Effect of pretreatment on the microstructure of multiwalled carbon nanotubes

Four kinds of multi-walled carbon nanotubes pretreated by different methods were studied. Chemically functionalized (hydroxylation and carboxylation) CNTs were prepared by oxidizing original CNTs in H2SO4 solutions of different temperatures and concentrations by KMnO4. Graphitized CNTs were prepared by heat-treating original CNTs in an inert gas at 2800°C for 20 hours. CNTs Nickel plating on the surface was obtained by electroless plating. The effect of pretreatment on the surface state and microstructure of carbon nanotubes was also studied. The results showed that Chemical functionalization could form some functional groups on the surface of CNTs, which could not only improve the compatibility of CNTs with some solvents, but also purified CNTs, which had a positive effect on the preparation of composite materials. High-temperature graphitization treatment could significantly increase the degree of crystallization of carbon nanotubes and reduce structural defects. After electroless nickel plating, evenly distributed nano-sized metal particles were formed on the surface of the CNTs, and the interface between the two was well bonded.