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Gelatin renaturation and viscosity of dilute gelatin solutions
Author(s) -
Horský Jiři,
Švantner Jiří
Publication year - 1993
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.4990320208
Subject(s) - gelatin , aqueous solution , viscosity , potassium thiocyanate , solvent , drop (telecommunication) , thermodynamics , chemistry , monomer , intrinsic viscosity , melting temperature , thiocyanate , reduced viscosity , polymer chemistry , materials science , organic chemistry , polymer , composite material , telecommunications , physics , computer science
Mechanical melting temperatures of gelatin gels determined by the ball‐drop method are decreased by several degrees if 0.5m potassium thiocyanate aqueous solution is used as solvent instead of pure water. In agreement with that, the growth with time of the viscosity of dilute gelatin solutions occurs at lower temperatures in 0.5m potassium thiocyanate. Surprisingly enough, the reduced specific viscosity after five hours at 5° C is lower in pure water. This is because the temperature dependence of this quantity in water is not monotonic, and the temperature 5° C is below that at which a distinct maximum is reached. No similar maximum has been reported so far for the temperature and time dependences of the extent of renaturation determined by optical techniques. The difference between the results of these two methods could be ascribed to the fact that the viscosity of solutions of partially renaturated gelatin is given not only by the fraction of monomer units in the helical conformation but also by the average length of created helices.