Effect of high-temperature heat treatment duration on the purity and microstructure of MWCNTs

• Published in: Bulletin of materials science Vol. 39; no. 1; pp. 41 - 46
• Main Authors: SRIKANTH, I, PADMAVATHI, N, PRASAD, P S R, GHOSAL, P, JAIN, R K, SUBRAHMANYAM, CH
• Format: Journal Article
• Language: English
• Published: Bangalore, India Indian Academy of Sciences 01.02.2016; Springer Nature B.V
• Subjects: Acids; Carbon; Chemistry and Materials Science; Decomposition; Degradation; Electron microscopy; Engineering; Heat treating; Heat treatment; High temperature; Impurities; Materials Science; Methods; Multi wall carbon nanotubes; Purity; Raman spectroscopy; Scanning electron microscopy; Thermogravimetric analysis; Netherlands; Carbon nanotubes; X-ray diffraction; electron microscopy; graphitization
• ISSN: 0250-4707; 0973-7669
• DOI: 10.1007/s12034-015-0891-2

The effect of high-temperature heat treatment on purity and structural changes of multiwalled carbon nanotubes (MWCNTs) were studied by subjecting the raw MWCNTs (pristine MWCNTs) to 2600 ∘ C for 60 and 120 min. Thermogravimetric analysis (TGA), X-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to study the effect of heat-treatment duration on the purity and structural changes of MWCNTs. Results show that high-temperature heat treatment can be used to purify MWCNTs with proper optimization of treatment time. It was observed that 60 min heat treatment of raw MWCNTs imparts high purity and structural perfection to MWCNTs, while 120 min heat treatment imparts structural degradation to MWCNTs with collapse of the innermost shells. The present study indicates that metal impurities act as moderators in controlling the degradation of MWCNTs up to certain duration, and once the metal impurities escape completely, further heat treatment degrades the structure of MWCNTs.