Kinetics of Oxidative Degradation: Applicability of Time and Temperature Superposition
作者:
Svajus Asadauskas,
JosephM. Perez,
SevimZ. Erhan,
期刊:
Tribology Transactions
(Taylor Available online 1999)
卷期:
Volume 42,
issue 4
页码: 860-866
ISSN:1040-2004
年代: 1999
DOI:10.1080/10402009908982293
出版商: Taylor & Francis Group
关键词: Vegetable Oils;Oleates;Triglycerides;Triolein;Unsaturation;Lubricants;Hydraulic Fluids;Biodegradable Oils;Polymerization;Gelation;Stability;Micro Oxidation;Kinetics
数据来源: Taylor
摘要:
New methodology is suggested to quantify the effect of temperature on oxidative degradation and compare test results obtained at different temperatures or evaluate changes in chemical mechanisms. Assumption of the pseudo-first-order kinetics to calculate activation energies in oxidative polymerization of uninhibited 100 percent oleic triglyceride under thin film oxidation provided only semiquantitative results from available oxypolymerization data at six temperatures from 100° to 175°C. As an alternative approach, Time and Temperature Superposition (TTS) was applied to analyze the data. Several TTS forms consistent with Arrhenius equation showed much greater accuracy in determining activation energies and induction periods. Different stages of oxidative degradation were identified after the data from different temperatures were combined into one kinetic map. Kinetic maps of alkali-refined high oleic sunflower oil, fully formulated synthetic oleate-based hydraulic fluid and additive-free super refined mineral oil showed their increasing resistance to oxypolymerization. Limitations of TTS were discussed.Presented at the 53rd Annual Meeting in Detroit, Michigan May 17–21, 1998
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