Investigation of the Deformation of Carbon Nanotube Composites Through the Use of Raman Spectroscopy

Since the discovery of carbon nanotubes in 1991, the study of these new carbon materials has undergone rapid development in this fast moving research area. The deformation micromechanics of single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) particulate nanocomposites have been studied using Raman spectroscopy. SWNTs and MWNTs prepared by two different methods (pulsed-laser and arc-discharge) have been used as reinforcement for a polymer matrix nanocomposite. A four-point bend test has been employed to deform samples of a dispersion of SWNT and MWNTs in epoxy resin to follow the deformation of the nanotubes with Raman spectroscopy. Both SWNT and MWNTs exhibit well-defined Raman peaks. It has been found that for all samples deformed, the Raman peak position chosen shifted to a lower wavenumber upon application of a tensile strain. In this way it has been possible to demonstrate that the effective modulus of SWNTs dispersed in a composite is in the range 100ȁ3500 GPa. In addition, it has been found that the bands in the Raman spectrum of SWNTs shift to a higher wavenumber when dispersed in ethanol and stays at this higher position even when the solvent is evaporated.