Characterization of dextrin hydrogels by FTIR spectroscopy and solid state NMR spectroscopy
authors Garcia, H; Barros, AS; Goncalves, C; Gama, FM; Gil, AM
nationality International
journal EUROPEAN POLYMER JOURNAL
author keywords dextrin; hydrogel; FTIR; CP/MAS; PLS; 2D-COS
keywords INFRARED-SPECTROSCOPY; ENZYMATIC-SYNTHESIS; STARCH GRANULES; REGRESSION/; INULIN
abstract Fourier transform infrared (FTIR) and C-13 solid state nuclear magnetic resonance (NMR) spectroscopy were used to study dextrin structural changes occurring upon hydrogel formation by vinyl acrylate (VA) grafting and subsequent free radical polymerization. The degrees of VA substitution (DS) and polymerization (DP) were quantified up to 40%VA by FTIR intensity measurements and partial least squares (PLS)/FTIR, the latter being a faster and less error-prone method. Above 40%VA, both parameters are underestimated by FTIR. A spin counting NMR experiment showed high carbon observabilities for hydrogels and improved PLS/NMR models were achieved for DS and DP determination. Alternative NMR integration methods are hindered by the broad VA peaks and need for area correction, due to their CP dynamics. NMR changes in Cl profile showed that a single helical conformation predominates at lower %VA, being replaced by disordered conformations as %VA increases. Furthermore, a correlation FTIR/NMR study indicated that ring conformations are significantly affected in hydrogels, compared to unpolymerized dextrin. (c) 2008 Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn 0014-3057
year published 2008
volume 44
issue 7
beginning page 2318
ending page 2329
digital object identifier (doi) 10.1016/j.eurpolymj.2008.05.013
web of science category Polymer Science
subject category Polymer Science
unique article identifier WOS:000258869300046
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