Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-15T21:40:48Z No. of bitstreams: 1 MariaAugustaCavalcantiSoares_DISSERT.pdf: 3097668 bytes, checksum: e79dcba5d529592b21331e686931f1c1 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-17T14:51:17Z (GMT) No. of bitstreams: 1 MariaAugustaCavalcantiSoares_DISSERT.pdf: 3097668 bytes, checksum: e79dcba5d529592b21331e686931f1c1 (MD5) / Made available in DSpace on 2018-01-17T14:51:17Z (GMT). No. of bitstreams: 1 MariaAugustaCavalcantiSoares_DISSERT.pdf: 3097668 bytes, checksum: e79dcba5d529592b21331e686931f1c1 (MD5) Previous issue date: 2016-12-19 / Nos ?ltimos anos o desenvolvimento de supercapacitores tem sido bastante pesquisado devido ? propriedade de possuir densidade de pot?ncia maior do que as baterias convencionais. Para atender as demandas tecnol?gicas da sociedade moderna, a cria??o de dispositivos de armazenamento de energia leves, flex?veis e port?teis, tamb?m chamados de supercapacitores flex?veis, est?o sendo estudados. Os nanotubos de carbono (CNTs ? Carbon nanotubes) incrementam propriedades especiais aos substratos t?xteis, tais como, melhoramento da condutividade el?trica e antiest?tica, aumento da durabilidade e condutividade/isolamento de calor e podem ser aplicados em diversas ?reas, podendo atuar como fornecedores de energia para dispositivos de monitoramentos biom?dicos ou implantes, equipamentos militares e para a constru??o civil. O presente trabalho tem como principal objetivo na forma??o de supercapacitores flex?veis utilizando um m?todo para prepara??o e modifica??o dos nanotubos de carbono de m?ltiplas camadas (MWCNT ? Multiwalled carbon nanotubes) para posterior impregna??o sobre substrato t?xtil de soja. A primeira etapa deste trabalho teve o objetivo de avaliar ? forma??o de grupos funcionais na estrutura dos MWCNTs para sua dispers?o em ?gua atrav?s da funcionaliza??o com diferentes ?cidos (H2SO4 ? ?cido sulf?rico e HNO3 ? ?cido n?trico), sendo purificados com HCl (?cido clor?drico) e neutralizados com NH4OH (hidr?xido de am?nio). Na segunda etapa este material foi funcionalizado com quitosana afim de cationizar os MWCNT e potencializar sua adsor??o sobre a malha de soja. Ap?s o estabelecimento dos par?metros adequados, foram analisadas as diferentes concentra??es de MWCNTs (0%, 1,0%, 2,0% e 3,0% sob peso do material funcionalizado), para a identifica??o do melhor resultado. As t?cnicas de caracteriza??o utilizadas comprovaram que o processo de funcionaliza??o ?cida foi satisfat?rio por promover a aberturas dos tubos dos MWCNTs, sendo identificadas atrav?s da Microscopia Eletr?nica de Transmiss?o (MET) e por facilitar a sua solubilidade em meio aquoso observados de acordo com a Espectroscopia de Absor??o UV-vis, al?m de diminuir a quantidade de impurezas met?licas constatadas em Fluoresc?ncia Raio X (FRX). Os efeitos da funcionaliza??o dos MWCNTs foram comprovados em Difra??o Raio X (DRX) e Espectroscopia Raman. A perda de massa do material identificada por An?lise Termogravim?trica (TG) mostra o aumento ap?s a funcionaliza??o. O processo de imobiliza??o dos nanotubos de carbonos sobre as fibras de soja foi comprovado via Microscopia Eletr?nica de Varredura (MEV), bem como, por an?lises eletroqu?micas que determinaram a forma??o de supercapacitores com maior capacit?ncia espec?fica, de 0,766 mF.cm-2, a uma concentra??o de 3,0%, com caracter?sticas t?xteis favor?veis. / In recent years the development of supercapacitors have been searched because of the property of possessing power density greater than conventional batteries. To meet the technological demands of modern society, the creation of energy storage devices, flexible and lightweight laptops, also called flexible supercapacitors are being studied. Carbon nanotubes (CNTs) increment special properties to textile substrates, such as, improving the electrical conductivity and antistatic, increased durability and heat insulation/conductivity and can be applied in various areas, and may act as energy suppliers for Biomedical monitoring devices or implants, military equipment and civil construction. The present work has as main objective in the formation of flexible supercapacitors using a method for preparation and modification of multiwall carbon nanotubes (MWCNT) for subsequent immobilization on soybean protein textile fabric. The first stage of this work corresponds to the formation of functional groups in the structure of MWCNTs for their dispersion in water through the functionalization with different acids (H2SO4 - sulfuric acid and HNO3 - nitric acid), being purified with HCl (hydrochloric acid) and neutralized with NH4OH (ammonium hydroxide). In the second step the material was functionalized with chitosan in order to cationize the MWCNT and potentiate its adsorption in soybean mesh. After establishing the appropriate parameters, different concentrations of MWCNTs (0%, 1.0%, 2.0% and 3.0% under weight of the functionalized material) were analyzed to identify the best result. The characterization techniques used proved that the acid functionalisation process was satisfactory for promoting the openings of the MWCNTs tubes, being identified by Transmission Electron Microscopy (TEM) and for facilitating their solubility in aqueous media observed in accordance with the Spectroscopy of UV-vis absorption, besides decreasing the amount of metallic impurities found in X-ray Fluorescence (XRF).The effect of the functionalization of MWCNTs was confirmed in X-ray Diffraction (XRD) and Raman Spectroscopy. The loss of mass of the material identified by Thermogravimetric Analysis (TG) shows the increase after the functionalization. The process of immobilization of the nanoparticles in the soybean substrate showed characteristic nanofilaments of the assembly of the MWCNTs on the surface of the samples visualized in Scanning Electron Microscopy (SEM), as well as, the electrochemical analyzes determined the formation of supercapacitors with greater specific capacitance of 0.766 mF.cm-2, at a concentration of 3.0%, with favorable textile characteristics.