporcionar o revestimento do nanotubo de carbono por partículas de óxido de zircônio e ítrio. Entretanto, ocasionou a formação de aglomerados e partículas de Y-TZP com tamanho maiores que 5 ?m. Uma densidade relativa de 97,4% foi alcançada para o compósito experimental de Y-TZP contendo MWCNT-COOH, tendo uma razão de contraste de 0.9929 ± 0.0012 e um valor de diferença de cor da Y-TZP convencional de 6,1 ± 3,1 ( ?E). As propriedades mecânicas da Y-TZP/MWCNT-COOH, dureza Vickers (10,14 ± 1,27 GPa; p=0,25) e tenacidade à fratura (4,98 ± 0,30 MPa.m1/2; p=0,39), não apresentaram diferença significativa da Y-TZP convencional (dureza: 8,87 ± 0,89; tenacidade à fratura: 4,98 ± 0,30 MPa.m1/2). Entretanto, para a resistência à flexão (p=0,003) e limite de fadiga cíclica (LFC) foram obtidos valores inferiores para o material experimental Y-TZP/MWCNT-COOH (resistência à flexão: 299,4 ± 30,5 MPa; LFC: 179,4 ± 22,5 MPa) quando comparado à Y-TZP controle (resistência à flexão: 623,7 ± 108,8 MPa; LFC: 439,0 ± 56,4 MPa). Com base nos resultados apresentados, é possível concluir que a síntese de um nanocompósito de Y-TZP/MWCNT-COOH com propriedades ópticas adequadas para aplicação na odontologia restauradora foi possível por meio dos métodos descritos, entretanto algumas adequações nos métodos de síntese e processamento para criação do nanocompósito devem ser realizadas para se evitar a acentuada diminuição de importantes propriedades mecânicas do material. / This study aim was to develop a technique for synthetize nanocomposite of Y-TZP/MWCNT-COOH (3 mol% Yttria-Stabilized Tetragonal Zirconia reinforced with COOH functionalized carbon nanotubes) with mechanical and optical properties that allow their future use as fixed dental prosthesis infrastructure and implant abutments. Thus, the following properties of the nanocomposite were investigated and compared to those measured for conventional Y-TZP (control): microstructure, flexural strength, fracture toughness, fatigue limit and optical properties. Y-TZP/MWCNT-COOH material was developed by the co-precipitation of mixed hydroxides associated with the hydrothermal/solvothermal treatment and uniaxial pressing to form blocks for CAD/CAM systems. The MWCNT-COOH powder was characterized by SEM-FEG, TEM, TGA, XRD and XRF prior to its use for the development of nanocomposite. Specimens were obtained from the Y-TZP/MWCNT-COOH material and characterized by XRD, SEM-FEG and TEM. After characterization, the material had their structural properties (density and contraction), optical, flexural strength, fracture toughness and fatigue limit compared to a conventional Y-TZP. The MWCNT-COOH material was observed to be a bundle formation of carbon nanotube covered with silica with an average length of 5.10 ± 1.34 ?m, with 90% of the measured lengths (D90) being below 6.9 ?m. It has been found to be not possible to use organic liquids on any step of the Y-TZP/MWCNT-COOH manufacturing process due to darkening of the composite, making it unfeasible to future clinical application. The hydrothermal treatment without the use of organic liquids was effective in providing the carbon nanotube coating by zirconium and yttrium oxide particles. However, this treatment led to the formation of agglomerates and particles of Y-TZP with larger than 5 ?m. A relative density of 97.4% was achieved for the Y-TZP/MWCNT-COOH composite, having a contrast ratio of 0.9929 ± 0.0012, and a color difference value from the conventional Y-TZP of 6.1 ± 3.1 (?E). The mechanical properties of Y-TZP/MWCNT-COOH, Vickers hardness (10.14 ± 1.27 GPa; p = 0.25) and fracture toughness (4.98 ± 0.30 MPa.m1/2; p = 0.39), showed no significant difference from the conventional Y-TZP (hardness: 8.87 ± 0.89; fracture toughness: 4.98 ± 0.30 MPa.m1/2). However, flexural strength (p = 0.003) and cyclic fatigue limit (CFL) showed lower values for the experimental material Y-TZP/MWCNT-COOH (flexural strength: 299.4 ± 30.5 MPa; CFL: 179.4 ± 22.5 MPa) compared to Y-TZP control (flexural strength: 623.7 ± 108.8 MPa; CFL: 439.0 ± 56.4 MPa). Based on the results presented, it could be conclude that the synthesis of a nanocomposite of Y-TZP/MWCNT-COOH with optical properties suitable for application in restorative dentistry was made possible by the described methods, however some adjustments in synthesis and processing methods for the nanocomposite creation should be taken; to avoid the sharp decrease of important mechanical properties of the material.

