ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

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

Mian-Ran Chao, Wei-Min Li, Li-Li Zhu, Hai-Hong Ma, and Xiao-Bo Wang

State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China

E-mail: wangxb@licp.cas.cn

Abstract: An oil-soluble antioxidant, alkylated diphenylamine (ADPA), was prepared by alkylation of diphenylamine. The influence of ADPA on the thermal-oxidative stability of poly-α-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 thermal-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 E_a value and enhancing the oxidative stability of PAO8. Good correlation between the applied test methods was established.

Keywords: antioxidant – alkylated diphenylamine (ADPA) – poly-α-olefin (PAO) – thermal-oxidative degradation

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0104

Chemical Papers 69 (7) 1004–1011 (2015)