Thermal characterization of bacterial cellulose-phosphate composite membranes
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Data
2007-03-01
Autores
Barud, H. S.
Ribeiro, Clovis Augusto [UNESP]
Crespi, Marisa Spirandeli [UNESP]
Martines, M. A. U.
Dexpert-Ghys, J.
Marques, Rodrigo Fernando Costa [UNESP]
Messaddeq, Younes [UNESP]
Ribeiro, Sidney José Lima [UNESP]
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Editor
Springer
Resumo
Cellulose-phosphate composite membranes have been prepared from bacterial cellulose membranes ( BC) and sodium polyphosphate solution. The structure and thermal behavior of the new composites were evaluated by X-ray diffraction (XRD), P-31-nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry (TG) and thermomechanical analysis (TMA). From XRD analyses the I alpha and I beta cellulose crystalline phases were identified together with crystalline sodium phosphate that covers the cellulose microfibrils as revealed by SEM. P-31 NMR spectra show peaks assigned to Q(0) and Q(1) phosphate structures to be compared to the Q(2) units that characterize the precursor polyphosphate. Glass transition temperature, T-g, obtained from TMA curves and thermal stability obtained from TG and DSC measurements, were observed to be dependent on the phosphate content.
Descrição
Palavras-chave
bacterial cellulose, cellulose-phosphate composites, sodium polyphosphate
Como citar
Journal of Thermal Analysis and Calorimetry. Dordrecht: Springer, v. 87, n. 3, p. 815-818, 2007.