电化学改性对PAN基碳纤维表面状态的影响

EFFECT OF ELECTROCHEMICAL MODIFICATION ON THE SURFACE STATE OF PAN-BASED CARBON FIBERS

采用电化学氧化法对聚丙烯腈(PAN)基碳纤维进行表面改性,利用扫描电子显微镜(SEM)、原子力显微镜(AFM)、X射线光电子能谱(XPS)和X射线衍射(XRD)对改性后的碳纤维表面状态进行了研究。同时探讨了碳纤维表面状态与其抗拉强度及其复合材料力学性能的关联。研究结果表明,碳纤维经电化学氧化后,表面的粗糙度提高了1.1倍;表面碳含量降低了9.7%,氧含量提高了53.8%,氮含量增加了7.5倍,羟基和羰基含量也有不同程度的提高;表面取向指数减小了1.5%,表面微晶尺寸减小,表面活性碳原子数增加了78%。电化学氧化法的刻蚀作用致使碳纤维拉伸强度降低了8.1%,但同时也改善了碳纤维表面的物理性质和化学性质,提高了碳纤维与树脂间的粘结性,使复合材料的ILSS提高26%。

The surface of PAN-based carbon fibers was modified by electrochemical oxidation. The surface state of modified carbon fibers was studied using SEM, AFM, XPS and XRD. The relationships of surface state of carbon fibers and its tensile strength and mechanical performance of carbon fiber reinforced PAN(CFRP) were discussed. The results show that surface roughness of modified carbon fibers was 1.1 times higher than that of the untreated one. Carbon contents decrease by 9.7%, oxygen and nitrogen contents increase by 53.8% and 7.5 times respectively, and the hydroxyl and carbonyl contents also increase. The surface orientation index reduces by 1.5%, and the rnicrocrystalline dimension also decreases, and the active carbon atoms of carbon fiber surface increase by 78%. The tensile strength of carbon fibers decreases by 8.1% due to corrosion process of the electrochemical oxidative method. The physical and chemical properties of carbon fiber, surface are modified during this process, the cohesiveness between the fibers and resin matrix is improved and the ILSS of CFRP is increased by 26%.