为了改善碳纤维增强复合材料(CFRP)表面浸润性及提高胶接强度,采用常温常压空气等离子方法对CFRP胶接表面进行预处理,测试了不同预处理参数下CFRP与水的接触角,计算了其表面能;利用原子力显微镜、傅里叶红外光谱仪和X射线光电子能谱仪分析不同处理参数下CFRP表面的物理和化学性能;采用4种胶粘剂测试CFRP的胶接拉剪强度.结果表明:喷头与CFRP表面的距离为6mm、喷头移动速度50mm/s为最佳的等离子处理条件;经等离子处理后,CFRP与水的接触角由处理前的114° 降低至23°,表面能由 32.49mJ/m2升高到 72.19mJ/m2;等离子处理增强了CFRP表面环氧官能团,降低了表面粗糙度,表面形成了大量微米级沟壑;采用等离子处理能够显著提高环氧树脂胶粘剂接头的拉剪强度,使其失效形式由界面失效转变为基材失效,而聚氨酯胶粘剂接头的拉剪强度变化不大,其失效形式由界面胶层与内聚复合失效转变为纯界面失效.
In order to improve the surface infiltration of carbon fiber reinforced plastic/polymer (CFRP) and improve the bonding strength, the CFRP bonding surface was pretreated by the normal temperature and pressure air plasma treatment method, the contact angle of CFRP under different pretreatment parameters was tested, the surface energy was calculated. By using atomic force microscope, Fourier infrared spectrometer and X-ray photoelectron spectrometer, the physical and chemical properties of CFRP surface were analyzed under different treatment parameters, and 4 kinds of adhesives were used to test the tensile shear strength of bonding joints. The results show that the distance between the nozzle and the CFRP surface is 6mm, the nozzle movement speed is 50 mm/s as the best treatment condition. After plasma treatment, the contact angle between CFRP and water is reduced from 114° to 23°, and the surface can be raised from 32.49mJ/m2 to 72.19mJ/m2. Plasma treatment enhances the epoxy functional groups on the surface of CFRP, reduces the surface roughness, forms a large number of micro-scale gullies on the surface. The use of plasma treatment significantly improves the tensile shear strength of epoxy adhesive joints, so that the failures such as the interface failure and the substrate damage decrease, but pull shear strength of polyurethane adhesive joints changes little. The failure form is transformed from the composite failure of the interfacial adhesive layer to pure interface failure.
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