Determination of Fluorocarbon Ether Autoxidative Degradation Mechanism.
Abstract
Elucidation of mechanisms operative in thermal oxidative degradation of hexafluoropropene oxide derived polyethers and the effect of metals and anti-oxidant/anti-corrosion additives on this process are reported. Thermal oxidative instability of the commercial fluid, Krytox MLO-71-6, at moderate temperatures (550 F) was found to be due to the presence of approx. 3% of hydrogen terminated chains; treatment at 650 F in oxygen volatilized these chains by unzipping. The hydrogen-free fluid was unaffected by oxygen at 650 F and by M-50 and Ti(4Al, 4Mn) alloys at 600 F in oxidizing atmospheres. M-50 alloy catalyzed the degradation of the hydrogen terminated chains below and at 600 F, but did not affect the remainder of the fluid at these temperatures. At 650 F a chain scission process promoted by the metals constituting the alloy or their oxides or fluorides came into play. Ti(4Al, 4Mn) alloy in the presence of CF3COF and COF2, formed via decomposition of hydrogen terminated chains, degraded poly(hexafluoropropene oxide) fluids at 550 F by chain scission. The additive MLO-76-30 arrested Krytox MLO-71-6 thermal oxidative degradation at 600 F and below both in the absence and in the presence of metals by preventing the degradation of the hydrogen terminated chains.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1977
- Accession Number
- ADA057785
Entities
People
- J. H. Nakahara
- Jason Kaufman
- K. L. Paciorek
- R. H. Kratzer