Crystallization study of glassy PET/PEN blends by means of real time X-ray scattering

The crystallization of several blends of polyethylene terephthalate) (PET) and polyethylene 2,6 naphthalene dicarboxylate) (PEN) has been investigated by wide angle- (WAXS) and small angle X-ray scattering (SAXS) using synchrotron radiation. The role of transesterification reactions, giving rise to a fully amorphous non-crystallizable material (copolyester) is brought up. For the blends rich in PET, crystallization temperatures (Tc) of 105 and 117°C were used. For blends rich in PEN, crystallization was performed at Tc= 150 and 165°C, respectively. The time variation of the degree of crystallinity was fitted into an Avrami equation considering the induction time prior to the beginning of crystallization. The Avrami parameters, the half times of crystallization, as well as the nanostructure development (SAXS invariant and long period) for the blends, are discussed in relation to blend composition and are compared to the parameters observed for the homopolymers PET and PEN. © 2001 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint, a member of the Taylor & Francis Group.Peer Reviewe