Increasing time of ignition for PS-clay nanocomposites filled with [Fe(bpy)3]2+-modified hectorite

While previously reported polystyrene(PS)-clay nanocomposites all show a reduced time of ignition (tig) compared to the neat polymer, we observe a significant longer tig for a clay filler that has been modified with a highly temperature stable inorganic complex cation, trisbipyridine-iron(II) ([Fe(bpy)3]2+). We compare cone data of nanocomposites filled with [Fe(bpy)3]2+- and alkylammonium(C18)-modified synthetic hectorite. While the peak of heat release was reduced to a comparative value (50% and 54% for [Fe(bpy)3]2+- and C18-modified composite, respectively), tig was significantly increased (76 ± 3 s, 84 ± 1 s, and 66 ± 1 s for PS, for [Fe(bpy)3]2+- and C18-modified composite, respectively). Moreover, the total smoke production was also reduced significantly (5017, 4415, and 5127 m2/m2 for PS, for [Fe(bpy)3]2+- and C18-modified composite, respectively). The clay nanocomposites were characterized by powder X-ray diffraction, transmission electron microscopy, and gas permeability measurements.