It is well known that nanostructures possess unique electronic, optical, magnetic, ferroelectric and piezoelectric properties that are often superior to traditional bulk materials. In particular, one dimensional (1D) nanostructured inorganic materials including nanofibres, nanotubes and nanobelts have attracted considerable attention due to their distinctive geometries, novel physical and chemical properties, combined effects and their applications to numerous areas. Metal ion doping is a promising technique which can be utilized to control the properties of materials by intentionally introducing impurities or defects into a material. γ-Alumina (Al2O3), is one of the most important oxides due to its high surface area, mesoporous properties, chemical and thermal properties and its broad applications in adsorbents, composite materials, ceramics, catalysts and catalyst supports. γ-Alumina has been studied intensively over a long period of time. Recently, considerable work has been carried out on the synthesis of 1D γ-alumina nanostructures under various hydrothermal conditions; however, research on the doping of alumina nanostructures has not been forthcoming. Boehmite (γ-AlOOH) is a crucial precursor for the preparation of γ-Alumina and the morphology and size of the resultant alumina can be manipulated by controlling the growth of AlOOH. Gallium (Ga) is in the same group in the periodic table as aluminum. β-Gallium (III) oxide (β-Ga2O3), a wide band gap semiconductor, has long been known to exhibit conduction, luminescence and catalytic properties. Numerous techniques have been employed on the synthesis of gallium oxide in the early research. However, these techniques are plagued by inevitable problems. It is of great interest to explore the synthesis of gallium oxide via a low temperature hydrothermal route, which is economically efficient and environmentally friendly. The overall objectives of this study were: 1) the investigation of the effect of dopants on the morphology, size and properties of metal ion doped 1D alumina nanostructures by introducing dopant to the AlOOH structure; 2) the investigation of impacts of hydrothermal conditions and surfactants on the crystal growth of gallium oxide nanostructures. To achieve the above objectives, trivalent metal elements such as iron, gallium and yttrium were employed as dopants in the study of doped alumina nanostructures. In addition, the effect of various parameters that may affect the growth of gallium oxide crystals including temperature, pH, and the experimental procedure as well as different types of surfactants were systematically investigated. The main contributions of this study are: 1) the systematic and in-depth investigation of the crystal growth and the morphology control of iron, gallium and yttrium doped boehmite (AlOOH) under varying hydrothermal conditions, as a result, a new soft-chemistry synthesis route for the preparation of one dimensional alumina/boehmite nanofibres and nanotubes was invented; 2) systematic investigation of the crystal growth and morphology and size changes of gallium oxide hydroxide (GaOOH) under varying hydrothermal conditions with and without surfactant at low temperature; We invented a green hydrothermal route for the preparation of α-GaOOH or β-GaOOH micro- to nano-scaled particles; invented a simple hydrothermal route for the direct preparation of γ-Ga2O3 from aqueous media at low temperature without any calcination. The study provided detailed synthesis routes as well as quantitative property data of final products which are necessary for their potential industrial applications in the future. The following are the main areas and findings presented in the study: • Fe doped boehmite nanostructures This work was undertaken at 120ºC using PEO surfactant through a hydrothermal synthesis route by adding fresh iron doped aluminium hydrate at regular intervals of 2 days. The effect of dopant iron, iron percentage and experimental procedure on the morphology and size of boehmite were systematically studied. Iron doped boehmite nanofibres were formed in all samples with iron contents no more than 10%. Nanosheets and nanotubes together with an iron rich phase were formed in 20% iron doped boehmite sample. A