The influence of high temperature oxidation on molecular structure and performance of aviation base oils

Abstract

In this paper, the dioctyl adipate (DIOA) and poly‐α‐olefin (PAO) were comparatively study to systematic evaluate the influence of high temperature oxidation on the molecular structure and performance of the base oil. Even the DIOA has better antioxidation properties, antioxidant could significantly reduce the molecular structure damage during high temperature oxidation for the both two kinds of base oils. Because the decrement of kinematic viscosity was slow down after antioxidant was added into the base oils, the kinematic viscosity ratio of DIOA and PAO is nearly 1.7 after oxidation at 300°C, which is down to 1.2 while antioxidant is applied. Based on the DSC analysis, the antioxidant could postpone the oxidation process of the PAO and DIOA oil samples and have longer oxidation induction time (17.5 and 35.1 min) and higher incipient oxidation temperature (262.3°C and 243.8°C), respectively. The oxidation induction time of DIOA is nearly twice (or triple) the value of PAO4, which suggests a much better antioxidation performance of DIOA. The GCMS results elucidate that the species and quantities of oxidation products are reduced simultaneously.

The Intrinsic Relationship Between Color Variation and Performances of the Deteriorated Aviation Lubrication Oil

“…Colorimeter has a long history for measuring the quality of the refined petroleum products since 1933 [7][8][9] , which also suggests the color is an important parameter of aviation lubrication oils. As reported by the previous study [10][11][12] , the molecular structure change and the properties deterioration of the oxidized oil samples are confirmed, which also result in gradually changing of the oxidized oil samples color. However, the intrinsic relationship between the oil molecules (oxidizing products and antioxidants) and the resulting color variation needs to be established which could develop a fast and low-cost strategy to rapidly estimate the oil quality.…”

“…The T531 also has similar effect on color change with T501, although in different base oils. Interestingly, the oxidized PAO oil sample which added 1% Tz516 and 1% T501 (P516/501) has lower color number (0-12) compared with the color number (11)(12)(13)(14) of PAO oil sample with 1% Tz516 (P516). Especially under shorter oxidation time, the color number of P516/501 is 0 after oxidizing for half an hour while the color number of P516 is 11.…”

Improving Tribological Performance of Porous Polyimide by Surface Polishing

“…Sliding against a 440C steel ball would press out the residual nanoparticles from the PG-PPI surface, causing three-body abrasive wear and degenerate lubrication properties. Previous research found that the degradation of PAO oil at high temperatures contributes significantly to the blackening phenomenon. The three-body contact increases the local contact stress and creates a high flash temperature, which is thought to be the primary source of more black products on the PG-PPI surface (Figure c) or the Al 2 O 3 abrasive particles added CP-PPI surface (Figure b).…”