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采用水溶性的聚乙烯醇修饰多壁碳纳米管表面,研究了聚乙烯醇修饰的碳纳米管在水浴摇床Tris-HCl缓冲溶液中的溶解过程。通过红外光谱,差示扫描量热仪,透射电镜及X光衍射的方法对聚乙烯醇修饰的碳纳米管在溶解过程中的显微结构变化进行了研究。结果表明:浸泡21d后,聚乙烯醇修饰的碳纳米管部分溶解于缓冲溶液,形成无定形碳碎片;但大部分碳纳米管没有溶解,仍然保持管状结构。揭示出聚乙烯醇修饰的碳纳米管的溶解过程为:碳—碳键在浸泡过程中发生断裂,碳纳米管的部分溶解产生了无定形碳碎片与残留纳米管层片,残留纳米管层片进一步溶解最终成为无定形碳。提出与讨论了聚乙烯醇修饰的碳纳米管在Tris-HCl缓冲溶液中可能的溶解机理是:修饰后的碳纳米管表面具有很多缺陷和断裂的碳键,在缓冲溶液中聚乙烯醇的溶解导致嫁接位置的碳管壁的碳原子的释放,最终导致其管状结构的破坏。
The surface of multi-walled carbon nanotubes was modified with water-soluble polyvinyl alcohol to study the dissolution process of polyvinyl alcohol-modified carbon nanotubes in Tris-HCl buffer solution. The microstructure changes of polyvinyl alcohol-modified carbon nanotubes (MWCNTs) in the process of dissolution were studied by IR, DSC, TEM and X-ray diffraction. The results showed that after immersing for 21 d, PVA-modified carbon nanotubes were partially dissolved in buffer solution to form amorphous carbon fragments. However, most of the CNTs remained undissolved and remained tubular. The dissolution process of polyvinyl alcohol-modified carbon nanotubes is revealed as follows: the carbon-carbon bond is broken during the soaking process, and the partially dissolved carbon nanotubes produce amorphous carbon fragments and residual nanotube layers, and the residual nanotube layers Further dissolution eventually becomes amorphous carbon. It is proposed and discussed that the possible dissolution mechanism of polyvinyl alcohol-modified carbon nanotubes in Tris-HCl buffer solution is as follows: the modified carbon nanotubes have many defects and broken carbon bonds on the surface, the dissolution of polyvinyl alcohol in the buffer solution The release of carbon atoms in the carbon nanotube wall at the grafting site ultimately leads to the destruction of its tubular structure.