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Polymerization and Polymer Properties of Some Alkylmethacrylates as Lubricating Oil Viscosity Modifiers

The paper describes the reaction and process parameters of terpolymerization reaction of the long chain methacrylic acid alkyesters by free radical initiation under homogenous conditions of the adiabatic and isothermal procedure. The examined ester monomers are: methyl-methacrylate (MMA), dodecy-methacrylate (DMA) and octadecyl-methacrylate (ODMA). The polymerization reactions of the monomers, as 50% solution in the base mineral oil, were carried out under controled temperature-time profile, with peroxide initiator and n-dodecyl mercaptane (n-DDM) as chain transfer. In the adiabatic process the molecular mass strongly depended on the reaction temperature and it was regulated by the chain transfer agent in the isothermal process. The properties of the obtained polymer additives, such as kinematic viscosity, index viscosity and shear stability were established and correlated to their molecular mass. An increase of molecular mass of the polymers caused the linear increase both the solution kinematic viscosity and their shear reduced viscosity. However, when M_w was less than 50 000 the change in the shear reduced viscosity is negligible.

Alkylmethacrylate polymers ; Polymerization processes ; Lubricating oil polymer additives ; Viscosity index improvers

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