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Determination of the partial specific volumes of thermoreversible gelatin/water and κ‐carrageenan/water gels
Author(s) -
Cöulfen Helmut,
Borchard Werner
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950405
Subject(s) - gelatin , carrageenan , polymer , chemistry , thermodynamics , inflection point , lower critical solution temperature , polymer chemistry , organic chemistry , mathematics , copolymer , biochemistry , physics , geometry
In this paper systematic density measurements of gelatin/water and κ‐carrageenan/water gels are presented in a wide range of concentrations and temperatures. From about 600 measurements for gelatin/water and about 500 measurements for the system κ‐carrageenan/water empirical relations for both systems have been derived which allow to calculate the densities of these gels in a limited concentration range if the temperatures and the polymer weight fractions are known. The calculated densities have an accuracy of better than 0,001 g/cm −3 compared with the directly measured densities. If the extrapolated partial specific volumes of the pure polymer are plotted against the temperature, a jump with an inflexion point can be detected at about 23–24°C for both systems. These data indicate a Λ‐type transition of the expansion coefficient α for both systems at 23–24°C although there are still too few data to make clear conclusions.