Radiation resistance of carbon fiber-reinforced epoxy composites optimized synergistically by carbon nanotubes in interface area/matrix

In order to investigate the effect of the addition of carbon nanotubes (CNTs) in carbon fibers reinforced epoxy matrix composites (CF/EP) on the ability of composites to resist gamma radiation. We used y irradiation and investigated composites, gamma-CF/EP without CNTs; gamma-CF/EP with CNTs in matrix (gamma-CF/EP-CNTs); gamma-CF/EP with CNTs in interface (gamma-CF-CNTs/EP) and gamma-CF/EP with CNTs both in the interface area and matrix (gamma-CF-CNTs/EP-CNTs). The results show that the bending strength and bending modulus of gamma-CF-CNTs/EP-CNTs are 28.59% and 41.44% higher than that of gamma-CF/EP before fatigue testing, and 32.19% and 73.51% higher than that of gamma-CF/EP after fatigue testing. Ultrasonic C-scan microscopic examination after fatigue test showed that the internal structure damage of gamma-CF-CNTs/EP-CNTs was the smallest, while gamma-CF/EP was the largest. The storage modulus of the three modified composites are significantly improved compared with the unmodified composite, especially the storage modulus of gamma-CF-CNTs/EP-CNTs is sharply improved from 2.53 GPa (gamma-CF/EP) to 5.66 GPa (gamma-CFCNTs/EP-CNTs). X-ray spectroscopy shows changes in the surface and internal valence content of the composites, further revealing the crosslinking reaction and the secondary curing reaction. Combined with scanning electron microscopy and crack propagation models, the microstructure and enhancement mechanisms of CNTs-reinforced composites for anti-gamma radiation are discussed. The CNTs synergistic enhance the composite's anti-gamma radiation performance with excellent effects when CNTs are added together into matrix and interface area.