Dispersion of Ultrafine Graphite

The dispersion behavior of ultrafine graphite in aqueous system was investigated by the sedimentation test. The dispersion effect of 12 kinds of dispersants were studied. By testing the changes of Zeta potential and the viscosity of suspensions with the addition of dispersants, the dispersion mechanism of dispersants was discussed by the calculation of the interaction energies between particles. The results show that traditional surfactants have poor performance on the stability of dispersion, but carboxymethylcellulose and polypropylene acid sodium are the efficient dispersants of graphite. The addition of dispersants can enlarge the absolute value of Zeta potential, increase the stability and decrease the viscosity of the dispersion. The optimum addition of dispersant is 500 mg/L and the suitable pH value is 8.510.5. The calculation results show that the dispersion of hydrophobic graphite does not conform to the DLVO theory. The hydrophobic interaction on the surface of particles controls the dispersion and coagulation of particles and the main effect of dispersants is to increase the electrostatic force and the interspace resistance.