This paper reports on the characterization techniques performed to evaluate the suitability of three different samples of a polyaniline (PANI) complex (PANIPOL(TM)) for the production of composites exhibiting a phase separated morphology with continuous elongated structures of PANI embedded in the bulk of an insulating polymer matrix by following an in-situ deformation process. The characterization techniques included rheometry, differential scanning calorimetry and thermogravimetry. In addition, X-ray diffraction, gravimetry, infrared spectroscopy, conductivity measurements, and optical and scanning electron microscopy were used to fully characterize the samples. The thermal limitations and stability of the samples were determined. At the same time, their flow properties in the molten state under different levels of shear were also analysed. The experimental results assisted in the identification of the samples' components and revealed that the PANI particles were 7 mum in diameter or smaller. (C) 2004 Kluwer Academic Publishers.