Made available in DSpace on 2015-04-14T13:58:46Z (GMT). No. of bitstreams: 1 436433.pdf: 3671091 bytes, checksum: e58d7613447bd2e75558f5959d5e2989 (MD5) Previous issue date: 2012-01-27 / Due to the demand of the current market of polymeric materials and materials based on a polymeric structure, as some composites and nanocomposites, the development of new materials is fundamental. Thus, this work aims to study the synthesis and experimental characterization of nanocomposites polyurethane/titanium dioxide, using commercial raw materials. The nanocomposites were synthesized by in situ polymerization reactions in which an inorganic filler was added, titanium dioxide (TiO2), in the following proportions by weight in relation to the mass obtained from the pure polymer: 0.5%, 1.0%, 2.0%, 3.0%, 5.0%, 7.0% e 10.0%. These reactions were based in poli(-caprolactone) (PCL) and 1,6-diisocyanate hexane (HDI). The materials were characterized by Infrared Spectroscopy Fourier Transform (FTIR), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry Analysis (DSC), Thermo-gravimetric analysis (TGA) and Thermodynamic and Mechanical Analysis (TDMA). Analyzing the results obtained, the materials that showed better thermo-mechanical performance were the polymers with 2.0, 3.0 and 5.0% of TiO2. Although showing a lower degradation temperature when compared to the materials with 7.0 and 10.0% of TiO2, the additions of 2.0, 3.0 and 5.0% proved to be the most efficient in tensile tests. It can be concluded that the nanocomposites synthesized by in situ polymerization showed, in general, superior thermal properties (degradation temperature) and mechanical properties when compared to the pure polymer. It is noteworthy that there was no need of any kind of treatment in the commercial filler, which leads to a reduction in the cost of the process / Devido ? grande demanda do mercado atual de materiais polim?ricos e de materiais baseados em uma estrutura polim?rica, como alguns comp?sitos e nanocomp?sitos, torna-se fundamental a busca e o desenvolvimento de novos materiais. Desta forma, neste trabalho foram estudadas experimentalmente a s?ntese e a caracteriza??o de nanocomp?sitos de poliuretano/di?xido de tit?nio, utilizando-se mat?rias primas comerciais. Nestas rea??es foram adicionados 0,5%, 1,0%, 2,0%, 3,0%, 5,0%, 7,0% e 10% em massa de di?xido de tit?nio (TiO2), levando em conta a massa de poliuretano formada na rea??o da Poli (-caprolactona) diol (PCL) e do 1,6-diisocianato de hexametileno (HDI). Os materiais foram caracterizados por Espectrometria de Infravermelho por Transformada de Fourier (FTIR), Microscopia Eletr?nica de Varredura (MEV), Calorimetria Diferencial Explorat?ria (DSC), An?lise Termo-Gravim?trica (TGA) e An?lise Termodin?mico-Mec?nica (DMA). Pela an?lise dos resultados obtidos, os materiais que apresentaram melhor desempenho termo-mec?nico foram os pol?meros com 2,0, 3,0 e 5,0% de TiO2. Apesar de apresentar uma temperatura de degrada??o inferior aos materiais com quantidades superiores de carga, as adi??es de 2,0, 3,0 e 5,0% mostraram-se as mais eficientes nos ensaios de tra??o. Concluiu-se ent?o que os nanocomp?sitos sintetizados por polimeriza??o in situ apresentaram, de forma geral, propriedades t?rmicas (temperatura de degrada??o) e mec?nicas superiores ao pol?mero puro. Ressalta-se, ainda, n?o haver necessidade de qualquer tratamento pr?vio na carga comercial utilizada, o que leva a uma redu??o no custo do processo

Made available in DSpace on 2015-04-14T13:59:07Z (GMT). No. of bitstreams: 1 458715.pdf: 5795681 bytes, checksum: 3ee2d099095b821e73a487ab66a67e36 (MD5) Previous issue date: 2014-03-20 / The use of electrostatic or magnetic lenses is an efficient but expensive way to obtain microbeams of high energy ions. The mechanical confinement of ion beams through linear structures is an alternative way to produce microbeams. In this work, we have used tapered glass micro-capillaries with exit openings between 2 m and 118 m produced by controlled heating and stretching. Microbeams of heavy ions in the MeV energy range were produced at the 3 MV HVEE Tandetron accelerator at the Federal University of Rio Grande do Sul. The transmission and beam energy straggling of different microcapillaries inserted into a goniometer were measured using 1-1,5 MeV H+ beams. The best alignment condition was obtained inspecting the goniometer position which maximized the beam count at the initial energy and minimize broadening of the detected beam energy. For some capillaries there was only one position corresponding to a maximum transmission of the beam. In other cases, the alignment is lost gradually. The energy spectra in the maximum transmission condition had FWHM between 18 and 158 keV and the angular dispersion ranged between 0.2? and 1.6?. The best beam collimation was obtained with capillary tips with intermediate diameters between 3 μm e 17 