Electric-thermal effects on moisture absorption behavior of carbon fiber/epoxy resin composites

This study focus on monitoring the surfacial temperature of carbon fiber/epoxy resin (CF/EP) composite under different electric current by electric-thermal damage test device,meanwhile deducing the resistivity variation law with temperature.The CF/EP specimens were dealed with moisture absorption treatment and the relationship between diffusion coefficients,saturated moisture absorption rate and electric current were obtained.The effects of current loading on moisture absorption behavior of CF/EP were analyzed by FTIR,flexural test and flexural fracture surface morphology.The results indicate that electric current make the equilibrium temperature increase and the resistivity decreases as the temperature increases.When current value 4 A (ρ=66.8 mA·mm^-2) is applied to CF/EP specimens,the diffusion coefficient and saturated moisture absorption rate are lower than that of untreated samples.Opposite trend is shown when current value is 5 A (ρ=83.6 mA·mm^-2) or 6 A (ρ=100.2 mA·mm^-2).Low current intensity can optimize the interfacial performance and enhance flexural strength,while the high current intensity destroy interfacial property and decline flexural strength.When CF/EP specimens are exposed to the coupled electro-thermal and hygrothermal loadings,the flexural performance of samples decrease and flexural reduction is positively correlated with moisture absorption.