Heterocoagulation of graphitized carbon blacks in aqueous solutions of sodium dodecyl sulphate

Abstract

Graphon and Sterling MTG are graphitized carbon blacks with chemically identical surfaces, but they differ in particle size. Dispersions of Graphon in dilute aqueous solutions of sodium dodecyl sulphate are stable but not those of Sterling MTG. The heterocoagulation behaviour of mixed dispersions of Graphon and Sterling MTG was examined over a range of relative particle concentrations. A marked reduction in the overall stability ratio for coagulation was found in the presence of small amounts of the unstable component. Experimental data for the interaction between the two carbon blacks show agreement with theoretical predictions based on an extension of DLVO theory.