μm. In order to evaluate the final beam, polycarbonate (PC) foils were exposed to different fluences (between 1014 e 1016 ions/cm2) of the produced microbeam (1 MeV H+ and 18 MeV Au7+). Markings were done on PC samples. In some cases the marks were not circular and appeared to be partially blocked. The increase of incident ions fluence in the sample results in the growth of the diameter of the produced markings. Profiles of the markings produced were evaluated. The FWHM was between 38 e 90 μm and the beam spread was between 0.15? and 0.20?. Experiments using a CCD camera to detect the microbeam were also performed. / O emprego de um conjunto de lentes eletrost?ticas ou magn?ticas ? uma maneira eficiente de se obter microfeixes i?nicos altamente energ?ticos, mas sua constru??o ? bastante dispendiosa. O confinamento mec?nico de feixes de ?ons atrav?s de estruturas lineares se apresenta como segunda via em rela??o a essa t?cnica tradicional. Foram fabricados microcapilares c?nicos de vidro com pontas entre 2 m e 118 m atrav?s de aquecimento e estiramento controlado. Experimentos de produ??o dos microfeixes com os microcapilares foram realizados no acelerador de ?ons 3 MV, do Laborat?rio de Implanta??o I?nica do IF-UFRGS. Utilizou-se feixes de H+ com energia entre 1 e 1,5 MeV e um goni?metro para testes de alinhamento e transmiss?o do feixe atrav?s dos microcapilares. Para cada capilar foi obtida uma posi??o bem definida de alinhamento. Em alguns casos observaram-se quedas bruscas do sinal ao variar o ?ngulo em 0,1? e em outros o alinhamento ? perdido de forma gradativa. Os espectros de energia apresentaram FWHM entre 18 e 158 keV na condi??o de transmiss?o m?xima. A dispers?o angular variou entre 0,2? e 1,6?. A melhor colima??o do feixe foi obtida com capilares de pontas com di?metros intermedi?rias, entre 3 μm e 17 μm. Amostras de policarbonato foram irradiadas com microfeixes de H+ de 1 MeV e Au7+ de 18 MeV, produzidos atrav?s dos capilares de vidro. A flu?ncia variou entre 1014 e 1016 ?ons/cm2. Diferentes padr?es na forma das marcas feitas nos pol?meros foram revelados: foram encontradas marcas circulares, marca??es em forma de c e em formato alongado. O aumento da flu?ncia de ?ons incidentes na amostra resulta no acr?scimo do di?metro da marca??o produzida. Os perfis das marca??es apresentaram FWHM ficou entre 38 e 90 μm e o grau de diverg?ncia do feixe est? entre 0,15? e 0,20?. Estudos preliminares de visualiza??o do microfeixe com uma c?mera CCD tamb?m foram implementados.

Made available in DSpace on 2015-04-14T13:59:08Z (GMT). No. of bitstreams: 1 458759.pdf: 2104393 bytes, checksum: c8a036ef074b4096decd5e0d8ed051ca (MD5) Previous issue date: 2014-03-27 / The International Standard Organization (ISO) defines the UHMWPE as having a molar ratio of at least 1 million g / mol mass, which results in a minimum degree of polymerization of n ≈ 36,000 per chain. It is a polymer of the polyethylene family manufactured under elevated pressure at temperatures above the melting temperature of approximately 135? C, with percent crystallinity from 58% to 75% depending on the resin. The UHMWPE has very long and very tangled chains, distinctive property of other polymers. Among the advantages offered by this polymer, the most important are excellent sliding properties, impact resistance, fatigue resistance and abrasion resistance. When processed by machining, this polymer generates enough waste and leftovers that end up being discarded. Many industries end up not knowing what to do to this product. By having a high cost, it is interesting to know whether it is possible to reprocess and reuse this material. In this research we study the mechanical, thermal and morphological properties of UHMWPE before and after reprocessing, through the techniques of compression molding and RAM extrusion, in order to verify whether it is possible to reuse this material in the industry. The results showed that it is possible to reprocess the UHMWPE after the micronization process of sheets obtained from virgin product, without loss in relation to its mechanical and thermal properties. Comparing results of Charpy Notched Impact Strength, Slurry Abrasion and Static and Kinetic Coefficients of Friction, the reprocessed product achieved better results compared to the virgin product. Reprocessing also showed that the process of compression molding has better tensile properties in relation to the RAM extrusion process. / A International Standard Organization (ISO) define o PEUAPM como tendo uma massa molar de pelo menos 1 milh?o g/mol, que resulta em um grau m?nimo de polimeriza??o de n ≈ 36.000 por cadeia. ? um pol?mero da fam?lia do polietileno, fabricado sob elevada press?o a temperatura acima da temperatura de fus?o, aproximadamente 135? C, com porcentagem de cristalinidade de 58 % a 75 % dependendo da resina. O PEUAPM possui cadeias extremamente longas e