Molecular motion in glassy water-malto-oligosaccharide (maltodextrin) mixtures as studied by conventional and saturation-transfer spin-probe e.s.r. spectroscopy
✍ Scribed by Marcel J.G.W. Roozen; Marcus A. Hemminga; Pieter Walstra
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 653 KB
- Volume
- 215
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
Conventional and saturation-transfer e.s.r. spectroscopy have been used to study the rotational behaviour of the spin probe 4-hydroxy-2,2,6&tetramethylpiperidine
N-oxyl (1, tempo]) around the glasstransition temperature of malto-oligosaccharide-water mixtures. The temperature at which an increase in mobility was observed agreed reasonably well with the glass-transition temperature as determined by d.s.c. The apparent activation energy for rotation in the glassy malto-oligosa~h~ride increased as the molecular weight became larger, p~sumably due to a decrease in the free volume of the sample. No influence of the water content of the glassy samples, at temperatures above the freezing point of water. on the apparent activation energy was observed.