Kinetic mechanism for air oxidation of PAN T-300 carbon fiber

Kinetic mechanism of air oxidation was studied for PAN T-300 carbon fiber in a temperature range from 500 to 600degC. Rates of the oxidation for the fiber can be described as the following auto-catalytic rate equation: dα/dt = kα(1-α) Arrehenius plot of the rate constant, k gave single straight line and the activation energy for the oxidation was estimated to be -22.7 kcal/mol. The energy was a half of that reported for Celion 6000 graphitized carbon fiber. A homogeneous shrinkage oxidation mechanism did not meet either with the oxidation rate behavior or the fiber radius change with burn-off. SEM observation and laser Raman spectroscopy for the oxidized fibers also supported the auto-catalytic oxidation mechanism. (author)