Este trabalho teve por objetivo avaliar \"in vitro\" a resistência ao cisalhamento de um selante resinoso (Fluroshield - F) em associação com um sistema adesivo total-etch (Adper Single Bond 2-SB) e um self-etching (Clearfil S3 Bond-S3) em condições de contaminação salivar, comparando dois protocolos de fotopolimerização: individual do sistema adesivo e, em seguida, do selante ou simultânea de ambos materiais conjuntamente. Superfícies mesiais e distais de 45 terceiros molares humanos hígidos foram incluídas e planificadas, o sítio de adesão delimitado (Ø 3mm) e os corpos-de-prova alocados aleatoriamente em 6 grupos experimentais (n=15), de acordo com o tratamento empregado: I- F aplicado sobre o esmalte condicionado com ácido fosfórico a 37% (controle). Os demais grupos foram contaminados com saliva (0,01ml por 10 s) e a seguir foram aplicados: II- SB e F fotopolimerizados separadamente; III- SB e F fotopolimerizados conjuntamente; IVS3 e F fotopolimerizados separadamente; V- S3 e F fotopolimerizados simultaneamente; VI- F aplicado sem associação com adesivos sobre o esmalte condicionado e contaminado. A seguir, um cilindro de selante foi confeccionado com o auxílio de uma mesa metálica e de matriz de teflon bipartida sobre o sítio de adesão. Após armazenamento durante 24 horas a 37°C em água destilada, os espécimes foram submetidos ao teste de resistência ao cisalhamento em Máquina de Ensaios Universal (0,5mm/min; 50Kgf). As interfaces adesivas foram analisadas quanto ao tipo de fratura em microscópio óptico com 20x de aumento e para análise qualitativa, três espécimes de cada grupo, foram selecionados e analisados em microscópio eletrônico de varredura. As médias obtidas, em MPa, e os desvios padrão foram: I-12,28 (±4,29); II-8,57 (±3,19); III-7,97 (±2,16); IV-12,56 (±3,11); V- 11,45 (±3,77); e VI-7,47 (±1,99). A análise estatística, por meio da Análise de Variância e teste de Fisher, demonstrou que a contaminação salivar afetou negativamente a resistência adesiva. A associação do sistema adesivo self-etching ao selante resultou em uma média semelhante estatisticamente ao grupo controle. Comparando os protocolos de fotopolimerização, não houve diferença estatisticamente significante entre os grupos nos quais foi realizada a fotopolimerização simultânea ou individual dos materiais. Com base nestes resultados pôde-se concluir que o protocolo de fotopolimerização não afetou os valores de resistência adesiva ao esmalte condicionado e contaminado. A associação do sistema adesivo self-etching Clearfil S3 Bond ao selante Fluroshield aumentou a resistência ao cisalhamento com diferença estastísticamente significante em relação aos grupos nos quais foi utilizado o sistema adesivo Adper Single Bond 2 e com valor médio semelhante ao grupo controle, no qual o selante foi aplicado em condições ideais, na ausência de contaminação salivar. / The purpose of this study was to evaluate in vitro the shear bond strength of a resin-based pit-and-fissure sealant (Fluroshield - F) associated with a total-etch (Adper Single Bond 2 - SB) and a self-etching adhesive system (Clearfil S3 Bond - S3) under conditions of salivary contamination, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal surfaces from 45 sound third molars were embedded, flattened and a 3-mm-diameter bonding site was demarcated. The specimens were randomly assigned to 6 experimental groups (n=15), according to the bonding technique: I - F was applied to the enamel etched with 37% phosphoric acid. The other groups were contaminated with saliva (0.01 mL during 10 s). II - SB and F were light cured separately; III - SB and F were light cured together; IV - 3S and F were light cured separately; V - 3S and F were light cured simultaneously; VI - F was applied to salivary-contaminated etched enamel without an intermediate bonding agent layer. Thereafter, a sealant cylinder was fabricated using a metallic clamping device and a split Teflon matrix placed over the bonding site. After 24-hour storage in distilled water at 37°C, shear bond strength was measured using a knifeedge blade in a universal testing machine (0.5 mm/mm; 50 kgf). The debonded interfaces were examined with an optical microscope to determine the failure modes. For a qualitative analysis, 3 specimens from each group were selected and observed under scanning electron microscopy. Means (±SD) in MPa were: I-12,28 (±4,29); II 8,57 (±3,19); III-7,97 (±2,16); IV-12,56 (±3,11); V-11,45 (±3,77); and VI-7,47 (±1,99). Statistical analysis by ANOVA and Fisher\'s test showed that salivary contamination affected negatively the bond strength. The association between the self-etching adhesive system and sealant yielded bond strength mean statistically similar to that of the control group. Comparing the curing protocols, there was no statistically significant difference between the groups with simultaneous or individual light curing of the materials. Based on these results, it may be concluded that the curing protocol did not affect the bond strength to the contaminated etched enamel. The association of Clearfil S3 Bond self-etching adhesive system to Fluroshield sealant increased the shear bond strength with statistically significant difference from the groups with Adper Single Bond 2 adhesive system, and showing mean value similar to that of the control group, in which the sealant was applied under ideal conditions, without salivary contamination.

