Sealed capsule differential scanning calorimetry - An effective method forscreening the oxidation stability of vegetable oil formulations

Vegetable oils are a potential source of environmentally-friendly base oils . They display excellent lubrication properties, but are limited as potenti al lubricants by low thermal and oxidative stabilities. To develop an effec tive vegetable oil lubricant formulation, with a reasonably high oxidation stability, requires an evaluation of an assortment of antioxidant and veget able base oil combinations. A majority of the existing techniques for asses sing the oxidative stability of oils are slow and the results are not alway s reliable. A sealed capsule differential scanning calorimetry (SCDSC) tech nique developed as part of this study to rapidly screen the oxidative stabi lity of a variety of lubricants, is reliable, precise, fast and uses only m icroliter quantities of the sample per test. In this study SCDSC was used t o examine the oxidative stability of a wide range of vegetable base oils. A s the level of unsaturation in the fatty acids increased the oxidation stab ility decreased. The effectiveness of butylated hydroxytoluene (BHT), diphe nylamine (DPA) and zinc dialkyldithiophosphate (ZnDDP) as antioxidants in v egetable oils was assessed using SCDSC.