Effect of particle size on gamma radiation shielding property of gadolinium oxide dispersed epoxy resin matrix composite

Epoxy resin matrix composites filled with dispersed micro and nano gadolinium oxide (Gd₂O₃) particles of different contents were fabricated in this study. The radiation shielding and mechanical properties of these micro and nano composites were evaluated by measuring mass attenuation coefficients at photon energies from 31 keV to 356 keV and flexural performances. Adding Gd₂O₃ obviously increases mass attenuation coefficients of composites, and the enhancement is stronger at low photon energy because of dominating photoelectric effect and k-edge of element gadolinium. Effect of Gd₂O₃ particle size on shielding property of composite was also discussed. The results show that nano-Gd₂O₃ composites have better ability to shield X and ray than micro-Gd₂O₃ composites, and an enhanced effect of ~28% is obtained with Gd₂O₃ content of around 5 wt.% at 59.5 keV. The reason is attributed to higher probability of interaction between ray and nano particles. Especially, this effect is prominent in low particle concentration. For flexural property, nano-Gd₂O₃/epoxy composite show equivalent flexural strength and up to15% higher flexural modulus compared with micro-Gd₂O₃/epoxy composite. Based on these experimental results, nano-Gd₂O₃ reinforced epoxy composite is believed to be a promising novel radiation shielding material.