Made available in DSpace on 2014-06-11T19:31:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-19Bitstream added on 2014-06-13T18:41:40Z : No. of bitstreams: 1 costa_sxs_dr_arafo.pdf: 852844 bytes, checksum: 8945fe6817e7f7f0051c98cb920416e1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho, dividido em três estudos, foi avaliar: (1) a influência da utilização de diferentes fontes de luz e métodos de fotoativação sobre o grau de conversão e a contração de polimerização de uma resina composta nanoparticulada; (2) a influência da utilização dos diferentes métodos de fotoativacao, disponibilizados por aparelhos LED de 2a geração, sobre a contração volumétrica das resinas compostas microhíbrida e nanopartículada e (3) as propriedades térmicas e o grau de conversão das resinas compostas microhíbrida e nanopartículada, submetidas aos diferentes métodos de fotoativação disponibilizados por aparelhos LED de 2a geracao. No primeiro estudo, o grau de conversão (GC) foi avaliado pelo metodo da espectroscopia infravermelha transformada de Fourier (FT-IR) e as forças de contração (C) mensuradas em máquina de ensaios universal (EMIC). Os dados obtidos para o GC e C foram analísados estatísticamente pelo teste da análise de variancia (ANOVA), sendo que para as forças de contração, a correção de Welch e o teste Tamhane também foram empregados. No segundo estudo, a contração volumétrica foi avaliada por um mecanismo de vídeo e imagem (AcuvolR/Bisco) e os dados obtidos foram análisados estatísticamente pelos testes ANOVA e Tukey. No terceiro estudo, o método da calorimetria exploratória diferencial foi empregado para avaliar a temperatura de transição vitrea (Tg) e de degradação dos materiais e o GC por FTIR. Os dados relativos ao GC foram análisados estatísticamente pelos testes ANOVA e Tukey. Os resultados demonstraram diferenças na contração de polimerização de acordo com o método de fotoativação empregado. No primeiro e segundo estudos, mesmo empregando diferentes metodologias, o método de fotoativação contínuo apresentou os maiores valores de contração. Por outro lado,o GC não... / The aim of this work, divided into three studies, was evaluate: (1) the influence of different light sources and photo-activation methods on degree of conversion and polymerization shrinkage of a nanocomposite resin; (2) the influence of different photo-activation methods, available by the 2nd generation LED light-curing units, on the volumetric shrinkage of microhybrid and nanocomposite resins and (3) thermal properties and degree of conversion of microhybrid and nanocomposite resins submitted to different photo-activation methods available by 2nd generation LED light-curing units. In the first study, degree of conversion (DC) was evaluated by Fourier transform infrared spectroscopy (FT-IR) and shrinkage forces (S) were measured in a universal testing machine (EMIC). The data obtained for DC and S were analyzed by Analysis of Variance test (ANOVA) and for S Welch’s correction and Tamhane’s tests were also employed. In the second study, volumetric shrinkage was evaluated by video-imaging device (AcuvolR/Bisco) and data were analyzed by ANOVA and Tukey’s test. In the third study, differential scanning calorimetry was used in order to observe glass transition temperature (Tg) and degradation peak of the materials and DC was evaluated for FT-IR. The DC data were analyzed by ANOVA and Tukey’s test. The results showed differences in the polymerization shrinkage according to photo-activation method employed. In the first and second studies, the continuous photo-activation methods presented the highest values for shrinkage even though different methodologies were used to assess. Moreover, DC was not influenced by the photo-activation method but was influenced by light sources. The lowest DC values were observed for halogen light-curing unit. In the second study beyond the influence of the photo-activation... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:31:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-10Bitstream added on 2014-06-13T19:40:56Z : No. of bitstreams: 1 queiroz_rs_dr_arafo.pdf: 679998 bytes, checksum: 47166f3c2a2f40adf0235d9237b0bd24 (MD5) / Esse estudo se propõe a avaliar as propriedades ópticas (Fluorescência e Absorbância) da resina composta fotoativada (4 SEASONS®) utilizando aparelho fotopolimerizador convencional (luz Halógena Ulttralux - DabiAtlant), e aparelho emissor de Diodo (Radii – SDI e Ultralume Led 5- Ultradent), em função da fonte de luz foto-ativadora, cor, espessura e tempo de armazenamento em saliva artificial. Foram confeccionadas 5 amostras (10,0x1,0 mm) para cada grupo experimental. Para a realização do teste de Absorbância foi utilizado aparelho espectrofotômetro de luz visível (Diode Array Spectrophotometer, HP – Serial Number: 8452-A). Para a obtenção dos valores de fluorescência emitida pelas amostras, foi utilizado espectrofotômetro (SPEX TRIAX FLUOROLOG 3, Jobin Yvon – Serial Number: 0135B-3-99). Os resultados foram julgados estatisticamente conforme a interação entre os fatores de avaliação nos distintos trabalhos. Pode-se concluir que a fonte de luz fotoativadora influenciou apenas a emissão fluorescente da resina de cor TC, não tendo efeito negativo na absorbância; o aumento na espessura da amostra acarretou uma diminuição na emissão fluorescente e na absorbância de todas as cores da resina, independente da fonte de luz; e as diferentes cores da resina exibiram diferentes emissões fluorescentes e absorbância... / The arm of this study is to evaluate optical properties (fluorescence and Absorbance) of a composite resin (4 SEASONS®) using light curing units (LCUs)-(QTH - Ulttralux – DabiAtlant and LEDs Radii – SDI and Ultralume Led 5- Ultradent) in function of LCUs, shade, thickness and storage times. 5 samples were prepared for each experimental group. To perform the Absorbance test, was used of UV-Vis spectrophotometer (Diode Array Spectrophotometer, HP – Serial Number: 8452-A). To obtain the fluorescence emission by samples, we used a spectrophotometer (SPEX TRIAX FLUOROLOG 3, Jobin Yvon – Serial Number: 0135B-3-99). The results were deemed statistically as the interaction between the evaluation factors in the different works. It can be concluded that the LCUs only influenced the fluorescent emission of resin color TC, having no negative effect on the absorbance; the increase in thickness of the sample decrease the fluorescent emission and absorbance for colors of the resin, independent of the LCUs; different colors of resin exhibited different fluorescent emission and absorbance.

