Evaluation of the influence of various (ether, ketone and sulfone) groups on the apparent activation energy values of polymer degradation

The kinetics of degradation of four model polymers containing ether, carbonyl and sulfone groups was studied in both N-2 flow and static air atmosphere, with the aim of evaluating the influence of various groups on the apparent activation energy values (E-a) of degradation. The initial temperatures of decomposition (T-i) and the temperatures of half decomposition (T-1/2), were also determined. The degradation of all polymers was carried out in the scanning mode and the Kissinger equation used to evaluate the E-a values of the first degradation stage. The results allowed us to make a kinetic stability classification among various groups (sulfone > ketone > ether) which could be explained on the basis of the double-bond character of the polymer chain links. The E-a values showed a trend analogous to the glass transition temperatures (T-g), in agreement with literature reports. By contrast, the characteristic temperatures of decomposition showed a different trend which could not be interpreted on the basis of the experiments until now performed. (C) 2003 Elsevier Science Ltd. All rights reserved.