Research On The Radiation Resistance Of Carbon Nanotubes Modified Carbon Fiber Composites

With the development of aerospace industry and national defense industry,traditional anti-radiation materials are gradually eliminated.Carbon fiber reinforced epoxy resin composites(CF/EP)are widely used because of their high strength,fatigue resistance and radiation resistance.CF/EP is a three-phase structure,and the properties of composites are determined by carbon fibers,resin matrix and interface.The gamma ray carries huge energy,which has a great influence on the structure and performance of the composite material.It is more representative,so y ray is selected as the irradiation line,? rays are electromagnetic waves that cause damage to the matrix and interface of the composite.Carbon nanotubes(CNTs)have extraordinary properties,such as radiation resistance.In order to resist the damage of CF/EP by y ray,this subject uses electrophoretic deposition and ultrasonic blending to introduce CNTs into the matrix and interface region of the composite.Composites(CF/EP-CNTs,CF-CNTs/EP and CF-CNTs/EP-CNTs)were prepared by matrix modification,interface modification,matrix and interface synergistic modification.The doses were gamma ray irradiation of OMGy,2MGy,7MGy and 20MGy.Further study on the mechanical,thermal and fatigue resistance properties of composites before and after modification,revealing the effects of y irradiation and CNTs on composites.The effects of CNTs and y rays on the mechanical properties of composites were studied by bending strength test,interlaminar shear strength test,fatigue resistance test and internal damage detection.It was found that the mechanical properties of the same composites first increased and then decreased with the increase of irradiation dosage.Under the same irradiation dosage,the flexural strength,flexural modulus,interlaminar shear strength and residual fatigue strength retention ratio of CF/EP,CF-CNTs/EP,CF-CNTs/EP,CF-CNTs/EP-CNTs increased compared with CF/EP.The flexural strength of CF-CNTs/EP-CNTs increased by 42.90%,40.91%,38.53%,15.28%,the flexural modulus increased by 58.64%,62.87%,55.33%,5.67%,the interlaminar shear strength increased by 42.8%,39.3%,24.6%,6.0%,and the residual fatigue strength retention rate was 92.9%,94.5%,91.7%,88.8%under four doses of OMGy,2MGy,7MGy and 20MGy.The thermal properties of CF/EP-CNTs,CF-CNTs/EP,CF-CNTs/EP,CF-CNTs/EP and EP-CNTs increased gradually with the same irradiation dose.For the same composite,with the increase of irradiation dose,E'increases first and then decreases.After irradiated by y rays,E'of the composites increases continuously during the heating process,and decreases after reaching the maximum value,resulting in secondary curing.In order to understand the mechanism of radiation resistance of CNTs reinforced composites,X-ray photoelectron spectroscopy,ultrasonic C-scan,scanning electron microscopy and crack propagation path simulation were used.It was found that the properties of the composites irradiated by gamma rays had dual effects of promoting and damaging.The addition of CNTs enhances the crosslink density of the composite,forms numerous micro interfaces,enhances chemical bonding at the interface,and enhances radiation resistance.The best way to improve the radiation resistance of composites is the synergistic enhancement of CNTs in the matrix and interface regions.