Os investimentos iniciais em moldes na indústria de pré-moldados de concreto de cimento Portland, em geral, são altos, havendo a necessidade de utilizá-los o mais intensivamente possível entre uma e outra moldagem. A conseqüência é que a desforma pode ocorrer em instantes inadequados, comprometendo a durabilidade do produto. Isto contraria o conceito fundamental da pré-moldagem que está relacionado ao rigoroso controle de qualidade do produto. A cura térmica é uma alternativa, pois é utilizada para acelerar a resistência mecânica inicial do concreto. Esse beneficio imediato é acompanhado por uma redução na resistência final comparativamente à cura normal em câmara úmida. Esta redução é atribuída ao desenvolvimento de uma microestrutura modificada. Para investigar esse fenômeno, com base nos conhecimentos em ciência e engenharia dos materiais, desenvolve-se um estudo experimental, aplicado a pré-moldados com pequena espessura. O objetivo principal é analisar tais modificações e os compostos hidratados, formados ao longo do tempo após a cura térmica, considerando os materiais empregados e estabelecendo relações com a perda de resistência final. Leva-se em conta a influência das adições e da duração dos ciclos térmicos. A análise da microestrutura está baseada nos seguintes ensaios: porosimetria por intrusão de mercúrio, microscopia eletrônica de varredura, termogravimetria e difração de raio-X. Confirma-se com base nos resultados que a cura térmica favorece a maior formação de portlandita e também acelera a reação pozolânica. Para a composição entre cimento Portland, a escória de alto forno (30%) e a sílica ativa (10%), submetidas a ciclos térmicos longos (12 horas Tmax=61°C), observa-se a maior perda na resistência mecânica a longo prazo. Neste caso, há fortes indícios de que há formação de fases com menor desempenho mecânico. Através de micrografias, para essa amostra, sugere-se a formação da etringita secundária com maior prejuízo na interface pasta-agregado. As conclusões sugerem que para minimizar as interferências no processo de cura e garantir resistências mínimas nas desmoldagens rápidas, com poucas perdas a longo prazo, é interessante associar ciclos térmicos curtos, cimento de alta resistência inicial, sílica ativa e superplastificante. / The initial investments of molds in the industry which makes pre-cast of Portland cement concrete is usually very high, thus creating a necessity to maximize the utilization of each moldings. The consequence is that the forms can be removed at inadequate time, which compromise the durability of the product. This contradicts the fundamental concepts of the pre-castings, which is related to a severe quality control. Steam curing is an alternative treatment and is used to accelerate the initial mechanical resistance of the concrete. This immediate benefit is accompanied by the decrease on final resistance compared to normal curing in humid chamber. This reduction is attributed to the development of a modified microstructure. To investigate this phenomenon, based on knowleledge of materials science and engineering, an experimental study is developed which is applied in pre-cast wich small thichness. The main objective of this work is to analyze the microstructure modifications and the hydrated compounds formed, after a period of steam curing, taking in account the used materiaIs, also to establish a relations with the loss of final strength. The influence of additions and duration of steam cycles are considered. The analyses of microstructures are based on the following tests: mercury intrusion porosimetry, scanning electron microscope, thermogravimetry and X-ray diffraction. Based on the results it can be confirmed that steam curing favors a large formation of ponlandite and also accelerates pozzolanic reaction. For the composition of Portland cement, slag fumace blast (30%) and active silica (10%), submitted for long period of thermal cycles (12 hours, Tmax=61°C), a great loss strength was observed. In this case it is possible the formation of phases with poor mechanical performance. Through micrographs, for this sample, it is observed the formation of secondary ettringite with a large damage in the interface aggregate-paste. The conclusions suggest that to minimize the interference in the process of curing and to guarantee a minimum strength during the rapid separation of the concrete from the molds, with a minor loss in a long term, it is interesting to associate short steam cycles, high initial resistance cement, adive silica and superplasticizer.

