Series of composites consisting of polypyrrole/montmorillonite nanocomposites in the matrix of Nylon6 has been synthesized and characterized in this work. The composites were processable, so that test samples were prepared by compression-molding of the materials for electrical property measurements. Intercalated structures were confirmed by wide-angle X-ray diffraction and TEM studies for PPy/MMT nanocomposites. A two-phase structure was determined for the fused samples consisting of two separated N6 and PPy phases by using scanning electron microscopy analyses. A conductivity threshold was measured at 15%(w/w) loading level of PPy in the composites. Electrical resistivity-temperature behavior of the samples was investigated and a resistivity peak was observed at 100 degrees C for the samples. It was proved that the glass transition temperature of PPy around 100 degrees C should be the responsible factor for the observed resistivity peak, as studied by thermogravimetic analysis and differential scanning calorimetry thermal methods. (c) 2007 Wiley Periodicals, Inc.