Investigation into the deformation of carbon nanotubes and their composites through the use of Raman spectroscopy

The deformation micromechanics of single-walled carbon nanotube (SWNT) and multi-walled carbon nanotube (MWNT) particulate nanocomposites has been stu died using Raman spectroscopy. SWNTs prepared by two different methods (pul sed-laser and are-discharge) and MWNTs have been used as reinforcement for a polymer matrix nanocomposite. The carbon nanotubes exhibit well-defined R aman peaks and Raman spectroscopy has been used to follow their deformation . SWNTs have been deformed with hydrostatic pressure in a diamond anvil pre ssure cell and has been found that the G' peak position shifts to a higher wavenumber with hydrostatic compression. It has been found that for all nan ocomposites samples deformed, the G' Raman band shifts to a lower wavenumbe r upon application of a tensile stress indicating stress transfer from the matrix to the nanotubes and hence reinforcement by the nanotubes. The behav iour has been compared with that of high-modulus carbon fibres and has been modelled using orientation factors suggested initially by Cox. In this way it has been possible to demonstrate that the effective modulus of SWNTs di spersed in a composite could be over 1 TPa and that of the MWNTs about 0.3 TPa. (C) 2001 Elsevier Science Ltd. All rights reserved.