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Friction and adsorption properties of normal and high‐oleic soybean oils
Author(s) -
Biresaw G.,
Adhvaryu A.,
Erhan S. Z.,
Carriere C. J.
Publication year - 2002
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-002-0434-5
Subject(s) - adsorption , degree of unsaturation , langmuir , soybean oil , chemistry , triglyceride , lubrication , oleic acid , chemical engineering , organic chemistry , materials science , composite material , food science , biochemistry , cholesterol , engineering
The steel/steel boundary friction properties of soybean oil (SBO) and high‐oleic soybean oil (HOSBO) are compared. HOSBO is significantly more saturated than SBO and more oxidatively stable. Changes in degree of unsaturation affect lateral interactions of adsorbate molecules, which in turn affects their adsorption and, hence, their boundary lubrication properties. To investigate this possibility, the free energies of adsorption (Δ G ads ) of SBO, HOSBO, and methyl laurate (ML) were determined from the analysis of friction‐derived adsorption isotherms using the Langmuir and Temkin adsorption models. The results showed a stronger adsorption for the vegetable oils than for ML, an indication of multiple interactions between the ester groups of the triglycerides and the steel surface. The result also showed no difference in the Δ G ads values of SBO and HOSBO obtained using either the Langmuir or Temkin models. This was interpreted as an indication of the lack of appreciable net lateral interaction between triglyceride adsorbates.