10.26 - Lubricant and Fuel Additives Based on Polyalkylmethacrylates

Abstract

Polyalkylmethacrylates (PAMA) have long been known in industry as key additives to formulate lubricant oils, particularly in the area of ‘green technology’-based additives. This paper gives a general overview of PAMA, starting from its manufacturing pathway to its fuel economy applications in the lubrication area. The monomers are derived from the esterification or transesterification of naturally derived vegetable-based fatty alcohols with methacrylic acid or methyl methacrylate (MMA). The flexible chemistry, the ready availability of a variety of monomers which are non-dispersant or dispersant type allows the production of polymers with the desired composition and properties. By modifying the polymer architecture from simple (linear, branched) to more complex types (block, star, comb), and by changing the comonomer compositions, the molecular weights and polydispersities via conventional or controlled free radical polymerization, PAMA polymers have been developed for a wide variety of applications. Viscosity index improvers (VII) and pour point depressants (PPD) for engine oils, driveline fluids and hydraulic fluids, based on PAMA chemistry are considered to be the most versatile among the other existing chemistries. PAMA-based friction modifiers, polymeric emulsions, and synthetic oils based on low molecular weight PAMA have been developed or already available in the market. Outside of lubricants, the excellent low temperature property of PAMA polymers enables them to act as a cold flow improvers for biofuels.