Engineering Green Lubricants IV: Influence of Structure on the Thermal Behavior of Linear and Branched Aliphatic Fatty Acid-Derived Diesters

Abstract

Fatty acid-derived aliphatic diesters and their branched derivatives are lubricating compounds that demonstrate predictable viscosity temperature profiles and remain fluid at extremely low temperatures. In this work, the influence of molecular structure on the high temperature thermal behavior of several series of aliphatic fatty acid-based diesters was investigated using thermogravimetric analyses (TGA). Evaporation behavior was determined as a function of molecular weight, saturation, symmetry and double bond position, and decomposition behavior as a function of molecular weight, branching, saturation and symmetry. The results revealed that the diol-derived diesters underwent predictable molecular weight-mediated evaporation, and that further refinement of the predicted evaporation temperatures could be obtained by accounting for saturation in the fatty acid moieties. Double bond position and symmetry did not measurably influence the evaporation temperatures of the diesters. Evaporation was successfully...