SAXS study on the crystallization of PET under physical confinement in PET/PC multilayered films

The present work is concerned with the study of the development of the crystalline structure of poly(ethylene terephthalate) in multilayered films of poly(ethylene terephthalate)/polycarbonate (PET/PC) prepared by means of layer multiplying coextrusion. Small angle X-ray scattering patterns were recorded during isothermal crystallization experiments and evaluated by means of Rulandʹs interface distribution function. Thus, structural parameters describing the thickness distribution of crystalline and amorphous layers were determinated. It is shown that the crystallization of PET is delayed with increasing confinement. However when the crystallization process comes to an end, the values of the nanostructural parameters of the lamellar system are nearly the same for the confined and non-confined PET.