Functionalized MWNTs have been of interest for dispersion enhancement in
processing or for chemical modifications. Modification of multiwall carbon
nanotubes (MWNTs) by ultrasonication with oxidizing acid mixtures is frequently
used to functionalize CNTs. In this work, the functionalization process of MWCNTs
involves using a mixture of concentrated sulfuric acid and nitric acid (95% H2SO4:
65%HNO3, 3:1 volume ratio), ultrasonicated at 250C for 30min. The results
confirmed by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction
(XRD), and Scanning Electron Microscopy (SEM). From the FTIR spectrum, the
existence of carboxyl group indicates the functionalization of MWCNTs on the outer
surface wall. SEM micrographs show the occurrence of surface modification on the
MWCNTs structure. Finally, a well dispersed of MWCNTs colloidal was
successfully obtained with less MWCNTs structure collapsed.
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