The mechanism of action of polyisobutenyl succinimide lubricating oil additives

Polyisobutenyl (PIB) succinimides are widely used as low/medium temperature detergent/dispersant additives in lubricants. To elucidate their mechanism of action, soluibility, micelle formation, adsorption, zeta potential, sedimentation and detergency studies have been carried out on a range of PIB succinimides in non-aqueous media. The results showed that the performance of PIB succinimides in various tests was dependent both on the molecular weight of the PIB and on the chemical structures of the amine used to make the succinimide. It was also concluded that these additives function by a steric stabilization mechanism and not by either electrostatic repulsion or micellar solubilization.