Krytox 157 FSL Oil | Performance Lubricant Serving as a SurfactantHighly Effective in Surface PretreatmentsKrytox 157 FSL Oil is a functionalized version of the DuPont series of Krytox fluorinated oils that acts as a surfactant. The functionality is a carboxylic acid group located on the terminal fluoromethylene group of poly(hexafluoropropylene oxide). Krytox 157 FSL is available in two relatively broad molecular weight ranges designated as low and high with the following typical properties. Like the other Krytox fluorinated oils, Krytox 157 FSL is insoluble in most common organic solvents. It is also nonflammable. Decarboxylation occurs on heating above about 170 °C (338 °F) and becomes vigorous at 200 °C (392 °F). The product formed appears to be a mixture, but is mainly a hydro-end-capped version of Krytox fluorinated oil. The decarboxylation of its alkali metal salts in the presence of water occurs at lower temperatures and yields essentially pure polymers end-capped with hydrogen.