Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-11-29T15:45:36Z No. of bitstreams: 1 DIS_THUANY_GARCIA_MARASCHIN_COMPLETO.pdf: 3644963 bytes, checksum: fa378de0f5287d6d9eeabe72fda2aa16 (MD5) / Made available in DSpace on 2016-11-29T15:45:36Z (GMT). No. of bitstreams: 1 DIS_THUANY_GARCIA_MARASCHIN_COMPLETO.pdf: 3644963 bytes, checksum: fa378de0f5287d6d9eeabe72fda2aa16 (MD5) Previous issue date: 2016-08-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The development of methodologies able to prepare new materials, using graphene in its structure, is technological innovation that converts low-cost products in advanced materials with aggregate amount. The present work is related with the preparation of graphene oxide (GO) and reduced graphene oxide (RGO) in reasonable quantities directed to prepare nanocomposites based on biodegradable polymeric matrix. Initiating from natural graphite, Grafine, experimental conditions were investigated to obtain the GO and its reduced form, RGO, by the method of chemical exfoliation followed by thermal reduction. In order to optimize the process were evaluated oxidation time (12, 24 and 48 hours) and temperature reduction (600?C and 1000?C). The films of the nanocomposites containing different amounts of graphene (0.5; 3 and 5% w/w) dispersed in the chitosan matrix were prepared using solvent evaporation method. The characterization analyses of materials obtained were made by: Scanning Electron Microscopy, Transmission and Atomic Force, X-ray Diffraction, Thermogravimetric analysis, Elemental Analysis, Raman spectroscopy and Electric Conductivity Analysis. The 24 hours of oxidation time was sufficient for the intercalation of functional groups between the sheets of graphene and obtain GO with 29% oxygen. The reduction in temperature of 1000?C was effective in restoring graphitic network and resulted in RGO with a stack of 7-8 sheets, thermally stable and electrical conductivity of 55 S/cm. Addition of graphene in the biodegradable matrix did not modify the thermal stability and it did not change substantially the process of degradation of the prepared nanocomposites. / O desenvolvimento de metodologias capazes de preparar novos materiais, que utilizem grafeno na sua estrutura, representa inova??o tecnol?gica que transforma produtos de baixo custo em materiais avan?ados com alto valor agregado. O presente trabalho est? relacionado com a prepara??o de ?xido de grafeno (OG) e ?xido de grafeno reduzido (OGR) em quantidades razo?veis visando ? prepara??o de nanocomp?sitos baseados em matriz polim?rica biodegrad?vel. Partindo do grafite natural, Grafine, foram investigadas condi??es experimentais para obten??o do OG e sua forma reduzida, OGR, pelo m?todo da esfolia??o qu?mica, seguida de redu??o t?rmica. A fim de otimizar o processo foram avaliados tempo de oxida??o (12, 24 e 48 horas) e temperatura de redu??o (600?C e 1000?C). Os filmes dos nanocomp?sitos com diferentes quantidades de grafenos (0,5; 3 e 5% m/m) dispersos na matriz de quitosana foram preparados usando a metodologia da evapora??o do solvente. A caracteriza??o dos materiais preparados deu-se por: Microscopia Eletr?nica de Varredura, de Transmiss?o e de For?a At?mica, Difra??o de Raios X, An?lise Termogravim?trica, An?lise Elementar, Espectrometria RAMAN e An?lise de condutividade el?trica. O tempo de oxida??o de 24 horas foi suficiente para a intercala??o de grupos funcionais entre as l?minas de grafeno e obten??o de OG com 29% de oxig?nio. A redu??o na temperatura de 1000?C foi eficiente na restaura??o da rede graf?tica e resultou em OGR com um empilhamento de 7-8 l?minas, est?vel termicamente e com condutividade el?trica de 55 S/cm. A adi??o dos grafenos na matriz biodegrad?vel n?o modificou a sua estabilidade t?rmica e n?o alterou significativamente o processo de perda de massa dos nanocomp?sitos preparados.

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.

