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VISCOSITY AND RHEOLOGICAL PROPERTIES OF MINERAL LUBRICATING OILS CONTAINING DISPERSIVE POLYMETHACRYLATE ADDITIVES
Ante Jukić
; Fakultet kemijskog inženjerstva i tehnologije, Sveučilište u Zagrebu
Sažetak
The viscometric and rheological behavior of solutions of the polymeric additives of lubricating oils that display dispersive properties was investigated. Additives are synthesized by radical copolymerization of styrene, dodecyl methacrylate, octadecyl methacrylate and dimethylaminoethyl methacrylate (DMAEMA, 2 and 4 mol. % share) in base mineral oil. All solutions of copolymers in basic oil displayed high values of kinematic viscosity and viscosity index (> 150). By embedding of DMAEMA into macromolecules the interactions between polymeric additives and oil change significantly. As a result, much larger hydrodynamic volume of polymeric molecules compared to the conventional methacrylate additives occurs. The viscosity increases due to the hydrodynamic volume increase, oppositely shear stability of solutions decreases while pour points are comparable. Relative, specific and reduced viscosities of diluted solutions of homopolymeric constituents of investigated additives: poly(alkyl methacrylate) (methyl-, PMMA; dodecyl-, PDDMA; octadecyl-, PODMA) and polystyrene (PS), as well as other most commonly used additives, ethylene-propylene (EPC) copolymes as well as styrene and hydrogenated butadiene (SHB) were determined, where following ranking was obtained: EPC ≥ SHB > PDMAEMA ≥ PS >> PDDMA > PMMA ≥ PODMA. Huggins’ equation describes concentration dependence of viscosity where limiting viscosity number and Huggins’ constants are determined as well. The obtained relationships between polymer composition and rheological properties of their solutions in oil, knowing of molecular interactions between polymers and solvents (base oil), enable formulating of lubricating oils of advanced application properties.
Ključne riječi
Mineral lubricating oils; Viscosity; Rheological properties; Dispersant polymethacrylate additives
Hrčak ID:
61888
URI
Datum izdavanja:
30.9.2010.
Posjeta: 5.453 *