he crystalline morphology

molecular weight and dynamic mechanical properties of PET/PBT blend with polyethylene glycol [PEG] as crystalline accelerater were investigated with the aid of SEM

DMA and U-Viscosimeter. It was found that the PEG has such functions as follows: (i) PEG makes polyester molecular chain move easier and is advantageous to the directonal arrangement of molecular chain on crystallization

so crystallites grow more rapidly; (ii) PEG makes the nucleating efficiency of nucleating agent rise

the formation rate of crystal increases and the crystal number grows;(iii) A portion of PEG takes part in the exchange ester reac-tion of polyester

which either increases or decreases the molecular weight of polye-ster

depending on the PEG level. Modulus and the intensity of the γ-loss peak ha-ve the maxima when the composition of PET/PBT/PEG is 30/30/3.6(wt ratio) and the dynamic mechanical properties are the best.