bastante emaranhadas, propriedade distintiva de outros pol?meros. Dentre as vantagens oferecidas por este pol?mero, destacam-se propriedades excelentes de deslizamento, resist?ncia ao impacto, ? fadiga e resist?ncia ? abras?o. Ao ser processado por usinagem, esse pol?mero gera bastante res?duo e sobras de suas aparas que acabam sendo descartados. Muitas ind?strias acabam n?o sabendo o que fazer ou como dar destino a esse produto. Por ter um custo elevado, torna-se interessante saber se ? ou n?o poss?vel reprocessar e reutilizar esse material. Neste trabalho foram estudadas as propriedades mec?nicas, t?rmicas e morfol?gicas do PEUAPM antes e ap?s o seu reprocessamento, atrav?s das t?cnicas de moldagem por compress?o e extrus?o RAM, com o intuito de verificar se seria poss?vel a reutiliza??o desse material na ind?stria. Os resultados obtidos mostraram que ? poss?vel reprocessar o PEUAPM ap?s o processo de microniza??o de placas obtidas do produto virgem, sem obter perdas em rela??o ?s suas propriedades mec?nicas e t?rmicas. Comparando resultados de Impacto Charpy, Abras?o Slurry e Coeficiente de Fric??o, o produto reprocessado obteve melhores resultados em compara??o ao produto virgem. O reprocessamento tamb?m mostrou que o processo de moldagem por compress?o apresenta melhores resultados de Tra??o em rela??o ao processo de extrus?o RAM.

Made available in DSpace on 2015-04-14T13:59:10Z (GMT). No. of bitstreams: 1 462026.pdf: 4874123 bytes, checksum: 1a15895448105e314b1f653aab8461a5 (MD5) Previous issue date: 2014-08-26 / The addition of inorganic fillers in polyurethane resins for use as coating has been of great technological interest because it leads to improvements in the properties and performance of existing materials, besides the possibility of reducing environmental impact and costs. In this context, this work presents the production of ternary composites with addition of commercial inorganics fillers, titanium dioxide (TiO2) and silica (SiO2), in aqueous polyurethane dispersions. These ternary composites were obtained from the addition of 1% of different combinations of proportion of fillers (TiO2: SiO2 = 0:100 25:75 50:50 75:25 to 100:0) in aqueous polyurethane dispersions (PUD) by the in situ polymerization process. The characteristics of the ternary composite were evaluated in the form of polymer dispersion (particle size, pH, viscosity and conductivity) and in the form of films (thermal, mechanical and morphological properties), as well as the study of degradation of these materials. The results show that the synergy resulting from the combination of the two fillers, SiO2 and TiO2, interferes with the formation of micelles in PUD colloidal system, changing the coalescence process in the formation of films and modifying light reflection and refraction in the composite making it opaque and matte. The presence of anatase crystalline phase in TiO2 particles provides better compatibility filler1-filler2-polymer increasing the tensile strength and thermal stability of the ternary composites. The presence of SiO2 retarded the degradation process in the soil of the ternary composites and they did not show biological material on the surface after degradation. / A adi??o de cargas inorg?nicas em resinas de poliuretano para aplica??o como revestimento tem tido grande interesse tecnol?gico, pois conduz a melhorias nas propriedades e no desempenho dos materiais j? existentes, al?m da possibilidade de redu??o de impacto ambiental e de custos. Neste contexto, este trabalho apresenta a produ??o de comp?sitos tern?rios com a adi??o de cargas inorg?nicas comerciais, di?xido de tit?nio (TiO2) e di?xido de sil?cio (SiO2), em dispers?es aquosas de poliuretano. Estes comp?sitos tern?rios foram obtidos a partir da adi??o de 1% de diferentes propor??es das cargas (TiO2:SiO2 = 0:100, 25:75, 50:50, 75:25 e 100:0) em dispers?es aquosas de poliuretano (DPU) pelo processo de polimeriza??o in situ. As caracter?sticas dos comp?sitos tern?rios foram avaliadas na forma de dispers?o polim?rica (tamanho de part?cula, pH, viscosidade e condutividade) e na forma de filmes (propriedades t?rmicas, mec?nicas e morfologia), bem como, o estudo de degrada??o destes materiais. Os resultados mostram que a sinergia resultante da combina??o das duas cargas, SiO2 e TiO2, interfere na forma??o das micelas no sistema coloidal DPU, alterando o processo de coalesc?ncia na forma??o dos filmes e modificando a reflex?o e a refra??o de luz no comp?sito deixando-o opaco e fosco. A presen?a da fase cristalina anatase nas part?culas de TiO2 propicia melhor compatibilidade carga1-carga2-pol?mero aumentando a resist?ncia a tra??o com altos percentuais de deforma??o e a estabilidade t?rmica dos comp?sitos tern?rios. A presen?a de SiO2 retardou o processo de degrada??o em solo dos comp?sitos tern?rios e estes n?o apresentaram material biol?gico na superf?cie depois da degrada??o.

