Transport properties of water in hydroxypropyl methylcellulose
Författare
Summary, in English
The relation between the self-diffusion coefficient, D-self, of water and the free volume hole size, V-h, has been investigated in a hydroxypropyl methylcellulose (HPMC)-water system in the water content range 0.08-0.36 w/w, at room temperature. Furthermore, the thermal properties of the water in the HPMC-water system, as measured with differential scanning calorimetry (DSC) and the tensile storage, E', and tensile loss, E '', moduli, of the HPMC-water systems, as determined with dynamic mechanical analysis (DMA), have been probed. Pulsed-field gradient nuclear magnetic resonance (PFG NMR) was used to measure the D-self of water and positron annihilation lifetime spectroscopy (PALS) was used to measure the ortho-Positronium (o-Ps) lifetime in the HPMC-water system. The glass transition temperature of the HPMC was found to be reduced by the water to room temperature in the water content range 0.10-0.15 w/w. The relation between ln D-self of water and the inverse free volume hole size of the HPMC-water system was non-linear. Furthermore, the PALS measurements showed that molecular water co-existed with water clusters in the HPMC-water system. (C) 2009 Elsevier Ltd. All rights reserved.
Avdelning/ar
Publiceringsår
2009
Språk
Engelska
Sidor
2812-2820
Publikation/Tidskrift/Serie
European Polymer Journal
Volym
45
Issue
10
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Chemical Sciences
Nyckelord
- Water clusters
- Self-diffusion coefficient
- Free volume
- Positron
- annihilation
- NMR
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0014-3057