  The research is important for a molecular theory of liquid and has a wide
interest as an example solving the problem when dynamic parameters of systems
can be indirectly connected with their equilibrium properties. In frameworks of
the reptation model the power law with the 3.5-exponent for the melt viscosity
relation to the molecular weight of flexible-chain polymer is obtained. In
order to find the exponent close to experimental values it should be taken into
account the rotation vibration precession motion of chain ends with respect to
the polymer melt flow direction.
