Magnetite nanoparticles are synthesized by thermal decomposition of Fe(acac)(3) and subsequently coated with a silica shell exploiting a water-in-oil synthetic procedure. The as-produced nanopowder is mixed with a photocurable hyperbranched resin and the polymerization process is studied by means of real-time FTIR (RT-FTIR). Owing to the presence of the silica shell, the photocuring ability of the systems containing core-shell structures is highly improved compared with that of the formulations filled with bare magnetite nanoparticles, allowing the efficient polymerization of a 100 mu m-thick film loaded with an unprecedented 8 vol% of magnetic filler. (c) 2013 Elsevier Ltd. All rights reserved.