The Influence of Treatment Time on the Characterization of NH₂-Functionalized Multiwalled Carbon Nanotubes

In this study, multi-walled carbon nanotubes (MWCNTs) are first, oxidized using a H 2 SO 4 / KMnO 4 mixtrue to introduce carboxy (-COOH) functional groups, followed by amination with ethylenediamine (EDA) at varying reaction times (4, 8 and 12 h). The functionalized MWCNTs were characterized by TGA), XRD, Raman spectroscopy and FE-SEM to explore changes in surface chemistry and morphology. FE-SEM images exhibited obvious morphological changes in increased surface roughnesses and the presence of nanoparticle-like structures or rather thin coatings, indicating the success of -NH 2 functionalization. Raman spectroscopic analysis indicates an increase in the I D /I G ratio from 1.038 to 1.287, suggesting more defective site in the functionalized MWCNTs. The XRD patterns of the MWCNTs clearly demonstrate diffraction peak at 25.5° corresponding to (002) planes which suggested successful functionalization. The TGA curve of the -NH 2 functionalized MWCNTs showed a weight loss in the temperature range from 200 to 450 °C due to the decomposition of the amine groups and the highest weight loss is obtained to be 6.6 wt% for 8 h reaction time. The results of this study have demonstrated that the surface functionalization of the MWCNTs can be controlled by the variation of treatment times.