电热作用对碳纤维/环氧树脂基复合材料吸湿行为的影响

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

采用复合材料电热实验机,对碳纤维/环氧树脂基复合材料(CF/EP)试样进行通电处理,同时测试其表面温度变化,并得出电阻率随温度的变化规律。对通电后的试样进行吸湿处理,获取扩散系数、饱和吸湿率与通电电流之间的关系,之后通过FTIR、弯曲性能测试以及弯曲断口的表面形貌分析研究了通电对试样吸湿行为的影响。结果表明:通电电流强度越大,CF/EP试样表面平衡温度越高,随着温度升高电阻率呈下降趋势;经4 A(ρ=66.8mA·mm^(-2))电流处理的试样,其扩散系数、饱和吸湿率均低于未处理试样,经5A(ρ=83.6mA·mm^(-2))、6A(ρ=100.2mA·mm^(-2))电流处理后,扩散系数及饱和吸湿率均高于未处理试样;小电流处理时,界面性能得到改善,提高弯曲强度,大电流处理对界面有一定损伤,降低弯曲强度,电热/湿作用下,CF/EP试样的弯曲强度下降,下降幅度与吸湿量呈正相关。

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 4A（ρ=66.8mA·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 5A（ρ=83.6mA·mm-2）or 6A（ρ=100.2mA·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.