change in synthesis procedure resulted in the formation of hematite large crystals. The resultant nanomaterials were characterized by a combination of XRD, TEM, EDX, SAED and N2 adsorption analysis. • Growth of pure boehmite nanofibres/nanotubes The growth of pure boehmite nanofibres/nanotubes under different hydrothermal conditions at 100ºC with and without PEO surfactant was systematically studied to provide further information for the following studies of the growth of Ga and Y doped boehmite. Results showed that adding fresh aluminium hydrate precipitate in a regular interval resulted in the formation of a mixture of long and short 1D boehmite nanostructures rather than the formation of relatively longer nanofibres/nanotubes. The detailed discussion and mechanism on the growth of boehmite nanostructure were presented. The resultant boehmite samples were also characterized by N2 adsorption to provide further information on the surface properties to support the proposed mechanism. • Ga doped boehmite nanostructures Based on this study on the growth of pure boehmite nanofibre/nanotubes, gallium doped boehmite nanotubes were prepared via hydrothermal treatment at 100ºC in the presence of PEO surfactant without adding any fresh aluminium hydrate precipitate during the hydrothermal treatment. The effect of dopant gallium, gallium percentage, temperature and experimental procedure on the morphology and size of boehmite was systematically studied. Various morphologies of boehmite nanostructures were formed with the increase in the doping gallium content and the change in synthesis procedure. The resultant gallium doped boehmite nanostructures were characterized by TEM, XRD, EDX, SAED, N2 adsorption and TGA. • Y doped boehmite nanostructures Following the same synthesis route as that for gallium doped boehmite, yttrium doped boehmite nanostructures were prepared at 100ºC in the presence of PEO surfactant. From the study on iron and gallium doped boehmite nanostructures, it was noted both iron and gallium cannot grow with boehmite nanostructure if iron nitrate and gallium nitrate were not mixed with aluminium nitrate before dissolving in water, in particular, gallium and aluminium are 100% miscible. Therefore, it’s not necessary to study the mixing procedure or synthesis route on the formation of yttrium doped boehmite nanostructures in this work. The effect of dopant yttrium, yttrium percentage, temperature and surfactant on the morphology and size of boehmite were systematically studied. Nanofibres were formed in all samples with varying doped Y% treated at 100ºC; large Y(OH)3 crystals were also formed at high doping Y percentage. Treatment at elevated temperatures resulted in remarkable changes in size and morphology for samples with the same doping Y content. The resultant yttrium doped boehmite nanostructures were characterized by TEM, XRD, EDX, SAED, N2 adsorption and TGA. • The synthesis of Gallium oxide hydroxide and gallium oxide with surfactant In this study, the growth of gallium oxide hydroxide under various hydrothermal conditions in the presence of different types of surfactants was systematically studied. Nano- to micro-sized gallium oxide hydroxide was prepared. The effect of surfactant and synthesis procedure on the morphology of the resultant gallium oxide hydroxide was studied. β-gallium oxide nanorods were derived from gallium oxide hydroxide by calcination at 900ºC and the initial morphology was retained. γ-gallium oxide nanotubes up to 65 nm in length, with internal and external diameters of around 0.8 and 3.0 nm, were synthesized directly in solution with and without surfactant. The resultant nano- to micro-sized structures were characterized by XRD, TEM, SAED, EDX and N2 adsorption. • The synthesis of gallium oxide hydroxide without surfactant The aim of this study is to explore a green synthesis route for the preparation of gallium oxide hydroxide or gallium oxide via hydrothermal treatment at low temperature. Micro to nano sized GaOOH nanorods and particles were prepared under varying hydrothermal conditions without any surfactant. The resultant GaOOH nanomaterials were characterized by XRD, TEM, SAED, EDX, TG and FT-IR. The growth mechanism of GaOOH crystals was proposed.

