Thermal preparation of conducting polyaniline/polypropylene composites and studies on their structure and specific electric conductivity

Specific conductivity (Figs. 4, 5) and structure (Figs. 2, 3; Table 3) of conducting composites based on the high-crystalline dielectric polypropylene (PP) matrix and containing phenylphosphonyl acid-doped polyaniline (PPA) and lauryl gallate as compatibilizer, were studied in relation to their composition, morphology and structure as characterized by microscopy and X-ray techniques (WAXS) (Table 1-3). The composites were prepared in the molten phase (180 degreesC); optimum thermal process conditions were established by differential scanning calorimetry. PPA, i.e., the protonating agent, was found to be required in excess, although a limiting proportion was established above which specific conductivity no longer increased (Fig. 4). In attempts at explaining the formation of the conducting phase, expected to occur via a rising separation of the components in the matrix (Fig. 5), a correlation was established between the conductivity and the average size of composite crystallites in the PP matrix (Table 3).