O preparo de misturas de areia-asfalto a frio com emulsão asfáltica possui algumas características que dificultam a avaliação de seu desempenho através de ensaios de laboratório. Estas características são atribuídas à emulsão asfáltica que necessita de cuidados adicionais em relação a outros tipos de ligantes betuminosos. Um desses cuidados é o procedimento de cura antes da compactação para favorecer a perda de umidade das misturas. Neste trabalho é avaliada a influência da perda de umidade de três tipos de misturas de areia-asfalto a frio - misturas sem filler, com filler de pedregulho britado e com filler de cimento Portland, sobre os resultados de alguns ensaios de laboratório. Os ensaios usados para esta avaliação foram: dosagens sem cura e com cura antes da compactação das misturas; controle da perda de umidade; ensaios Marshall com variação da perda de umidade e fluência por compressão uniaxial estática. A perda de umidade antes da compactação das misturas mostrou-se um importante fator de influência nos resultados do ensaio Marshall. Porém, o ensaio de fluência por compressão uniaxial estática revelou que mesmo as misturas com melhor desempenho no ensaio Marshall são muito suscetíveis à deformação permanente e com ruptura frágil mesmo sob a ação de tensões axiais relativamente baixas. / The preparation of cold sand-asphalt mixtures with asphalt emulsion has some characteristics that can affect the laboratory evaluation of its performance. These characteristics are attributed to asphaltic emulsion that needs additional cares in relation to others types of bituminous binders. One of these cares is the curing procedure before compaction, to favor moisture loss. In this work the influence of moisture loss on the results of some laboratory tests is evaluated for three cold sand-asphalt mixtures - mixtures without filler, with crushed gravel filler and with portland cement filler. The tests used for this evaluation are: optimum asphalt content with and without curing before the mixtures compaction, moisture loss control, Marshall tests with moisture loss variation and static creep test. Moisture loss before compaction showed to have a clear influence on the results of Marshall tests. However the static creep test revealed that even those mixtures with the best Marshall test performances are very susceptible to permanent deformation and fragile rupture under low axial stress.

<p>Sintetisane su klasične alkidne smole polazeći od ricinolne kiseline, anhidrida ftalne<br />kiseline i tri poliola (glicerina, trimetilolpropana i etoksilovanog pentaeritritola), kao i<br />hiperrazgranati alkidi na osnovu ditrimetilolpropana, dimetilolpropionske kiseline i<br />ricinolne kiseline. Smole su karakterisane određivanjem hidroksilnog i kiselinskog broja,<br />viskoznosti, srednjih molskih masa i njihove raspodele. Struktura sintetisanih smola je<br />potvrđena infracrvenom spektroskopijom sa Furijeovom transformacijom (FTIR).<br />Sintetisani alkidi imaju veliki sadržaj hidroksilnih grupa, a mali kiselinski broj. Prisustvo<br />hidroksilnih grupa, kao krajnjih funkcionalnih grupa, omogućuje modifikaciju alkidnih<br />smola i dobijanje materijala različitih svojstava. Sintetisani alkidi su umrežavani sa<br />triizobutoksimetil i heksametoksimetil melaminskom smolom u cilju dobijanja umreženog materijala željene strukture i svojstava za primenu u premazima. Umrežavanje sme&scaron;a smola praćeno je FTIR spektroskopijom, dinamičko skanirajućom kalorimetrijom (DSC), reometrijom, kao i određivanjem sadržaja gela. Ispitivana su toplotna svojstva, dinamičkomehaničko pona&scaron;anje, fizičko-mehaničke karakteristike i hemijska otpornost filmova premaza. Umrežavanje sme&scaron;a smola teče uglavnom preko hidroksilnih i karboksilnih grupa alkida sa izobutoksimetil i metoksimetil grupama u melaminskim smolama. Sintetisane klasične alkidne smole u sme&scaron;i sa melaminskim smolama umrežavaju u temperaturnom opsegu od 90 do 170&nbsp;⁰C, a hiperrazgranati alkidi od 80 do 170&nbsp;⁰C, &scaron;to su uobičajene temperature u tehnologiji lakova koji umrežavaju &ldquo;pečenjem&ldquo;. Umreženi filmovi premaza su toplotno veoma stabilni, budući da početak razgradnje premaza započinje na temperaturama od 281 do 330 ⁰C. Potvrđeno je da postoji linearna zavisnost između modula izgubljene energije na 25 ⁰C, koji je mera viskoznog odgovora materijala, i tvrdoće premaza određene metodom klatna. Svi projektovani premazi, bez obzira na nesavr&scaron;enost nastale polimerne mreže, su pokazali zadovoljavajuća svojstva. Najbolja svojstva od klasičnih alkidnih premaza ima onaj na osnovu sme&scaron;e alkida sa etoksilovanim pentaeritritolom i heksametoksimetil melaminske smole. Kori&scaron;ćenje hiperrazgranatih alkidnih smola kao veziva u ekolo&scaron;ki prihvatljivim premazima ima prednost zbog manjeg sadržaja organskih rastvarača i manje viskoznosti u odnosu na klasične smole. Pretpostavljeno je da bi sme&scaron;e sintetisanih klasičnih i hiperrazgranatih alkida sa melaminskim smolama (maseni odnos 70:30) bile pogodne za primenu u industriji boja i lakova. Potvrđeno je da su sistemi alkid/melaminska smola veoma složeni. Dobijeni rezultati omogućuju da se objasni uticaj građe prekursora na strukturu nastale polimerne mreže, a time i na svojstva premaza.