A new mechanism in the formation of PET extended-chain crystal

In order to obtain a better understanding of the effect of transesterificat ion in PET extended-chain crystallization, the crystallization behaviors of the PET samples with added catalysts and inhibitors of transesterification have been investigated at high pressure. The catalyst accelerated PET crys tallization in two facets: (I) increasing the crystallinity; and (II) accel erating the thickening process of lamellar crystals. On the contrary, the i nhibitor hindered crystallization. This indicates that transesterification can promote PET crystallization and improve the formation of extended-chain crystals. The different effects of transesterification to crystallization in amorphous region or molten state and on folded-chain surface of lamellar crystals has also been discussed; it suggested that transesterification be tween lamellar crystals is more effective for lamellar crystal thickening. (C) 2000 Elsevier Science Ltd. All rights reserved.