Made available in DSpace on 2015-04-14T13:59:13Z (GMT). No. of bitstreams: 1 465109.pdf: 1597249 bytes, checksum: 8d8d15194dba51bfadcec2082e93418b (MD5) Previous issue date: 2015-01-20 / The development of new materials with distinct properties is needed today; nanocomposites represent a new group of materials that stand out in this current market demand. Polyurethanes for having versatility as the processes of synthesis and composition are an object of study in various industrial segments. One method to improve the properties of the polyurethane is the addition of inorganic fillers. Thus, this work aims to study the interaction and incorporation of silico-metallic mineral synthetic particles with different hydrothermal treatments (7h and 24h), comparing the influence of the size, distribution and surface area on the properties of polyurethane nanocomposites. PU nanocomposite / SSMMP (7h and 24h) with defined amounts of 0.5%, 1%, 2%, 3% and 5% by weight relative to the pure polymer were synthesized. Technical Analysis of X-Ray Diffraction (XRD) Analysis of Specific Surface Area (BET) spectroscopy, Fourier Transform Infrared (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TGA), Gel Permeation Chromatography (GPC), Dynamic-Mechanical Analysis (DMTA) and Scanning Electron Microscopy (SEM) were used to characterize materials. The XRD analysis showed that the synthetic silico-metallic mineral fillers exfoliated/well dispersed in the polyurethane matrix. The high surface area of SSMMP influenced the crystallization, and also on the thermal and mechanical properties of nanocomposites. Both PU/ SSMMP (7h and 24h) showed an increase in mechanical properties, although the PU/ SSMMP 7h nanocomposites have a Young's modulus higher than PU / SSMMP 24h. The creep- recovery tests showed that the SSMMP (7h and 24h) restricted the movement of PU chains. The results showed the importance of controlled synthesis of SSMMP for obtaining new materials with desired properties / O desenvolvimento de novos materiais com propriedades distintas se faz necess?rio nos dias atuais e os nanocomp?sitos polim?ricos se destacam nesta demanda do mercado. Os poliuretanos, por terem uma versatilidade quanto a processos de s?ntese e composi??o, s?o objeto de estudo em diversos segmentos industriais. Um dos m?todos para melhorar as propriedades do poliuretano ? a adi??o de cargas inorg?nicas. Neste trabalho foram estudadas a intera??o e incorpora??o de part?culas minerais silico-met?licas sint?ticas com diferentes tratamentos hidrot?rmicos (7h e 24h) na matriz polim?rica, comparando a influ?ncia do tamanho, distribui??o e ?rea superficial nas propriedades dos nanocomp?sitos de poliuretano. Foram sintetizados nanocomp?sitos PU/SSMMP (7h e 24h) com quantidades definidas de 0,5%, 1%, 2%, 3% e 5% em rela??o ? massa do pol?mero puro. Para a caracteriza??o dos materiais foram utilizadas as t?cnicas de An?lise de Difra??o de Raios-X (DRX), An?lise da ?rea Superficial Espec?fica (BET), Espectroscopia de Infravermelho por Transformada de Fourier (FTIR), Calorimetria Explorat?ria Diferencial (DSC), An?lise Termogravim?trica (TGA), Cromatografia de Permea??o em Gel (GPC), An?lise Din?mico-Mec?nica (DMTA) e Microscopia Eletr?nica de Varredura (MEV). As an?lises de DRX indicaram que as cargas minerais silico-met?licas esfoliaram/dispersaram na matriz de poliuretano. As altas ?reas superficiais dos SSMMP tiveram influ?ncia sobre a cristaliza??o, e tamb?m nas propriedades t?rmicas e mec?nicas dos nanocomp?sitos. Ambos PU/SSMMP(7h e 24h) apresentaram um aumento nas propriedades mec?nicas, apesar de os nanocomp?sitos PU/SSMMP 7h apresentarem um M?dulo de Young maior que os PU/SSMMP 24h. Os testes de creep-recovery mostraram que os SSMMP (7h e 24h) restringem o movimento das cadeias do PU. Os resultados mostraram a import?ncia da s?ntese controlada dos SSMMP para a obten??o de novos materiais com propriedades desejadas

