Physical structure and thermal behavior of ethylcellulose

The physical structure and properties of ethylcellulose (EC) powders of different molecular weights were examined. A molecular weight in the range of 20–144 kDa with a large polydispersity was determined. EC thermal analysis revealed a glass transition at ~130 °C and a melting temperature at ~180 °C...

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Veröffentlicht in:Cellulose (London) 2014, Vol.21 (5), p.3243-3255
Hauptverfasser: Davidovich-Pinhas, M, Barbut, S, Marangoni, A. G
Format: Artikel
Sprache:eng
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Zusammenfassung:The physical structure and properties of ethylcellulose (EC) powders of different molecular weights were examined. A molecular weight in the range of 20–144 kDa with a large polydispersity was determined. EC thermal analysis revealed a glass transition at ~130 °C and a melting temperature at ~180 °C. Glass transition temperatures increased with polymer molecular weight. Wide angle (WAXS) analysis detected an amorphous broad peak at q = 1.5 Å⁻¹ and a distinct Bragg’s peak at 12.6 Å, which seems to be related to a supramolecular ordered structure of the polymer. These observations were confirmed using high temperature powder X-ray diffraction analysis where the crystalline peak disappeared above the melting temperature of the polymer. Ultra-small angle (USAXS) results were fitted to the Bouacage fractal unified model and fractals with an average size of 100–600 nm with a relatively smooth surface were predicted. This prediction was confirmed by transmission electron microscopy (TEM) images. According to our results, the EC polymer has a semi-crystalline structure, with crystalline domains within an amorphous background.
ISSN:0969-0239
1572-882X
DOI:10.1007/s10570-014-0377-1