Evaluation on synergistic antioxidation of methylene dibutyldithiocarbamate with tolutriazole derivative

Abstract The antioxidation properties of methylene bis(di‐n‐butyldithiocarbamate) (V 7723)‐ and tolutriazole derivative (V 887)‐containing poly‐α‐olefin (PAO)‐derived lubricants were evaluated by differential scanning calorimetry (DSC) and modified penn state micro‐oxidation test (PMOT). The DSC test measured the onset temperature (OT) and induction time (IT) of the lubricant at high temperatures, and oxidation stability of oil by weight loss was measured by the PMOT. The DSC test showed that the OT and IT of V 7723‐containing PAO were improved significantly by the addition of V 887. The PMOT indicated that when combined with V 7723 antioxidants, V 887 could also effectively reduce the increase in the weight loss of PAO. These results suggested that the V 887 showed a good oxidative synergism with the V 7723 antioxidant. In addition, Fourier Transform Infrared (FTIR) results from the PMOT confirmed that the addition of V 887 could significantly enhance the oxidation IT of oils and inhibit the formation of oxidation products containing carbonyl bonds or hydroxyl group. Copyright © 2007 John Wiley and Sons, Ltd.