: In recent years, waterborne polyurethane dispersions as in coatings and adhesives formulations have attracted considerable attention because they are non-toxic, non-?ammable and friendly to environment. Besides environmental management, the ?exibility, low temperature property, high tensile strength, good adhesion and improved rheological property are specific properties of waterborne polyurethanes. However, these materials have some defects such as weak water resistance in the moisture environment due to sensitivity of their hydrophilic ionic bonds, and ester groups to hydrolysis, short shelf life stability, which need to be improved. Also, low heat resistance of these materials is due to a relatively low crystalline melting point or glass transition temperature of hard segments. One of the best ways to solve these problems and improve their properties for different applications are addition of acrylate polymers and inorganic fillers especially Nano-sized layered silicates within poly urethane acrylate matrix. In this work, waterborne poly (urethane acrylate) Nano composites with Polycaprolactone polyol, IPDI, and methyl methacrylate were synthesized by two different methods; Reverse emulsion and semi Inter penetrating Networks. The acrylic to urethane ratio was kept at 15:85 and 30:70 by weight throughout. The chemical formation of dispersions Stability of dispersion, Thermal properties and mechanical properties, were studied by ATR- FTIR spectroscopy, dynamic light scattering and Zeta potential, TGA and Tensile test, respectively. The results showed that stable PUA dispersions have been successfully synthesized but poly (urethane acrylate) dispersion made in semi penetrating networks method by urethane acrylate ratio 70/30% showed better properties.
