Effects of Proton Irradiation on the Mechanical and Physical Properties of Carbon Nanotube Based Composites

In this study, the effects of proton irradiation on carbon nanotube (CNT)-epoxy composites are investigated for potential applications in radiation shielding for spacecraft. CNT-epoxy composites were prepared using multiwall and single wall CNTs and exposed to proton beams of energies ranging from 6 MeV to 12 MeV. The nanocomposites shielding capabilities against the different energetic proton beams were measured by tracking the beam's energy before and after penetrating the samples. The microstructures of the samples were characterized using scanning electron microscopy (FESEM). The effect of proton irradiation on the electrical resistivity was measured using a high resolution multimeter. Finally the influence of the irradiation on the mechanical properties, such as the elastic modulus and hardness, was probed using instrumented nanoindentation tests.

The proton stopping power of the epoxy was shown to be unchanged by the addition of CNTs, which is a promising result since the hardness of the samples was shown to be increased by addition of CNTs. Unfortunately, however, the surface of the samples proved to be too rough for nanoindentation to yield more detailed results. This was due to the use of a diamond saw in cutting the samples to size. The addition of CNTs was shown to reduce the volume electrical resistivity of the neat epoxy by almost five orders of magnitude and the irradiation further reduced it by a factor of 2-16.