A vermiculite (VMT) dispersion in water was blended with aqueous poly(vinyl alcohol) (PVA). The properties of the PVA-VMT nanocomposites greatly depended on the preparation procedure because of the chemical reactions and physical interactions involved. The samples were prepared in two steps to investigate the properties of the PVA-VMT nanocomposites. The VMT was first pretreated and delaminated with hydrochloric acid. The delaminated VMT was then added to the PVA solution with various mixing times. The structure and properties of the films were investigated. From X-ray diffraction and transmission electron microscopy, the VMT layers were found to be well dispersed individually in the PVA-VMT blends. The effect of the VMT content on the thermal behavior of the PVA-VMT blends was also studied with differential scanning calorimetry. (C) 2003 Wiley Periodicals, Inc.