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Molecular interaction originating from polar functional group in lubricants and its relationship with their traction property under elastohydrodynamic lubrication
Author(s) -
Takiwatari Koji,
Nanao Hidetaka,
Hoshi Yasushi,
Mori Shigeyuki
Publication year - 2015
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.1278
Subject(s) - lubrication , traction (geology) , lubricant , fourier transform infrared spectroscopy , materials science , ether , hydrogen bond , boundary lubrication , composite material , tribology , polymer chemistry , chemical engineering , chemistry , organic chemistry , molecule , mechanical engineering , engineering
The correlation between molecular interaction and traction properties was investigated using a traction tester and in situ observation of elastohydrodynamic lubrication film with a micro‐Fourier transform infrared spectrometer. The sample oils used were polypropylene glycols (PPGs) with the end‐group of alcohol or ether and a synthetic hydrocarbon oil, poly‐α‐olefin. From the traction tests, it was found that the traction coefficient of PPG was sensitive to the end‐group. PPG with alcohol as the end‐group showed a higher traction coefficient than that with the ether group. In situ observation with a micro‐Fourier transform infrared was performed in order to investigate the molecular interaction of the lubricant oil. It was found that the hydrogen bonding of hydroxyl groups in PPG was strengthened by high pressure in the Hertzian contact region. These results suggest that the rheological properties in the elastohydrodynamic lubrication contact region were affected by the strengthened hydrogen bonding. Copyright © 2014 John Wiley & Sons, Ltd.