|Adhvaryu, Atanu - PENN STATE UNIV.|
Submitted to: Society of Tribologists and Lubrication Engineers
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2005
Publication Date: May 19, 2005
Citation: Kurth, T.L., Adhvaryu, A., Biresaw, G. 2005. FFG adsorption behavior of methyl esters from hexadecane [abstract]. Society of Tribologists and Lubrication Engineers. p.171. Technical Abstract: The adsorption properties of several fatty acid esters (methyl stearate, -palmitate, -oleate, and -laurate), from hexadecane, were examined in the boundary lubrication regime using a steel ball-on-disk test geometry. The resulting friction coefficient data were analyzed via non-linear least squares iterative fitting of a variety of adsorption models without prior assumptions. This study indicates that the Langmuir and Temkin adsorption models do not sufficiently account for the concentration dependence of the coefficients of friction for each additive. The Frumkin-Fowler-Guggenheim model, which incorporates attractive lateral interactions, successfully accounts for the observed concentration dependence. The results show that methyl stearate adsorbs to the greatest extent at low concentration. Methyl palmitate and -oleate display increased relative lateral interactions. Bulk solvent viscosities for each of the additive concentrations were measured. These data suggest that, for the concentration ranges studied, the additive lateral interactions result from the adsorptive pre-association.