碳纤维电化学氧化表面处理效果的动态力学热分析研究

DMTA STUDY ON ELECTROCHEMICAL OXIDATION EFFECT OF CARBON FIBERS SURFACE

利用动态力学热分析(DMTA)、扫描电镜(SEM)、X射线光电子能谱(XPS)对聚丙烯腈基(PAN)碳纤维电化学氧化表面处理效果进行了研究。研究结果表明,DMTA谱图中经电化学氧化处理的碳纤维增强树脂基复合材料(CFRP)其损耗角正切(tanδ)较未处理的降低30%,玻璃化温度(Tg)与tanδ峰值的变化可以有效地表征PAN基碳纤维表面处理的效果。这一结论与SEM观察CFRP断口形貌的结果相符。经定量计算出的界面粘结参数A和α与CFRP的层间剪切强度(ILSS)所反映的碳纤维与树脂间界面粘结效果是一致的。同时,XPS表面化学分析表明,经电化学氧化处理后的碳纤维表面羟基含量提高55%及活性碳原子数增加18%,采用适当的处理条件可使CFRP的ILSS提高20%以上。

Dynamic mechanical thermal analysis (DMTA), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were used to study the surface of polyacrylonitrile (PAN)-based carbon fiber (CF) treated by electrochemical oxidation. The results show that the loss tangent (tanδ) of treated carbon fibers reinforced epoxy declines to 30% compared with the untreated in DMTA chart, and the change of glass transition temperature (Tg) and the peak of tanδ can availably characterize the electrochemical treatment effect of carbon fiber surface, which corresponds to SEM analysis. Quantitative analysis results reveal that the interfacial adhesion parameter A and α can reflect the interfacial bonding effect between carbon fibers and epoxy, which is compatible with what is reflected by the ILSS value of CFRP. XPS analysis indicates that the hydroxyl group content and active carbon atom of the treated CF are higher than those of the untreated CF, which is improved to 55% and 18% respectively. Appropriate oxidative conditions can make interlaminar shear strength (ILSS) increase over 20%.