Abstract: | Poly (imide–benzimidazole)/polyhedral oligomeric silsesquioxane (POSS), nanocomposites were prepared by the reaction of the heterocyclic diamine monomer 2,2‐(1,2‐phenylene)‐bis(5‐aminobenzimidazole), octa(aminophenyl)silsesquioxane(OAPS), and benzophenonetetra carboxylic dianhydride (BTDA). The structure of the prepared monomers was confirmed by FTIR and NMR (29Si, 1H, and 13C) spectral studies. The thermal stability behavior of the poly (imide–benzimidazole) and poly (imide–benzimidazole)–POSS nanocomposite films were studied by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). Dynamic mechanical analysis shows that the glass transition temperatures of the polyhedral oligomeric silsesquioxane (POSS) containing poly (imide–benzimidazole) nanocomposites are higher than that of the corresponding neat poly (imide–benzimidazole) systems. Decrease in the dielectric constant was observed with an increase in the determined amount of amino‐functionalized POSS in the poly (imide–benzimidazole) matrix. Further, the morphological studies were carried out by X‐ray diffraction and transmission electron microscopy. POLYM. COMPOS., 34:825–833, 2013. © 2013 Society of Plastics Engineers |