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-10T00:17:19Z No. of bitstreams: 1 FranciscoClaudivanDaSilva_TESE.pdf: 104448273 bytes, checksum: 6fc093e63486403fa90fe3c9a04747ab (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-10T23:41:42Z (GMT) No. of bitstreams: 1 FranciscoClaudivanDaSilva_TESE.pdf: 104448273 bytes, checksum: 6fc093e63486403fa90fe3c9a04747ab (MD5) / Made available in DSpace on 2016-06-10T23:41:42Z (GMT). No. of bitstreams: 1 FranciscoClaudivanDaSilva_TESE.pdf: 104448273 bytes, checksum: 6fc093e63486403fa90fe3c9a04747ab (MD5) Previous issue date: 2015-12-14 / A sustentabilidade tem sido cada dia mais um tema em evid?ncia no mundo, atualmente organiza??es t?m buscado estar cada vez mais dentro desta filosofia em seus processos, produtos ou servi?os. No presente trabalho foram fabricados ecocomp?sitos com a fibra animal (l? canina) que atualmente ? descartada no meio ambiente sem nenhum aproveitamento. As fases do projeto consistiram em tratamento inicial das fibras em solu??o alcalina (NaOH) ? 0,05 mols para retirada das impurezas presentes, e desenvolver m?todos para converter estas fibras (refor?o) misturadas com o poliuretano de mamona (matriz) em eco-comp?sito com distintas propor??es (5%, 10%, 15% e 20%). Foram estudadas as propriedades da fibra pela an?lise de MEV, DRX e FTIR. Os comp?sitos foram fabricados em molde por compress?o com dimens?es 30x30x1cm com um tempo de cura de 24 horas. Para caracteriza??o dos comp?sitos foram realizados os seguintes ensaios normatizados: mec?nicos (tra??o, compress?o, dureza shore A), testes absor??o de ?gua, moisture regain e biodegrada??o. As propriedades t?rmicas nas fibras e comp?sitos foram analisadas por TG, DSC, condutividade t?rmica, resistividade, capacidade calorifica, resist?ncia t?rmica e dilatometria. Analisando os resultados destes testes, observou-se que o comp?sito refor?ado com 20% apresentou um melhor comportamento t?rmico em rela??o aos demais comp?sitos e estabilidade dimensional quando comparado aos isolantes t?rmicos comerciais. Sendo tamb?m poss?vel observar um equil?brio na absor??o de umidade dos comp?sitos sendo evidenciado com o seu maior ?ndice de absor??o nesta mesma amostra (20%). As micrografias demonstram as regi?es de intera??o da fibra com o poliuretano com preenchimento dos espa?os vazios. Nos testes de dureza e compress?o podemos identificar que com o aumento do percentual de fibras o material adquire uma maior rigidez fazendo se necess?ria uma maior tens?o utilizada para deforma??o. Portanto mediante os testes realizados nos eco-comp?sitos, o de maior percentual de fibra utilizado como refor?o em sua composi??o obteve melhor desempenho frente aos demais eco-comp?sitos, chegando a valores bem pr?ximos ao do PU. / The Sustainability has been evidence in the world today; organizations have sought to be more and more into this philosophy in their processes, whether products or attendance. In the present work were manufactured eco-composites with animal fiber (dog wool) that is currently discarded into the environment without any use. Project phases consisted on the initial treatment of fibers with alkaline solution (NaOH) at 0.05 mols for removal of impurities, developing methods to convert these fibers (reinforcement) blended with castor oil polyurethane (matrix) in eco-composite with different proportions (5%, 10%, 15% and 20%). Fiber properties were evaluated by analysis of SEM, XRD and FTIR. The composites were produced by compression molding with dimensions 30x30x1cm. For characterization of the composites the following tests were performed: mechanical (tensile, compression, shore hardness A) according the standards and testing water absorption, moisture regain and biodegradation. The analysis of thermal properties on fibers and composites were by TG, DSC, thermal conductivity, resistivity, heat capacity and thermal resistance. Analyzing the results of these tests, it was observed that the composite reinforced with 20% showed a better thermal performance between others composites and dimensional stability when compared to commercial thermal insulation. Also is possible to observe a balance in moisture absorption of the composite being shown with its higher absorption rate in this same sample (20%). The micrographs show the fiber interaction regions with polyurethane to fill the empty spaces. In hardness and compression testing can identify that with increasing percentage of the fiber material acquires a greater stiffness by making a higher voltage is used for forming necessary. So by the tests performed in eco-composites, the highest percentage of fiber used as reinforcement in their composition obtained a better performance compared to the remaining eco-composites, reaching values very close to the PU.

