Dissipation in the hagedorn early universe

The viscosity coefficients of the Hagedorn hadronic matter are obtained by solving the Boltzmann kinetic equation in the relaxation-time approximation. The upper limit for the increase of entropy per baryonic charge was found to be < 10$^{-4}$ in the "hadron era" of the Friedman universe and the model behaves almost like dust-filled models. There is no anisotropy damping in the Bianchi type I universe but a substantial growth of entropy is possible in that era when anisotropy has an extremely high value.