Synthesis and tribological testing of poly(methyl methacrylate) particles containing encapsulated organic friction modifier

• Published in: Tribology international Vol. 124; pp. 124 - 133
• Main Authors: Mitchell, Karen, Neville, Anne, Walker, Gary M., Sutton, Michael R., Cayre, Olivier J.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-08-2018; Elsevier BV
• Subjects: Additives; Boundary; Chemical synthesis; Coefficient of friction; Dodecane; Encapsulation; Friction; Lubricant additives; Morphology; Particles; Polymethyl methacrylate; Tribology; Lubricant additives; Particles; Boundary
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/j.triboint.2018.04.009

The tribological behaviour of polymer particles containing an encapsulated, organic friction modifier (FM) is presented. Particles comprising of a poly (methyl methacrylate) (PMMA) shall and a methanol core, into which FM was dissolved, were produced via a dispersion polymerization producing a core-shell morphology. The inclusion of these particles dramatically increased the overall concentration of FM which could be blended into dodecane.
The tribological behaviour of the particles produced, both with and without encapsulated FM, was tribologically tested in pure dodecane.
The addition of as little as 1.5 wt% particles was found to decrease the friction coefficient and measured wear volumes below those for dodecane saturated with FM. Data suggests that the FM delivery method may be dominated by a bursting mechanism.
•Encapsulation of organic friction modifier is possible by dispersion polymerization.•Blending particles into an oil dramatically increases additive concentration.•Friction and wear can be lower than measured for traditionally blended oil.•SEM analysis of tribotested samples suggests particles work via a burst mechanism.•Particles will act as an “additive reservoir” until burst.