Os implantes mamários de silicone têm sido empregados, tanto nas cirurgias de aumento das mamas, quanto na reconstrução do tecido mamário após mastectomia. A segurança biológica dos implantes de silicone merece estudo relacionado aos processos de esterilização empregados, pois podem constituir-se em fator de comprometimento da estrutura química do polímero e, conseqüentemente, da biocompatibilidade. Este estudo consistiu na avaliação da biocompatibilidade de implantes mamários de silicone após terem sido submetidos aos processos de esterilização por calor seco, radiação gama e óxido de etileno. O parâmetro avaliado foi a viabilidade celular, empregando o método de difusão em agar e de captura do vermelho neutro. As amostras compreenderam implantes de silicone gel lisos, texturizados e revestidos com poliuretano e implantes texturizados pré-cheios com solução salina. Também foi realizado o teste de endotoxinas bacterianas pelo método do LAL e determinação da taxa de migração do gel de silicone (teste de bleed). Os três métodos de esterilização mostraram-se igualmente eficientes pela comprovação da condição de esterilidade dos implantes através de metodologia descrita na Farmacopéia Americana 27 edição. Os níveis de endotoxinas bacterianas dos implantes, também atenderam aos requisitos dos compêndios oficiais. Na avaliação da biocompatibilidade todos os implantes, independente dos processos de esterilização utilizados, apresentaram ausência de citotoxicidade. Os resultados do teste de bleed mostraram uma maior taxa de migração de gel para os implantes de superfície lisa em comparação com os implantes de superfície texturizada e revestida com poliuretano, quando esterilizados por calor seco. Ao comparar a taxa de migração do gel para os implantes de superfície lisa esterilizados por calor seco e óxido de etileno, obteve-se uma maior taxa de migração para aqueles implantes esterilizados por óxido de etileno. As diferentes avaliações realizadas neste estudo abrangeram aspectos biológicos, químicos e físicos relevantes para garantir um produto de boa qualidade e que, por assegurar a manutenção da característica de biocompatibilidade, resulta na segurança biológica deste tipo de implante. / Silicone breast implants have been widely used for mammary augmentation and reconstruction surgery. Biological safety of these implants can be damaged by sterilization methods. This study consisted of the biocompatibility assessment of breast implants through cell viability, employing the agar diffusion test and neutral red uptake. Four silicone breast implants were tested: smooth, textured, polyurethane covered silicone gel breast implant and textured saline-filled breast implant. Sterilization methods comprised dry-heat, ethylene oxide and γ-radiation. Detection of bacterial endotoxins employing LAL test and gel bleed was also performed. The three methods of sterilization revealed equally efficacious, through the sterility confirmation of implants employing methodology described in 27th edition of United States Pharmacopeia. At the same way the leveis of bacterial endotoxins of implants accorded with the pharmacopeial requirements. In theevaluation of biocompatibility ali the implants, independently of the sterilization process used, showed no cytotoxicity signals. The results of gel bleed revealed a higher migration rate from the smooth implants in comparison with the textured and polyurethane-covered implants sterilized by dry-heat. When was compared the gel migration of smooth implants sterilized by dry-heat and ethylene oxide, was obtained a higher rate of gel bleed of those implants sterilized by ethylene oxide. The different evaluations performed in this study comprised biological, chemical and physical aspects, that are relevant to assure a good quality product and by having maintained the characteristics of biocompatibility, resulted in the biological safety on this kind of implant.

