The supermolecular structures and structural relaxation of the waste rubber-urethane composites are discussed on the basis of results of calorimetric measurements and mechanical spectroscopy. The results give a broader understanding of the relationship between processing history and morphology in the resultant engineering products. The effect of different kinds of urethane prepolymer on the thermomechanical properties of commercial composite products is presented. The idea of reaction between rubber granulate and urethane prepolymer is under consideration. The shear and tensile modes were applied to better explore relaxations that occur in rubber grains and in an interphase area created by the urethane agents. The rubber waste management problem was taken into account also. (C) 2004 Wiley Periodicals, Inc.