In this study, the mechanisms and kinetics of thermal degradation of the homopolyesters and copolyesters with different amounts of β-hydrogen were examined using thermogravimetric analysis (TGA) combined with low-temperature plasma (LTP) mass spectroscopy (MS), which allowed the identification of specific volatile compounds issued from the degradation. This study contains two parts. In the first part, TGA experiments temperature were set from 30 ºC to 700 ºC with a heating rate of 10 ºC/min under nitrogen. From the beginning of the loss of weight, recorded the variants of mass spectra with an interval of 1 minutes (10 ºC), and guessed not only the thermal degradation products but the thermal degradation mechanism as well by the appeared m/z. First, aliphatic homopolymer did β-hydrogen bond scission. Second, the carboxyl end group removed succinic anhydride to form the hydroxyl end group or went decarboxylation to form the methyl end group.
In the second part, we used thermogravimetric analysis figure, which came from the first part. We selected the temperature on the 10% of weight loss, and set programmed from 30 ºC to this temperature then did isothermal continued 20 minutes. In this part, aliphatic and aromatic homopolymer were also done likely scission. First, they did β-hydrogen bond scission. Second, PBSu, PMPSu, PPSu, PESu homopolymer removed succinic anhydride to form the hydroxyl end group, and PBT, PET homopolymer removed 4- formaldehyde acid to form the hydroxyl end group. Third, the hydroxyl end group did β-hydrogen bond scission.