A novel clay/waterborne polyurethane (WPU) nanocomposite was synthesized from polyurethane and organoclay. The clay was organically modified with a swelling agent, namely, 1,12-diaminododecane. The nanocomposite was characterized using Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). The d-spacing of clay was determined by X-ray diffraction (XRD) and confirmed by transmission electron microscopy (TEM). XRD and TEM analyses indicated that clay retains a layer structure in the clay/waterborne polyurethane (WPU) nanocomposite. Consequently, these materials are an intercalated nanocomposite with a d-spacing of around 4 to 5 nm. FT-IR revealed that adding clay does not affect the synthesis of the waterborne polyurethane. GPC results indicated that molecular weight decreased as the clay content increased. The thermal properties of the nanocomposite were examined using a thermogravimetric analyzer (TGA). Results showed that adding clay increased the temperature of thermal degradation by 15degreesC. (C) 2005 Springer Science + Business Media, Inc.