Abstract
Polyethyleneterephthalate (PET) is a versatile engineering plastic with excellent thermal and chemical resistance and mechanical performance. It is extensively used as fibers for apparel, films for packaging, in bottles for beverages, and also in engineering components. Because of the high melting point (ca. 255°C) and glass transition temperature (ca. 7O°C), PET retains its good mechanical properties at temperatures up to 175°C. It is a semi-crystalline polymer composed of crystalline and amorphous regions. A great variety of microstructures can be developed in PET by changing the crystallization conditions. The crystallite size and shape, volume fraction, orientation, and perfection can be varied through control of crystallization process. Study of the crystallization process and the microstructure devel-opment is intriguing and provides deeper insight into the effect of process parameters on the structure development and ultimately the properties of the end product.