用碳纤维的电沉积处理来提高其增强塑料的层间剪切强度

 用电沉积方法将含羧基的共聚物沉积于碳纤维表面后,可以使单向碳纤维增强环氧的层间剪切强度从未处理时的650kg/cm~2提高到1000kg/cm~2以上,用扫描电子显微镜观察剪切断口,得到与强度数据一致的破坏模式,表明电沉积层的界面粘合作用提高了纤维-树脂基体界面传递应力的能力,改变了界面附近裂缝的形成和扩展。已有数据还表明,此法在提高层间剪切强度的同时,并不削弱其它力学性能。用红外光谱等实验初步证实了电沉积过程的负离子——自由基机理,观测到沉积层在纤维表面的附着情况。

ENHANCEMENT OF INTERLAMINAR SHEAR STRENGTH OF CFRP BY ELECTRODEPOSITION OF CARBON FIBER

In order to improve the shear property and water endurance of CFRP, the adhesion and the shear failure of epoxy resin reinforced by electrodeposited carbon fiber were investigated and the mechanism of eiec-trodeposition was discussed.Specimens of epoxy resin reinforced unidirectionally by electrodepo-sited carbon fiber have been tested. The results are shown in tables 1 and 2. It is obvious that the interlaminar shear strength of specimens reinforced by the treated fiber is enhanced up to 1000kg/cm2. It is worth notice that there are no losses in other mechanical properties, especially in impact strength with enhancement of ILSS.The electrodeposition mechanism on carbon fiber was investigated by means of IR and NMR （Figs 4 and 5）. The observation of the electrode-posited layer on fiber with SEM and ESCA（Fig. 6） demonstrated that the layer covered the fiber uniformly, compactly and completely, even entered tiny holes and grooves on the fiber surface. As the interface between fiber and deposited layer is a key problem due to the reaction of large number of carboxyl groups on the deposited layer with epoxy resin matrix, it displays interface adhesion fully with "anchor" effect, transfers the stress at the interface effectively, changes the formation and the development of cracks and confines the way of water penetration. The tailoring of the electrodeposited interlayer turnsathe simple shear failure at the interface into a complex failure mode, which enhances a series of mechanical properties such as shear strength, water endurance, impact strength and others.