The kinetics of the oxidative 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 approx 100 kJ mol exp --1 . At higher isothermal temperatures, however, the rates appear to be controlled by diffusion factors and high apparent activation energies are noted of approx 185 kJ mol exp --1 for the earlier weight-loss fractions and of approx 220 kJ mol exp --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. 11 ref.--AA