Effect of CNT modified matrix of epoxy CFRPs on hydrothermal behaviour of material. Evaluation of water uptake using electrical resistance measurements

In the present work, reference and nano-modified unidirectional and quasi-isotropic, epoxy matrix, carbon fibre reinforced polymers, were exposed to distilled water at hydrothermal environment. Water uptake was investigated as a function of the CNT matrix wt-% content up to saturation level. In parallel the variation of glass transition temperature T_g was also monitored using DMA tests. The distilled water absorption process was modelled following the Fick's law, and the experimental results found to be in very good agreement to the theoretical predictions up to saturation. During the tests, at defined time intervals, the variation of the electrical conductivity of the investigated materials was studied and a correlation between the water absorption and the variation of the electrical conductivity was established. Finally, all the reference materials and the ones concluded at the saturation stage were exposed to broadband dielectric measurements at frequency range of 0·1 Hz to 1 MHz.