Dispersibility Evaluation of Carbon Nanotubes Using Bead Mill

Abstract

Carbon nanotubes (CNTs) possess various qualities such as outstanding brightness, strength, conductivity, heat conduction, and the ability to emit electrons. In general, such characteristics can be expressed by dispersing a CNT material into a solvent. However, CNTs cannot be dispersed easily because their aggregates are very hard. In the experiment described in this study, we used a bead mill and an ultrasonic homogenizer to mechanically disperse CNTs into a solvent. The devices were used to disperse multi-wall carbon nanotubes (MWCNT) into a solvent. To evaluate the dispersion efficiency of the bead mill, we examined the relation among dispersion time, specific energy, and median diameter (X₅₀) of MWCNTs obtained through dispersion under different conditions. The results indicated that the dispersion efficiency of MWCNTs varies, depending on the operating conditions. In addition, by using a specific energy, it was demonstrated that the diameter of the beads exerts a great effect on dispersion efficiency. A comparison of the bead mill and ultrasonic homogenizer showed that the shape and hardness of the initial MWCNT's aggregates have an effect on the dispersion efficiency.