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Functional mechanism of formation of friction polymer with dihydroxydocosanoic acid
Author(s) -
Hu Zhimeng,
Tao Dehua,
Wang RuLin
Publication year - 1995
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.3010070308
Subject(s) - rubbing , base oil , infrared spectroscopy , polyester , materials science , auger electron spectroscopy , polymer , zinc , organic chemistry , polymer chemistry , chemistry , nuclear chemistry , scanning electron microscope , metallurgy , composite material , physics , nuclear physics
The results of wear tests with a four‐ball machine showed that dihydroxydocosanoic acid has good antiwear properties, comparatively approaching those of zinc dialkyldithiophosphate (ZDDP): the four‐ball wear‐scar diameters, d 30 min/294 N, with dihydroxydocosanoic acid, ZDDP, and 400 neutral base oil are 0.36, 0.35, and 0.62 mm, respectively. In order of effectiveness the antiwear ability of the C 22 acids is: 13,14‐dihydroxydo‐cosanoic acid (I) 13(14)‐mono‐hydroxydocosanoic acid (II) docosanoic acid (III), showing that their antiwear properties are remarkably improved after introduction of the hydroxy group into fatty acids. Work on dihydroxy acid as an antiwear agent is not much reported in the literature up to now. In the present work, it was verified with infrared spectroscopy that polyester is formed on the rubbing surfaces with I and II by tribochemical reaction. An oxygen‐rich protective film on the rubbing surfaces was identified with Auger Electron Spectroscopy analysis. These results are identical to the high oxygen‐containing polyester film shown by IR analysis. It is preliminarily confirmed that the functional antiwear mechanism is, principally, the formation of a polymeric friction film on the rubbing surfaces.