In this study, we modified silica nanoparticles with (3-trimethoxysilylpropyl)diethylenetriamine (TPDT) silane coupling agent which has one primary and two secondary amino groups in a molecule, to introduce amino groups on the silica surface. After modification of silica, we used acrylate group containing 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to introduce free radical polymerizable methacrylate groups by aza-Michael addition reaction. We used fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), liquid state 1H and 13C nuclear magnetic resonance spectroscopy (NMR) and solid state cross polarization magic angle spinning (CP/MAS) 13C and 29Si NMR to investigate effects of various reaction conditions on the degree of reaction between N-H groups of TPDT modified silica surface and acrylate groups of AHM monomer. We found increased amount of methacrylate group introduction with increase of mole ratio of AHM to N-H groups of TPDT modified silica by aza-Michael addition reaction. We also found about 48% of N-H groups on the TPED modified silica surface reacted with acrylate groups of AHM compared to about 83% of reaction between N-H groups of pure TPDT with acrylate groups of pure AHM at same reaction conditions. This lower degree of aza-Michael addition reaction between N-H groups on the solid TPDT modified silica with acrylate groups of liquid AHM than N-H groups of pure liquid TPDT with acrylate groups of pure liquid AHM may be caused by lower mobility of grafted N-H groups of TPDT moiety on solid silica particle and higher steric hindrance caused by solid silica particles. Using TPDT modified silica nanoparticles as fillers, we synthesized nanocomposites by UV-curing with conventional photo-curable acrylic resins. We will present influence of the filler contents on their mechanical properties.