Theoretical Simulations of Electron-Induced Degradation of Perfluoropolyether

Abstract

Electron-induced degradation of perfluoropolyether (PFPE) was simulated by a semi-empirical molecular orbital calculation of a model using a methylene oxide segment. The calculated heat of formation of the optimized structure showed that the anion radical was more stable than the neutral molecule by 186.9 kj/mol, while the cation radical had higher energy by 1281.7 kj/mol compared with the neutral. The calculated bond order indicated that several carbon-oxygen bonds were weakened in the anion radical. The estimated activation energies for the cleavage of the weakest C-O bond of the anion radical, the cation radical, and the neutral were 68.0, 22.1 and 334.2 kj/mol, respectively, and the ion radicals were expected to decompose easily. The anion intermediate formed after the above degradation of the anion radical was suggested to successively degrade to produce carbonyl fluoride.

Presented as a Society of Tribologists and Lubrication Engineers paper at the STLE/ASME Tribology Conference in Kissimmee, Florida, October 8–11, 1995

KEY WORDS:

• Polyethers
• Lubricant Degradation/Stability
• Interaction of Additives
• Hard Disks

Notes

Presented as a Society of Tribologists and Lubrication Engineers paper at the STLE/ASME Tribology Conference in Kissimmee, Florida, October 8–11, 1995