碳纳米管在接枝二元胺过程中微结构的变化

Microstructure Transformation of Multi-walled Carbon Nanotubes during Diamine Grafting Process

通过对酸化的多壁碳纳米管(MWNTs)进行酰氯化,在碳纳米管表面接枝己二胺.用红外光谱、热重分析、拉曼光谱和场发射扫描电镜对处理前后的碳纳米管进行分析表征.结果表明,经过酰氯活化,己二胺比较容易被接枝到碳纳米管上.而且还发现碳纳米管在酸化后形成紧密块状结构,在接枝胺后重新变得蓬松,其表观比容甚至大于原始碳纳米管.从理论上分析了碳纳米管的反应过程,对碳纳米管在接枝胺过程中微结构的变化机理进行推测,认为通过接枝,己二胺插入碳纳米管之间,改变了碳纳米管之间的相互作用,使得酸化后因形成氢键而导致的紧密堆砌结构被破坏.

1,6-hexamethylene diamine （HMD） was grafted onto multi-walled carbon nanotubes （MWNTs） via acid-thionyl chloride route. The characterization of MWNTs was carried out by Fourier transform infrared spectrum, thermal gravimetric analysis, field emission scanning electron microscopy and Raman spectrum. The results show that HMD is covalently bonded on the MWNTs after activating by thionyl chloride. During this process, the compact stacking microstructure induced by acid treatment is deaggregated. The apparent specific volume of functionalized MWNTs is even larger than that of the pristine MWNTs. The chemical processing of MWNTs modification was analyzed theoretically in detail and the mechanism of microstructure transformation was speculated It is proposed that HMD molecules inserted in different carbon nanotubes and break the hydrogen bond structure formed in acidification process. Therefore the dense structure derived from acidification is modified, leading to a less compact stacking and larger apparent specific volume of MWNTs.