电热载荷对碳纤维表面物化性质的影响

Effect of Electric-thermal Load on the Physical and Chemical Properties of Carbon Fiber's Surface

目的探索用低强度电流(毫安级)处理碳纤维单丝的实验方法,讨论电热载荷对碳纤维表面物化性质的影响,为碳纤维复合材料电热损伤机制研究提供理论基础。方法采用直流恒流精密电源对T300碳纤维单丝以不同强度的电流通电,利用扫描电子显微镜(SEM)和原子力显微镜(AFM)测试手段分析碳纤维表面形貌和粗糙度的变化,利用X射线光电子能谱(XPS)对电热处理后的碳纤维表面的化学性质进行分析,并得出纤维表面活性的变化。结果经过不同电流强度处理的碳纤维表面发生了明显的变化,2 m A和4 m A处理的纤维表面出现了很多裂纹,且粗糙度随着电流的升高而降低,6 m A处理的纤维表面沟壑被填充且粗糙度稍有上升;随着电流的升高,纤维表面的C含量随之升高,O含量则呈现相反趋势,C—C稍有降低,C—O键降低明显。结论电热载荷对纤维表面的浆料有烧蚀作用,未反应的浆料残留在碳纤维表面,并且使凹槽变浅,粗糙度也有所降低;电热产生的高温反应掉了很多上浆剂成分,使更多的纤维本体裸露出来,更多的羟基转化成了羰基和羧基,而纤维表面活性则稍有增强。

Objective To explore the experimental method that uses low intensity current（ m A） treatment of carbon fiber monofilament,and to discuss the effect of electric-thermal on the physicochemical properties of the surface of carbon fibers,in order to provide theoretical basis for the electric heat damage mechanism of carbon fiber composite. Methods Constant DC precision power was used to supply electric current on T300 carbon fiber monofilaments. Scanning electron microscope（ SEM） and atomic force microscope（ AFM） were used to analyze the change in the surface morphology and roughness of carbon fibers. X photoelectron spectroscopy was used to characterize the surface＇s chemical property of carbon fibers before and after electric-thermal treatment. And the changes of the surface activity of the fibers were obtained. Results The surface of carbon fiber treated by different current intensity changed significantly. Many cracks appeared on the surface of 2 m A and 4 m A treated fibers,and the roughness was reduced with the increase of current. The gullies on the surface after 6 m A treatment were filled and the roughness was slightly improved.With the increase of current,the C content on the surface of carbon fibers also increased,while the content of O showed the opposite trend,the content of C—C decreased slightly,while C—O decreased significantly. Conclusion The electric-thermal load showed ablation effect on the sizing agent on the surface of carbon fibers. Unreacted sizing agent remained on the surface of carbon fibers,it also shallowed grooves,reduced roughness. As a result of the high temperature generated by electric heat,the sizing agent＇s components dropped a lot,with more of fiber＇s real body exposed,more hydroxy group converted into carbonyl and carboxyl,while the surface activity of the fiber was slightly enhanced.