Made available in DSpace on 2014-12-17T14:58:17Z (GMT). No. of bitstreams: 1 FranciscoCS_DISSERT.pdf: 2144999 bytes, checksum: 11a0f7255d18cc7bb37fb7499b866d52 (MD5) Previous issue date: 2012-07-16 / The Sustainability has been evidence in the world today; organizations have sought to be more and more into this philosophy in their processes, whether products or attendance. In the present work were manufactured eco-composites with animal fiber (dog wool) that is currently discarded into the environment without any use. The fibers were characterized and made matting (non-woven). The phases of the project were consisted to develop methods and to convert these fibers (booster) blended with polyester resin (matrix) in different proportions (10%, 20% and 30%) at the composite. Were studied fiber characteristics, mechanical properties of the composites, water absorption and scanning electron microscopy. Initially, the fibers were treated with solution of sodium hydroxide of 0.05 mols, and then taken to matting preparing at the textile engineering laboratory - UFRN. The composites were made by compression molding, using an orthophthalic polyester resin as matrix and 1% MEK (methyl ethyl ketone peroxide) as initiator (catalyst). To evaluate the mechanical tests (tensile and flexural) and water absorption were made twelve specimens with dimensions 150x25x3 mm were cut randomly. According to the standard method, tensile tests (ASTM 3039) bending tests (ASTM D790) were performed at the mechanical testing of metals at laboratory UFRN. The results of these tests showed that the composite reinforced with 30% had a better behavior when exposed to tension charge; while on the three points bending test showed that the composite reinforced with 10% had a better behavior. In the water absorption test it was possible to see that the highest absorption happened on the composite reinforced with 30%. In the micrographs, it was possible to see the regions of rupture and behavior of the composite (booster / matrix) / A sustentabilidade tem sido cada dia mais um tema em evid?ncia no mundo, atualmente organiza??es t?m buscado estar cada vez mais dentro desta filosofia em seus processos, seja produtos ou servi?os. No presente trabalho foram fabricados eco-comp?sitos com a fibra animal (l? canina) que atualmente ? descartada no ambiente sem nenhum aproveitamento. As fibras foram caracterizadas e em seguida confeccionadas mantas (n?o tecidas). As fases do projeto consistiram em desenvolver m?todos para converter estas fibras (refor?o) misturadas com resina de poli?ster (matriz) em distintas propor??es (10%, 20% e 30%) nos comp?sitos. Foram estudadas as caracter?sticas da fibra, propriedades mec?nicas dos comp?sitos, absor??o de ?gua e microscopia eletr?nica de varredura. Inicialmente as fibras foram tratadas com uma solu??o de 0,05 mols de hidr?xido de s?dio, em seguida levadas a um preparador de mantas no Laborat?rio de Engenharia T?xtil da UFRN. Os comp?sitos foram fabricados em molde por compress?o, utilizando a resina de poli?ster ortoft?lico como matriz e 1% de per?xido MEK (per?xido de metil etil cetona) como iniciador (catalizador). Para avalia??o dos ensaios mec?nicos (tra??o e flex?o) e absor??o d agua, foram confeccionados corpos de prova com as dimens?es 150x25x3 mm. De acordo com as normas, os ensaios de tra??o (ASTM 3039) e flex?o em tr?s pontos (ASTM D790) foram realizados no Laborat?rio de metais e ensaios mec?nicos da UFRN. Analisando os resultados destes ensaios, observou-se que o comp?sito refor?ado com 30% apresentou um melhor comportamento quando expostos a carregamentos de tra??o, enquanto que no teste de flex?o observou-se que o comp?sito refor?ado com 10% apresentou um melhor comportamento. No ensaio de absor??o d agua foi poss?vel observar um equil?brio na absor??o de umidade dos comp?sitos sendo seu maior percentual de absor??o no comp?sito de 30%. Nas micrografias, se observa as regi?es de ruptura do comp?sito e seu comportamento (fibra/matriz)