In the six months spent at the Musee d'art et d'histoire, Geneva, Switzerland, as a staff member in the dual role of paintings conservator and research conservator, there was achieved an excellent rapport with the staff of the Musee, a work record which was very successful, and research results which were received with enthusiasm, having broad implications for the Musee. Following the two months as a contract conservator in Vienna, research developments were applied in practice, under severe time constraints and the resulting treatment was successfully achieved with the wholehearted support and co-operation of staff and officials, resulting in offers of lectureships and lecture tours for the Academy of Fine Arts - Conservation School, Vienna in Austria and Germany. In evaluative terms, it is considered that the programme met the objectives very well, and in addition the results have potential for part of an ongoing programme of research into fire-damaged paintings and varnish removal, with solid lines of co-operation in the establishments in Europe.

Cette thèse porte sur le développement de résines polyesterimides insaturés pour des applications de type vernis d'imprégnation pour isolation électrique. Il s’agit de matériaux polymères thermodurcissables, qui assurent la double fonction d'isolant et d'agent de cohésion du système isolé. Ils se différencient en classes thermiques, qui définissent leur température maximale d'utilisation. Dans le cadre de cette étude, nous cherchons à développer des produits de classe thermique supérieure ou égale à 180°C. Une première partie de cette étude a porté sur l'amélioration de deux produits commerciaux à base de polyesters insaturés à fonctions terminales imides. Notre attention s'est portée sur la modification de leur structure chimique, afin de voir comment les différents précurseurs utilisés influencent les propriétés des résines. Une seconde partie a consisté à développer de nouvelles résines à base de polyesterimides insaturés, à partir de trois types de précurseurs imides difonctionnels. / This thesis focuses on the development of unsaturated polyesterimide resins as impregnating varnishes for electrical insulation applications. These thermosetting polymer materials provide the dual function of insulating and cohesion agent of the isolated system. They differ in thermal classes, which define their maximum operating temperature. In this study, we tried to develop products with a thermal class above or equal to 180°C. The first part of this study focused on the improvement of two commercial products based on imide-endcapped unsaturated polyester. Our attention turned to the modification of their chemical structure, to see how the different precursors used affect the thermal and mechanical properties of resins. A second part was to develop new unsaturated polyesterimide resins, using three types of difunctional imide precursors.

In this diploma thesis the basic principles of inkjet print, ink composition, print media and degradation mechanisms of ink dyes are summarized. The thesis deals with study of varnish barrier properties in coloured inkjet prints. Permeability of water vapour and oxygen (parts of atmosphere) depending on different coatings are tested there. In addition the influence of ozone on degradation of dyes was studied, while ozone was permeating through barrier varnish layer of inkjet print. Ozone plays an important role in degradation processes of the inkjet prints and it also causes a gas-fading. Concentrations of acting ozone were established by iodometric titration. Simultaneously kinetics of degradation of Orange 7 was studied on indicator papers.

The diploma thesis is focused on the preparation of test samples of paint-filled micronized mica and analysis of electrical properties of insulating material values in different environmental conditions. For this purpose, it was created five sets of composite paint primers with different ratio of mica. Samples were gradually exposed to the environment relative humidity of 0%, 33%, 55%, 65% and 75%. For each environment with a defined moisture characteristics were observed in samples exposed to the temperature of 20 to 50 ° C. The diploma paper analyzed the influence of the mass implementation of mica in each set of samples and placed on the surface structure of samples.

