简介：Methyldiethanolaminefattyacidesters,viz.methyldiethanolamineoctanoateandmethyldiethanolamineoleate,wereprepared.Theirimpactsonthebiodegradabilityandtribologicalpropertiesofmineralbaseoil400SNwereevaluatedbyatesterforfastevaluatingthebiodegradabilityoflubricantsandbyafour-balltester,respectively.Theresultsshowedthatmethyldiethanolamineoctanoateandmethyldiethanolamineoleatebothcouldmarkedlypromotethebiodegradationoftheoilandimproveditstribologicalproperties.Theimprovementofbiodegradabilitywasattributedtotheenhancedgrowthandquantityofmicrobesbymethyldiethanolaminefattyacidesters.Thewornsurfaceswereanalyzedbyascanningelectronmicroscope(SEM)equippedwithanenergydispersivespectrometer(EDS)andanX-rayphotoelectronspectroscope(XPS).Theresultsindicatedthattheenhancementoffriction-reducingandanti-wearpropertiesofthemineraloilwasattributedtotheformationofcomplicatedboundarylubricationfilmscomposedofspeciessuchasFe2O3,Fe3O4andorganicnitrogen-containingcompoundswithastructureof–C-N-orR-NH2.