Os implantes mamários de silicone têm sido empregados, tanto nas cirurgias de aumento das mamas, quanto na reconstrução do tecido mamário após mastectomia. A segurança biológica dos implantes de silicone merece estudo relacionado aos processos de esterilização empregados, pois podem constituir-se em fator de comprometimento da estrutura química do polímero e, conseqüentemente, da biocompatibilidade. Este estudo consistiu na avaliação da biocompatibilidade de implantes mamários de silicone após terem sido submetidos aos processos de esterilização por calor seco, radiação gama e óxido de etileno. O parâmetro avaliado foi a viabilidade celular, empregando o método de difusão em agar e de captura do vermelho neutro. As amostras compreenderam implantes de silicone gel lisos, texturizados e revestidos com poliuretano e implantes texturizados pré-cheios com solução salina. Também foi realizado o teste de endotoxinas bacterianas pelo método do LAL e determinação da taxa de migração do gel de silicone (teste de bleed). Os três métodos de esterilização mostraram-se igualmente eficientes pela comprovação da condição de esterilidade dos implantes através de metodologia descrita na Farmacopéia Americana 27 edição. Os níveis de endotoxinas bacterianas dos implantes, também atenderam aos requisitos dos compêndios oficiais. Na avaliação da biocompatibilidade todos os implantes, independente dos processos de esterilização utilizados, apresentaram ausência de citotoxicidade. Os resultados do teste de bleed mostraram uma maior taxa de migração de gel para os implantes de superfície lisa em comparação com os implantes de superfície texturizada e revestida com poliuretano, quando esterilizados por calor seco. Ao comparar a taxa de migração do gel para os implantes de superfície lisa esterilizados por calor seco e óxido de etileno, obteve-se uma maior taxa de migração para aqueles implantes esterilizados por óxido de etileno. As diferentes avaliações realizadas neste estudo abrangeram aspectos biológicos, químicos e físicos relevantes para garantir um produto de boa qualidade e que, por assegurar a manutenção da característica de biocompatibilidade, resulta na segurança biológica deste tipo de implante. / Silicone breast implants have been widely used for mammary augmentation and reconstruction surgery. Biological safety of these implants can be damaged by sterilization methods. This study consisted of the biocompatibility assessment of breast implants through cell viability, employing the agar diffusion test and neutral red uptake. Four silicone breast implants were tested: smooth, textured, polyurethane covered silicone gel breast implant and textured saline-filled breast implant. Sterilization methods comprised dry-heat, ethylene oxide and γ-radiation. Detection of bacterial endotoxins employing LAL test and gel bleed was also performed. The three methods of sterilization revealed equally efficacious, through the sterility confirmation of implants employing methodology described in 27th edition of United States Pharmacopeia. At the same way the leveis of bacterial endotoxins of implants accorded with the pharmacopeial requirements. In theevaluation of biocompatibility ali the implants, independently of the sterilization process used, showed no cytotoxicity signals. The results of gel bleed revealed a higher migration rate from the smooth implants in comparison with the textured and polyurethane-covered implants sterilized by dry-heat. When was compared the gel migration of smooth implants sterilized by dry-heat and ethylene oxide, was obtained a higher rate of gel bleed of those implants sterilized by ethylene oxide. The different evaluations performed in this study comprised biological, chemical and physical aspects, that are relevant to assure a good quality product and by having maintained the characteristics of biocompatibility, resulted in the biological safety on this kind of implant.