MCM-22 is a typical representative of the MWW family zeolite being obtained from laminated precursor MCM-22 (P) after calcination process having high surface area and high thermal stability. In this work, we carried out an optimization of the synthesis process of MCM-22 zeolite, in order to reduce the amount of reactants used and the crystallization time. The zeolite was synthesized using three different sources of silicon (Aerosil silica, silica gel and Ultrasil 60) and static hydrothermal treatment; in order to evaluate the influence of silicon source on the formation of the structure and physicochemical properties. The syntheses were performed without aging and with aging at room temperature and at 40 ° C for each source of silicon. It was also a study on the influence of calcination on the formation of MCM-22 structure. The materials (MCM-22 (P) and MCM-22) were characterized by X-ray diffraction (XRD); textural analysis of nitrogen adsorption at low temperature; scanning electron microscopy (SEM); spectroscopy in the infrared (FT-IR); thermogravimetry / derivative thermogravimetry (TGA / DTG) and determination of acidity termoprogramada desorption of NH3 (NH3-TPD). The X-ray diffraction showed that the synthesis of the materials has been successful, with the characteristic peaks of the MWW topology. In the conditions proposed in this work it was possible to optimize the synthesis of MCM-22 zeolite, which is obtained in a short time of 4 days without aging, for the sources of silica and Aerosil Ultrasil, and 3-day aging at 40 ° C for source of Aerosil silica. Unable to the formation of MCM-22 zeolite with silica gel within 8 days. The X-ray diffraction confirmed the obtaining of MCM-22 with high purity and crystallinity without the presence of any contaminant phase in a short time (4 days) in the absence of aging. Through the analysis (FT-IR) was confirmed the presence of the intrinsic vibrations of TO4 tetrahedrons that provide internal and external bands characteristics of these materials. Through the thermogravimetric analysis (TGA / DTG) it was found that higher weight loss occurred between 180 and 530 ° C and corresponds to the output of most of the organic driver. The results of BET showed that the textural properties of MCM-22 zeolite were heavily dependent on silicon source and treatment of synthesis gel. Generally, the samples showed a surface area higher than 500 m2 / g. From acid analysis by NH3-TPD it was observed that acid sites present in the samples were predominantly mild and strong acid sites. The source of silicon and the aging of the gel did not influence the acidity of the material. The evaluation method of calcination showed that the form of calcination used to obtain MCM-22 influences the textural properties of the zeolite. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A MCM-22 é uma zeólita típica representante da família MWW, sendo obtida a partir do precursor lamelar MCM-22(P) após processo de calcinação possuindo elevada área superficial e alta estabilidade térmica. Neste trabalho, realizou-se uma otimização do processo de síntese da zeólita MCM-22, com a finalidade de reduzir a quantidade de reagentes utilizados e o tempo de cristalização. A zeólita foi sintetizada empregando três diferentes fontes de silício (Sílica Aerosil, Ultrasil e Sílica gel 60) e tratamento hidrotérmico estático; com o objetivo de avaliar a influência da fonte de silício sobre a formação da estrutura e propriedades físico-químicas. As sínteses foram realizadas sem envelhecimento e com envelhecimento a temperatura ambiente e a 40°C, para cada fonte de silício. A influência do processo de calcinação sobre a formação da estrutura da MCM-22 também foi estudada. Os materiais obtidos (MCM-22 (P) e MCM-22) foram caracterizados por difração de raios-X (DRX); análise textural por adsorção de nitrogênio a baixa temperatura; microscopia eletrônica de varredura (MEV); espectroscopia na região do infravermelho (FT-IR); termogravimetria/termogravimetria derivada (TG/DTG), e determinação de acidez por dessorção termoprogramada de NH3 (TPD-NH3).Os difratogramas de raios-X comprovaram que a síntese dos materiais foi bem sucedida, apresentando os picos característicos da topologia MWW. Nas condições propostas neste trabalho foi possível otimizar a síntese da zeólita MCM-22, em um tempo curto de 4 dias sem envelhecimento, para as fontes de sílicas Aerosil e Ultrasil, e com 3 dias com envelhecimento a 40°C para a fonte de sílica Aerosil.Não foi possível a formação da zeólita MCM-22 com a sílica gel no período de 8 dias. Os difratogramas de raios-X comprovaram a obtenção da MCM-22 com alta pureza e cristalinidade, sem a presença de nenhuma fase contaminante, em um tempo reduzido (4 dias), e na ausência de envelhecimento. Por meio das análises (FT-IR) foi possível confirmar a presença das vibrações intrínsecas dos tetraedros TO4 que fornecem as bandas internas e externas características desses materiais. Através das análises termogravimétricas (TG/DTG) verificou-se que a maior perda de massa ocorreu entre 180 e 530 °C, e corresponde à saída da maior parte do direcionador orgânico. Os resultados de BET mostraram que as propriedades texturais da zeólita MCM-22 foram fortemente dependentes da fonte de silício e do tratamento do gel de síntese. De uma forma geral, as amostras apresentaram área superficial superior a 500 m2/g. A partir das análises de acidez por TPD-NH3 observou-se que os sítios ácidos presentes nas amostras foram, predominantemente, sítios ácidos moderados e fortes. A fonte de silício e o envelhecimento do gel não influenciaram na acidez do material. A avaliação do método de calcinação revelou que a forma de calcinação empregada para a obtenção da MCM-22 influencia nas propriedades texturais da zeólita.

