Effect of alkylated diphenylamine on thermal-oxidative degradation behavior of poly-α-olefin

An oil soluble antioxidant alkylated diphenylamine (ADPA), was prepared by alkylation diphenylamine .The influence of ADPA on the thermal-oxidative stability of poly-alpha-olefin (PAO8) was evaluated by thermogravimetry (TG). For comparison, the thermal-oxidative stability of PAO8 with zinc dialkyl dithiophosphate (ZDDP) was also investigated. Activation energy (E-a) of the corresponding theririal-oxidative degradation process was evaluated by the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. To demonstrate the reliability of the kinetic: study, the antioxidant performance of ADPA and ZDDP in PAO8 was also studied by the pressure drop (PDT) and accelerated oxidation (AOT) tests. The results indicate that ADPA has better antioxidant ability than ZDDP in increasing the Ea value and enhancing the oxidative stability of PAO8. Good correlation between the applied test methods was established. (C) 2015 Institute of Chemistry, Slovak Academy of Sciences