Development of Conductive Elastomer Foams by in Situ Copolymerization of Pyrrole and N-Methylpyrrole

Abstract

This chapter presents the development of conductive elastomer foams by in situ copolymerization of pyrrole and N-methylpyrrole. A process was developed for producing conductive elastomeric foams by polymerizing conductive polypyrrole (PPy) or copolymers of pyrrole and N-methylpyrrole in the cell walls and struts of a preformed polyurethane foam. The process consisted of first diffusing an oxidant into the dense polymer phase of a solvent-swollen foam and then diffusing a vapor of pyrrole and N-methylpyrrole into the dried foam. An in situ chemical oxidative polymerization of conductive polymer or copolymer occurred where the oxidant was present. Because the conductive polymer was confined to the dense polymer phase, conductivity of the foam composites was achieved at relatively low concentrations of the conductive polymer concentration: ca. 5 wt%. The conductivity of the composite foam was reproducibly controlled between 10-7 and 10-1 S/cm by varying either the amount of oxidant used, which controls the amount of conductive polymer produced, or the copolymer composition. Preliminary experiments using ferric tosylate as the oxidant and dopant suggested that l–2 orders of magnitude greater conductivity could be attained at an equivalent PPy concentration compared with those using FeCl3.