Este estudo teve como objetivo principal desenvolver uma técnica para síntese de um nanocompósito de Y-TZP/MWCNT-COOH (Zircônia estabilizada por 3 mol% de ítria reforçada por nanotubos de carbono funcionalizado em -COOH) com propriedades mecânicas e ópticas que permitam a sua futura utilização como infraestrutura de próteses fixas dentárias e pilares protéticos para implantes. Assim, foram avaliados a microestrutura, resistência à flexão, tenacidade à fratura, limite de fadiga e propriedades ópticas do nanocompósito e comparada àquelas medidas para Y-TZP convencional (controle). O material Y-TZP/MWCNT-COOH foi desenvolvido pelo processo de co-precipitação de hidróxidos mistos associado ao tratamento hidrotérmico/solvotérmico e prensagem uniaxial em formato de blocos para sistemas CAD/CAM. O pó de MWCNT-COOH foi caracterizado por meio de MEV-FEG, TEM, TGA, DRX e FRX previamente a sua utilização para desenvolvimento do nanocompósito. Espécimes foram obtidos a partir do material Y-TZP/MWCNT-COOH para caracterização por meio de DRX, MEV-FEG e TEM, e comparação de suas propriedades estruturais (densidade e contração), ópticas, resistência à flexão, tenacidade à fratura e limite de fadiga com a Y-TZP convencional. O MWCNT-COOH apresentou-se em feixes de nanotubos de carbono recobertos por sílica tendo comprimento médio de 5,10 ± 1,34 ?m, com 90% dos comprimentos medidos (D90) estando abaixo de 6,9 ?m. Foi verificado a não possibilidade da utilização de líquidos orgânicos em nenhum passo da fabricação dos compósito Y-TZP/MWCNT-COOH por levar ao escurecimento do compósito, inviabilizando sua futura aplicação clínica. O tratamento hidrotérmico sem uso de líquidos orgânicos mostrou-se eficaz em proporcionar o revestimento do nanotubo de carbono por partículas de óxido de zircônio e ítrio. Entretanto, ocasionou a formação de aglomerados e partículas de Y-TZP com tamanho maiores que 5 ?m. Uma densidade relativa de 97,4% foi alcançada para o compósito experimental de Y-TZP contendo MWCNT-COOH, tendo uma razão de contraste de 0.9929 ± 0.0012 e um valor de diferença de cor da Y-TZP convencional de 6,1 ± 3,1 ( ?E). As propriedades mecânicas da Y-TZP/MWCNT-COOH, dureza Vickers (10,14 ± 1,27 GPa; p=0,25) e tenacidade à fratura (4,98 ± 0,30 MPa.m1/2; p=0,39), não apresentaram diferença significativa da Y-TZP convencional (dureza: 8,87 ± 0,89; tenacidade à fratura: 4,98 ± 0,30 MPa.m1/2). Entretanto, para a resistência à flexão (p=0,003) e limite de fadiga cíclica (LFC) foram obtidos valores inferiores para o material experimental Y-TZP/MWCNT-COOH (resistência à flexão: 299,4 ± 30,5 MPa; LFC: 179,4 ± 22,5 MPa) quando comparado à Y-TZP controle (resistência à flexão: 623,7 ± 108,8 MPa; LFC: 439,0 ± 56,4 MPa). Com base nos resultados apresentados, é possível concluir que a síntese de um nanocompósito de Y-TZP/MWCNT-COOH com propriedades ópticas adequadas para aplicação na odontologia restauradora foi possível por meio dos métodos descritos, entretanto algumas adequações nos métodos de síntese e processamento para criação do nanocompósito devem ser realizadas para se evitar