Chemically-modified fatty acids are prepared by reacting epoxidized fatty acids, their esters or triglyceride oils with amines of cyclic or aromatic hydrocarbons. The fatty acid derivatives produced are of the formula: wherein R is an H, branched or straight chain alkyl or alkenyl group, aromatic-containing group, glycerol, or glyceride, R″ is a C3 to C29 aliphatic chain comprising one or more of the derivatized methylene groups of the formula: wherein R1 and R2 are independently selected from the group consisting of H, cyclic hydrocarbons, substituted cyclic hydrocarbons, and aryl groups, with the proviso that only one of said R1 and R2 may be H. These fatty acid derivatives have utility as antiwear/antifriction additives for industrial oils and automotive applications.