A ring-like structures of carbon nanotubes formation conditions at polymer composites matrixes were considered. On the base of fractal analyses the methods of evaluation of parameter above structures have been proposed. A role of structure formation is considered together with mechanical propecties of composites filled with carbon nano-tubes. It has been shown sharp reduction of interfacial adhesion level at ring-like structures radius decreasing. This parameter enhancement results to simultaneous elasticity modulus increase and melt viscosity reduction of composites.