Polystyrene-clay nanocomposites have been prepared using a bulk polymerizat
ion technique. Three new "onium" salts have been used to prepare the nanoco
mposites, two are functionalized ammonium salts while the third is a phosph
onium salt. By TGA/FTIR, both ammonium and phosphonium treatments have been
shown to degrade by a Hofmann elimination mechanism at elevated temperatur
es. TGA/FTIR showed that the phosphonium treatment is the most thermally st
able treatment when compared to the two ammonium salts. The nanocomposites
were characterized by X-ray diffraction, transmission electron microscopy,
strength and elongation at break, as a measure of the mechanical properties
, thermogravimetric analysis, and cone calorimetry. The onset temperature o
f the degradation is increased by about 50 degreesC and the peak heat relea
se rate is reduced by 27-58%, depending upon the amount of clay that is pre
sent. The mass loss rates are also significantly reduced in the presence of
the clay.