Synergistic lubrication effect of antioxidant and low content ZDDP on PFPE grease

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Penghao Qi ◽  
Shijian Wang ◽  
Jing Li ◽  
Yue Li ◽  
Guangneng Dong
Keyword(s):  
High Temperature ◽  
Thermal Oxidation ◽  
Oxidation Stability ◽  
Wear Property ◽  
Content Type ◽  
Theoretical Support ◽  
Thermal Analyzer ◽  
Dialkyl Dithiophosphates ◽  
Thermal Oxidation Stability ◽  
Lubrication Effect

Purpose The purpose of this study is to reduce the use of Zinc dialkyl dithiophosphates (ZDDP) and improve the frictional properties and thermal oxidation stability of Perfluoropolyether (PFPE) grease by adding antioxidant additives. The addition of antioxidants can reduce the consumption of ZDDP as an antioxidant, thus improving the anti-wear efficiency of ZDDP and reducing the excess phosphorus element in the grease. Design/methodology/approach In this study, an antioxidant with good comprehensive performance was selected from several antioxidants by tribological tests and high-temperature tests. Then, the effect of its combination additive with ZDDP on PFPE grease was investigated. The anti-wear property, anti-friction property, thermal oxidation stability and extreme pressure property of greases containing different proportions of ZDDP and antioxidant were tested by four-ball tester and synchronous thermal analyzer (STA). The effects of additives on properties of grease were analyzed by SEM, EDS, LSCM, XPS and FT-IR. Findings The research shows that 2,6-Di-tert-butyl-4-methylphenol (BHT) can be used as an antioxidant in combined additives to reduce the antioxidant reactions of ZDDP, thus improving the anti-wear efficiency of ZDDP and further enhancing the anti-wear performance of the grease. Moreover, BHT and ZDDP have a synergistic effect on the high temperature performance of the PFPE grease due to their different antioxidant mechanisms. Social implications In this paper, the problems related to PFPE grease are studied, which has a certain guiding effect on the industrial application of fluorine grease and the related formulation design. Originality/value In this paper, the properties of PFPE grease under different lubricating condition were studied. The synergistic lubrication effect of antioxidant and ZDDP are discussed. It provides experimental and theoretical support for reducing the content of ZDDP and improving the performance of additives.

Effects of crystal planes of ZnO nanocrystal on crystalline, thermal and thermal-oxidation stability of iPP

2021 ◽  
Vol 28 (5) ◽  
Author(s):  
Jianqi Yao ◽  
Faliang Luo ◽  
Jie Mao ◽  
Yuting Li ◽  
Xiaolei Sun ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Stability ◽  
Thermal Oxidation Stability ◽  
Zno Nanocrystal

In situ Raman spectroscopy study on the effect of antioxidants on high temperature oxidation properties of TMPTO

2019 ◽  
Vol 71 (5) ◽  
pp. 706-711 ◽  
Author(s):  
Bingxue Cheng ◽  
Haitao Duan ◽  
Yongliang Jin ◽  
Lei Wei ◽  
Jia Dan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Thermal Oxidation ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
In Situ Raman Spectroscopy ◽  
Temperature Oxidation ◽  
Content Type ◽  
Structure Changes ◽  
Oxidation Properties

Purpose This paper aims to investigate the thermal oxidation characteristics of the unsaturated bonds (C=C) of trimethylolpropane trioleate (TMPTO) and to reveal the high temperature oxidation decay mechanism of unsaturated esters and the nature of the anti-oxidation properties of the additives. Design/methodology/approach Using a DXR laser microscopic Raman spectrometer and Linkam FTIR600 temperature control platform, the isothermal oxidation experiments of TMPTO with or without 1.0 wt. % of different antioxidants were performed. Findings The results indicated that the Raman peaks of =C-H, C=C and -CH2- weaken gradually with prolonged oxidation time, and the corresponding Raman intensities drop rapidly at higher temperatures. The aromatic amine antioxidant can decrease the attenuation of peak intensity, as it significantly reduces the rate constant of C=C thermal oxidation. The hindered phenolic antioxidant has a protective effect during the early stages of oxidation (induction period), but it may accelerate the oxidation of C=C afterwards. Originality/value Research on the structure changes of synthetic esters during oxidation by Raman spectroscopy will be of great importance in promoting the use of Raman spectroscopy to analyze the oxidation of lubricants.

scholarly journals The results of the research of motor oils by the method of predicting indicators of thermal-oxidation stability

2019 ◽  
Vol 1399 ◽  
pp. 055055
Author(s):  
Yu N Bezborodov ◽  
N N Lysyannikova ◽  
A A Kirpichenko ◽  
A V Lysyannikov ◽  
M A Kovaleva ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Stability ◽  
Motor Oils ◽  
Thermal Oxidation Stability

scholarly journals Thermal-Oxidation Stability of Soybean Germ Phytosterols in Different Lipid Matrixes

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4079 ◽  
Author(s):  
Jingnan Chen ◽  
Dami Li ◽  
Guiyun Tang ◽  
Jinfen Zhou ◽  
Wei Liu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Olive Oil ◽  
Thermal Oxidation ◽  
Loss Rate ◽  
Unsaturated Fatty Acids ◽  
Oxidation Stability ◽  
Oxidation Products ◽  
Higher Temperature ◽  
The Stability ◽  
Thermal Oxidation Stability

The stability of soybean germ phytosterols (SGPs) in different lipid matrixes, including soybean germ oil, olive oil, and lard, was studied at 120, 150, and 180 °C. Results on the loss rate demonstrated that SGPs were most stable in olive oil, followed by soybean germ oil, and lard in a decreasing order. It is most likely that unsaturated fatty acids could oxidize first, compete with consumption of oxygen, and then spare phytosterols from oxidation. The oxidation products of SGPS in non-oil and oil systems were also quantified. The results demonstrated that at relatively lower temperatures (120 and 150 °C), SGPs’ oxidation products were produced the most in the non-oil system, followed by lard, soybean germ oil, and olive oil. This was consistent with the loss rate pattern of SGPs. At a relatively higher temperature of 180 °C, the formation of SGPs’ oxidation products in soybean germ oil was quantitatively the same as that in lard, implying that the temperature became a dominative factor rather than the content of unsaturated fatty acids of lipid matrixes in the oxidation of SGPs.

Thermal-oxidation stability of jet fuels in a two-phase closed system

2009 ◽  
Vol 45 (2) ◽  
pp. 115-121
Author(s):  
G. N. Kishkilev ◽  
V. A. Astaf’ev ◽  
A. V. Isaev ◽  
M. I. Fakhrutdinov
Keyword(s):  
Thermal Oxidation ◽  
Closed System ◽  
Oxidation Stability ◽  
Jet Fuels ◽  
Two Phase ◽  
Thermal Oxidation Stability
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