MECHANISM OF DENSIFICATION AND CRYSTAL PERFECTION OF POLY(ETHYLENE-TEREPHTHALATE)

Amorphous poly(ethylene terephthalate) has been isothermally annealed in a wide range of temperatures from Tg to Tm. The effects of temperature and time of thermal treatment on density, melting curve and WAXS have been systematically explored. The results showed that densification and crystal perfection take place through a step mechanism involving partial melting and diffusion. The evaluation of the activation energies suggests that diffusion is the rate determining step in the low temperature range. © 1979.