The kinetics of the oxidattve degradation of poly(aryl-ether-ether-ketone) (PEEK)

The kinetic parameters of the thermal decomposition of poly(aryl-ether-ether-ketone) (PEEK) in air have been investigated using an isothermal weight-loss method. The results from these studies indicate that the decomposition process is a complex one which proceeds in several overlapping stages. Calculation of the kinetic parameters by a variety of models suggests that at the lower isothermal temperatures the initial weight-loss process occurs with an apparent activation energy of about 100 kJ mol−1. At higher isothermal temperatures, however, the rates appear to be controlled by diffusion factors and higher apparent activation energies are noted of around 185 kJ mol−1 for the earlier weight-loss fractions and of about 220 kJ mol−1 for the later weight-loss data. The analyses presented demonstrate the difficulties which can arise in determining meaningful mechanistic information from standard weight-loss data even when isothermal heating conditions are employed.