Volume 5, Issue 10 (November 2008)

    Study on Antioxidative Synergism of Molybdenum Dialkydithiocarbamate with Alkylated Diphenylamine Antioxidants

    (Received 28 April 2008; accepted 29 September 2008)

    Published Online: 2008


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    The antioxidation properties of molybdenum dialkyldithiocarbamate, p,p-dioctyldiphenylamine and mixed octylated and butylated diphenylamine additives in poly-α-olefin (PAO) lubricant or mineral oil 150 SN were evaluated by differential scanning calorimetry (DSC) and the Modified Penn State Micro-oxidation Test (PMOT). DSC test measures incipient oxidation temperature and oxidation induction time of the lubricants at high temperatures and the weight loss of oil with deposits formed are measured by the PMOT test. DSC results show that antioxidation properties and of p,p-dioctyldiphenylamine and octylated and butylated diphenylamine were improved significantly by molybdenum dialkyldithiocarbamate addition. PMOT results indicate that when it was combinied with p,p-dioctyldiphenylamine, molybdenum dialkyldithiocarbamate can also effectively reduce the increase in weight loss of oils and deposits formed in oils. These results suggest that the molybdenum dialkyldithiocarbamate shows a good antioxidative synergism with alkylated diphenylamine antioxidants. In addition, FTIR results from the PMOT test confirm that the addition of molybdenum dialkyldithiocarbamate can significantly enhance the oxidation induction time of oils containing p,p-dioctyldiphenylamine and inhibit formation of oxidation products including carbonyl bonds or hydroxyl group. ESR analysis from the PMOT test indicate that molybdenum dialkyldithiocarbamate may form stable radicals with arylamine by the coordination effect. Finally, the proposed mechanism of the inhibition involves a synergy between molybdenum dialkyldithiocarbamate and arylamine antioxidants.

    Author Information:

    Zhang, Yi
    Engineering Institute, Air Force Engineering University, Xi’an

    Zeng, Xian-Jun
    Xuzhou Air Force College, Xuzhou

    Hu, Jian-Qiang
    Xuzhou Air Force College, Xuzhou

    Fu, Yan
    Xuzhou Air Force College, Xuzhou

    Luo, Yan
    Air Force Equipment Academy, Beijing

    Stock #: JAI101814

    ISSN: 1546-962X

    DOI: 10.1520/JAI101814

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    Title Study on Antioxidative Synergism of Molybdenum Dialkydithiocarbamate with Alkylated Diphenylamine Antioxidants
    Symposium , 0000-00-00
    Committee D02