A Comparison of the Thermo-Oxidative Stability of Commercial Graphite Fibers for Composite Applications

The thermo-oxidative stability of various commercial graphite fibers was determined at 316°C (600°F) for over 4000 hours. In addition, to understand how graphite fiber surface properties affect thermo-oxidative stability of high temperature polymer composites containing these fibers, the surfaces were analyzed by electron spectroscopy for chemical analysis. The fiber systems studied were Celion 6000, G40-700, T-40R, IM6, AS4 and T-300R. The thermo-oxidative stability of T-40R and G40-700 was found to be superior to Celion 6000, T-300R and AS4. This improved stability of T-40R and G40-700 was found to be related to the carbon, oxygen and nitrogen concentrations. These fiber surfaces contained higher carbon contents and much lower concentrations of oxygen and nitrogen than the other fibers.