a acentuada diminuição de importantes propriedades mecânicas do material. / This study aim was to develop a technique for synthetize nanocomposite of Y-TZP/MWCNT-COOH (3 mol% Yttria-Stabilized Tetragonal Zirconia reinforced with COOH functionalized carbon nanotubes) with mechanical and optical properties that allow their future use as fixed dental prosthesis infrastructure and implant abutments. Thus, the following properties of the nanocomposite were investigated and compared to those measured for conventional Y-TZP (control): microstructure, flexural strength, fracture toughness, fatigue limit and optical properties. Y-TZP/MWCNT-COOH material was developed by the co-precipitation of mixed hydroxides associated with the hydrothermal/solvothermal treatment and uniaxial pressing to form blocks for CAD/CAM systems. The MWCNT-COOH powder was characterized by SEM-FEG, TEM, TGA, XRD and XRF prior to its use for the development of nanocomposite. Specimens were obtained from the Y-TZP/MWCNT-COOH material and characterized by XRD, SEM-FEG and TEM. After characterization, the material had their structural properties (density and contraction), optical, flexural strength, fracture toughness and fatigue limit compared to a conventional Y-TZP. The MWCNT-COOH material was observed to be a bundle formation of carbon nanotube covered with silica with an average length of 5.10 ± 1.34 ?m, with 90% of the measured lengths (D90) being below 6.9 ?m. It has been found to be not possible to use organic liquids on any step of the Y-TZP/MWCNT-COOH manufacturing process due to darkening of the composite, making it unfeasible to future clinical application. The hydrothermal treatment without the use of organic liquids was effective in providing the carbon nanotube coating by zirconium and yttrium oxide particles. However, this treatment led to the formation of agglomerates and particles of Y-TZP with larger than 5 ?m. A relative density of 97.4% was achieved for the Y-TZP/MWCNT-COOH composite, having a contrast ratio of 0.9929 ± 0.0012, and a color difference value from the conventional Y-TZP of 6.1 ± 3.1 (?E). The mechanical properties of Y-TZP/MWCNT-COOH, Vickers hardness (10.14 ± 1.27 GPa; p = 0.25) and fracture toughness (4.98 ± 0.30 MPa.m1/2; p = 0.39), showed no significant difference from the conventional Y-TZP (hardness: 8.87 ± 0.89; fracture toughness: 4.98 ± 0.30 MPa.m1/2). However, flexural strength (p = 0.003) and cyclic fatigue limit (CFL) showed lower values for the experimental material Y-TZP/MWCNT-COOH (flexural strength: 299.4 ± 30.5 MPa; CFL: 179.4 ± 22.5 MPa) compared to Y-TZP control (flexural strength: 623.7 ± 108.8 MPa; CFL: 439.0 ± 56.4 MPa). Based on the results presented, it could be conclude that the synthesis of a nanocomposite of Y-TZP/MWCNT-COOH with optical properties suitable for application in restorative dentistry was made possible by the described methods, however some adjustments in synthesis and processing methods for the nanocomposite creation should be taken; to avoid the sharp decrease of important mechanical properties of the material.

