The radiation degradation of a nanotube-polyimide nanocomposite

The radiation degradation of a nanotube-polyimide nanocomposite was studied. Radiation chemistry was observed that was not present in the unmodified polymer or in the imbedded single-walled carbon nanotubes (SWNTs) themselves. The tensile properties were found to be improved by the addition of SWNTs in the unirradiated materials, and no deterioration in these properties with irradiation was observed. The SWNTs were found to have a detrimental effect on the optical properties however. The transparency of the composite was degraded significantly faster by electron-beam radiation than the neat polymer was. This may make the SWNT/polyimide composites unsuitable for some space applications. Electron Spin Resonance (ESR) measurements determined that the SWNTs interfere with the radical chemistry in the irradiated materials. This could be due to energy dissipation by the SWNT network, preventing the formation of radical species, or alternatively, preferential reaction or termination of radicals by the nanotubes. FT-Raman spectroscopy was found to be a very useful tool for examining SWNTs embedded at low concentrations. It revealed no signs of SWNT degradation up to 10 MGy.