Investigation of Shear-Thinning Behavior on Film Thickness and Friction Coefficient of Polyalphaolefin Base Fluids With Varying Olefin Copolymer Content Academic Article uri icon


  • This study investigates the rheological properties, elastohydrodynamic (EHD) film-forming capability, and friction coefficients of low molecular mass poly--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 PAOOCP 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 303K, 348K, and 398K. Film thickness and friction were studied at entrainment speeds relevant to the boundary, mixed, and full-film lubrication regimes. The PAOOCP mixtures underwent temporary shear-thinning resulting in decreases in film thickness and hydrodynamic friction. These results demonstrate that the shear characteristics of PAOOCP mixtures can be tuned with the OCP content and provide insight into the effects of additives on EHD characteristics.

published proceedings

  • Journal of Tribology

author list (cited authors)

  • Zolper, T. J., He, Y., Delferro, M., Shiller, P., Doll, G., LotfizadehDehkordi, B., ... Wang, Q.

citation count

  • 5

complete list of authors

  • Zolper, Thomas J||He, Yifeng||Delferro, Massimiliano||Shiller, Paul||Doll, Gary||LotfizadehDehkordi, Babak||Ren, Ning||Lockwood, Frances||Marks, Tobin J||Chung, Yip-Wah||Greco, Aaron||Erdemir, Ali||Wang, Qian

publication date

  • March 2017