Les silicones auto-cicatrisants de façon autonome (sans stimulus externe) présentent de faibles propriétés mécaniques, limitant leur utilisation industrielle. L’objectif de cette étude était de dépasser cette limitation. Nos travaux se sont intéressés aux copolymères segmentés PDMS-urée constitués de blocs souples (SS) et rigides (HS). Tout d’abord, nous avons étudié la relation entre la structure des bis-urées et les propriétés macroscopiques. Nous avons ainsi montré que la symétrie des HS gouverne la rigidité de ces matériaux. Toutefois, la présence de HS symétriques inhibe la cicatrisation du matériau. Puis, nous avons développé un nouveau concept permettant d’accélérer leur cinétique de cicatrisation. Un stoppeur de chaine macromoléculaire a été ajouté à la formulation de ces silicones thermoplastiques, créant un défaut dans l’assemblage supramoléculaire, conduisant à des clusters organiques plus petits et plus dynamiques. Néanmoins, contrairement aux plastifiants, la chute du module de Young observée par rapport à la matrice est limitée. D’ailleurs, nous reportons la synthèse d’un copolymère PDMS-urée avec un module de traction de 1MPa dont 90% de la contrainte à rupture peut être récupérée après cicatrisation pendant 24h à 25°C. Ce concept a aussi été adapté à un thermoplastique commercial (GENIOMER80). Enfin, notre défi a été d’optimiser la balance entre rigidité et autocicatrisation. Dans ce contexte, nous avons synthétisé de nouvelles matrices plus rigides, ainsi que des additifs avec des groupements associatifs de plus grande énergie cohésive. Nous avons alors pu repousser la limite de rigidité accessible aux silicones auto-cicatrisants de façon autonome (3MPa). / Autonomous self-healable (without external stimulus) silicones exhibit too low mechanical properties restricting their use in industry. The aim of this study was to overcome this limitation. We focused our work on segmented PDMS-urea copolymers made of soft (SS) and hard segments (HS). First the investigation of the relationship between the bis-urea chemical structure and the macroscopic properties was made. Results shown that, the symmetry of HS governs materials rigidity. Moreover, with a too symmetrical HS, the material does not exhibit self-healing abilities. We have developed a new concept improving the healing efficiency of these materials. The idea was to add to the formulation of these silicone thermoplastics a macromolecular chain stopper. The new additive creates a defect in the supramolecular assembly which leads to smaller and more dynamic H-bonding clusters and hence a faster healing kinetic. Unlike plasticizers, this additive deteriorates the tensile modulus only marginally. We therefore report a stress at break recovery of 90% after 24 hours at room temperature for a PDMS-urea copolymer with a tensile modulus of 1MPa. The concept was also extented to a commercial thermoplastic (GENIOMER80). Finally, our last challenge was to manage the balance between rigidity and chains dynamics allowing self-healable materials with good mechanical properties. In this context we have synthesized new matrixes with higher HS percentage and additives with stickers with higher cohesive energy. These new syntheses have led to an improvement of the rigidity limit reachable by the autonomous self-healable silicones (3MPa).

Over the last 20 years "composite" insulators have been increasingly used in high voltage applications as an alternative traditional materials. More recently, polydimethylsiloxane (PDMS) have been used as weather sheds on these composite insulators. The main attraction with PDMS is that the surface hydrophobicity can be recovered following pollution or surface discharges. Among the possible mechanisms for recovery the most likely is the migration of low molecular weight silicone oil (LMWS) from the bulk to the surface encapsulating pollutant particles. Although it is widely recognised that the migration of LMWS is the cause of this recovery of hydrophobicity, the mechanism of what actually occurs is not well understood. It is also not known for how long this process will continue. The main objective of this study program was to gain improved understanding of the surface hydrophobic recovery process that is unique to polydimethlysiloxane high-voltage insulators. Fundamental knowledge of this mechanism has been increased through the development of the Contact Angle DRIFT Electrostatic Deposition (CADED) novel analytical technique. This technique enabled study of the degradation of silicone elastomers subjected to high voltage environments by closely following LMWS migration from the bulk material to the surface and linking it to the contact angle measurements. The migration rate data showed that the aged material recovered faster that the virgin material. Differences in the rate and maximum surface levels of silicone were seen between materials from different manufacturers. This has significant implications for the life-time of these materials A model system has been developed to examine LMWS diffusion through the bulk material and into the interface of surface and pollutant. This was achieved by examining theoretical and empirically derived equations and using existing experimental data to better understand the mechanism of recovery. This diffusion was Fickian in the initial stages of recovery. X-ray photoelectron spectroscopy (XPS) and contact angle measurements were used to substantiate the degree of degradation in in-field silicone insulators by quantifying the levels of the major degradation products: silica and silica-like material and alumina.

