[The hydrothermal contraction of collagen fibers as a method of its structure investigation].
The hydrothermal contraction of collagen fibers, that is sharp decrease of the fiber length in the narrow temperature range during their heating in water, is a typical example of phase transition which is analogous to melting. General thermodynamic consideration of the melting of oriented polymer fibers was carried out by Gee (1947) and Flory (1956). Flory derived and equilibrium dependence of force on temperature considering the melted polymer as an ideal rubber. We proposed an experimental method for quantitative investigation of this process including estimation of two critical parameters, which are the critical tension and the critical temperature. The necessary condition for the critical parameters estimation is the prior cross-linking of the fiber. We studied theoretically and by experiment the influence of different factors on these critical parameters. We demonstrated the critical tension of hydrothermal collagen contraction to be an important characteristic making possible the estimation of native collagen structure retaining and molecular orientation's degree. The critical tension value was used do advantage for the collagen structure characteristic in some mammoth fossils skin, in bovine skin in the process of leather manufacture and in artificial collagen fibers. The initial temperature of hydrothermal collagen contraction, what is known as shrinkage temperature using widely for the collagen tannage estimation, was shown to be dependent on the occurrence of non-collagenous sheath on native collagen fibers.
Kukhareva
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D000818:Animals; D002417:Cattle; D004548:Elasticity; D024022:Fibrillar Collagens / Q000737:chemistry*; D005580:Fossils; D006358:Hot Temperature; D051381:Rats; D012867:Skin / Q000737:chemistry; D013816:Thermodynamics; D014867:Water
D024022:Fibrillar Collagens; D014867:Water