Time resolved small angle scattering during isothermal crystallization of unoriented poly(ethylene terephthalate) using synchrotron radiation

Abstract

Abstract The time course of the small angle scattering pattern of amorphous poly(ethylene terephthalate), (PET), was measured during isothermal crystallization using synchrotron radiation. The samples were heated to temperatures between 117 and 145°C in an oven placed in the path of the X‐ray beam. The scattering curves were measured within 10 s at intervals of 1 s so as to follow the kinetics of the process continuously. It appears that the distance between the centres of mass of the crystallites decreases with increasing crystallization time as in oriented PET. The integrated small angle scattering follows approximately the same time course as the increase in the degree of crystallinity during an isothermal crystallization yielding Avrami exponents between 5 and 7. Guinier plots of the low angle region show that the scattering can be attributed to rod‐like particles.