Submitted by Gustavo Nascimento (gustavo.diniz@ufcg.edu.br) on 2018-01-29T11:51:13Z No. of bitstreams: 1 DANIELLA CIBELE BEZERRA - TESE PPGCMAT 2014.pdf: 4550868 bytes, checksum: d91b2b560040e4f5f101c7f129c13aab (MD5) / Made available in DSpace on 2018-01-29T11:51:13Z (GMT). No. of bitstreams: 1 DANIELLA CIBELE BEZERRA - TESE PPGCMAT 2014.pdf: 4550868 bytes, checksum: d91b2b560040e4f5f101c7f129c13aab (MD5) Previous issue date: 2014-11-03 / CNPq / Um dos principais problemas do isolamento elétrico externo é o acúmulo de contaminantes em sua superfície. A ocorrência deste evento faz com que a resistência da superfície diminua, aumentando a presença de correntes de fuga pela superfície. Entre as técnicas desenvolvidas para diminuir esse tipo de efeito, está o revestimento do isolador existente convencional (porcelana ou vidro, conforme o caso) com uma borracha de silicone que é vulcanizada à temperatura ambiente (BS). O objetivo deste trabalho foi desenvolver uma mistura de borracha de silicone/alumina trihidratada/nanosílica (BS/ATH:NS) para ser usada em revestimento de isoladores elétricos de vidro. Cargas de ATH e NS foram adicionadas à BS, produzindo uma mistura feita em diferentes proporções mássicas (79/21; 77/23 e 75/25) de BS/ATH:NS, utilizada nos revestimento dos isoladores elétricos de vidro. As cargas e os revestimentos foram caracterizados por difração de raios X (DRX), microscopia eletrônica de varredura (MEV), teste de inflamabilidade, ensaio na câmara de névoa salina, molhabilidade e avaliação da hidrofobicidade. As cargas apresentaram características morfológicas bem distintas, o que interferiu diretamente na morfologia dos revestimentos. A silanização das cargas favoreceu uma interação entre elas, assim como houve uma pequena melhora na interação das cargas com a BS. Observou-se também que no teste de inflamabilidade, os revestimentos que continham ATH, apresentaram resultados mais significativos, não havendo queima. Para os ensaios na câmara de névoa salina, o revestimento com BS/20:1 e os revestimentos com cargas silanizadas apresentaram os menores valores de corrente de fuga, o que foi comprovado com a avaliação da hidrofobicidade, na qual estes conseguiram recuperar a hidrofobicidade até HC=1 (nível de hidrofobicidade), de acordo com o guia STIR (Swedish Transmission Research Institute). / One of the main problems of external electrical isolation is due to accumulation of contaminants on its surface. The occurrence of this event causes the insulation resistance of the surface decreases, increasing the flow of leakage currents on the surface. Among the techniques developed to reduce this type of event is the coating of the conventional existing insulator (porcelain or glass, as appropriate) with a silicone rubber vulcanized at room temperature (BS). The aim of this study was to develop a mixture of silicone rubber/ alumina trihydrate/nanosílica (BS/ATH:NS) for use in coating glass electrical insulators. Loads of ATH and NS were added to BS, producing a mixture made in different mass ratios (79/21, 77/23 and 75/25) BS/ATH:NS used in the coating of glass electrical insulators. Loads and coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), flammability test, measurement salt spray chamber, test of wettability and hydrophobicity. Loads showed distinct morphological features, which directly affects the morphology of the coatings. The silanization loads favored interaction among them, as there was a small improvement in the interaction of the loads with the BS. It was also observed that the flammability test, the coatings containing ATH showed more significant results, without burning. For tests of the salt spray chamber, coat with BS/20:1 and with silanized fillers had the lowest leakage current, which was confirmed by measuring the hydrophobicity, where they managed to recover the hydrophobicity HC = 1 (level of hydrophobicity) according to STIR (Swedish Transmission Research Institute) guide.