Made available in DSpace on 2015-04-14T13:59:10Z (GMT). No. of bitstreams: 1 462029.pdf: 6506501 bytes, checksum: ac4fdb8832287abddfd8e14f596d52a1 (MD5) Previous issue date: 2014-03-28 / Injury of peripheral nerves of accidents at work or home are common carriers and scallfolds of biodegradable polymers with temporary structural function to assist in the regeneration of damaged living tissue are being explored. Conducting polymers such as polypyrrole (PPy), have also been explored because of biocompatibility to various cell types and ease of synthesis. Artificial Nerve Guidance Conduits with multifunctional growth factors (GF) have been studied to improve the regeneration of injured peripheral nerves. The main objective is to prepare polymer composites of poly (lactic - co - glycolic acid) - (PLGA) with PPy nanofibers able to act as a conduit in peripheral nerve regeneration. PPy nanofibers were synthesized via chemical oxidative polymerization with different dopants. Films PLGA / nanofiber PPy / tacrolimus (FK506) were prepared by sandwich solvent casting method. The PPy nanofibers were characterized by FTIR, SEM, electrical impedance spectroscopy and TGA. In vitro degradation of PLGA/PPy composite films was also evaluated. PPy nanofibers of electrically condutive 8.10-4 S / cm were obtained with dopant p-toluenesulfonic acid (PTSA) in the ratio [dop]: [Py] = 4 and 0 ? C. Films PLGA / PPy-nanofibers exhibit irregular surface morphology with voids that can serve as framewoks for cell growth guided. The degradation of PLGA / PPy films did not alter the pH of the buffer solution, an increase of thickness and mass loss was in the range of 7-21% until 28 days of degradation reviews. The addition of nanofibers favored the process of mass loss of about 4% for the PLGA / PPy thicker (≥ 0.6g of PLGA) films and 6% for thinner films (0.2 g PLGA) until 28 days degradation. / Les?es dos nervos perif?ricos por acidentes de trabalho ou dom?stico s?o comuns e suportes de pol?meros biodegrad?veis com fun??o estrutural tempor?ria para auxiliarem na regenera??o de tecidos vivos lesados v?m sendo explorados. Pol?meros condutores, como o polipirrol (PPy), tamb?m t?m sido investigados devido facilidade de s?ntese e biocompatibilidade.Condutos Artificiais de Orienta??o Neural multifuncional com fatores de crescimento (FC) v?m sendo estudados para aperfei?oar a regenera??o de feridas em nervos perif?ricos. O objetivo principal deste trabalho ? preparar comp?sitos polim?ricos de poli (?cido l?ctico-co-?cido glic?lico) - (PLGA) com nanofibras de PPy capazes de atuarem como conduto guia na regenera??o de nervos perif?ricos. Nanofibras de PPy foram sintetizadas via polimeriza??o qu?mica oxidativa com diferentes agentes dopantes. Filmes de PLGA/nanofibras PPy/Tacromilus (FK506) foram preparados pelo m?todo do sandu?che por evapora??o do solvente. As nanofibras de PPy foram caracterizadas por FTIR, MEV, espectroscopia de imped?ncia el?trica e TGA. Tamb?m foi avaliada a degrada??o in vitro dos filmes comp?sitos de PLGA/PPy. As nanofibras de PPy com condutividade el?trica de 8.10-4 S/cm foram obtidas com dopante ?cido p-toluenosulf?nico (APTS) na raz?o [dop]:[Py] = 4 e na temperatura de 0?C. Filmes de PLGA/PPy-nanofibras apresentam morfologia superficial irregular fibrosa com poros aleat?rios que podem servir de arcabou?os para o crescimento celular. A degrada??o dos filmes PLGA/PPy n?o alteraram o pH do meio, houve aumento de espessuras e as perdas de massas ficaram na faixa de 7-21 % at? os 28 dias de degrada??o avaliados. A adi??o das nanofibras favoreceu o processo de perda de massa cerca de 4% para os filmes PLGA/PPy mais espessos (≥ 0,6g de PLGA) e 6% para filmes mais finos (0,2 g de PLGA) at? os 28 dias de degrada??o.

