Phase transitions in fiber materials

We propose a theory for the phase transitions in materials made from natural fibers. At heating, the theory predicts structural phase transitions of the first order. The normalized thermodynamical characteristics show the universal behavior of a scaling law, which is unusual for first order phase transitions The scaling exponents depend only on the exponent of the energy of small-angle interaction between fiber segments. We consider here some specific fibers like collagen which ``melt'' (denaturate) at higher temperature and we found explicit expressions for the thermodynamics characteristics, which can be verified by experiment.