Blends of poly (methyl methacrylate) (PMMA)/Polypyrrole (PPy) were synthesized by emulsion polymerization of methyl methacrylate (MMA) and in situ oxidative polymerization of pyrrole (Py) with varying concentrations of Py and ferric chloride. The influence of the varying concentrations of ferric chloride, Py, and MMA on the morphological, spectral, thermal, and conductance characteristics of the blends were investigated. Hydrogen bonding between PPy and PMMA was inferred from FUR studies that indicate blend formation. DSC and TGA analysis of the blends were done. A curious thermal behavior was observed that the blends lost their elasticity and flexibility on heating and turned into rigid and brittle material. DSC thermogram did not show glass transition temperature, indicating molecular and chain reorganization on heating. We have therefore called these blends pseudothermoset. The physicomechanical characteristics of the films of the blends were found to deteriorate with the increased ratio of ferric chloride in the blend, causing a decrease in the conductivity. Maximum conductivity (percolation threshold) was found at 14 wt % loading of Py in the blend (1.6 x 10(-3) S cm(-1)), which was further correlated with the morphology of the films. (C) 2004 Wiley Periodicals, Inc.