Defects and Structural Analysis of Multi-Wall Carbon Nano Tubes via Ball milling and Cryo-milling

Nano fillers are part of new studies to enhance various properties of fluids and solids. For example, adding nanoparticles as an enforcement in nanocomposites or as an additive to improve thermal or electrical properties in nano-fluids are of extreme importance in science and industry. There are numerous methods to uniformly disperse nanoparticles in fluid and solid phase. One of the well-used techniques is utilizing ball mills. Milling method is treated widely to uniformly disperse Carbon Nano Tubes (CNTs) in solid or fluid state materials. However, the issue is that this method abolishes some part of CNTs structure. As a result, this defect adversely decreases the improvement of designated properties. In this research, two methods of milling conditions have been analyzed to find out their impacts on CNTs structure. The first method is milling Multi-Wall Carbon Nano Tubes (MWCNTs) in ambient temperature. On the other hand, in the second method the temperature dwindled to -196°C by Retsch new generation ball mills (Cryo-mill). This apparatus flows liquid nitrogen (LN2) around the shaking jar and decreases the temperature as low as -196°C. To analyze the impact of these methods of milling on MWCNTs, Field Emission Gun-Scanning Electron Microscopy micrograph, X-Ray Diffraction, Raman Spectroscopy, and Thermo Gravimetric Analysis are scrutinized on MWCNTs’ structure. In conclusion, all the aforementioned experiments provide sufficient support to implicitly convince that cryo-milling method has less defective impact on initial MWCNTs.

Keywords:

Ball mill , Cryo-mill , MWCNTs , Raman spectrometry , TGA , XRD