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以微波辅助液相氧化法制备羧酸化多壁碳纳米管,并以4,4’-二氨基二苯醚(ODA)、羧酸化多壁碳纳米管(MWNTs-COOH)与均苯四甲酸二酐(PMDA)为原料,原位聚合制备羧酸化多壁碳纳米管/聚酰亚胺纳米(PI/MWNTs-COOH)复合薄膜。通过拉曼光谱(Raman)、透射电镜(TEM),傅里叶红外光谱(FT-IR)证实修饰后的碳纳米管表面接上-COOH等极性基团;扫描电镜(SEM)图片显示出MWNTs-COOH能均一分散在聚酰亚胺基体中,并通过傅里叶红外光谱(FT-IR)和X射线衍射光谱(XRD)证明聚酰亚胺与多壁碳纳米管的结构在薄膜制备过程中很稳定。通过动态力学(DMA)和差示扫描量热(DSC)分析发现薄膜的耐热性较好,且通过热失重(TGA)测试发现纳米复合材料的热稳定性比纯聚酰亚胺要高,主要是因为修饰后的多壁碳纳米管和聚酰亚胺基底之间强烈的相互作用,这就有利于耐热材料的实际应用。
Carboxylated multi-walled carbon nanotubes were prepared by microwave-assisted liquid-phase oxidation. 4,4 ’-diaminodiphenylether (ODA), carboxylated multiwalled carbon nanotubes (MWNTs-COOH) (PMDA) as raw materials, in-situ polymerization of carboxylated multi-walled carbon nanotubes / polyimide nano (PI / MWNTs-COOH) composite film. The modified carbon nanotubes were confirmed to have polar groups such as -COOH by Raman, TEM and FT-IR. Scanning electron microscopy (SEM) images showed that MWNTs-COOH can be uniformly dispersed in the polyimide matrix, and the structure of the polyimide and the multi-walled carbon nanotubes is verified by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) The process is very stable. The thermostability of the films was better than that of pure polyimides by thermogravimetric analysis (DMA) and differential scanning calorimetry (DSC). The thermal stability of nanocomposites was higher than that of pure polyimides by TGA, Mainly due to the strong interaction between the modified MWCNTs and the polyimide substrate, which is beneficial to the practical application of heat-resistant materials.