表面处理碳纤维增强聚酰亚胺复合材料力学性能

采用空气氧化法和硝酸氧化法对碳纤维进行表面处理，研究了碳纤维(CF)增强热塑性聚酰亚胺(TPI)复合材料的力学性能。采用Boehm滴定方法测定了经过硝酸处理后CF表面酸性官能团数量。结果表明:CF表面酸性官能团的数量随着浓硝酸处理时间的增加而增加；浓硝酸处理效果比空气氧化好，当浓硝酸处理CF的时间为20 min时，CF/TPI复合材料拉伸强度和弯曲强度分别提高10 %和14 %，XPS表明此时CF表面活性官能团比未处理增加35.89 %。AFM表明，浓硝酸对CF表面刻蚀沟明显；SEM表明，CF与TPI基体之间形成良好的界面，CF起到了增强效果。 

Mechanical properties of carbon fiber modified thermoplastic polyimide with surface treatment

The short cut carbon fibers (CF) were treated by air oxidation and nitric acid oxidation，and the mechanical properties of CF reinforced thermoplastic polyimide(TPI) resin matrix composites (CF/TPI) were studied.The results of Boehm titration method show that the acidic functional groups on the treated surface of CF increase as the treating time extends，and the nitric acid oxidation is better than the air oxidation. Compared with the untreated composite，the tensile strength and flexural strength are improved by 10% and 14%，when the treatment time of nitric acid is 20 min. X-ray photoelectron spectroscopy (XPS) indicates that the acidic oxygen functional groups on CF increase by 35.89 %. The atomic force microscopy (AFM ) images show that the nitric acid is capable of increasing the roughness of CF. The scanning electron microscopy(SEM) photograph of the fracture surface reveals that there is interface bonding between treated CF and TPI .