A comparative study of the mechanism of the thermo-oxidative degradation of poly(ethylene 2,6-naphthalate) and poly(butylene 2,6-naphthalate)

A comparison is made between the thermo-oxidative degradation of poly(ethyl ene 2,6-naphthalate) (PEN) and that of poly(butylene 2,6-naphthalate) (PBN) using oxygen uptake, FTIR (before and after chemical treatments) and color measurements. The model compounds ethylene dinaphthoate (EDN) and butylene dinaphthoate (BDN) were used to identify possible oxidation products. The results showed that thermal oxidation of PEN and PEN yields mainly naphthoi c acid end groups and anhydrides, which indicates that the oxidation is ini tiated at the methylene group in the ct position to the eater group. The re sults clearly showed that PEN is more stable towards oxidation than PEN. (C ) 2000 Elsevier Science Ltd. All rights reserved.