In this study, polymer clay nanocomposites (PCNs) composed of poly(vinyl alcohol)s (PVAs), poly(2-acrylamido-2-methyl-1-propane sulfonic acid), and fullers earth were prepared by the effective dispersal of inorganic nanoclays in the organic PVA matrix via in situ free-radical polymerization with potassium persulfate as an initiator and N,N-methylene bisacrylamide as a crosslinker. The monomer, 2-acrylamido-2-methyl-1-propane sulfonic acid, was grafted onto the PVA backbone, and at the same time, fullers earth layers were intercalated and exfoliated into the grafted copolymer, especially at a low or moderate loading of the fullers earth. The synthesized PCN materials were characterized by Fourier transform infrared spectroscopy and wide-angle X-ray diffraction techniques. The morphological features of the synthesized materials were studied by scanning electron microscopy; this revealed that the swelling ratio of this nanocomposite increased with increasing fullers earth content. The X-ray diffraction results indicated that the fullers earth was exfoliated in the nanocomposite matrix, and its introduction into the polymer matrix enhanced the percentage crystallinity of the polymer. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 1230-1239, 2010