The Decomposition of a Commercial Perfluoropolyalkylether on Alpha and Gamma Catalytic Aluminas

The decomposition of a commercial perfluoropolyalkylether liquid lubricant (PFPE Z) was studied using a thermal gravimetric and differential scanning calorimetry unit. Small porous alumina pellets (alpha and gamma forms) were charged with approximately 5 mg of PFPE Z, and the charged pellets were then placed inside the thermal units where decomposition started to occur over the. narrow temperature range of 198° to 210°C under a nitrogen atmosphere. At the end of a test, 1,1,2-trichlorotrifluoroethane solvent was used to extract PFPE Z and decomposition products from the pellets. This extract was analyzed using high-pressure liquid chromatography in the size exclusion mode. The alumina pellets were examined using X-ray photoelectron spectroscopy. Analysis of the thermal, chromatography, and X-ray photoelectron spectroscopy data support evidence that there are two different decomposition mechanisms for PFPE Z. The data indicated, that active surface sites, other than Lewis acid sites, were responsible for PFPE Z decomposition.