Catalytic Degradation of a Perfluoroalkylether in a Thermogravimetric Analyzer

Catalytic degradation of perfluoroalkylethers (PFAEs) by various substrates can be a significant problem, resulting in the formation of corrosive degradation products and loss of lubricant. The determination of catalytic degradation of a linear PFAE (PFAE-D) by various substrates was made by controlled-diffusion thermogravimetric analysis. The use of a sealed gold pan with a small pinhole in the lid allowed for the measurement of catalytic degradation of PFAE-D by increases in the rate of volatilization relative to a control. Catalytic degradation was observed under ramped conditions (to 500°C) for most commonly used metals and alloys except Inconel 600, silver and pure silicon nitride. Analysis of degradation products confirmed that degradation was occurring by a molecular disproportionation reaction. Milder isothermal conditions (300° C) resulted in catalytic degradation for aluminum, M-50 steel, carbon-carbon composite and some binder components used in silicon nitride balls.