Synthesis of a Multi-phenol Antioxidant and Its Compatibility with Alkyl Diphenylamine and ZDDP in Ester Oil

In this study, a multi-phenol antioxidant 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylthio)-1,3,5-triazine (THA) was synthesized. The thermal stability of THA and its oxidation resistance in triisodecyl trimellitate (TDTM) ester oil were evaluated compared with several commercial phenol antioxidants. Further investigations on the oxidation resistance and tribological performance of THA with dinonyl diphenylamine (Am) and ZDDP composites were conducted to determine the additive compatibility in TDTM. The results indicate that the THA possesses higher thermal stability and more effectiveness of oxidation resistance than the commercial phenol antioxidants. The synergistic anti-oxidative effect is confirmed for the THA/Am mixtures in TDTM ester oil. However, the addition of THA alone or THA/Am mixtures shows no improvement for the tribological performance of TDTM. Excitingly, the THA/Am/ZDDP composite additives not only have the superior oxidation resistance, but exhibit the effective friction and wear reductions. It suggests the excellent compatibility of the synthesized THA antioxidant with Am and ZDDP additives in TDTM ester oil.