Abstract: The thermal and crystallization properties of ordinary polyester (PET I) and solid-phase polycondensation thickened polyester chips (PET II) were analyzed by DSC and thermal gravimetric analysis. On the first heating of DSC, no crystallization endothermic peak was observed on PET II, indicative that the solid-phase polycondensation not only increased the molecular weight, but also completed the crystallization. The melting point of PET II increased. The crystallinity of PET II was lower, the size of PET II was smaller, the crystallization rate of PET II was smaller, compared with PET I. The thermal stability of PET II was better than PET I.

Key words: poly(ethylene terephthalate), solid-phase polycondensation, thermal property, crystallization