Submitted by Andrea Pereira (andrea.pereira@unipampa.edu.br) on 2017-05-11T13:21:31Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Valeska_Versão 11 CORRIGIDO.pdf: 3238487 bytes, checksum: 73f10af9da8be85f8bdd630332f49d0a (MD5) / Approved for entry into archive by Andrea Pereira (andrea.pereira@unipampa.edu.br) on 2017-05-11T13:21:53Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Valeska_Versão 11 CORRIGIDO.pdf: 3238487 bytes, checksum: 73f10af9da8be85f8bdd630332f49d0a (MD5) / Made available in DSpace on 2017-05-11T13:21:53Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Valeska_Versão 11 CORRIGIDO.pdf: 3238487 bytes, checksum: 73f10af9da8be85f8bdd630332f49d0a (MD5) Previous issue date: 2015-03-24 / Um processo corrosivo em embalagens metálicas para alimentos pode ser iniciado durante a fabricação destas, bem como em todo o período no qual o alimento está em contato com a mesma. O uso de extratos de plantas como inibidores naturais em recobrimentos protetores para o alumínio podem auxiliar na redução da corrosão, além de diminuir a preocupação com o risco de toxicidade causada por inibidores sintéticos industrialmente utilizados. Extratos da espécie Solidago chilensis, conhecida como arnica-brasileira, abundante em todo o Brasil e em maior concentração na região Sul do país, ainda não foram relatados na literatura no uso como inibidores naturais de corrosão, porém, possuem propriedades e compostos que já foram apresentados que indicam capacidade anticorrosiva. O presente estudo busca desenvolver um recobrimento contendo Solidado chilensis como inibidor natural de corrosão para aplicação em embalagens de ligas de alumínio para alimentos. Para avaliar estes recobrimentos foram realizados ensaios de Polarização Potenciodinamica (PP), Espectroscopia de Impedância Eletroquímica (EIE), Microscopia de Força Atômica (MFA), Espectroscopia na região do Infravermelho com Transformada de Fourier (FT-IR) e Difração de Raios-X (DRX). Considerando a possibilidade de alteração da resistência à corrosão devido a algum dano mecânico foi avaliada a adesão do recobrimento através de ensaios de resistência mecânica por Análise Mecânico-Dinâmica (AMD). Para o desenvolvimento da superfície foram realizadas: anodizações, com objetivo de proteção contra a corrosão e aderência do inibidor e do recobrimento; e aplicados o inibidor natural (Solidago chilensis) e o recobrimento de verniz, com o objetivo de proteção contra a corrosão. As anodizações foram realizadas em três diferentes tempos 15, 20 e 30 minutos, após as amostras foram imersas em solução inibidora contendo três diferentes concentrações de inibidor (2,5, 5 e 15 g/L de metanol) e por fim foram recobertas com verniz. A resistência à corrosão e a eficiência do inibidor foram avaliadas através de ensaios eletroquímicos. O módulo de elasticidade das amostras foram avaliadas através do AMD. A morfologia das amostras foram determinadas através de MFA. A composição do inibidor e a interação entre as ligações químicas de compostos do inibidor, do verniz, da anodização e do alumínio foram determinadas por FT-IR. A estrutura cristalina das amostras foram determinadas por DRX. Os resultados apontaram que o melhor tempo de anodização quanto a resistência à corrosão e a resistência mecânica do sistema foi de 15 min. As amostras anodizadas nesse tempo foram escolhidas para serem imersas em solução contendo o inibidor natural. Os resultados eletroquímicos indicaram que a maior concentração de inibidor de corrosão (15 g de extrato de Solidago chilensis por L de solvente) obteve maior eficiência à corrosão, 92,5 %. O uso do inibidor de corrosão natural junto a anodização e ao recobrimento de verniz diminuiu a degradação da amostra ao longo do tempo, aumentou o potencial de corrosão e a resistência de polarização. A rigidez do sistema diminuiu com a aplicação do verniz mas não foi influenciada significativamente, p≤0,05 pela anodização. Estes resultados indicaram que o Al anodizado contendo extrato de Solidago chilensis como inibidor de corrosão recoberto com verniz pode ser uma alternativa interessante na industria de alimentos na utilização em embalagens metálicas. / A corrosion process in metallic food packing can be started during the manufacturing of these, as well as throughout the period in which the food is in contact with it. The use of plant extracts as green inhibitors in protective coatings for aluminum can help reduce corrosion, and reduce concern about the risk of toxicity caused by synthetic inhibitors used industrially. Extracts of the species Solidago chilensis, known as arnica-Brazilian, abundant in Brazil and in greater concentration in the southern region of the country, have not yet been reported in the literature used as natural corrosion inhibitors, however, have properties and compounds that have been presented indicating corrosion efficiency. This study aims to develop a coating containing solidated chilensis as green corrosion inhibitor for use in packaging of aluminum alloys for food. To evaluate these coatings were conducted Potentiostatic Polarization tests (PP), Electrochemical Impedance Spectroscopy (EIS), Atomic Force Microscopy (AFM), Infrared Spectroscopy in the region Fourier Transform (FT-IR) and X-Ray Diffraction (XRD). Considering the possibility of change in resistance to corrosion due to some mechanical damage was assessed the adhesion of coating by mechanical strength tests for Dynamic-Mechanical Analysis (DMA). For the development of the surface were carried out anodizing, in order to corrosion protection and adhesion inhibitor and coating; and applied the natural inhibitor (Solidago chilensis) and the varnish coating, in order to protect against corrosion. The anodizing was performed in three different times 15, 20 and 30 minutes after the samples were immersed in inhibitor solution containing three different inhibitor concentrations (2.5, 5 and 15 g/L methanol) and finally were coated with varnish. The corrosion resistance and the efficiency of the inhibitor were evaluated by electrochemical tests. The modulus of elasticity of the samples were evaluated by DMA. The morphology of the samples were determined by AFM. The inhibitor composition and interaction between the chemical bonding inhibitor compounds, varnish, and anodization of aluminum are determined by FT-IR. The crystal structure of the samples were determined by XRD. The results showed that the best time of anodization as the corrosion resistance and the mechanical strength of the system was 15 min. The anodized samples at this time were chosen to be immersed in a solution containing the natural inhibitor. The electrochemical results indicated that the highest concentration of corrosion inhibitor (15 g of Solidago chilensis extract per L of solvent) had higher efficiency corrosion, 92.5%. The use of natural corrosion inhibitor with anodization and varnish coating reduced the degradation of the sample over time, potential increased corrosion resistance and polarization. The system stiffness decreased with the application of varnish but was not significantly influenced by p≤0,05 anodizing. These results indicated that the anodized Al containing Solidago chilensis extract as a corrosion inhibitor coated with varnish can be an interesting alternative in the food industry in use in metal packaging.

