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

The degradations of five aromatic thermoplastics, containing carbonyl, ethe r and sulfone linkages and in whose repeating units the -ArCONaphCOAr- moie ty (where Ar = 1,4 substituted phenylene; Naph = 2,6 substituted naphthalen e) 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 supe rimposed with the initial process. The Kissinger method was used to determi ne the apparent activation energy (E-a) associated with the first degradati on stage, and double linear relationships, attributable to slow diffusion o f degradation products in the melt, were found in some cases. A thermal sta bility classification among the studied polymers was made on the basis of t he obtained E-a values. This classification was compared with those previou sly obtained for two analogous groups of thermoplastics and some correlatio ns between thermal stability and polymer chain structure were drawn. (C) 19 99 Elsevier Science Ltd. All rights reserved.