复合处理碳纤维增强聚酰亚胺复合材料力学性能

Mechanical properties of compound modification carbon fiber reinforced thermoplastic polyimide

摘要: 采用浓硝酸氧化和聚酰亚胺(PI)包覆复合方法对短切碳纤维(CF)进行表面改性，提高CF增强热塑性聚酰亚胺复合材料(CF/TPI)力学性能。采用比表面积及孔容分析、原子力显微镜、扫描电子显微镜、热重分析仪研究了CF表面处理前后结构和形貌的变化。结果表明：CF经浓HNO₃处理后比表面积增加144.2%，CF表面沟壑加深；复合处理后有PI层包覆在 CF表面；包覆处理后CF耐热性能提高。力学性能测试表明，经过包覆处理后CF/TPI复合材料的拉伸强度比未处理的提高11.34%，弹性模量提高109.2%，弯曲强度提高18.78%，冲击强度提高74.15%。

Abstract: To improve the mechanical properties of the short cut carbon fiber reinforced thermoplastic polyimide composites (CF/TPI)，the compound modification method of nitric acid oxidation and polyimide coating was adopted to modify the CF. The t reated and untreated CF were characterized by BET，AFM，SEM and TGA. The results show that the specific surface area of CF increases 144.2% after nitric acid oxidation，by increasing the roughness of CF. A PI layer is coated on the CF，and the CF thermal stability increases after coating PI. The tensile strength，elastic modulus，flexural strength and impact strength of the CF/TPI composites are improved by 11.34%，109.2%，18.78% and 74.15% respectively after compound modification of the carbon fiber.