Bisphenol A epoxy diacrylate (EA)/clay nanocomposites were prepared by UV-curing from a series of styrene based polymerically-modified clays and EA resin. Effects of the chemical structure of the polymeric surfactants on the morphology and tensile properties of nanocomposites have been explored. X-ray diffraction and transmission electron microscopy experimental results indicated that surfactants having hydroxyl or amino group show better dispersion and some of the clay platelets were fully exfoliated. However, the composites formed from pristine clay and other polymerically-modified clays without hydroxyl or amino groups typically contained both intercalated tactoids and few collapsed clay particles with, if any, exfoliated platelets. The tensile strength and the elongation at break of composites were greatly improved, where the organoclays dispersed well. Thermo gravimetric analysis and differential scanning calorimeter were carried out to examine the thermal properties of the composites. The results showed that the loading of polymerically-modified clays enhanced the thermal stability of EA/clay composites, and depressed the T-g of composites. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 1278-1283, 2010