THERMAL-DEGRADATION STUDIES OF NOVEL DIETHYLENE GLYCOL BASED UNSATURATED POLYESTERS IN AIR

Thermal degradation of some unsaturated polyesters synthesized by '1-s tep', '2-step' and '3-step' polyesterification processes, and designat ed as NUP-I, NUP-II and NUP-III, respectively, have been studied using thermogravimetry (TG), derivative thermogravimetry (DTG), differentia l thermal analysis (DTA), isothermal TG, infrared (IR) spectroscopy an d hot stage microscopy. The data from dynamic studies in static air an d dynamic nitrogen suggest that the mode of degradation is different i n air and nitrogen. The degradation in static air involves two stages as against single stage degradation in nitrogen. Isothermal studies in air reveal that the degradation follows a two-step first-order reacti on. IR studies show that the degradation starts with the breaking of e ster linkages and CO2 is the initial gaseous product detected at 300 d egrees C. (C) 1998 Elsevier Science Limited. All rights reserved.