Polystyrene (PS)/ZnAl layered double-hydroxide (LDH) nanocomposites were synthesized via in situ emulsion and suspension polymerization in the presence of N-lauroyl-glutamate surfactant and long-chain spacer and characterized with elemental analysis, Fourier transform infrared spectrum, X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis. The XRD and TEM results demonstrate that the exfoliated ZnAl-LDH layers were well dispersed at molecular level in the PS matrix. The completely exfoliated PS/LDH nanocomposites were obtained even at the 20 and 10 wt % LDH loadings prepared by emulsion polymerization and suspension polymerization, respectively. The PS/LDH nanocomposites with a suitable amount of LDH showed apparently enhanced thermal stability. When the 50% weight loss was selected as a comparison point, the decomposition temperature of the exfoliated PS/LDH sample prepared by emulsion polymerization with a 5 wt % LDH loading was about 28 degrees C higher than that of pure PS. (c) 2006 Wiley Periodicals, Inc.