Xiao Jingdong

Effect of Proton Irradiation on Mechanical Properties of Carbon/Epoxy Composites

Irradiation using 120-keV protons was performed on the AG-80 epoxy resin and the unidirectional M40J/AG-80 composite. Changes in the bend strength, bend modulus, interlayer shear strength, and mass loss ratio were examined. Experimental results show that by using proton fluences lower than approximated, the cross-linking density increases with the fluence in the surface layer of the AG-80 epoxy matrix and increases the bend strength and modulus for the composite. Increasing the fluence above 6.3 × 1015 cm−2, the cross-linking density, bend strength, and bend modulus are decreased. The mass loss ratios for both the AG-80 epoxy resin and the M40J/AG-80 composites increase with increasing proton fluence, and then level off.

Effect of nano-SiO2 films on the electron radiation induced conductivity of polyimide

The radiation induced conductivity (RIC) behaviors in nano-SiO2 deposited polyimide (PI) were investigated using the in situ measurement technique. The results indicate that, by comparison with the case of virgin polyimide, the RIC in nano-SiO2 /polyimide shows low steady state values. Moreover, the steady state RIC is a power function of the dose rate with a power index of 0.659, lower than that of 0.76 in the virgin polyimide. The interfacial barrier and trapping effects are the main reasons for the change. Meanwhile, both of the interfacial effects also result in a unipolar carrier transportation mechanism in nano-SiO2 deposited PI from the dipolar one in the virgin PI. The mechanisms of the RIC behaviors are discussed in the paper.