Novel PSMA-POSS nanocomposites were prepared, in which N-phenylaminomethyl polyhedral oligomeric silsesquioxane (POSS) was conducted as crosslink agent to incorporate to poly(styrene-co-maleic anhydride) (PSMA). FOSS was introduced by one-step reactive solution blend in amounts of 1-30 Wt%. FTIR measurement evidenced the occurrence of amidation reaction between the anhydride group of PSMA and the secondary amino group of POSS. This reaction turned out to promote FOSS well dispersed in the polymer matrix, and the PSMA-POSS hybrids showed no macro phase separation even if POSS concentration was up to 30 wt%. DSC results showed that the glass transition temperature (T-g) increased to 168 degrees C with the increase of FOSS loading. Dynamic mechanical thermal analysis (DMTA) revealed the storage modulus at high temperature increased with the addition of FOSS due to the formation of a permanent network. Incorporation of FOSS also improved the thermal properties of PSMA-POSS composites. (C) 2012 Elsevier Ltd. All rights reserved.