engleski

Optimization of alkyl methacrylate terpolymer properties as lubricating oil rheology modifier

Solution terpolymerization processes of methyl methacrylate, dodecyl methacrylate and octadecyl methacrylate using bifunctional 1-di(tert-butylperoxy)-3, 3, 5-trimethylcyclohexane or monofunctional tert-butylperoxy-2-ethylhexanoate initiator were investigated. The first set of terpolymerizations was performed in 2 M xylene solutions, isothermally at 91, 100, 105 and 115 oC. The terpolymerization kinetics, concentrations of molecular species, kinetic chain length, molar mass averages as functions of the reaction time was modeled by the Villermaux-Blavier tendency kinetic model for radical polymerization. Complete monomer conversions and high molar masses of terpolymers were achieved in a simple batch process with bifunctional initiator. The second set of polymerization reactions was performed in 2 M mineral base oil solutions, under isothermal conditions at 115 and 120 oC, using the bifunctional initiator. By varying the monomer mixture composition and concentrations of the initiator and chain transfer agent, n-dodecyl mercaptan, the terpolymers of different composition and molar mass were obtained. The solution properties of alkyl methacrylate terpolymers as lubricating oil rheology modifiers, kinematic viscosity, viscosity index, shear stability and pour point were established. A strong correlation between molar mass distribution of synthesized polymers and rheological properties of polymer solutions was revealed by an applied optimization procedure.

lubricating oil rheology modifiers ; alkyl-methacrylates ; bifunctional peroxide ; terpolymerization ; modeling ; optimization

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