AGEING BEHAVIOR OF MULTI-WALL CARBON NANOTUBES EMBEDDED IN SILICONE RUBBER BY RAMAN SPECTROSCOPY

Nowadays there is a growing interest in using multi-wall carbon nanotubes (MWCNTs) for development of new materials with unique properties. An example of such new material is MWCNTs-embedded silicone rubber sealing material. Electrical resistivity measurements showed that by adding 10 wt. % conductive-MWCNT to the insulating matrix (>MWcm) the resistivity was reduced to 8.7 Wcm.

Accelerated radiation tests are required for all materials, especially new nano-composite materials that are considered for future space systems and structures. One common method to simulate total ionizing dose sustainability is by exposing the materials to Co⁶⁰ g-ray photons with energy in the range of 1.17–1.33 MeV up to a total absorbed dose of interest.

Understanding the radiation induced ageing processes of new materials is critical for their long term performances in harsh environments. Non-destructive Raman spectroscopy can provide information regarding the ageing mechanism. MWCNTs possess strain-sensitive band shift of the 2D band upon exposure to ionizing radiation. The 2D band position at about 2678 cm^-1 is an indication of strain due to interactions between the walls. In the present work samples of conductive-MWCNTs/silicone rubber were exposed to various doses of ionizing radiation, and after each exposure the Raman spectrum was taken. The results have indicated the benefit of using MWCNT embedded in the matrix as an in-situ fingerprint for the composite material degradation.