L'effet des traitements hydrothermiques et l’effet des arômes sur la structure de l'amidon et de ses propriétés physiques ont été étudiés. L’amidon de blé natif a été traité à 2 hydratations différentes (rapports eau-amidon: 50/50 et 80/20 g/g) et à 2 températures (65 et 85 °C) en présence d’ arômes (hexanoate d'éthyle et de 2-hexanone). Les échantillons fraîchement préparés ont été soumis à l’analyse calorimétrique (AED) et au dosage d’ arôme. Aucun complexe d'inclusion entre amidon et arôme n’a pu être détecté par AED cependant le résultat de l'analyse aromatique a prouvé qu'il y avait des interactions arôme-amidon. Les deux composés d’arôme (hexanoate d'éthyle et 2-hexanone) ont interagi avec l'amidon à des teneurs comparables. Les pertes d’arômes ont été trouvées les plus élevées dans les échantillons traités aux plus hautes hydratation et température . La perte d’arôme était principalement liée à l’évaporation lors des traitements hydrothermiques. Après les traitements hydrothermiques, les échantillons ont été lyophilisés ont montré une stabilité d’arôme à la lyophilisation. Les échantillons lyophilisés ont été soumis à diverses études: DSC (Tg), RVA, la taille des granules, XRD, WAXS, SAXS étude et de stockage. Les traitements hydrothermiques ont conduit à des échantillons avec des propriétés différentes. A haute hydratation, la température influence la taille des granules et des propriétés rhéologiques à la cuisson (pasting). Les échantillons chauffés à 65 °C présentaient des tailles de granules significativement plus importantes, une viscosité maximale (en RVA) inférieure à celles des échantillons chauffés à 85 °C mais de significative différence en % de cristallinité. A faible hydratation, la température de chauffage n’avait pas d’influencer significative sur la taille des granules, mais un effet significatif sur les propriétés rhéologiques à la cuisson, le degré de cristallinité et le profil SAXS. Les échantillons chauffés à 65°C avaient une viscosité maximale supérieure , un degré de cristallinité plus élevé et des pics SAXS plus importants qu’après un chauffage à 85 °C. La teneur résiduelle en arôme n'a eu aucune influence significative sur la structure, mais semble affecter les propriétés rhéologiques à la cuisson. En ce qui concerne l'étude à la conservations, les échantillons ont été stockés à 58 et 75% d'humidité relative et étudiés par analyse SPME, par extraction d’arôme et par AED pour un suivide relaxation d’enthalpie après de 2, 4 et 14 semaines de stockage. Les échantillons avaient une plus grande libération de l'arôme à 75% HR et l’hexanoate d’éthyle montré une plus grande libération de 2-hexanone. Les échantillons ont montré une augmentation de relaxation d'enthalpie de lors d'un stockage. / The effect of hydrothermal treatments and flavours addition on starch structure and its physical properties were studied. Native wheat starch was treated at 2 different hydrations (water-starch ratios: 50/50 and 80/20 g w/w) and temperatures (65 and 85 °C) in the presence of flavours (ethyl hexanoate and 2-hexanone). The freshly prepared samples were subjected to DSC and flavour analysis. Flavour inclusion complex could not be detected by DSC, however the result of flavour analysis proved that there were flavours interactions with starch. Both ethyl hexanoate and 2-hexanone interacted with starch at similar rates. The highest flavour loss was found in the samples at high hydration and heated at 85 °C. The loss of flavour was mainly due to vaporisation during hydrothermal treatments. After hydrothermal treatments, the samples subjected to freeze-drying and they showed flavour stability upon freeze-drying. The freeze-dried samples were subjected to various studies: DSC (Tg), RVA, granule size, XRD, WAXS, SAXS and storage study. The hydrothermal treatments resulted in samples with different properties. At high hydration, temperature influenced granule size and pasting properties. The samples heated at 65 °C had significantly greater granule diameter, lower peak viscosity than samples heated at 85 °C and no significantly difference in % crystallinity. At low hydration, heating temperature had no significantly influence on granule diameter but significantly affected pasting properties, % crystallinity and SAXS profile. The samples heated at 65 °C had a greater peak viscosity, % crystallinity and greater peak on SAXS than after a treatment at 85 °C. The residual flavour contenthad no significant influence on structure but affected pasting properties. Regarding storage study, the samples were stored at 58 and 75 % RH and withdrawn for SPME, flavour residual extraction and DSC (enthalpy of relaxation) at 2, 4 and 14 weeks of storage. The samples had greater flavour release at 75% RH and ethyl hexanoate showed greater release than 2-hexanone. The samples showed increasing of enthalpy relaxation upon storage.