The effectiveness of carbon nanotubes (CNT) deagglomeration by rapid expansion of supercritical suspensions (RESS) in nitrogen and carbon dioxide fluids was studied in this work. Two different mechanisms of deagglomeration were proposed for these two fluids at various temperature and pressure conditions. Ultrasound attenuation spectroscopy was applied as an express method of determining median diameter and aspect ratio of CNTs. At least twofold reduction of the diameter was shown for CNT bundles processed by RESS technique. Aspect ratio of processed CNTs, calculated from acoustic attenuation spectra, increased to 340. These results were in a good agreement with atomic force microscopy data.
Keywords: RESS; carbon nanotubes; supercritical fluids; ultrasound.