Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/20361

TitleEffect of solvent-dependent viscoelastic properties of chitosan membranes on the permeation of 2-phenylethanol
Author(s)Caridade, S. G.
Silva, Ricardo M. P. da
Reis, R. L.
Mano, J. F.
KeywordsChitosan
Diffusion
Glass transition
Membranes
Swelling
Issue date2009
PublisherElsevier
JournalCarbohydrate Polymers
Abstract(s)The viscoelastic behaviour of chitosan was followed by dynamic mechanical analysis (DMA) while the sample was immersed in gradient compositions of water/ethanol mixtures. The swelling equilibrium of chitosan membranes, both crosslinked with genipin or not, increased linearly with the water content. Increasing the water content, it was simultaneously observed a peak in the loss factor (around 25 vol.%) and a reduction of the storage modulus, which was attributed to the a-relaxation of chitosan. This was the first time that the glass transition dynamics in a polymer was monitored in immersion conditions where the composition of the plasticizer in the bath is changed in a controlled way. The water content at which tan d presented a maximum increased with both increasing frequency and increasing crosslinking density. The permeability decreased steadily with the ethanol content, reaching very low values around the glass transition. Therefore we hypothesize that conformational mobility of the polymeric chains may play an important role in the diffusion properties of molecules trough polymeric matrices.
TypeArticle
URIhttp://hdl.handle.net/1822/20361
DOI10.1016/j.carbpol.2008.09.011
ISSN0144-8617
Peer-Reviewedyes
AccessOpen access
Appears in Collections:3B’s - Artigos em revistas/Papers in scientific journals

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