Nanocompósitos de matriz epóxi reforçados com nanotubos de carbono

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The addition of small amounts of carbon nanotubes (CNTs) in polymeric matrices has the potential to origin structural materials with exceptionally high modulus and strength. The extent to which these characteristics will actually be observerd depends on parameters such as degree of purity of the CNT, viscosity of the resin, the cure of the nanocomposites, among others. Aiming to establish an adequate route for the preparation of epoxy nanocomposites, the following aspects have been studied: (i) the effect of acetone addition on the physical and mechanical properties of epoxy; (ii) the CNT reinforcement role in epoxy nanocomposites with different matrix stiffnesses prepared following different curing cycles and (iii) the influence of the CNT content on the nanocomposites. In the first study, solutions with different solvent:epoxy ratio (w/w), namely 0.0, 7.0, 10.0 and 13.0 wt.%, were prepared. It was found that a 10 wt.% acetone addition to the epoxy resin is very beneficial to processes where finely divided fillers, such as carbon nanotubes, are to be incorporated into a resin. Thermogravimetric analysis showed that the cross-linking process of the epoxy was compromised by the presence of residual solvent. Carbon nanotubes (0.25 wt.%) raised the thermal stability of the resin, suggesting a homogeneous dispersion, wich increased its thermal conductivity. The observed increase in Tg indicates that the introduction of nanotubes in the epoxy matrix restricted the movements of the polymeric chains. The viscosity of the epoxy/acetone solution showed a maximum, 12% higher, for a 0.1 wt.% of CNT. Variation in the amount of CNT did not show a significant effect on the thermal stability of the nanocomposites. The DSC, DMA and mechanical test results suggested that the 0.1 wt.% CNT dispersion was more homogeneous than that for 0.25 wt.% SWNT.

ASSUNTO(S)

nanocomposites epoxy epóxi polimeros carbon nanotubes nanocompósitos acetone acetona nanotubos de carbono

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