Made available in DSpace on 2015-04-14T13:59:12Z (GMT). No. of bitstreams: 1 462534.pdf: 6291609 bytes, checksum: bcc4cc22e65f1ab2007237af4334f85d (MD5) Previous issue date: 2014-08-29 / The purpose of this research was to prepare biocompatible and absorbable polymeric composites films of chitosan and PLGA with PPy nanofibers for application in peripheral nerve regeneration. The QT and PLGA films were prepared by solvent evaporation technique and PPy was synthesized by chemical oxidative polymerization using PTSA as dopant agent. In order to check the degradation time of the films, were performed a in vitro degradation tests. The nanofibers and PPy films produced were characterized by Scanning Electron Microscopy (SEM), Infrared Spectroscopy Fourier Transform (ATR / FT-IR), Thermal Gravimetric Analysis (TGA), Atomic Force Microscopy (AFM), X-ray Computed Microtomography (μCT), Electrical Impedance Spectroscopy (EIS) and Electrometer. The PPy nanofibers synthesized showed a conductivity of 8x10-4 S/cm and the PLGA - PPy film produced showed a conductivity of 1x10-7 S/cm. The addition of PPy nanofibers accelerated the degradation of the composite films when compared to the array and significantly changed the morphology of the films of PLGA and QT, forming frameworks that may promote nerve regeneration. / A finalidade desta pesquisa foi preparar filmes biocompat?veis e reabsorv?eis de comp?sitos polim?ricos de quitosana (QT) e poli (?cido l?ticoco- ?cido glic?lico) (PLGA) com nanofibras de polipirrol (PPy) para aplica??o na regenera??o de nervos perif?ricos. Os filmes de QT e PLGA foram preparados pelo m?todo de evapora??o do solvente e a polimeriza??o do PPy foi realizada via polimeriza??o qu?mica oxidativa usando APTS como agente dopante. Com o intuito de verificar o tempo de degrada??o dos filmes, foram realizados ensaios de degrada??o in vitro. As nanofibras de PPy e os filmes produzidos foram caracterizados por Microscopia Eletr?nica de Varredura (MEV), Espectroscopia no Infravermelho por Transformada de Fourier (ATR/FT-IR), An?lise termogravim?trica (TGA), Microscopia de For?a At?mica (AFM), Microtomografia Computadorizada de Raios X (Micro CT), Espectroscopia de Imped?ncia El?trica (EIE) e Eletr?metro. As nanofibras de PPy sintetizadas apresentaram uma condutividade 8x10-4 S/cm e o filme de PLGA-PPy apresentou uma condutividade de 1x10-7 S/cm. A adi??o das nanofibras de PPy acelerou a degrada??o dos filmes comp?sitos em rela??o a matriz e modificou significativamente a morfologia dos filmes de PLGA e QT formando arcabou?os que podem vir a favorecer a regenera??o nervosa.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-04-17T13:52:43Z No. of bitstreams: 1 467312 - Texto Completo.pdf: 12104060 bytes, checksum: fab068a173a82aab41a55d8875dc36ae (MD5) / Made available in DSpace on 2015-04-17T13:52:43Z (GMT). No. of bitstreams: 1 467312 - Texto Completo.pdf: 12104060 bytes, checksum: fab068a173a82aab41a55d8875dc36ae (MD5) Previous issue date: 2015-03-30 / In this study the spatial confinement effects on the topological (mass transport and particle ejection) and chemical modifications of poly(methyl methacrylate) thin films (1<?<360 nm) irradiated by swift heavy ions were systematically investigate. The surface tracks dimensions were characterized by atomic force microscopy and the results show that the surface effects are weakened when the length of the ion track is spatially confined down to few nanometers. The deviation from bulk-like behavior starts at a critical thickness ?1 as large as ~40 nm to the ridge volume, due to effects associated to cooperative action of excited material along the track. However, ?1 is much smaller for effects related to events close to the surface, such as the crater size (?1~10 nm). Analytical calculations based on the pressure pulse model were carried out to investigate theoretical aspects of the ion-matter energy transfer in the transport and dissipation of the deposited energy. The results obtained from these calculations match the experimental observations. Chemical modifications were investigated by quantifying bond breaking rates, extracted by x-ray photoelectron spectroscopy. Cross sections for carbon-oxygen bonds for films under Bi irradiation are slightly smaller for thinner films, whilst for proton irradiation the values do not show substantial difference down to the smallest thickness viable for analysis (?