Adsorption of Engine Lubricant Dispersants and Polymers Onto Carbon Black Particles

The aim of this paper is to understand the soot dispersion mechanism in used lubricants. The efficiency of dispersant additives and polymers on particle stabilization in a lubricating oil is investigated by adsorption and sedimentation experiments. Carbon black particles are chosen as a model for soot present in lubricants. Comparison between diesel soot and carbon black, using Transmission Electronic Microscopy photographs, shows that both kind of particles exhibit a fractal structure with similar aggregate size. Sedimentation experiments in oil show that polymers and ashless dispersants stabilize particles over a critical concentration. Adsorption isotherms in oil are carried out in order to determine the action mechanism of dispersant against particles aggregation