均苯四甲酸二酐和二氨基二苯醚溶解在N,N-二甲基乙酰胺中,室温下聚合为聚酰胺酸。以聚酰胺酸溶液作为前驱体,在20 kV电压下静电纺丝,然后进行350℃热亚胺化处理可得到定向排列的聚酰亚胺纳米纤维,再于900℃炭化、3000℃石墨化,得到均匀连续、定向排列的聚酰亚胺基炭纳米纤维,纤维直径约100 nm。结果表明,聚酰胺酸质量分数为20%的溶液电纺性能最佳,3000℃石墨化处理后的炭纳米纤维具有典型的石墨结构。
Polyimide ( PI) is a good carbon precursor owing to its high carbon yield and easy graphitization. PI nanofibers pre-pared by electrospinning were carbonized and graphitized to prepare aligned carbon nanofibers. Pyromelliticdianhydride and 4,4'-di-aminodiphenyl ether were dissolved in N,N-dimethylacetamide at room temperature and stirred for 2 h to obtain a polyamide acid ( PAA) solution, which was electrospun into aligned PAA nanofibers at 20 kV and collected by a rolling cylinder 18 cm below the needle with a rolling speed of 2 800 r/min. The PAA nanofibers were first imidized into the PI nanofibers at 350 ℃, then carbon-ized at 900 ℃ at a heating rate of 5 ℃/min and finally graphitized at 3 000 ℃ to obtain continuous and aligned polyimide-based carbon nanofibers. The PAA solution with a concentration of 20% was the most suitable for electrospinning. SEM characterization shows that the average diameter of the carbon nanofibers is around 100 nm. The carbon nanofibers after graphitization at 3 000 ℃have a typical graphite structure.
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