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-06-24T21:45:32Z No. of bitstreams: 1 471013 - Texto Completo.pdf: 1943495 bytes, checksum: 36e051cefa7a9d47d6a0d608dff24d67 (MD5) / Made available in DSpace on 2015-06-24T21:45:32Z (GMT). No. of bitstreams: 1 471013 - Texto Completo.pdf: 1943495 bytes, checksum: 36e051cefa7a9d47d6a0d608dff24d67 (MD5) Previous issue date: 2012-07-16 / The following paper reports the synthesis of polyaniline (PANI) nanofibers and the making of nanocomposites that have polypropylene as their polymer matrix. Polyaniline nanofibers have been synthesized by the quick-mix method. Hydrochloridric and sulfuric acids were evaluated as dopant agents in different reaction temperatures: 25, 60 and 100 ?C. Polypropylene (PP) nanocomposites were prepared by adding 1 and 3% (m/m) of PANI nanofibers through three different methods utilized for dispersing the nanocharge in the polymer matrix. This way parameters such as quick-mix in the fusion chamber, masterbach prepping and pre- dispersion of the charge in ethanol were appraised. The morphology and the electric, thermic and mechanic properties of the PANI nanofibers as well as the nanocomposites prepared were evaluated by means of Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Electrical Impedance Spectroscopy (EIS). Nanofibers of the upmost definition were obtained with hydrochloridric acid as the dopant agent in a temperature of 60 ?C. The nanofibers prepped using this methodology presented electrical resistivity of 10? Wcm and a decomposition temperature near 300 ?C. AFM pictures indicate good charge distribution in the polymer matrix regardless of the chosen preparation method. It was verified that the nanocomposites? thermic properties were not negatively affected by the addition of PANI nanofibers and composites with similar traction properties to PP?s matrices were produced with a larger ultimate elongation and electrical conducting properties. / O presente trabalho relata a s?ntese de nanofibras de polianilina (PANI) e a prepara??o de nanocomp?sitos contendo polipropileno como matriz polim?rica. Nanofibras de polianilina foram sintetizadas pelo m?todo da mistura r?pida. ?cido clor?drico e ?cido sulf?rico foram avaliados como agentes dopantes em diferentes temperaturas de rea??o: 25, 60 e 100 ?C. Nanocomp?sitos de polipropileno (PP) foram preparados adicionando-se 1 e 3% (m/m) de nanofibras de PANI por tr?s diferentes m?todos utilizados para dispersar a nanocarga na matriz polim?rica. Assim foram avaliados par?metros como a mistura direta na c?mara de fus?o, prepara??o de masterbach e pr?-dispers?o da carga em etanol. A morfologia, as propriedades el?tricas, t?rmicas e mec?nicas das nanofibras de PANI e dos nanocop?sitos preparados foram avaliados por Microscopia Eletronica de Varredura (MEV), Microscopia de For?a At?mica (AFM), An?lise Termogravim?trica (TGA), Calorimetria Diferencial Explorat?ria (DSC) e Espectroscopia de Imped?ncia El?trica (EIE). Nanofibras com morfologia mais definida foram obtidas quando foi utilizado o ?cido clor?drico como agente dopante, na temperatura de 60?C. As nanofibras preparadas por essa metodologia apresentaram resistividade el?trica na ordem de 102 ?cm e temperatura de decomposi??o pr?xima a 300?C. Imagens de AFM indicam uma boa distribui??o da carga na matriz polim?rica, independentemente do m?todo de prepara??o utilizado. Foi verificado que as propriedades t?rmicas dos nanocomp?sitos n?o foram afetadas negativamente com a adi??o das nanofibras de PANI, e foram produzidos comp?sitos com propriedades de tra??o semelhantes ? matriz de PP, com maior alongamento na ruptura e propriedades el?tricas condutoras.

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 2015-11-26T11:39:49Z 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.