~5 nm). From these set of data it is verified that the ionic irradiation effects on polymer thin films are weakened under spatial confinement into layers with ? below a certain critical value ?1, dependent on the probed effect. Substantial difference on the surface track dimensions were not observed between the distinct substrates investigated. / Neste trabalho foram investigados sistematicamente os efeitos de confinamento espacial nas modifica??es topol?gicas (transporte de massa e eje??o de part?culas) e qu?micas induzidas por ?ons pesados de alta energia (de dezenas a milhares de MeV) em filmes finos de poli(metacrilato de metila) (1< ? <360 nm). As dimens?es dos efeitos de superf?cie induzidos pela irradia??o foram caracterizadas por microscopia de for?a at?mica e os resultados mostram claramente o enfraquecimento dos efeitos induzidos pela irradia??o quando o comprimento da trilha ? reduzido a poucos nan?metros. Desvios do comportamento observado para filmes bulk come?am em uma espessura cr?tica ?1 t?o grande quanto ~40 nm para o volume da protuber?ncia, devido ? redu??o dos efeitos de a??o cooperativa de material excitado ao longo da trilha. Entretanto, ?1 ? bem menor para efeitos relacionados a eventos pr?ximos ? superf?cie, como o tamanho cratera (?1~10 nm). C?lculos anal?ticos pelo modelo do pulso de press?o foram utilizados para investigar aspectos te?ricos da transfer?ncia de energia ?on-material no transporte e dissipa??o da energia depositada. Os resultados obtidos a partir desses c?lculos corroboram com observa??es experimentais. As modifica??es qu?micas foram investigadas atrav?s das se??es de choque de quebra de liga??es, extra?das por espectroscopia de fotoel?trons por raios x. As se??es de choque de danos para as liga??es carbonooxig?nio, obtidas para irradia??es com ?ons de Bi de 2,2 GeV, s?o levemente reduzidas para filmes mais finos, enquanto as se??es de choque para filmes irradiados com pr?tons de 2 MeV n?o mostram diferen?as significativas at? a espessura mais fina acess?vel por an?lise de XPS (?~5 nm). A partir desse conjunto de dados verificou-se o enfraquecimento dos efeitos induzidos pela irradia??o em filmes polim?ricos sob confinamento espacial em camadas com ? abaixo de um valor cr?tico ?1, sendo ?1 dependente do efeito sondado. N?o foram observadas diferen?as significativas do efeito da espessura para diferentes substratos.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-06-29T11:27:22Z No. of bitstreams: 1 471334 - Texto Completo.pdf: 4524191 bytes, checksum: f5450152427bd38ead2e27ad8d28c46b (MD5) / Made available in DSpace on 2015-06-29T11:27:23Z (GMT). No. of bitstreams: 1 471334 - Texto Completo.pdf: 4524191 bytes, checksum: f5450152427bd38ead2e27ad8d28c46b (MD5) Previous issue date: 2012-07-12 / This work aims to obtain polymer blends containing polypropylene wtih conductive nanofibers formed by polyaniline and graphite nanosheets. Will study the effects of morphology and the electrical and mechanical properties of the resulting polymer. The polyaniline nanofibers are synthesized in the presence of graphite nanosheets using the methodology of rapid mixing. The preparation of blends of polypropylene is made by melting in the inner chamber. The morphology and structure of the nanofillers and blends will be evaluated by scanning electron microscopy (SEM), and Atomic Force Microscopy (AFM). The mechanical properties through tensile testing. The electrical properties by impedance spectroscopy. It was observed that a better dispersion of graphite with polyaniline nanofibers occurs when made in the aqueous solution containing the monomer, aniline in the presence of APS ultrasound for 1 hour. The electrical properties of the synthesized nanocomposite indicate characteristics of semiconductor. The mechanical and thermal properties of the blends did not change significantly with the addition of nanofillers, Higher conductivity values were obtained for high values of frequency, 106 Hz / Este trabalho busca a obten??o de blendas polim?ricas de polipropileno contendo nanocarga condutiva formada por nanofibras de polianilina (PANI) e nanol?minas de grafite (NLG). Foram estudados os efeitos da nanocarga na morfologia e nas propriedades el?tricas e mec?nicas do pol?mero resultante. As nanofibras de PANI foram sintetizadas na presen?a das nanol?minas de grafite por meio da metodologia da mistura r?pida. A prepara??o das blendas com polipropileno foi realizada por fus?o em c?mara interna. A morfologia e estrutura da carga nanom?trica e das blendas foram avaliadas por meio da Microscopia Eletr?nica de Varredura (MEV) e Microscopia ?tica, as propriedades mec?nicas por meio de ensaio de tra??o, as propriedades el?tricas por meio da Espectroscopia de Imped?ncia. Foi observado que a melhor dispers?o das nanol?minas de grafite junto ? polianilina ocorre quando feita na solu??o aquosa contendo o mon?mero, anilina, na presen?a do Persulfato de Am?nio (APS) durante 1h de ultrassom. As propriedades el?tricas dos nanocomp?sitos sintetizados indicam caracter?sticas de semicondutor. As propriedades mec?nicas e t?rmicas das blendas n?o sofreram altera??es significativas com a adi??o da nanocarga. Maiores valores de condutividade foram obtidos para elevados valores de frequ?ncia, 106 Hz.