Synthesis, characterization, and properties of a polyhedral oligomeric octadiphenylsulfonylsilsesquioxane

A novel polyhedral oligomeric octadiphenylsulfonylsilsesquioxane (ODPSS) was synthesized from octaphenylsilsesquioxane and benzenesulfonyl chloride via a Friedel-Crafts reaction with a high yield. ODPSS was identified by Fourier transform infrared spectroscopy, ¹H-NMR, ¹³C-NMR, ²⁹Si-NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), wide-angle X-ray diffraction, and elemental analysis to be a kind of polyhedral oligomeric silsesquioxane of a T ₈R₈ structure. ODPSS exhibited superior thermal stability according to thermogravimetric analysis. Its initial thermal decomposition temperature (T_onset) was at 491°C in air and 515°C in nitrogen. Thermal and mechanical properties of epoxy resin (EP) composites with ODPSS added were studied by differential scanning calorimetry and tensile testing. The results show that the incorporation of ODPSS at a low loading content not only improved the glass-transition temperature of the EP composites but also enhanced their tensile strength.