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-20T14:23:35Z No. of bitstreams: 1 GLERYSTON THIAGO GOMES DA SILVA - DISSERTAÇÃO (PPGEM) 2017.pdf: 4116473 bytes, checksum: 5df445f57ab1b4d9326f681288378141 (MD5) / Made available in DSpace on 2018-08-20T14:23:35Z (GMT). No. of bitstreams: 1 GLERYSTON THIAGO GOMES DA SILVA - DISSERTAÇÃO (PPGEM) 2017.pdf: 4116473 bytes, checksum: 5df445f57ab1b4d9326f681288378141 (MD5) Previous issue date: 2017-05-03 / Capes / O presente trabalho avalia a adesão entre fios e fitas de uma liga com memória de forma (LMF) de Ni-Ti e uma borracha de silicone, para o desenvolvimento de estruturas flexíveis. A avaliação da adesão foi realizada através de ensaios de extração (Pull Out). Para realização dos ensaios, foram produzidos seis tipos de corpos de prova (CPs) em que os fios e as fitas foram embebidos em uma matriz de borracha de silicone. Primeiramente, as fitas foram obtidas laminando a frio fios de Ni-Ti superelástico. Após a laminação as fitas foram submetidas a tratamento térmico em temperaturas e tempos diferentes, a fim de obter dois tipos de fitas: uma com característica de superelasticidade (SE) e outra com o efeito memória de forma (EMF). Um promotor de adesão Dow Corning 1200 Primer foi aplicado nas superfícies dos fios e das fitas para aumento da adesão. Os fios e as fitas de Ni-Ti e a borracha de silicone foram individualmente caracterizados por Calorimetria Exploratória Diferencial (DSC), Análise Dinâmico-Mecânica (DMA) e tração uniaxial, analisando o comportamento do fator de amortecimento, módulo de elasticidade, tensões de transformação e temperaturas de transformação de fase. O ensaio de carregamento – descarregamento em tração na borracha de silicone também foi realizado para analisar a presença do efeito Mullins. Para verificação qualitativa do aumento da rugosidade e da adesão geradas pelo processo de laminação e pela aplicação do primer, respectivamente, foram realizadas imagens por Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Energia Dispersiva (EDS) nos fios e nas fitas de Ni-Ti antes e após o ensaio de extração (Pull Out). A partir dos resultados obtidos, observa-se que o fio superelástico e as fitas de Ni-Ti laminadas e tratadas termicamente sem aplicação do primer não apresentam adesão suficiente para o desenvolvimento de estruturas flexíveis compostas por borracha de silicone e elementos atuadores como fios e fitas de Ni-Ti, sendo necessária a aplicação de um promotor de adesão (primer) nas superfícies das LMF. / The present work evaluates the adhesion between Ni-Ti Shape Memory Alloy (SMA) wires and ribbons embedded into a silicone rubber, for the development of flexible structures. Adhesion evaluation was performed through pullout tests. To perform the tests, six types of specimens were produced, in which the wires and ribbons were embedded in a silicone rubber matrix. Firstly, the ribbons were obtained by cold rolling of a superelastic Ni-Ti wire. After the cold rolling, the ribbons were subjected to heat treatment at different temperatures and times in order to obtain two types materials: one with Superelasticity (SE) property and other with Shape Memory Effect (SME). A Dow Corning 1200 Primer adhesion promoter was applied to the surfaces of the wires and ribbons to improve adhesion. Ni-Ti wire and ribbons and silicone rubber were characterized by Differential Scanning Calorimetry (DSC), Dynamic-Mechanical Analysis (DMA) and uniaxial tensile tests, to obtain loss factor behavior, elastic modulus, tensile stress transformations and phase transformation temperatures. Analysis of tensile loading - unloading test on silicone rubber was also performed to evaluate the presence of the Mullins effect. For the qualitative verification of the roughness and adhesion improvement, generated by the cold rolling process and the application of the primer, respectively, images of Scanning Electron Microscopy (SEM) and Dispersive Energy Spectroscopy (EDS) in the Ni- Ti wire and ribbons were performed before and after the pullout tests. The obtained results indicate that the Ni-Ti superelastic wires and heat treated cold rolled ribbons without primer do not present sufficient adhesion for the development of silicone rubber flexible structures with embedded Ni-Ti wires and ribbons, requiring the application of an adhesion promoter (primer) on the surfaces of the SMA.

