The effect of phosphonium salt adapted Turkish bentonite, which was synthesized through the reaction of between allylphosphonium bromide and bentonite, was studied on the properties of polyurethane acrylate based materials such as physical,mechanical and thermal properties, especially flame retardancy. The effects of phosphonium adapted bentonite content andneat bentonite in polymer matrix studied as well. Chemical and morphological structures of the composites were characterizedby FTIR, XRD and SEM analysis. XRD and SEM images confirmed which the adapted bentonite was exfoliated in thepolymer structure due to its good dispersion. Moreover, thermal, flame retardant, mechanical and optical properties ofurethane acrylate based materials results showed that the materials containing phosphonium adapted bentonite pointed outhigher modulus, better thermal properties due to increasing the crosslinking density as compared with the UV-cured materialswhich contained pure bentonite. In addition to this, the existed of the phosphonium compound advanced the flame retardancyof the urethane acrylate based materials.