In this paper, we synthesized two types of epoxy group containing POSS derivatives: mono and poly Double-Decker Silsesquioxanes (mono DDSQ and poly DDSQ). The performance of epoxy resin with different DDSQ loading ratios was investigated, including curing kinetics, thermal, mechanical and surface properties. Both mono and poly DDSQ significantly improved thermal and mechanical properties of the epoxy thermosets. The mono DDSQ showed more flexible structure and toughened the epoxy resin better, while the branched poly DDSQ exhibited better thermal resistance. In addition, the DDSQ altered surface of the epoxy resin from hydrophilic to hydrophobic. (C) 2017 Elsevier Ltd. All rights reserved.