Kinetic study of the thermal degradation of some poly(arylenether)s containing naphthalene units

The degradations of five aromatic thermoplastics, containing carbonyl, ether and sulfone linkages and in whose repeating units the -ArCONaphCOAr- moiety (where Ar = 1,4 substituted phenylene; Naph = 2,6 substituted naphthalene) was present, were performed under N-2 flow in dynamic heating conditions. The obtained results suggested that degradations occurred through random chain scission followed by branching and crosslinking, which partially superimposed with the initial process. The Kissinger method was used to determine the apparent activation energy (E-a) associated with the first degradation stage, and double linear relationships, attributable to slow diffusion of degradation products in the melt, were found in some cases. A thermal stability classification among the studied polymers was made on the basis of the obtained E-a values. This classification was compared with those previously obtained for two analogous groups of thermoplastics and some correlations between thermal stability and polymer chain structure were drawn. (C) 1999 Elsevier Science Ltd. All rights reserved.