</p> / <p>Conventional alkyd resins based on ricinoleic acid, phthalic anhydride and three polyols (glycerin, trimethylolpropane or ethoxylated pentaerythritol), as well as hyperbranched alkyds based on ditrimethylolpropane, dimethylol propionic acid and ricinoleic acid were synthesized. Prepared alkyds were characterized by the determination of hydroxyl and acid numbers, viscosity, average molecular masses and molecular masses distribution. The structure of synthesized resins is confirmed by Fourier Transform Infrared Spectroscopy (FTIR). Obtained alkyd resins have high content of hydroxyl groups and low acid number. The presence of hydroxyl groups as functional end groups opens up a high potential for further chemical modifications and for obtaining materials with different properties. Synthesized alkyds were cured by triisobutoxymethyl- and hexamethoxymethyl melamine resins, in order to obtain crosslinked material with desired structure and properties for coating applications. Curing of the resin mixtures were examined by FTIR spectroscopy, dynamic scanning calorimety (DSC), rheometry and by the determination of gel content. Thermal properties, dynamic mechanical behavior, physico-mechanical characteristics and chemical resistance of coated films were determined. Curing of the resin mixtures proceeds via the reactions between hydroxyl and carboxyl groups of alkyds with isobutoxymethyl and metoxymethyl groups in melamine resins. Synthesized alkyd/melamine resin mixtures became cured in the temperature range from 80 to 170 0C, which is the usual temperature range employed in the baking enamel technology. Cured films are thermally very stable since the onset of films degradation starts at high temperatures (from 281 to 330 0C). It is confirmed that there is a linear dependence between the loss modulus at 25 0C, which is the measure of the material viscosity response, and the coating hardness determined by pendulum method. All projected coatings, despite of defects in the resulting polymer networks, show satisfying properties. Among the conventional systems coating based on mixture of alkyd with ethoxylated pentaerythritol and hexamethoxymethyl melamine resin show the best properties. Application of hyperbranched alkyd resins, as binders in environment friendly coatings has an advantage due to less content of organic solvent and lower viscosity, compared to conventional alkyd resins. It is supposed that the combination of synthesized conventional and hyperbranched alkyds with melamine resins (weight ratio of 70:30 based on dried mass) could be employed as new materials for the industrial preparation of baking enamels. It is confirmed that alkyd/melamine resin systems are very complex. Results obtained enable to explain the effect of precursor type on the structure of resulting polymer network, and thus, on the coating properties.</p>

Le projet de la thèse a consisté au développement et à l’évaluation des performances d’une mousse syntactique phénolique pour la réalisation d’un système sandwich multicouche (cœur/peau en matériau composite). Il permet d’assurer la protection thermique, mécanique et au feu en particulier contre l’impact d’un feu torche. Un feu torche peut survenir sur un site pétrochimique suite à l’inflammation d’une fuite de fluides inflammables sous pression pouvant être très dévastateur par son effet abrasif et le flux convectif et radiatif intense. Le travail s’est essentiellement axé sur l’étude de l’efficacité de la mousse syntactique phénolique à partir d’une analyse de la relation microstructure-propriété. Les exigences de mise en œuvre ont imposé une maîtrise de la formulation par une bonne compréhension de la réactivité de la résine, notamment par rapport aux différentes transformations physiques (gélification, vitrification) qui ont lieu pendant le processus de réticulation. Il s’agit alors d’optimiser le dosage des différents composés actifs et additifs vis-à-vis des contraintes de mise en œuvre afin de parvenir à des propriétés optimales du matériau final. L’efficacité de ce dernier dans les conditions normales d’utilisation a été déterminée par une phase d’expérimentation complète sur ses propriétés mécaniques, thermiques et thermomécaniques. Des tests au feu ont permis d’étudier son comportement au feu afin de vérifier ses propriétés protectrices sous l’impact d’une flamme issue d’un feu torche. Enfin, un essai instrumenté capable de reproduire en condition réelle une fuite de gaz de propane à haute pression a été mis au point pour évaluer la performance au feu torche d’un prototype industriel complet. En parallèle, un modèle numérique simplifié a été proposé afin de simuler l’impact d’un tel feu. / This work consisted in the development and the evaluation of a phenolic syntactic foam performance for the production of a multilayer sandwich system (core/skin in composite material). It ensures thermal, mechanical and fire protection, in particular against the impact of a jet fire. A jet fire can occur on a petrochemical site resulting from the combustion of a fuel continuously released under pressure. It can be very devastating for its abrasive effect and intense convective and radiative flux. The work focuses mainly on the study of the effectiveness of the phenolic syntactic foam through the analysis of the relationship microstructure-propriety. The manufacturing process requirements imposed to control the elaboration via a good understanding of the reactivity of the resin, especially in relation to various physical transformations (gelation, vitrification) that take place during the curing mechanisms. That involves optimizing the proportions of the various active compounds and additives depending on the working conditions in order to achieve optimal properties of the final material. The effectiveness of this final material under normal conditions of use was determined by a complete testing phase on its mechanical, thermal and thermomechanical properties. Fire tests were also conducted to investigate the material burning behavior to ensure its protective properties under a jet flame impact. Finally, a large-scale instrumented test, reproducing in real conditions a propane gas leak at high pressure, was developed to evaluate the resistance to a jet fire of a complete industrial prototype. In parallel, a simplified numerical model was also proposed to simulate the impact of such a fire.