环氧树脂基体中碳纤维单丝及其界面的温敏效应

为探索树脂基碳纤维复合材料(CFRP)温敏效应的机理,针对环氧树脂基体中碳纤维单丝及正交搭接的碳纤维界面进行了温敏效应实验。实验结果表明碳纤维单丝具有NTC效应,其温敏曲线线性稳定,碳纤维单丝被树脂浸润后,由于树脂膨胀带动纤维在其轴向的伸长,使得树脂基中碳纤维单丝的NTC效应有所减弱;树脂基中碳纤维界面表现出非线性变化的PTC效应,温度越高,其界面电阻随温度变化的趋势越显著,树脂基碳纤维复合材料的温敏特性是树脂基体中碳纤维单丝及其界面的温敏效应协同作用的结果,相对于碳纤维本身而言,碳纤维界面对温度变化更敏感,在CFRP温敏效应中占主导地位。

Temperature sensitivities of carbon fiber and carbon fiber interface in epoxy

In order to reveal the mechanism of temperature sensitivity for polymer-matrix carbon fiber composite(CFRP),the resistance variation with the temperature was measured for the carbon fiber itself and the overlapped carbon fiber interface of cross-ply configuration in epoxy.The NTC effect with good linearity and stability was found for the bare carbon fiber in the test,and it was weakened in the epoxy matrix due to the longitudinal tension caused by the matrix expansion.The carbon fiber interface in epoxy exhibits nonlinear PTC effect in which the interface resistance increased with the temperature with an increasing speed.The temperature sensitivity of CFRP originates from the temperature sensitivity of carbon fiber and the carbon fiber interface,and it was governed by the second one which was more sensitive to the temperature.