碳纤维丝束表面润湿性能的红外热成像法观测

Observation of Surface Wettability of Carbon Fiber Tow by Means of IR Thermal Imaging

碳纤维表面的润湿性能是影响碳纤维复合材料性能的重要因素.由于碳纤维的丝径过小以及测量工质的透明特征,在采用传统的润湿性能测试方法测试时操作要求苛刻和润湿边界模糊,实验的可重复性小和误差较大.为此,文中提出了一种新的碳纤维毛细润湿红外热成像观测法,观测了光滑形貌和粗糙形貌碳纤维表面的润湿性能,考察了碳纤维丝束润湿高度随时间的变化趋势,并将实验结果与毛细上升的经典理论LaplaceWashburn模型进行对比.结果表明,碳纤维丝束在快速润湿阶段的润湿高度与润湿时间的平方根成正比(h∝t),在过渡阶段的润湿高度与润湿时间的立方根成正比(h∝3t),与理论研究结果一致,从而验证了红外热成像法观测的碳纤维丝束润湿高度实验数据的准确性,可用于表征碳纤维丝束的表面润湿性能.

The surface wettability of carbon fiber is an essential factor affecting the performance of carbon fiber composite material. Due to the small fiber diameter and the transparent characteristic of working medium,the conventional measurements of wettability need demanding operation whereas wetting boundary is blurred,and thus the reiteration rate of experiment is low and large errors occur. In order to solve this problem,a novel observing method of wettability using IR thermal imaging is proposed. The superficial wettability of carbon fibers with smooth or rough morphology is observed,the variation tendency of wetting height with time is explored,and a comparison is made between the experimental results and the theoretical ones obtained by classical Laplace-Washburn model.The results show that the wetting heights measured in the rapid wetting stage and the transitional stage are respectively in direct proportion to the square root of wetting time（ h ∝√t） and to the cube root of wetting time（ h ∝3√t）,which means that the proposed IR thermal imaging method helps obtain accurate wetting height of carbon fiber tow and can be applied to the characterization of surface wettability of carbon fiber tow.