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-06-15T14:11:52Z No. of bitstreams: 1 BÁRBARA JORDANI_.pdf: 2132585 bytes, checksum: 322ec6d990fc948ff3060abffa46014a (MD5) / Made available in DSpace on 2016-06-15T14:11:52Z (GMT). No. of bitstreams: 1 BÁRBARA JORDANI_.pdf: 2132585 bytes, checksum: 322ec6d990fc948ff3060abffa46014a (MD5) Previous issue date: 2016-03-31 / FAPERGS - Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Nos últimos anos o setor da construção civil está buscando alternativas para substituir as matérias primas utilizadas no processo de produção do concreto, visando preservar o meio ambiente reduzindo extrações da natureza. Diante disso, surge a reciclagem de materiais, que vem ganhando cada vez mais espaço dentro da atividade da construção civil. Uma das alternativas é a utilização de agregados reciclados de concreto (ARC), que podem ser empregados como substituição ao agregado natural. Outra possibilidade é o uso de pozolanas provenientes de resíduos, e dentre as diferentes opções a cinza de casca de arroz se destaca. A cinza de casca de arroz ainda não é largamente utilizada no ocidente, porém vem sendo explorada, sendo um resíduo do setor agropecuário. Após o processo de queima da casca do arroz, surge a cinza que possui grande concentração de sílica. O uso destas pozolanas contribui para diminuir o consumo de cimento. Além disto, o emprego de agregados reciclados pré-saturados pode atuar como um agente de cura interna de concretos, o que, em caso de concretos com pozolanas, pode ser um aspecto positivo para obter-se uma boa hidratação da pasta aglomerante. Este trabalho propõe investigar o efeito do emprego de agregados graúdos reciclados de resíduo de concreto (AGRC) como agente de cura interna em concretos produzidos com pozolana, frente a aspectos vinculados à durabilidade e ao comportamento mecânico. Avaliou-se a substituição do agregado graúdo natural (AN) por (AGRC) em teor determinado pelo Método de Dosagem para Cura Interna, seco e úmido, associado com a substituição de cimento por cinza de casca de arroz em teor de 20%, em dois ambientes de cura (U.R 60% e 100%). Para o estudo foi utilizado três relações a/agl (0,31; 0,42; e 0,53). Os resultados apontaram um efeito positivo do emprego da CCA em concretos fabricados com AGRC. A substituição de cimento por CCA em média pode aumentar a resistência à compressão. Os concretos fabricados com relação a/agl 0,31, para todos os concretos ensaiados, retornaram resistências na faixa de 35-45 MPa. Também foi possível notar retrações significativas até os 28 dias. Já para cura interna cabe ressaltar que o AGRC empregado saturado não apresenta comportamento de agente de cura interna, principalmente no ambiente crítico de ambiente com umidade relativa na ordem de 60%, considerada baixa. / During the last years, the construction sector has been looking for alternatives to replace the raw materials used for concrete production, in order to reduce environmenal impact. The waste recycling as raw material for civil construction can be one of solutions to this problem. One example of this kind of solution is to use the recycled concrete aggregate, which can be used as alternative for the natural aggregate. Another possibility is to use some waste as pozzolanic material, as the rice husk ash. After the burning of the rice hull, it becomes the ash, which has a large concentration of silica. The use of these pozzolans can contribute to reduce the consumption of cement. Furthermore, the usage of pre-saturated recycled aggregate can act as an internal concrete curing agent, which in the case of concretes with pozzolans can be a good way to obtain a better hydration of the binder paste. This study proposes to investigate the effect of the usage of concrete recycled coarse aggregate (RCCA) as an internal curing agent in concrete produced with pozzolan, in order to evaluate the durability and mechanical behaviour. It was evaluated the replacement of natural coarse aggregate (AN) by RCCA. The content of RCCA is related to the binder consumption and it was employed dry and wet. The cement replacement by rice husk ash was done at 20% and it was used three water to binder (w/t) relationships (0.31, 0.42, and 0.53). The curing process was developed in two cure environments (U.R 60% and 100%).The results indicated that the CCA produces positive effect on concrete made with AGRC. The concrete made with respect to w/b 0.31 for all tested concretes returned resistances in the range of 35-45 MPa. The effect of RCCA as internal curing agent is significant when the concrete is cured in a humid environment only for compressive strength. In dry environment, it does not work as internal curing agent. It was also noted significant retractions up to 28 days. As for domestic demand it is noteworthy that the saturated employee AGRC has no internal curing agent behaviour, especially in the critical environment with relative humidity of around 60%, considered low.

