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Frequency dependence of viscoelastic properties of some physical gels near the gel point
Author(s) -
Cuvelier Gérard,
Launay Bernard
Publication year - 1990
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19900400105
Subject(s) - gel point , viscoelasticity , biopolymer , gelatin , exponent , power law , sol gel , materials science , melting point , dynamic mechanical analysis , dynamic modulus , polymer , thermodynamics , chemistry , composite material , physics , nanotechnology , organic chemistry , mathematics , linguistics , philosophy , statistics
The sol‐gel and gel‐sol transitions of three biopolymer gelling systems (gelatin, iota‐carrageenan and xanthan‐carob) have been studied by dynamic measurements. At the gel point a power law dependence of the storage (G') and loss (G”) moduli on frequency is observed, with an exponent varying from 0.5 to 0.65. The variation of log(tg δ = G”/G') versus the gelation (or melting) parameter (time or temperature) at different frequencies leads to a precise determination of the gel point.