Lubrication properties of polyalphaolefin and polysiloxane lubricants: Molecular structure-tribology relationships

Thomas Zolper, Zhong Li, Changle Chen, Manfred Jungk, Tobin Marks, Yip Wah Chung, Qian Wang

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34 Citations (Scopus)

Abstract

This study investigates the rheological properties, elastohydrodynamic film thickness, and friction coefficients of several commercially available polyalphaolefin (PAO) and polydimethylsiloxane (PDMS)-based lubricants to assess relationships between molecular structure and lubricant performance. Molecular structures and masses were determined by nuclear magnetic resonance spectroscopy and gel permeation chromatography, respectively. Density and viscosity are measured from 303 to 398 K, while elastohydrodynamic lubricant film thickness and friction measurements were made at temperatures, loads, and speeds that are representative of boundary, mixed, and full-film lubrication regimes. The results show that PDMS-based lubricants are thermally and oxidatively more stable than PAOs, while the viscosity of PDMS-based lubricants is generally less temperature sensitive than PAOs, except for highly branched polysiloxanes. In particular, this study provides quantitative insight into the use of PDMS-based lubricants to obtain low friction through the entire lubrication regime (boundary to full film) by optimal tuning of the molecular mass and chain branching.

Original languageEnglish
Pages (from-to)355-365
Number of pages11
JournalTribology Letters
Volume48
Issue number3
DOIs
Publication statusPublished - Dec 2012

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Keywords

  • EHL friction
  • EHL with non-Newtonian lubricants
  • Oxidation resistance
  • Silicones
  • Synthetic base stocks

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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