L’objectif de cette thèse est de développer des matériaux polymérisés par rayonnement ultra-violet possédant une bonne balance des propriétés thermomécaniques entre résistance à la température, rigidité (strength) et résistance à l’impact. Une direction vers cet objectif est l’utilisation de résines (meth)acrylate modifiées avec des thiols polyfonctionnels. Cependant, les thiol-ene en général sont sujets à un problème de polymérisation prématurée incontrôlée même à l’abri de la lumière. Ce problème doit être traité puisque celui-ci conditionne le succès des thiol-ene dans le domaine des photopolymères. La première partie de cette thèse concerne l’élaboration de résine (meth)acrylate modifiée par l’incorporation d’un polythiol, le pentaerythritol tetrakismercaptopropionate (PETMP), à différents ratio. Les propriétés thermomécaniques et photochimiques de ces résines sont à l’étude. La seconde partie traite du problème de polymérisation prématurée incontrôlée des thiol-ene. Une étude de stabilité thermique aboutissant à des résultats très encourageant est proposée. Finalement, la dernière partie porte sur la caractérisation des réseaux photo-réticulés par pyrolyse-GC/MS. La compréhension de la constitution des réseaux tridimensionnels devraient apportés des avancées dans l’élaboration de nouveaux matériaux. Une nouvelle méthode de caractérisation utilisant la pyrolyse-GC/MS directe à multi-étapes est développée. Enfin, des résultats sur l’application de la méthode sur des matériaux à base de (meth)acrylate difonctionnel photopolymérisés ainsi qu’une tentative de caractérisation de matériaux à base de polythiol/(meth)acrylates photopolymérisés sont reportés puis discutés. / This thesis fall within an approach aiming to develop UV-processed materials having a good thermo-mechanical properties balance between strength, temperature resistance and impact resistance. A direction toward this objective is the use of photocurable (meth)acrylate resins modified with polyfunctional thiols. Indeed, thiol-ene chemistry is known to have poor sensitivity toward oxygen inhibition, to improve the dimensional stability and toughness properties of photocured materials. However, thiol-ene resins are subjected to premature uncontrolled dark polymerization, an issue that has to be solved for their success in the photopolymers area. The first part of this work is focused on the thermo-mechanical and the photopolymerization properties investigation of a pentaerythritol tetrakismercaptopropionate (PETMP) modified (meth)acrylate based resin by looking at different ratio of polythiol/(meth)acrylate. The second part is dedicated to the understanding of the thermal instability of such systems and to the solving of this issue. Finally, a special interest is brought to the characterization of photopolymeric networks by pyrolysis-GC/MS. The lake of deep understanding and view about how the cured networks are really constituted due to the difficulty to analyze insoluble cured polymers, prevents improvements in the formulation of high performance materials. Further information on cured networks constitution could bring useful information for the elaboration of new materials. A new characterization method based on direct multi-step pyrolysis-GC/MS is developed and an attempt on the characterization of polythiol (meth)acrylate material by Py-GC/MS is reported and discussed.

Die Einbrennsilikonisierung wird schon lange verwendet, um spezielle Eigenschaften bei pharmazeutischen Glasbehältnissen zu erzielen. Üblicherweise werden Silikonöle verwendet um Gleitfilme auf den Oberflächen vorgefüllter Glasspritzen zu erzeugen oder die Glaswand zu hydrophobieren damit wäßrige Inhalte sauber ablaufen können. Weiterhin kann durch die hydrophobe Deaktivierung der Glaswände eine Reduktion der Adsorption von Wirk- und Hilfsstoffen sowie eine Erhöhung der hydrolytischen Resistenz erreicht werden. Wegen des parenteralen Verwendungszweckes werden meistens Gläser der Glasart 1 entsprechend dem europäischen Arzneibuch eingesetzt. Die Silikonölfilme (Trimethylsiloxy-endgeblockte Polydimethylsiloxane, PDMS) werden aus verdünnter wäßriger Emulsion auf der inneren Behältnisoberfläche gespreitet und anschließend bei Temperaturen oberhalb von 300°C für ca. 10-30 min hitzebehandelt. Neben der Sterilisation und Entpyrogenisierung wird der Silikonfilm durch das Einbrennen verändert. In der Literatur wurde dieser Prozeß bisher als Hitzefixierung oder -härtung bezeichnet in der Annahme, daß das Silikonöl durch Glasbindung oder Quervernetzung immobilisiert wird. Es wurden weitere Effekte wie Verdampfung oder Zersetzungsreaktionen als Folge der Hitzebehandlung angenommen. Die Dissertation hatte daher zum Ziel diese Vorstellungen analytisch zu belegen. Die Eigenschaften einbrennsilikonisierter Gläser lassen sich durch einfache Experimente beschreiben. Durch organische Extraktion der Gläser (z.B. Toluol, Dichlormethan) läßt sich der überwiegende Silikonanteil (ca. 80%) wiederfinden. Nach erschöpfender Extraktion zeigt sich eine beständige Hydrophobie z.B. durch die Ausbildung hoher Randwinkel von Wasser oder das veränderte Ablaufverhalten von Flüssigkeiten in diesen Behältnissen festgestellt werden. Basierend auf diesen Beobachtungen wurde die Anwesenheit einer gebundenen neben einer löslichen Silikonölfraktion nach dem Einbrennen angenommen. Alle analytischen Studien wurden an dieser zwei Lagen Theorie orientiert und durchgeführt. Dazu wurden einige oberflächensensitive Techniken wie z.B. die kombinierte Röntgenphotoelektronen- und Augerelektronenspektroskopie (XPS/AES) und die Flugzeit-Sekundärionenmassenspektroskopie (TOF-SIMS) eingesetzt. Durch chemische Zustandsdiagramme und massenspektroskopische Strukturanalyse konnte die Ausbildung von Bindungen zwischen Glas und Silikon detektiert werden. Kontaktwinkelmessungen zeigten, daß das gebundene Silikon bis ca. 400°C thermostabil ist und oberhalb von 450°C pyrolysiert wird. Die extrahierbare Silikonfraktion wurde ebenfalls mit einigen analytischen Techniken im Vergleich mit den jeweiligen unbehandelten Ausgangsmaterialien untersucht. Chromatographische Studien mittels Größenausschluß- und Hochtemperatur-Gaschromatographie (SEC,GC) zeigten signifikante Unterschiede in der polymeren Zusammensetzung des PDMS. Die Molekulargewichtsmittel stiegen