Thermal behaviour and molecular modelling of some aromatic polyethers containing a hexamethylenic spacer

We report a study of the thermal stability of some aromatic copolyethers co ntaining a hexamethylenic spacer. The polymers were synthesized by phase tr ansfer catalysis tin a liquid/liquid system) starting from 1,6-dichlorohexa ne and different bisphenols: 4,4 ' -dihydroxyazobenzene, 4,4 ' -dihydroxydi phenyl, bisphenol A and 2,7-dihydroxynaphthalene. Thermal stability was inv estigated by thermogravimetric analysis, in a static air atmosphere the hea ting rate being 10 degreesC/min. Molecular modeling was used as a complemen tary analysis method for the best understanding of the relationship between the chain conformation and polarity and the thermal behavior. CERIUS2 and HYPERCHEM programs were used to perform the molecular modelling. All the sy nthesized polymers present similar values of the starting point of the weig ht loss. This behavior can be explained by supra-molecular ordering, which is probably more important than the chemical structure. The presence of the hexamethylenic spacer leads to a micro-phase separation, with a favourable influence on the ordering in the solid state. All polymers showed low valu es of the polar surface, with interchain interactions playing a secondary r ole in the thermal stability. (C) 2001 Elsevier Science Ltd. All rights res erved.