Fechar

@MastersThesis{Marques:2015:CoTeNa,
               author = "Marques, Vagner Eduardo Caetano",
                title = "Comp{\'o}sitos termor{\'{\i}}gidos com nanotubos de carbono 
                         verticalmente alinhados crescidos sobre a fibra de carbono",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2015",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2015-04-24",
             keywords = "nanotubos de carbono, fibra de carbono, nanocomp{\'o}sitos, 
                         catalisador flutuante, carbon nanotubes, carbon fiber, 
                         nanocomposites, floating catalyst.",
             abstract = "A presente disserta{\c{c}}{\~a}o consiste no estudo de 
                         nanocomp{\'o}sitos feitos a partir da deposi{\c{c}}{\~a}o de 
                         nanotubos de carbono verticalmente alinhados sobre tecidos de 
                         fibras de carbono e sua posterior impregna{\c{c}}{\~a}o com 
                         resina ep{\'o}xi, com a finalidade de melhorar as propriedades 
                         mec{\^a}nicas interlaminares de comp{\'o}sitos com fibra de 
                         carbono. O maior desafio deste trabalho foi a 
                         otimiza{\c{c}}{\~a}o e o escalonamento do processo de 
                         deposi{\c{c}}{\~a}o dos nanotubos de carbono para permitir 
                         amostras extensas suficientes para confec{\c{c}}{\~a}o dos 
                         corpos de prova de comp{\'o}sitos estruturais. Foi desenvolvida 
                         uma forma de uniformizar a deposi{\c{c}}{\~a}o de uma 
                         intercamada de sil{\'{\i}}cio amorfo (depositado por plasma DC 
                         de silano), que serve como barreira de difus{\~a}o de ferro. O 
                         ferro {\'e} o material utilizado na forma de nano 
                         part{\'{\i}}culas como catalisador da nuclea{\c{c}}{\~a}o do 
                         crescimento de materiais graf{\'{\i}}ticos. Esta camada de 
                         sil{\'{\i}}cio amorfo foi, tamb{\'e}m, utilizada como interface 
                         CNT/resina que nos permitiu obter resposta ao cisalhamento 
                         interlaminar e um ganho nas propriedades el{\'e}tricas. Foi 
                         utilizada a t{\'e}cnica Deposi{\c{c}}{\~a}o Qu{\'{\i}}mica de 
                         Vapor em um forno tubular para os crescimentos dos nanotubos de 
                         carbono. Ensaios de tra{\c{c}}{\~a}o tamb{\'e}m foram 
                         realizados nos feixe de fibras para certifica{\c{c}}{\~a}o de 
                         que suas propriedades mec{\^a}nicas foram mantidas ap{\'o}s as 
                         deposi{\c{c}}{\~o}es realizadas. Para diversas etapas do 
                         processo, foram produzidas amostras de comp{\'o}sito atrav{\'e}s 
                         dos m{\'e}todos infus{\~a}o/inje{\c{c}}{\~a}o com baixas 
                         press{\~o}es em moldes fechados. Foi realizada an{\'a}lise 
                         morfol{\'o}gica e estrutural, atrav{\'e}s de Microscopia 
                         Eletr{\^o}nica de Varredura e Espectroscopia Raman. Na 
                         caracteriza{\c{c}}{\~a}o mec{\^a}nica, foram feitos testes de 
                         DMA e cisalhamento interlaminar (norma ASTM 2344), e as fraturas 
                         dos corpos de prova foram analisadas atrav{\'e}s de Microscopia 
                         {\'O}ptica. O ganho no comportamento el{\'e}trico, conseguido 
                         tanto pelos nanotubos quanto pela camada de Si amorfo, foi 
                         determinado pelo M{\'e}todo de duas pontas para medida de 
                         resistividade DC. Foi obtida a resistividade el{\'e}trica dos 
                         comp{\'o}sitos tanto na dire{\c{c}}{\~a}o paralela aos tecidos 
                         de fibra de carbono quanto na dire{\c{c}}{\~a}o perpendicular. 
                         ABSTRACT: This dissertation is the study of nanocomposites made 
                         from the deposition of vertically aligned carbon nanotubes on 
                         carbon fibers cloths and subsequent impregnation with epoxy resin, 
                         in order to improve the interlaminar mechanical properties of 
                         carbon fiber composites. The biggest challenge of this work was 
                         the optimization and scaling up of carbon nanotubes deposition 
                         process to allow samples sufficiently extensive for the 
                         fabrication of structural composites specimens. A way for uniform 
                         deposition of an amorphous silicon interlayer was developed 
                         (deposited by DC plasma of Silane), which serves as a diffusion 
                         barrier to iron. The iron is used as catalyst nanoparticles for 
                         growth of graphitic materials. This amorphous silicon layer was 
                         also used as CNT/resin interface which allowed us a response to 
                         the interlaminar shear and a gain on the electrical properties. 
                         Chemical vapor deposition technique has been used in a tubular 
                         furnace for growth of carbon nanotubes. Tensile strength tests 
                         were also carried out on the fiber tow to certification that their 
                         mechanical properties were maintained after the depositions 
                         process. Composite samples for the several process steps were 
                         produced by the infusion/injection methods at low pressures at 
                         closed molds. Morphological and structural analysis were 
                         performed, through scanning electron microscopy and Raman 
                         spectroscopy. In mechanical characterization, DMA and interlaminar 
                         shear tests were performed (standard ASTM 2344), and the fractures 
                         of the specimens were analyzed by optical microscopy. The gain in 
                         the electrical behavior, achieved by the nanotubes and by the 
                         amorphous Si layer, was determined by the method of two points DC 
                         resistivity measurement. The electrical resistivity of the 
                         composites was obtained both in the parallel direction to the 
                         carbon fiber cloth and in the perpendicular direction.",
            committee = "Corat, Evaldo Jos{\'e} (presidente/orientador) and Antunes, Erica 
                         Freire (orientador) and Machado, Jo{\~a}o Paulo Barros and Lobo, 
                         Anderson de Oliveira",
           copyholder = "SID/SCD",
         englishtitle = "Thermoset composite with carbon nanotubes vertically aligned grown 
                         on carbon fiber",
             language = "pt",
                pages = "119",
                  ibi = "8JMKD3MGP3W34P/3JCA8KE",
                  url = "http://urlib.net/ibi/8JMKD3MGP3W34P/3JCA8KE",
           targetfile = "publicacao.pdf",
        urlaccessdate = "28 mar. 2024"
}


Fechar