Physico-chemical characterization of base stocks and thermal analysis by differential scanning calorimetry and thermomicroscopy at low temperature

A conventional base stock, solvent refined (SR) and a hydroisomerized base stock (HI) in which differences in behavior of Pour Point Depressant Additi ve are observed, have been dewaxed and these oils and their fractions have been characterized by analytical methods and thermal analysis. Differential scanning calorimetry (DSC) is a rapid and valuable technique f or characterization of the thermal behavior of lubricating oils, allowing t he determination of crystallization temperature and amount of precipitated fractions versus temperature. Differences between these basestocks, more pa rticularly in the amount of crystals which precipitate versus temperature c an explain selective effectiveness of pour point Depressant (PPD) additives . (C) 2000 Elsevier Science B.V. All rights reserved.