Nano-structured polymer blends: phase structure, crystallisation behaviourand semi-crystalline morphology of phase separated binary blends of poly(ethylene oxide) and poly(ether sulphone)

The crystallisation behaviour and morphology of binary phase separated crys talline/amorphous blends of poly(ethylene oxide) (PEO) and poly(ether sulph one) (PES) are investigated. The crystallisation behaviour of the PEO/PES b lends changes strongly with demixing time and temperature. A method is prop osed to determine the composition and amount of PEO-rich phase in the parti ally demixed blend systems from the dynamic crystallisation behaviour, The results are in agreement with the structure development as predicted for sp inodal decomposition that proves the validity of this method. The phase and semi-crystalline morphologies are visualised by scanning electron microsco py and atomic force microscopy. The semi-crystalline morphology is also stu died by real-time small angle and wide angle X-ray scattering. It is shown that, depending on the blend composition, a spherulitic or isolated lamella r crystalline morphology is formed in the demixed PEO/PES blends. (C) 1999 Elsevier Science Ltd. All rights reserved.