Made available in DSpace on 2016-12-08T17:19:37Z (GMT). No. of bitstreams: 1 1_Introducao.pdf: 64784 bytes, checksum: a1b19b41bade65db44f4ab7b4a5561dc (MD5) Previous issue date: 2011-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Polyamide-imide (PAI) is a polymer widely used in magnet wires for electrical applications due to combination of their mechanical, electrical and thermal properties. This polymer can be improved by the addition of inorganic moieties, among them silsesquioxanes, forming organic/inorganic hybrids. This dissertation presents the preparation of hybrid polymers PAI/copolysilsesquioxane (PAI/coPSQ), where the matrix of polyamide-imide (PAI) is prepared from the condensation of trimellitic anhydride (TMA) and diphenylmethane-4 ,4-diisocyanate (MDI), and the copolysilsesquioxane is prepared by the sol-gel method from alkoxide precursors, in this case, 3-aminopropyltriethoxysilane (APES) and phenyltrietoxisilane (PTES). The methods for obtaining the hybrid PAI/coPSQ by simple mixing and in situ reaction were evaluated. The hybrid polymers were characterized by their spectroscopic characteristics, morphology, electrical, mechanical and thermal properties. The PAI/coPSQs coatings prepared with APES-rich coPSQ presented gelatinization due to high crosslinking generated by the polymer chains of PAI and the amine groups of PSQ. The method of in situ reaction mixture was more efficient in the generation of hybrid PAI/coPSQ, minimizing the occurrence of gelatinization. The SEM and AFM confirmed the absence of separation between the organic and inorganic phases and the FTIR and NMR 13C and 29Si analysis confirmed the formation of a Si-O-Si network. PAI/coPSQ hybrid samples showed no significant changes of Tg, while PAI/PTES hybrid obtained by polycondensation of PTES presented a decrease of Tg. PAI/PSQs hybrids were analyzed by thermogravimetry and showed a small improvement in thermal resistance. The results of nanoindentation tests confirmed the influence of adding coPSQ to increase hardness and elastic modulus of PAI films, while the average performance of dielectric strength showed trends of increasement. / O polímero poliamida-imida (PAI) é amplamente utilizado em fios esmaltados para aplicações elétricas devido ao balanço de suas propriedades mecânicas, elétricas e térmicas. Este polímero pode ser melhorado pela adição de cargas inorgânicas em sua matriz, dentre elas os silsesquioxanos, formando híbridos orgânicos/inorgânicos. O presente trabalho apresenta o preparo de polímeros híbridos PAI/copolissilsesquioxano (PAI/coPSQ), onde a matriz de poliamida-imida (PAI) é preparada a partir da reação de condensação entre o anidrido trimelitico (TMA) e o difenilmetano-4,4-diisocianato (MDI), e o copolissilsesquioxano é preparado pelo método sol-gel a partir de precursores alcóxidos, neste caso o 3-aminopropiltrietoxissilano (APES) e o feniltrietoxissilano (PTES). Foram avaliadas as metodologias de obtenção do híbrido PAI/coPSQ por mistura simples e por reação in situ. Os polímeros híbridos foram caracterizados quanto às suas características espectroscópicas e morfológicas, propriedades elétricas, mecânicas e térmicas. Os vernizes de PAI preparados com coPSQs ricos em APES apresentaram gelatinização devido ao alto grau de reticulação gerado pelas ligações cruzadas entre as cadeias poliméricas do PAI e os grupos amínicos. O método de mistura por reação in situ mostrou-se mais eficiente na geração do híbrido PAI/coPSQ, minimizando a ocorrência de gelatinização. As análises morfológicas confirmaram a ausência de separação entre as fases orgânica e inorgânica e as análises de FTIR e NMR 13C e 29Si confirmaram formação da rede Si-O-Si. As amostras híbridas PAI/coPSQ não apresentaram alterações significativas de Tg, enquanto que o híbrido PAI/PTES obtido pela policondensação somente do PTES apresentou grande diminuição de Tg. Os híbridos PAI/PSQs apresentaram uma pequena melhoria na estabilidade térmica analisada por termogravimetria. Os resultados do ensaio de nanoindentação confirmaram a influência da adição do coPSQ para o aumento da dureza e do módulo de elasticidade dos filmes de PAI, enquanto que os resultados médios da propriedade de rigidez dielétrica apresentaram tendência de aumento.

