Chemical functionalization of carbon nano tube

It is well known that carbon nanotubes do not represent significant reinforcement for composite but once functionalized it shows interesting new properties. In the present paper MWCNTs were initially chemically treated with mixture of 3:1 (v/v) of concentrated $H2SO4/HNO3$⁠. This treatment modifies the surface of MWCNT but it has not disrupted its main structure. This acid treatment introducing the carboxylic acid groups only at defect sites and end of CNTs, then this carboxylic acid groups were first converted to acyl chlorides by using Thionyl chloride. Further this Chlorinated CNTs were functionalized with p-phenylenediamine to form amide bond that kept a long chain attached. The functionalized procedure was characterized by using Raman spectroscopy and scanning electron microscopy.