Hybrid latex particles with core-shell nanostructure were prepared via miniemulsion polymerization. Copolymer of (methyl methacrylate-butyl acrylate-methacrylic acid) was formed the shell on the surface of modified SiO2 nanoparticles as the core. In order to create compatibility between inorganic and polymeric phases, modification of SiO2 nanoparticles was performed with methylene diphenyl diisocyanate and 2-hydroxy ethyl methacrylate with an optimized procedure for the first time, and then miniemulsion polymerization was carried out in the presence of modified SiO2. The products of each step were characterized. The results of DLS, TEM and SEM analyses proved the formation of encapsulated hybrid latex particles. DLS and SEM data revealed that the sizes of nanocomposite particles vary between 60 and 120 nm for 0-10 wt% of the modified SiO2 nanoparticles. Thermal stability and thermomechanical properties of the obtained nanocomposite films were studied by TGA and DMTA, respectively. It was found that the best improvement of properties is achieved for nanocomposite containing 7 wt% modified silica nanoparticles. (C) 2016 Elsevier Ltd. All rights reserved.