Made available in DSpace on 2015-04-14T13:59:01Z (GMT). No. of bitstreams: 1 451408.pdf: 2001756 bytes, checksum: 64067e77cbea30ac7596f0d09843bc92 (MD5) Previous issue date: 2013-08-09 / Due to search for different properties in polymeric materials, have increasing studies in the composites and the nanocomposites field, using inorganic fillers. Within this context one this work, which has as main objective to study experimentally the synthesis and characterization of nanocomposites of aromatic polyesters / titanium dioxide (PEA/TiO2), using raw materials trade. To do so, it was used the in situ polymerization technique to prepare the nanocomposites with PEA/TiO2 with different concentrations of the load (0%, 0.5%, 1.0%, 2.0%, 3.0% and 5.0% m/m of the polymer mass). It was used as starting materials: dimethyl terephthalate (DMT), polyethylene terephthalate (PET) and a mixture of 1,4-butanediol and 1,6-hexanediol. The nanocomposites were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Gel Permeation Chromatography (GPC). Shore D hardness, contact angle and X-ray Diffraction (DRX). The results show that there was an interaction filler/polymer evidenced by XRD and FTIR analysis. The thermal properties of nanocomposites suffered no significant changes. It was also possible to observe a change in the surface of the synthesized material indicating good compatibility btween filler and polymeric matrix and a decrease of surface hydrophilicity (measured by the contact angle) as well as an increase in hardness of the material compared to pure polymer. / Devido ? busca de propriedades diferenciadas em materiais polim?ricos, t?m-se um aumento crescente nos estudos de comp?sitos e nanocomp?sitos utilizando cargas inorg?nicas. Dentro deste contexto insere-se este trabalho, que tem como objetivo principal estudar, experimentalmente, a s?ntese e a caracteriza??o de nanocomp?sitos de poli?steres arom?ticos/di?xido de tit?nio (PEA/TiO2), utilizando-se mat?rias-primas comerciais. Para isso, utilizou-se a t?cnica de polimeriza??o in situ para preparar nanocomp?sitos de PEA/TiO2 com diferentes concentra??es da carga (0%, 0,5%, 1,0%, 2,0%, 3,0% e 5,0% m/m sobre a massa do pol?mero). Utilizou-se como reagentes iniciais: o Dimetil Tereftalato (DMT), o Politereftalato de Etileno (PET) e uma mistura de 1,4- butanodiol e 1,6- hexanodiol. Os nanocomp?sitos preparados foram caracterizados por Espectroscopia de Infravermelho por Transformada de Fourier (FTIR), Microscopia Eletr?nica de Varredura (MEV), Calorimetria Diferencial Explorat?ria (DSC), An?lise Termogravim?trica (TGA), Cromatografia em Permea??o em Gel (GPC), Dureza Shore D, ?ngulo de contato e Difra??o de Raios- X (DRX). Pelos resultados obtidos neste trabalho, pode-se ressaltar que houve intera??o carga/pol?mero comprovada pelas an?lises de DRX e FTIR onde as mesmas interferiram nas intensidades das bandas proporcionais a quantidade de carga adicionada. As propriedades t?rmicas do material analisadas por DSC e TGA n?o sofreram modifica??o significativa. Tamb?m foi poss?vel observar uma mudan?a na superf?cie do material sintetizado mostrando uma boa compatibilidade da carga com a matriz polim?rica e uma diminui??o da hidrofilicidade da superf?cie (avaliada atrav?s do ?ngulo de contato), al?m de um aumento na dureza do material quando comparado ao pol?mero puro.

Made available in DSpace on 2015-04-14T13:59:01Z (GMT). No. of bitstreams: 1 451790.pdf: 380413 bytes, checksum: 93bdbfaddeeadb736f607d61d5cef5ab (MD5) Previous issue date: 2013-08-23 / The mechanisms of initiation, transport and deposition of sediment in turbidity currents have been studied because of its potential environmental impact and for containing the main hydrocarbon reservoirs. Several research groups have performed simulations of these phenomena in reduced models, using the coal 205 as sediment. However, this material has limitations on its use in noninvasive imaging techniques for monitoring of turbidity currents in tanks of hydraulic simulation. Thus, this study aimed the preparation of polymer nanocomposites with the potential to replace the coal 205 in these simulations. Polymer nanocomposites based on thermosetting matrices containing inorganic filler (clay, graphite and carbon black) were prepared.By means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs it was possible to verify that the fillers incorporated into polymer matrices showed nanometric dimensions and were dispersed homogeneously, except the carbon black that