A bifunctional reactive surfactant containing a polymerizable methacrylate group and a benzophenone group, [2-(methacryloyloxy)ethyl](4-benzoylbenzyl)dimethylammonium bromide (MDAB), was synthesized to modify montmorillortite (MMT) for the preparation of nanocomposites via photoinduced polymerization. Fourier transform infrared, thermogravimetric analysis, and X-ray diffraction results indicated that MDAB-modified MMT was obtained and had intercalated structures. The morphology of the ultraviolet-cured bisphenol A epoxy diacrylate/MMT nanocomposites prepared from the organically modified MMTs was studied with X-ray diffraction and transmission electron microscopy, and the results showed an intercalated structure with partial exfoliation for all the samples. Experimental results from thermogravimetric analysis, differential scanning calorimetry, and mechanical property testing also indicated that the thermal and mechanical properties of the ultraviolet-cured nanocomposites were significantly enhanced by the presence of this bifunctional, reactive, organically modified MMT. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 813-818, 2009