The effect of irradiation on electrical and electrodynamic properties of nanocarbon-epoxy composites

Abstract

The aim of this work is to examine the effect of irradiation on the structure, the electrical resistivity and electromagnetic radiation (EMR) shielding (frequency range of f = 25.5–37.5 GHz) of nanocarbon–epoxy composites (CMs). The graphite nanoplatelets (GNPs) and multi-walled carbon nanotubes (MWCNTs) are used as fillers in epoxy polymer matrix (epoxy resin ED20). Nanocarbon filler content is 1–2.2 vol.%. Polymer-nanocarbon CMs were irradiated by different methods: UV irradiation for 51 h, СuKα X-ray radiation (U = 30 kV, i = 20 mA) for 1 h, electron irradiation (1.8 MeV, the absorbed dose is 1 MGr), ions H+ (1.5 MeV, 5 × 1016), C+ (3 MeV, 4 × 1016). It was shown, that the different types of radiation provide different influence both on the value and character of the temperature dependence of resistivity. The most significant change of resistivity was observed for the specimen irradiated by UV – resistivity decreases almost by three orders (by 806 times), the temperature dependence of resistivity being weakened. For specimens irradiated by UV and X-ray we also have observed the increase of shielding efficiency as compared with initial CM, while the irradiation of specimen by electrons leads to a decrease of shielding efficiency SET. According to Raman investigation results, the irradiation by H+ ions of CM 2 wt.% MWCNTs-ED20 with intensity 1.5 MeV leads to significant destroying of nanotube structure and formation of homogeneous amorphous material.