presented some points of agglomeration. The forms of particles are also evaluated by SEM , classified as semi-angular and semi-rounded. The electrical properties were investigated using electrical impedance spectroscopy. The materials studied presented values of settling velocities and density near the coal 205. Thus, all nanocomposites prepared exhibited the desired characteristics to replace the coal 205 in tank hydraulics simulation. / Os mecanismos de inicia??o, transporte e deposi??o de sedimentos em correntes de turbidez v?m sendo estudados devido ao seu potencial impacto ambiental. Al?m disso, os mecanismos de forma??o cont?m os principais reservat?rios de hidrocarbonetos. Grupos de pesquisas t?m realizado simula??es desses fen?menos, em modelos reduzidos, utilizando o carv?o 205 como sedimento. Por?m, esse material apresenta limita??es quanto ao seu uso em t?cnicas de imageamento n?o invasivo para acompanhamento das correntes de turbidez em tanques de simula??o hidr?ulica. Assim, essa pesquisa teve como objetivo preparar material polim?rico com o potencial de substituir o carv?o 205 nessas simula??es. Foram preparados nanocomp?sitos baseados em matrizes termorfixas contendo carga inorg?nica (argila, grafite e negro de fumo). Por meio de micrografias de microscopia eletr?nica de varredura (MEV) e microscopia eletr?nica de transmiss?o (MET) foi poss?vel verificar que as cargas incorporadas ?s matrizes polim?ricas apresentavam dimens?es nanom?tricas e estavam dispersas homogeneamente, exceto o negro de fumo que apresentou alguns pontos de aglomera??o. Tamb?m por MEV foram avaliadas as formas das part?culas, as quais foram classificadas como semi-angulares e semi-arredondadas. As propriedades el?tricas foram investigadas por meio de espectroscopia por imped?ncia el?trica. Os materiais avaliados apresentaram velocidades de queda e massa espec?fica pr?ximas as do carv?o 205. Assim, todos os nanocomp?sitos preparados apresentaram caracter?sticas desejadas para substituir o carv?o 205 em tanques de simula??o hidr?ulica.

Made available in DSpace on 2015-04-14T13:59:02Z (GMT). No. of bitstreams: 1 452931.pdf: 3193003 bytes, checksum: 17279c114312e7c4576c7e96d9be1750 (MD5) Previous issue date: 2013-03-27 / Thermoplastic elastomers, like triblock copolymers, more specifically SBS with linear arrangement, were used to obtain polymeric nanocomposites. Employing spherical TiO2 nanofiller and nanofiller clay with lamellar structure, through mixing method, based on solvent followed by dispersion into mechanical stirring and ultrasound batch, which nanofiller were incorporated in quantities of 0,5%, 1%, 2% and 3% relative to the polymeric matrix mass. The characterization was done using thermal mechanical analytical methods like thermal gravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The monitoring of the morphological structure of nanocomposite and nanofiller was performed by scanning electron microscopy. The results indicate the availability of the proposed technique for incorporation of nanofillers into the matrix and highlight the requirement for surface treatments for improved performance. The use of nanofillers with distinct characteristics can be used for directing the studies of the relation with charge and polymeric matrix and evaluation of properties in charge-matrix interface. / Elast?meros termopl?sticos do tipo copol?meros tribloco, especificamente neste trabalho copol?meros SBS de arranjo linear foram utilizados para a obten??o de nanocomp?sitos. Empregou-se a utiliza??o de nanocargas esf?ricas de TiO2, e nanocargas de argila, com estrutura lamelar, atrav?s de m?todo de mistura em base solvente seguido por dispers?o em agita??o mec?nica e banho de ultrassom, onde foram incorporadas as nanocargas nas quantidades de 0,5%, 1%, 2% e 3%, em rela??o ? massa da matriz polim?rica. A caracteriza??o foi realizada por m?todos anal?ticos t?rmico-mec?nicos, como TGA, e DMTA, e o acompanhamento da estrutura morfol?gica do nanocomp?sito e da nanocarga utilizada foi feito por micrografias atrav?s de microscopia eletr?nica de varredura (MEV). Os resultados obtidos indicam a viabilidade da t?cnica proposta para incorpora??o de nanocargas na matriz e evidenciam a necessidade de tratamentos superficiais para melhorias no desempenho. A utiliza??o de nanocargas com caracter?sticas morfol?gicas distintas serve como par?metro para o direcionamento de estudos sobre a rela??o carga-matriz polim?rica e avalia??o de propriedades na interface carga-matriz.