Rigid polyurethane-clay nanocomposite foams considered in this work are made with different clay types and for different clay concentrations. The densities of the foams are in the range of 140-160 kg/m(3) with possible application as structural materials and for underwater buoyancyrelated uses. Wide-angle X-ray diffraction and transmission electron microscopy studies confirm the formation of nanocomposites. The compressive modulus and the storage modulus of the foams increase and the mean cell size decreases with addition of clay. However, the hydraulic resistance of the nanocomposite foams, a measure of the strength of the foam lamellae, is lower than that of the foams without clay. (c) 2006 Wiley Periodicals, Inc.