abstract: This thesis concerns the flashover issue of the substation insulators operating in a polluted environment. The outdoor insulation equipment used in the power delivery infrastructure encounter different types of pollutants due to varied environmental conditions. Various methods have been developed by manufacturers and researchers to mitigate the flashover problem. The application of Room Temperature Vulcanized (RTV) silicone rubber is one such favorable method as it can be applied over the already installed units. Field experience has already showed that the RTV silicone rubber coated insulators have a lower flashover probability than the uncoated insulators. The scope of this research is to quantify the improvement in the flashover performance. Artificial contamination tests were carried on station post insulators for assessing their performance. A factorial experiment design was used to model the flashover performance. The formulation included the severity of contamination and leakage distance of the insulator samples. Regression analysis was used to develop a mathematical model from the data obtained from the experiments. The main conclusion drawn from the study is that the RTV coated insulators withstood much higher levels of contamination even when the coating had lost its hydrophobicity. This improvement in flashover performance was found to be in the range of 20-40%. A much better flashover performance was observed when the coating recovered its hydrophobicity. It was also seen that the adhesion of coating was excellent even after many tests which involved substantial discharge activity. / Dissertation/Thesis / M.S. Electrical Engineering 2013

L'objectif de ces travaux était de mettre au point une nouvelle voie de modification de la silice comme renfort d'élastomères silicones. La polymérisation par ouverture de cyclosiloxanes anionique (POCA) amorcée directement à partir de la silice dispersée en phase aqueuse a été réalisée. Les caractéristiques des silices utilisées dans cette étude ainsi que leur comportement en dispersion aqueuse ont tout d'abord été étudiés. La silice affiche des groupements silanolates à la surface de la silice pour des pH supérieurs au point de charge nulle. A pH 7, ces groupements silanolates en surface sont capables d'amorcer une polymérisation des cyclosiloxanes, et pas en suspension aqueuse. L'influence du contre-ion et de sa concentration sur le greffage obtenu s'est avérée primordiale, en complément des propriétés adsorbantes de la silice via les liaisons siloxanes. Les silices obtenues par ce nouveau procédé ont fait l'objet d'analyses poussées par thermogravimétrie, fragmentation-CPG, 29Si RMN simple impulsion et pyrolyse CPG-SM dans le but de décrire précisément la conformation du greffage. Le procédé a été transféré à plus grande échelle pour permettre la production d'importantes quantités de silice qui ont ensuite été incorporées dans une matrice silicone. Des limites de densités de greffage au-delà et en deçà desquelles la silice est mal dispersée dans le matériau ont été mises en évidence par traitement d'image. Les propriétés des élastomères ont été évaluées à partir de tests de dureté, de traction uniaxiale, de traction cyclique et de résistance à la déchirure dans le but d'étudier l'influence du greffage (conformation et groupements vinylés) sur le renforcement. / This work deals with a new way of modifying silica surface in a view to reinforce silicone elastomers. The surface-initiated ring-opening-polymerization (Si-ROP) of cyclosiloxanes was performed directly from the surface of silica dispersed in water. The characteristics of silica used in this study and their behavior in aqueous dispersion were first studied. For pH higher than the Point of Zero Charge, silica presents silanolate groups at its surface that are able to initiate the ROP of cyclosiloxanes from the surface, and not in aqueous suspension. The influence of the counter-cation and its concentration proved to be essential, in addition to silica's adsorbing properties. Modified silicas obtained by this new process were deeply analyzed by thermogravimetric analyses (TGA), fragmentation-GC, simple impulsion 29Si RMN and pyrolysis GC-MS in order to describe precisely the grafting conformation. The polymerization process was then scaled up to produce higher quantities of modified silica, which were incorporated in a model silicone formulation. Highest and lowest grafting densities tended to poor silica dispersions, as shown by image treatment. Hardness tests, uniaxial tensile and cyclic tests and tear resistance tests were performed in order to evaluate the influence of the grafting (conformation and vinylated groups) on silicone elastomers properties.