engleski

Crystallization and pour point of solutions of the dispersant poly(styrene-co-methacrylate) viscosity modifiers in lubricating base oil

Dispersant viscosity index improvers were synthesized by free radical copolymerization of N, N-dimethylaminoethyl methacrylate (DMAEMA), dodecyl methacrylate, octadecyl methacrylate, and styrene in solution of mineral base oil. Studies included the dependence of the pour point and low- temperature crystallization behavior (characteristic temperatures and enthalpies) of the solutions of these polymer viscosity modifiers (VMs) on the amount of dispersant comonomer, DMAEMA, in the copolymer, weight average molecular weight of the copolymer, and concentration of the polymer in oil. Incorporation of dispersant comonomer in poly(styrene-alkyl methacrylate) structure additionally decreases the pour point of its solutions even for a very small concentration: the pour point of the base oil reduces from −9 to −25°C and −33°C for the 0.1 and 0.5 wt% concentrations of polymer, respectively. For concentrated 50 wt% solutions the enthalpy of crystallization decreases linearly with a decrease in the long-chain alkyl methacrylate share in copolymer. There is no unambiguous correlation between the pour point and crystallization parameters of semidiluted and diluted polymer solutions obtained by differential scanning calorimetry. © 2017 Society of Tribologists and Lubrication Engineers.

crystallization ; dispersant ; viscosity index improvers ; pour point

Glavni autori: Elvira Vidović i Ante Jukić