Dickite particles were exfoliated by the thermal decomposition of molecular urea in the interlayer of dickite. The exfoliated dickite (ED) was composed with linear low-density polyethylene (LLDPE) to prepare a novel LLDPE/dickite nanocomposite (LDN-5). X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to evaluate the exfoliation effect. FTIR spectra showed that the inner-surface hydroxyls of dickite decreased because of the sufficient exfoliation of the dickite layers. The 001 diffraction of dickite in the XRD pattern almost disappeared after exfoliation; this indicated the random orientation of dickite platelets. SEM and TEM micrographs confirmed the effective thermal decomposition of the interlamellar molecular urea ED layers, which resulted in smaller particle sizes and better dispersions of dickite in the resulting LLDPE/dickite composite. The microstructure of LDN-5 showed that most of the dickite platelets were exfoliated and homogeneously dispersed in the LLDPE; this led to increases in the anticorrosion properties and thermal stabilities of LDN-5. The results of salt-spray tests illustrated that the corrosion rate of the iron coupon decreased from 23% (LLDPE packing) to 0.4% (LDN-5 packing). Moreover, the thermal degradation temperature corresponding to a mass loss of 10% increased from 330 degrees C (pure LLDPE) to 379 degrees C (LDN5). (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 1736 1743, 2011