期刊
CARBOHYDRATE POLYMERS
卷 114, 期 -, 页码 416-423出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.carbpol.2014.08.020
关键词
Bacterial cellulose; Surface esterification; Organocatalysis; Characterization
资金
- Consejo Nacional de Investigaciones Cientificas y Tecnicas [CONICET-PIP 11220110100608]
- University of Buenos Aires [UBACYT 20020090100065]
- Agencia Nacional de Promocion Cientifica y Tecnologica [PICT 1957 2012 - PRESTAMO BID]
Bacterial cellulose nanofibers were esterified with two short carboxylic acids by means of a simple and novel organic acid-catalyzed route. The methodology proposed relayed on the use of a non-toxic biobased alpha-hydroxycarboxylic acid as catalyst, and proceeded under moderate reaction conditions in solventless medium. By varying the esterification interval, acetylated and propionized bacterial cellulose nanofibers with degree of substitution (DS) in the 0.02-0.45 range could be obtained. Esterified bacterial cellulose samples were characterized by means of Solid-State CP/MAS C-13 Nuclear Magnetic Resonance spectroscopy (CP/MAS C-13 NMR), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and chosen hydrophobicity test assays. TGA results showed that the esterified nanofibers had increased thermal stability, whereas XRD data evidenced that the organocatalytic esterification protocol did not alter their crystallinity. The analysis of the ensuing modified nanofibers by NMR, FTIR, XRD and TGA demonstrated that esterification occurred essentially at the surface of bacterial cellulose microfibrils, something highly desirable for changing their surface hydrophilicity while not affecting their ultrastructure. (C) 2014 Elsevier Ltd. All rights reserved.
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