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-03T16:47:38Z No. of bitstreams: 1 jaianebandolimonteiro.pdf: 2039791 bytes, checksum: c3f28c1a95fdef73d0cc0190a9dfa169 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-03T21:29:38Z (GMT) No. of bitstreams: 1 jaianebandolimonteiro.pdf: 2039791 bytes, checksum: c3f28c1a95fdef73d0cc0190a9dfa169 (MD5) / Made available in DSpace on 2015-12-03T21:29:38Z (GMT). No. of bitstreams: 1 jaianebandolimonteiro.pdf: 2039791 bytes, checksum: c3f28c1a95fdef73d0cc0190a9dfa169 (MD5) Previous issue date: 2015-04-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo foi avaliar a alteração dimensional dos moldes de silicona por condensação imediatamente, 30min, 1h e 7 dias após a moldagem, com o auxílio da máquina de medição tridimensional por coordenadas. Os grupos foram divididos em: G1: Speedex Putty/Speedex Light Body (Coltene/Vigodent AS Indústria e Comércio), G2: Optosil P Plus/Xantopren L Blue (Heraeus Kulzer GmbH), G3: Zetaplus Putty/Oranwash L (Zhermack SpA) e G4: Precise SX (Dentsply Indústria e Comércio Ltda). Para a obtenção das 80 medições dos 4 materiais (n=20), foi usado um dispositivo composto por uma moldeira perfurada e uma outra parte com 3 edentações pré-estabelecidas. Para a avaliação dimensional, a máquina Crysta-Plus M 574 (Mitutoyo) realizou cada medida 3 vezes nos tempos estabelecidos e obteve-se a média aritmética. A média final das 4 distâncias I, II, III e IV do dispositivo edentado foi novamente aplicada. A análise estatística foi realizada com o teste de Kolmogorov-Smirnov que rejeitou a hipótese nula de distribuição assimétrica. Posteriormente, foi feita a ANOVA para comparar os 4 materiais simultaneamente e o teste paramétrico t de Student para comparar os materiais 2 a 2. O nível de significância global foi de p≤0,05. A maior contração linear foi observada na Speedex, mas não foi significante (p=0,08). A Zetaplus Putty/Oranwash L parece ser a mais estável (p=0,99), mas não foi significante. Não houve diferença estatisticamente significante entre nenhuma silicona por condensação quando comparadas simultaneamente nos 4 tempos ou quando comparadas 2 a 2, à exceção, Precise SX e a Speedex (p=0,05) no tempo T3. Todas as siliconas por condensação testadas apresentam alteração dimensional clinicamente aceitável e podem ser vazadas imediatamente, 30min, 1h e 7 dias após a moldagem. / The purpose was to evaluate the dimensional changes of condensation silicone impressions by immediately, 30min, 1h and 7 days after impression, with the help of threedimensional measuring coordinate machine. The groups were divided in: G1: Speedex Putty/Speedex Light Body (Coltène/Vigodent S/A Ind and Com), G2: Optosil P Plus/Xantopren L Blue (Heraeus Kulzer GmbH), G3: Zetaplus Putty/Oranwash L (Zhermack SpA) and G4: Precise SX (Dentsply Ind and Com Ltda). To obtain 80 measurements of 4 material (n=20) was used a device consisting of a perforated tray and one another part with 3 pre-established indentations. For dimensional evaluation, the Crysta-Plus M574 machine (Mitutoyo) held each measurement 3 times at the established times and obtained the arithmetic mean. The final average of the 4 distances of I, II, III and IV the edentulous device was again applied. Statistical analysis was performed using the Kolmogorov-Smirnov test to reject the null hypothesis of asymmetric distribution. Subsequently, ANOVA was performed to compare the four materials simultaneously and Student's t parametric test to compare the 2 by 2 materials. The overall significance level of p≤0,05. The higher linear contraction was observed in Speedex, but was not significant (p=0,08). The Zetaplus Putty/Oranwash L seems to be more stable (p=0,99) but was not significant. There was no significant difference between any silicone condensation compared simultaneously in 4 times or compared 2 by 2, except, Precise SX and Speedex (p=0,05) in T3 time. All tested condensation silicones exhibit clinically acceptable dimensional change and can be leaked immediately, 30min, 1h and 7 days after impression.

