The conductivity, thermal, mechanical and electrochemical properties of poly(vinyl chloride)/polypyrrole blends are described in this paper. These blends were prepared by oxidative chemical polymerization of pyrrole, in the vapour phase, in PVC films impregnated with FeCl3. They were characterized by attenuated total reflectance FTi.r. spectra, differential scanning calorimetry and dynamic-mechanical analysis. Infrared reflectance spectra suggested that the polymerization occurs preferentially on the matrix surface producing sandwich-type structures. The mechanical, thermal and conducting behaviour showed a dependence on (1) initial concentration of FeCl3 in the matrix and (2) exposition time to pyrrole vapour. By cyclic voltammetry we observe that blends synthesized by oxidative chemical polymerization show electrochemical properties similar to blends prepared by electrochemical methods. Their conductivity varies from 10(-4) to 10(-1)S cm(-1). Dynamic-mechanical analysis results suggest a certain degree of miscibility among the polymeric components of the blend. Copyright (C) 1996 Elsevier Science Ltd.372351655170