Utilize este identificador para referenciar este registo: http://hdl.handle.net/1822/8161

TítuloCharacterization of dextrin hydrogels by FTIR spectroscopy and solid state NMR spectroscopy
Autor(es)Garcia, Helga
Barros, António
Gonçalves, Catarina
Gama, F. M.
Gil, Ana M.
EditoraElsevier Ltd.
RevistaEuropean Polymer Journal
Citação"European Polymer Journal". ISSN 0014-3057. 44:7 (July 2008) 2318-2329.
Resumo(s)Fourier transform infrared (FTIR) and 13C 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 C1 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.
Arbitragem científicayes
Aparece nas coleções:CEB - Publicações em Revistas/Séries Internacionais / Publications in International Journals/Series

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