Les stents urétéraux et les sondes de néphrostomie sont constitués de silicone ou de polyuréthane thermoplastique (TPU). Afin de limiter les risques infectieux lors de leur implantation, une modification topographique par création de pores permettrait de limiter l’adhésion des bactéries et de former des réservoirs pour une libération in situ de substances antiinfectieuses. Ce travail vise à préparer des surfaces en polymère ayant un motif poreux tubulaire ordonné. Une réplication en deux temps à partir de surfaces ordonnées poreuses d’oxyde d’aluminium (PAAO) préparées par 2 méthodes (double anodisation douce et double anodisation dure/douce) a été mise en œuvre pour reproduire le motif initial sur des surfaces en silicone et TPU. Pour le moule intermédiaire trois matériaux ont été testés (acrylonitrile butadiène styrène, polystyrène et résine polyacrylate). Les surfaces ont toutes été caractérisées par des techniques microscopiques et spectroscopiques. Les surfaces en PAAO préparées par double anodisation douce possédaient des pores d’environ 50 nm de diamètre et 100 nm de profondeur, alors que celles obtenues après mise au point de la méthode dure/douce étaient de taille supérieure, d’environ 125 nm de diamètre et ayant des profondeurs de quelques centaines de nanomètres. La surface du moule intermédiaire est constituée de picots. Une adhésion latérale de ceux-ci a été observée pour certaines conditions. La meilleure réplication du motif a été obtenue pour le TPU. Les surfaces ainsi obtenues pourront être utilisées et optimisées lors de l'étude ultérieure de l'adhésion du biofilm. / Ureteral stents and nephrostomy catheters are made of silicone or thermoplastic polyurethane (TPU). A topographical modification creating an ordered porous surface could limit the infectious risks during their implantation, by reducing bacterial adhesion and creating a loading platform from which anti-infectious compounds could be released.In this work, a two-steps replication method was used to create ordered porous polymer surfaces (silicone or TPU) using porous anodic aluminium oxide (PAAO) as master template. The PAAO surfaces were prepared by double mild or double hard/mild anodization. Three intermediate mould materials were tested (acrylonitrile butadiene styrene, polystyrene, polyacrylate resin). The polymer material (silicone or TPU) was then moulded onto the intermediate mould surfaces that possessed freestanding pillar arrays, to imprint pores. The obtained surfaces were characterized by microscopic and spectroscopic methods. The initial PAAO surfaces prepared by double mild anodization possessed pores of about 50 nm diameter and 100 nm depth, whereas those prepared after development of the double hard/mild anodization method were bigger, of about 125 nm diameter and several hundred nanometers deep. The intermediate mould structure possessed freestanding arrays, but instabilities (lateral adhesion) were noted for certain conditions. The best pattern replication was observed for TPU. In conclusion, these novel porous polymeric surfaces could be optimized and tested for an anti-biofilm effect.