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Materiais Compósitos Reforçados com Nanotubos de Carbono
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Abstract(s)
A presente dissertação tem como objetivo principal a elaboração de um estado de arte baseado em materiais compósitos reforçados com nanotubos de carbono (NTC). Os objetivos deste trabalho
consistem em: mostrar novas técnicas e procedimentos para a fabricação de materiais nanocompósitos com NTC, apresentar as principais vantagens e os principais inconvenientes destes nanocompósitos e apresentar uma boa quantidade de informações sobre materiais reforçados com NTC, preenchendo a lacuna existente no conhecimento sobre estes novos materiais.
Ao longo deste trabalho é dado maior ênfase às modificações provocadas pela presença dos nanotubos de carbono em matrizes poliméricas e cimentícias. São tidos em conta diversos processos de funcionalização a fim de melhorar a interação dos nanotubos com a pasta de cimento e aprimorar a sua dispersão na matriz. É feita referência a várias composições reforçadas com nanotubos de
carbono de modo a poder-se efetuar uma comparação entre as principais propriedades alcançadas.
Os efeitos da adição de NTC sobre as propriedades frescas e endurecidas de betão foram medidos através de resultados experimentais relatados na literatura.
São observados resultados contraditórios na literatura. Verifica-se que a maior ou menor influência dos NTC nas propriedades físicas, mecânicas e de durabilidade das matrizes compósitas depende do teor característico do NTC, dispersão na matriz, aderência e interação com o compósito. Os processos de funcionalização mostram-se capazes de modificar as características dos nanotubos,porém em certos casos não são eficientes para melhorar a sua dispersão e a interação com a matriz de cimento.
Abstract The main goal of this work is to overview the potentiality of the carbon nanotubes (CNT) in the reinforcement of composite material, with polymer and cementitious materials. The objectives of this work are: (i) to show new techniques and procedures to manufacture CNT nanocomposite materials, (ii) to present the main advantages and major drawbacks in the usage of these nanocomposites and (ii) to present in this way the highest degree of information on CNT-based materials, filling the gap in knowledge on these new materials. Throughout this study, great emphasis is dedicated on the modifications triggered by the presence of CNT in the polymers and cement matrices. In order to improve the interaction between the CNT and the cement paste as well as the CNT dispersion in the matrix, different processes were taken into account and described herein. In order to compare the main properties exhibited by the CNT based composites, reference was made to several works connected out by other researchers. Laboratorial tryouts were carried out in order to measure fresh and hardened properties of concrete under the influence of the addition of CNT in the mixture, the data of these results are experimental results reported in literature. Contradictory results are observed in literature. It’s noted that greater or lesser influence of CNT on physical, mechanical and durability properties of these composite matrices content, depends on the CNT characteristic the dispersion in the matrix, interaction and adherence with the composite. It is shown that the functionalization processes leads to modifications on the CNT characteristics. However, these processes seems to be less effective in improving the dispersion and interaction between the CNT and cement matrix.
Abstract The main goal of this work is to overview the potentiality of the carbon nanotubes (CNT) in the reinforcement of composite material, with polymer and cementitious materials. The objectives of this work are: (i) to show new techniques and procedures to manufacture CNT nanocomposite materials, (ii) to present the main advantages and major drawbacks in the usage of these nanocomposites and (ii) to present in this way the highest degree of information on CNT-based materials, filling the gap in knowledge on these new materials. Throughout this study, great emphasis is dedicated on the modifications triggered by the presence of CNT in the polymers and cement matrices. In order to improve the interaction between the CNT and the cement paste as well as the CNT dispersion in the matrix, different processes were taken into account and described herein. In order to compare the main properties exhibited by the CNT based composites, reference was made to several works connected out by other researchers. Laboratorial tryouts were carried out in order to measure fresh and hardened properties of concrete under the influence of the addition of CNT in the mixture, the data of these results are experimental results reported in literature. Contradictory results are observed in literature. It’s noted that greater or lesser influence of CNT on physical, mechanical and durability properties of these composite matrices content, depends on the CNT characteristic the dispersion in the matrix, interaction and adherence with the composite. It is shown that the functionalization processes leads to modifications on the CNT characteristics. However, these processes seems to be less effective in improving the dispersion and interaction between the CNT and cement matrix.
Description
Keywords
Nanotubos de carbono Nanotecnologia Nanomateriais Nanocompósitos Fibras de reforço