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Keywords:

  • polystyrene;
  • organoclay;
  • nanocomposites;
  • solvent blending;
  • thermal stability

Abstract

In this study, intercalated/exfoliated polystyrene (PS)/organoclay nanocomposites containing different concentration of organoclay have been prepared via solvent blending method, using xylene as a solvent. Some resulting intercalated nanocomposites are transformed to exfoliated nanocomposites by increasing the refluxing temperature or refluxing time for a constant organoclay loading. The X-ray diffraction results reveal the formation of intercalation/exfoliation of organoclay in the PS matrix. The Fourier transform infrared spectroscopy and transmission electron microscopy results confirm the presence of nanomaterial in PS/organoclay nanocomposites. Completely exfoliated nanocomposites are achieved by decreasing the content of organoclay and elongating the refluxing temperature or refluxing time. Thermogravimetric analysis data show that the PS/organoclay nanocomposites have significant enhanced thermal stability. When 50% weight loss is selected as a point of comparison, the thermal decomposition temperature (Td) of the exfoliated PS/organoclay nanocomposites with 7 wt % of organoclay is 17°C higher than that of pure PS. Thermal decomposition temperature of exfoliated PS/organoclay nanocomposites is better than that of intercalated nanocomposites for a constant organoclay loading. The glass transition temperature (Tg) of PS/organoclay nanocomposites is ∼ 7.1–8.6°C higher than that of pure PS. The thermal degradation activation energy of the nanocomposites is determined via Coats-Redfern method. The improvement of thermal stability of nanocomposites is also confirmed by increasing the activation energies (Ea) and the integral procedural decomposition temperature. Criado method is finally used to determine the degradation reaction mechanism of various samples. The water uptake capacity of PS/organoclay nanocomposites is negligible when compared with pure PS. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011