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-07-07T12:57:05Z No. of bitstreams: 1 471707 - Texto Completo.pdf: 875696 bytes, checksum: 681f03e704120fe92558e48e363af3d4 (MD5) / Made available in DSpace on 2015-07-07T12:57:05Z (GMT). No. of bitstreams: 1 471707 - Texto Completo.pdf: 875696 bytes, checksum: 681f03e704120fe92558e48e363af3d4 (MD5) Previous issue date: 2015-03-27 / Introduction : Non-living tissues have shown to be an important source of biomaterials, with advantages such as hydrophilicity, low toxicicidade, low immunogenicity, in addition to good adherence and cell multiplication. However, for these biomaterials to be used, techniques of descellularization is being used to make it less antigenic and also to serve as scaffolds.Objectives : The present study aims to compare different agents of descellularization regarding the above mentioned parameters, using detergents known to be effective for these processes.Materials and Methods : The samples used in this study were obtained from saphenous veins of seven individuals donors, in treatment of myocardial revascularization surgery and provided by the team of cardiovascular surgery of Hospital S?o Lucas da PUCRS, after signing the informed consent form.These samples were tested simultaneously three different detergents, sodium dodecyl sulfate (SDS), TRITON-X and trypsin, in addition to a control group containing Phosphate-Buffered Saline (PBS). After the process of descellularization and prior to the determination of cellularity, the samples were fixed in buffered formalin 10% during 24 hours, included in paraffin, sectioned (5 ?) and stained with hematoxylin and eosin. The number of cores was quantified in a radius of 0.025 mm (objective 40x), in duplicate, corresponding to eight fields, with the aid of the software Image Pr?-Plus 4.5.1. Data were analyzed using a model of analysis of variance for repeated measures (randomized blocks) with adjustment for multiple comparisons procedure of Finner's procedure were used.Results : The results evaluated all treatments showed a decrease in the number of cells, and the SDS the agent with greater descellularization. The TRITON-X and the Trypsin obtained similar values and there was no difference between them, for this process.Conclusion : In this way, it could be demonstrated that all detergents used, and the methodology it self, acts as agentes of descellularization in human veins and proved to be a promising agents to remove cells. / Introdu??o : Tecidos n?o vivos tem se mostrado uma importante fonte de biomateriais, apresentando vantagens como hidrofilidade, baixa toxicicidade, baixa imunogenicidade, al?m de boa ades?o e multiplica??o celular. Contudo, para que esses biomateriais sejam utilizados, t?cnicas de descelulariza??o v?m sendo utilizadas para que sejam menos antig?nicos e tamb?m para que sirvam como scaffolds.Objetivos : O presente estudo tem o objetivo de comparar diferentes agentes de descelulariza??o quanto aos par?metros citados acima, utilizando detergentes reconhecidamente eficazes para esses processos.Materiais e M?todos : As amostras utilizadas neste estudo foram obtidas de veias safenas de sete indiv?duos doadores, em tratamento de cirurgia de revasculariza??o do mioc?rdio e fornecidas pela equipe de cirurgia cardiovascular do Hospital S?o Lucas da PUCRS, ap?s assinatura do termo de consentimento livre e esclarecido (TCLE). Nessas amostras foram testados simultaneamente tr?s diferentes detergentes, s?dio dodecil sulfato (SDS), TRITON-X e tripsina, al?m de um grupo controle, contendo Phosphate-Buffered Saline (PBS) e um controle ?a fresco?. Ap?s o processo de descelulariza??o e previamente ? determina??o da celularidade, as amostras foram fixadas em formalina tamponada 10% durante 24horas, inclu?das em parafinas, seccionadas (5?) e coradas com hematoxilina e eosina. O n?mero de n?cleos presentes foi quantificado em um raio de 0,025 mm (objetiva 40x), em duplicata, correspondente a oito campos, com o aux?lio do software Image Pr?