Synthesis, characterization and ac-conductivity measurements of polyaniline based composites with fly-ash and clinker

We report the synthesis, characterization and ac-conductivity (σ_ac) results of some polyaniline (PAni) based composites. These materials were synthesized through incorporation of various fractions (20 to 60% by weight) of insulating fly-ash (FA) or clinker (Ck) in semiconducting PAni host. The synthesis was carried out for two different polymerization times (tp) of 8 and 14 h, at 5 °C through oxidative polymerization, using ammonium-persulfate as initiator. Characterization of samples was done using x-ray diffraction (XRD), electron microscopy (SEM), and infrared spectroscopy (FTIR). Electrical conductivity analysis showed that synthesis for longer tp produced more conducting samples because it allowed the formation of longer and thicker polymer chains. In general, σ_ac of the composites further increased with the fraction of FA or Ck, at least up to their maximum concentration studied in this work. Uniformly dispersed particles of FA or Ck apparently occupied the vacant spaces within the intertwined bundles of several polymer chains in such a way that continuity of the latter was not broken. Consequently, their presence pushed the bundles, and thus the individual chains, closer to each other, making the polymer parts more compact. The increased compactness of these conductive parts facilitated better mobility of charge carriers and therefore, the electrical conductivity increased.