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Microstructure of Banded Polymer Spherulites: New Insights from Synchrotron Nanofocus X-Ray Scatteringстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Ivanov Dimitri A., Martin Rosenthal
- Журнал: Advances in Polymer Science
- Год издания: 2016
- Издательство: Springer Verlag
- Местоположение издательства: Germany
- DOI: 10.1007/12_2016_352
- Аннотация: We report on the banded polymer morphology of several semicrystalline commodity polymers such as high-density poly(ethylene), poly(trimethylene terephthalate), poly(vinylidene fluoride), and poly(3-hydroxybutyrate). The internal structural organization and 3D shape of the constitutive crystalline lamellae have been topics of interest in polymer physics for the last 50 years. However, conventional morphological characterization techniques (electron and/or optical microscopy) can be misleading in such analyses and have resulted in wrong interpretations of the twisted lamella growth mechanisms. We present nanofocus synchrotron X-ray scattering experiments and describe the analysis used to interpret the arrays of nanodiffractograms acquired along the spherulitic radii. It is shown that the crystal twist occurring during radial outward growth is regular and uniform. The 3D lamella shape is in most cases similar to the classic helicoid, whereas in other cases, such as the lamellae of poly(propylene adipate), it corresponds to a spiral structure. Access to comprehensive microstructural information about bulk samples makes it possible to better understand the twisted growth mechanisms and check the premises of the Keith and Padden model linking the direction of chain tilt and lamella twist hand. It is demonstrated that this model cannot explain the banding behavior in poly(trimethylene terephthalate) and therefore needs reconsideration. In-depth analysis of the microstructure allows more general conclusions to be drawn regarding correlation of chiralities pertinent to different spatial scales, ranging from that of the constitutive monomer to the supramolecular level of twisted lamellae.
- Добавил в систему: Иванов Дмитрий Анатольевич