This work deals with issues of elecroinsulating varnish and composite materials. The general aim is to observe impact of fulfilment and size of particle against measured values.

This work deals with issues of dielectric composite materials. The general aim is to observe how the amout of nanofilling influence dielectric spectrum in dependence on relative humidity and temperature which is measured on prepared samples. For this purpose had been created variety of a samples of electroinsulating varnish with different percentage of filling with nanoparticles. Experimental material is epoxy resin NH91 LV filled by Al2O3 nanoparticles.

The bachelor thesis submitted deals with properties of electro-insulating lacquer hardenable by ultraviolent radiation and temperature. Within the theoretical part a summary of electro-insulating lacquers used in electrotechnics has been elaborated. Chemical changes that take place in this material group have been described during hardening process. A method of dielectric relaxation spectroscopy specifically focused on mathematic and physical description of polarisation and conductive mechanisms taking place in the structure of the given material has been closely studied. In the experimental part a workplace for hardening and long-term exposition of lacquered samples during simultaneous effect of various climatic elements has been designed and built. The selected electric and mechanical properties have been monitored on three sets of experimental samples prepared by means of different methodical procedures. The results gained have been mathematically evaluated and physically interpreted in term of methodical procedure of hardening and different temperature of measurement.

Indiana University-Purdue University Indianapolis (IUPUI) / Purpose: This in vitro study aims to analyze the effect of combining two ADA-recommended professionally applied 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) and professionally prescribed 5,000 ppm fluoride toothpaste ((PreviDent 5000 Plus)) on reducing lesion depth and increasing mineral content Materials & Methods: Forty-eight dentin specimens were randomly distributed into four treatment groups (n=12 per treatment). Biofilms of Streptococcus mutans and Candida albicans were created on the polished surfaces of bovine root dentin specimens (n=12 per treatment). 1:1 Chlorhexidine/Thymol varnish was applied once then the tested 5,000 ppm fluoride toothpaste was applied for 120 seconds twice daily over the course of 2 days. Tested groups were: (1) 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) (C/T). (2) 5,000 ppm F toothpaste ((PreviDent 5000 Plus)) (F). (3) Combination of 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) & 5000 ppm F toothpaste ((PreviDent 5000 Plus)) (C/T+F). (4) Deionized water (DIW) as control group. Biofilms were analyzed for biofilm dry weight. Dentin specimens were analyzed using transversal microradiography (TMR) for mineral content change and lesion depth. PH data was analyzed using two-way ANOVA. Total biofilm dry weight data was analyzed using one-way ANOVA. Integrated mineral loss and lesion depth data was analyzed using two-way ANOVA All pair-wise comparisons from ANOVA analysis were made using Fisher’s Protected Least Significant Differences to control the overall significance level at 5%. Results: Treatment with (C/T+F) resulted in higher mean pH values compared to the control group (DIW) and (F) group. The average pH values of group (C/T) were not statistically different than group (C/T+F). the biomass of the combined S. mutans & C. albicans biofilm among all the groups were not significantly different. (DIW) presented significantly deeper lesions for both surfaces (sound &demineralized) when compared to (F) (P=0.0118), (C/T) (P=0.0002), and (C/T+F) (P<.0001). The sound surfaces for the specimens for group (C/T) and Group (F) showed superficial lesion depth. However, the sound surfaces of specimens treated with (C/T+F) showed the most superficial depth. Due to mineral gain, the demineralized surfaces of the specimens of both (C/T) & (C/T+F) showed a decrease in the lesion depth. Conclusion: Within the limitations of our study. The combination of 5,000 ppm fluoride toothpaste and CHX/Thymol had no significant effect on mineral content. However, the combination had a considerable effect on lesion depth reduction.