| Abstract: | Physical aging of amorphous PET, at aging temperatures (Ta) of 40 and 60°C and different aging times (ta), has been studied by DSC using two kinds of samples with different thermal history: Liquid-Nitrogen-Quenched samples (LNQ) and DSC cooled samples at a controlled cooling rate of 60 K/min (CC). At Ta = 40°C, a sub-Tg peak appears in LNQ samples but is not clearly observed in the CC samples. At Tg = 60°C, a superposed peak to Tg is observed in both kinds of samples. This different behaviour can be explained considering the distribution of relaxation times in the polymer. |