als Folge von Verlusten von niedermolekularen Siloxanen einer Größe zwischen 0-100 Siloxaneinheiten (SU) an. Diese Defizite können auf Verdampfungs- (0-50 SU) und Zersetzungsreaktionen (50-100 SU) zurückgeführt werden. Die Untersuchung des extrahierbaren eingebrannten Silikonöls mit der Fourier Transform Infrarot Spektroskopie (FTIR) zeigte keine strukturelle Veränderung der PDMS Moleküle, z.B. durch Hydrolyse, Oxidation oder Verzweigung an. Die Emulgatoren werden durch das Einbrennen zerstört. Dies wurde durch die 1H-Kernresonanz Spektroskopie (1H-NMR) nachgewiesen. Die Thermostabilität des PDMS wird durch katalytische Effekte der Emulsionshilfsstoffe und durch die Anwesenheit von Sauerstoff erniedrigt, wie aus thermogravimetrische Analysen (TGA) mit kommerziellen Silikonölen und Ölemulsionen modellhaft abgeleitet wurde. Um die Migration von Silikonölspuren in Arzneimittel in silikonisierten Glasbehältnissen zu bewerten wurde eine Atom Absorptions spektroskopische (AAS) Methode entwickelt und entsprechend den ICH-Richtlinien validiert (Bestimmungsgrenze in Liquida 10 mg/L). Die Schlußfolgerung aus den Analysen ist, daß nach der Einbrennsilikonisierung zwei differenzierbare Silikonfraktionen an der Glasoberfläche anwesend sind. Die kovalent gebundene Dünnschicht ist unlöslich und verliert ihren Ölcharakter, ist aber für die Hydrophobisierung ausreichend. In der löslichen Fraktion, werden die mittleren Molekulargewichte durch den Verlust von niedermolekularen Anteilen erhöht. Der Anteil dieser Schicht hängt von der eingesetzten Ausgangsmenge an Silikonöl ab. Durch die Entfernung der niedermolekularen Anteile und die Zerstörung der Emulgatoren können toxikologische Bedenken zurückgestellt werden. / Heat Curing Siliconization of Pharmaceutical Glass Containers The heat curing siliconization has long since been used to introduce special properties to pharmaceutical glass containers. Silicone oils are usually applied to the containers to form lubricating films on the inner surface of prefilled syringes or to gain hydrophobic container walls for clear draining aqueous solutions, e.g. in injection vials. Furthermore the deactivation of the glass wall reduces adsorption of hydrophilic drug compounds and increases the hydrolytic stability of the glass surface. Due to the parenteral targeting the glass containers are made from glass type 1 according to the European Pharmacopoeia. The silicone oil films (= trimethylsiloxy endcapped polydimethylsiloxane, PDMS) are spread from diluted aqueous silicone oil emulsions on the inner surface and successively heat treated above 300°C for 10-30 minutes. Apart from sterilization and depyrogenation, the silicone layer is changed by the burning-in treatment. In literature the process has previously been designated as heat fixing or heat curing assuming that silicone oil is immobilized by bonding to the glass or branching. Further effects such as vaporization or degradation were suggested along with the heating. Proving these suggestions analytically was therefore the aim of the dissertation. The properties of siliconized glass containers can be characterized by simple experiments. Extraction of the glasses with suitable organic solvents (e.g. toluene, dichloromethane) recovers most of the silicone (approximately 80%) after a typical heat curing process. Still, after exhaustive solvent extraction there are persisting hydrophobic properties of the glasses evidenced by high contact angles of water and changed draining behaviour of fluids in the containers. From this observations it was assumed that a bound and a soluble silicone species is present after the heat curing siliconization. All analytical studies were based on the two-layer hypothesis and thus divided in two parts. Several surface analysis techniques were employed to detect and characterize the fixed silicone layer among them the combined X-ray photoelectron and augerelectron spectroscopy (XPS/AES) and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). The formation of new bonds between silicone and glass was evidenced by chemical state plots and mass spectroscopic structural analysis. Contact angle measurements showed that the bound silicone was thermostable up to 400°C and pyrolyzed at temperatures above 450°C. The extractable silicone was also studied with several analytical techniques in comparison with the respective uncured starting materials. Chromatographic studies using size exclusion (SEC) and high temperature gas chromatography (GC) revealed significant changes in the composition of the silicone polymer. The molecular weight averages increase because low molecular weight siloxanes (LMWS) with 0-100 dimethylsiloxane units are removed through the heat curing process. These deficits can be related to vaporization (molecules from 0-50 units) and degradation (molecules from 0-100 units) effects. A Fourier transform infrared spectroscopic (FTIR) investigation of the molecular structure of the extractable PDMS after heat treatment showed no chemical changes e.g. by hydrolysis, branching or oxidation. The emulsifiers are destroyed in the heating process which was proved by a proton nuclear magnetic resonance (1H-NMR) study. The thermostability of the silicones is decreased by katalytic effects of auxiliary substances in the emulsions and the presence of oxygen. This was concluded from model thermogravimetric studies (TGA) with commercial medical grade silicone oils and emulsions. To evaluate migration of silicone traces to drug formulations in siliconized glass containers a trace analytical method by graphite furnace atomic absorption spectrometry (GF-AAS) was developed and validated according to the ICH guidelines. In liquid formulations levels of 10µg/L can be properly quantified. It was concluded that two main species of silicone can be differentiated on the glass surface after heat curing siliconization. The bonded thin layer is insoluble and sufficient for hydrophobic deactivation. The oil properties are lost. The extractable fraction is altered by removal of LMWS which increases molecular weight and viscosity and determines the lubricating properties. Its amount depends on the used silicone mass. No toxicological concern has to be made about LMWS and emulsifiers in the drug product due to their removal in the curing step.