COMPOSITES OF POLYPYRROLE AND CARBON-BLACK .3. CHEMICAL SYNTHESIS ANDCHARACTERIZATION

A new class of molecular composites of carbon black and an electronica lly conducting polymer, namely polypyrrole, has been synthesized by ch emically polymerizing pyrrole in an aqueous dispersion of carbon black . The carbon black content of these composites can be varied from simi lar to 5% to similar to 85% (by weight). The surface area and density of these composites were compared to corresponding mixtures of carbon black and polypyrrole. The influence of carbon black on the efficiency of polymerization of pyrrole is described. The effect of carbon black content on the electronic conductivity of the composite has been mapp ed, and compared with the corresponding behavior of a mixture of carbo n black and polyvinylchloride. The influence of the parent black chara cteristics (porosity, void volume, surface area) on the electronic con ductivity of the resultant composite has been probed by comparing the behavior of composites derived from six commercial and experimental bl acks. The temperature dependence of the composites has been studied as a function of the carbon black content. Finally, the application of t hese new materials is an environmental remediation scenario is demonst rated for Cr(VI) as a model pollutant.