TY - JOUR
T1 - Investigation of shear-Thinning behavior on film thickness and friction coefficient of polyalphaolefin base fluids with varying olefin copolymer content
AU - Thomas, J. Zolper
AU - He, Yifeng
AU - Delferro, Massimiliano
AU - Shiller, Paul
AU - Doll, Gary
AU - Dehkordi, Babak Lotfizadeh
AU - Ren, Ning
AU - Lockwood, Frances
AU - Marks, Tobin J
AU - Chung, Yip Wah
AU - Greco, Aaron
PY - 2017/4/1
Y1 - 2017/4/1
N2 - This study investigates the rheological properties, elastohydrodynamic (EHD) filmforming capability, and friction coefficients of low molecular mass poly-A-olefin (PAO) base stocks with varying contents of high molecular mass olefin copolymers (OCPs) to assess their shear stability and their potential for energy-efficient lubrication. Several PAO-OCP mixtures were blended in order to examine the relationship between their additive content and tribological performance. Gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy were used to characterize the molecular masses and structures, respectively. Density, viscosity, EHD film thickness, and friction were measured at 303 K, 348 K, and 398 K. Film thickness and friction were studied at entrainment speeds relevant to the boundary, mixed, and full-film lubrication regimes. The PAO-OCP mixtures underwent temporary shear-Thinning resulting in decreases in film thickness and hydrodynamic friction. These results demonstrate that the shear characteristics of PAO-OCP mixtures can be tuned with the OCP content and provide insight into the effects of additives on EHD characteristics.
AB - This study investigates the rheological properties, elastohydrodynamic (EHD) filmforming capability, and friction coefficients of low molecular mass poly-A-olefin (PAO) base stocks with varying contents of high molecular mass olefin copolymers (OCPs) to assess their shear stability and their potential for energy-efficient lubrication. Several PAO-OCP mixtures were blended in order to examine the relationship between their additive content and tribological performance. Gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy were used to characterize the molecular masses and structures, respectively. Density, viscosity, EHD film thickness, and friction were measured at 303 K, 348 K, and 398 K. Film thickness and friction were studied at entrainment speeds relevant to the boundary, mixed, and full-film lubrication regimes. The PAO-OCP mixtures underwent temporary shear-Thinning resulting in decreases in film thickness and hydrodynamic friction. These results demonstrate that the shear characteristics of PAO-OCP mixtures can be tuned with the OCP content and provide insight into the effects of additives on EHD characteristics.
KW - elastohydrodynamic lubrication
KW - fluid friction (traction)
KW - lubricant additives
KW - viscosity
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U2 - 10.1115/1.4033716
DO - 10.1115/1.4033716
M3 - Article
AN - SCOPUS:84982262150
VL - 139
JO - Journal of Tribology
JF - Journal of Tribology
SN - 0742-4787
IS - 2
M1 - 021504
ER -