-Plus 4.5.1. Os dados foram analisados em modelo de an?lise de vari?ncia de medidas repetidas (blocos casualizados) com ajuste de compara??es m?ltiplas pelo procedimento de Finner.Resultados : Dos resultados avaliados todos os tratamentos mostraram um decr?scimo no n?mero de c?lulas, sendo o SDS o agente com maior descelulariza??o. O TRITON-X e a Tripsina obtiveram valores similares e n?o houve diferen?a entre eles, para esse processo.Conclus?o : Dessa forma, demonstrou-se que todos os detergentes empregados agem como descelularizadores em veias humanas, e mostram-se como promissores agentes de remo??o celular.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-11-26T11:39:49Z No. of bitstreams: 1 476451 - Texto Completo.pdf: 8210475 bytes, checksum: d312c576e78b0f9de246885a55a53e56 (MD5) / Made available in DSpace on 2015-11-26T11:39:49Z (GMT). No. of bitstreams: 1 476451 - Texto Completo.pdf: 8210475 bytes, checksum: d312c576e78b0f9de246885a55a53e56 (MD5) Previous issue date: 2015-03-03 / The search for improvements in the properties of polymer matrices has been the subject of several studies. Among these, the use of inorganic fillers has shown results that demonstrate improvements in many properties of the polymers. In this context, this study aimed to preparation of titanates nanotubes (TNT) and its application in polyurethane nanocomposites (PU). In order to the TNT were synthesized from commercial TiO2 in anatase phase by hydrothermal method. After, these TNT were functionalized (TNTF) with hexamethylene diisocianato (HDI) and silanes compounds: aminopropyl trimethoxysilane (APTMS) and tetraethyl orthosilicate (TEOS) in order to study the interaction of the functionalizated charge with the polymer matrix. The titanates nanotubes (TNT) and titanates nanotubes functionalized (TNTF) were characterized regarding their morphological and structural properties. Nanocomposites of PU with TiO2, TNT and TNTF were synthesized, via in situ polymerization and characterized by FTIR, GPC, SEM, TEM (just NTT), AFM, TGA, DSC and DRX techniques. The results showed that the TNT synthesis by hydrothermal method was effective and was obtained nanotubes formed with a minimum of 3 staked sheets. The TNTF functionalized with APTMS and TEOS showed clustered structures whereas with HDI has a separation of nanotubes. The addition of TNT-HDI provided an increase of polymer molar weight. All nanocomposites showed higher thermal stability (between 330-340oC) than the pure PU (325oC). Nanocomposites PU/TNTF presented the highest values for crystallization temperature (? 6-10oC) when compared to pure PU (5oC), besides of its enthalpies, indicating that TNTF promote the increase of the polyurethane crystallinity. / A busca por melhorias nas propriedades de matrizes polim?ricas tem sido motivo de muitos estudos. Entre estes, a aplica??o de cargas inorg?nicas tem apresentado resultados que evidenciam melhorias nas diversas propriedades dos pol?meros. Dentro deste contexto insere-se este trabalho, que teve como objetivo principal a prepara??o de nanotubos de titanatos (NTT) e sua aplica??o em nanocomp?sitos de poliuretano (PU). Para tanto, os NTT foram sintetizados partindo de TiO2 comercial na fase anat?sio por m?todo hidrot?rmico. Ap?s, estes NTT foram funcionalizados (NTTF) com hexametilenodiisocianato (HDI) e os compostos: aminopropil trimetoxisilano (APTMS) e tetraetil ortosilicato (TEOS) a fim de estudar a influ?ncia destas funcionaliza??es na intera??o da carga com a matriz polim?rica. Os nanotubo de titanatos (NTT) e os nanotubos de titanatos funcionalizados (NTTF) foram caracterizados em rela??o as suas propriedades morfol?gicas e estruturais. Nanocomp?sitos de PU com TiO2, NTT e NTTF foram sintetizados, via polimeriza??o in situ, e caracterizados por t?cnicas de FTIR, GPC, MEV, MET (somente os NTT), AFM, TGA, DSC e DRX. Os resultados mostraram que a s?ntese dos NTT pelo m?todo hidrot?rmico foi eficiente e obteve-se nanotubos formados por no m?nimo 3 folhas empilhadas. Os NTTF funcionalizados com APTMS e TEOS apresentaram estruturas aglomeradas enquanto que com HDI houve afastamento dos nanotubos. A adi??o de NTT-HDI proporcionou um aumento da massa molar do pol?mero e maior mobilidade para a cadeia. Todos os nanocomp?sitos apresentaram maior estabilidade t?rmica (entre 330-340oC) que o PU padr?o (325oC). Os nanocomp?sitos PU/NTTF apresentaram os maiores valores para as temperaturas de cristaliza??o (? 6-10oC) comparado ao PU padr?o (Tc=5oC), al?m das respectivas entalpias indicando que os NTTF aumentam a cristalinidade do poliuretano.