Synthesis and characterization of differently substituted phenyl hepta isobutyl‐polyhedral oligomeric silsesquioxane/polystyrene nanocomposites

Variously substituted polyhedral oligomeric silsesquioxanes (POSSs)/polystyrene (PS) nanocomposites of general formula R 7 R′(SiO 1.5 ) 8 /PS (where R = isobutyl and R′ = 4‐methoxyphenyl, 4‐methylphenyl, 3,5‐dimethylphenyl, 4‐fluorophenyl, 2,4‐difluorophenyl, 4‐chlorophenyl) were prepared by in situ polymerization of styrene in the presence of 5% w/w of POSS. The actual filler concentration in the obtained nanocomposites was checked by 1 H NMR spectroscopy. Scanning electron microscopy and FTIR spectroscopy evidenced the presence of filler‐polymer interactions. Inherent viscosity ( η inh ) determinations indicated that the average molar mass of polymer in halogenated derivatives was lower than neat PS, and were in agreement with calorimetric glass transition temperature ( T g ) measurements. Finally, a comparative study concerning the thermal stability of synthesized nanocomposites was carried out in both inert (flowing nitrogen) and oxidative (static air) atmospheres into a thermobalance, in the scanning mode, at 10°C min −1 , and the temperatures at 5% mass loss ( T 5% ), of various compounds were determined. The results were discussed and interpreted. POLYM. COMPOS., 35:151–157, 2014. © 2013 Society of Plastics Engineers