Halogen-induced chemical copolymerization of pyrrole with N-methylpyrrole

Abstract

Due to their inherent stability under ambient conditions, conductive polyheterocycles has become a topic of great research interest. Simultaneous chemical copolymerization and oxidation of pyrrole and N-methylpyrrole by bromine and iodine has been carried out. The composition of the copolymers can be effectively controlled by varying the monomer feed ratio. From elemental analysis the copolymer composition and the monomer reactivity ratios have been determined. As the copolymer composition changes, the IR absorption spectra show changes in the intensity of certain bands. In bromine-induced polymerization, the electrical conductivity, thermal stability, and bromine content of the copolymer complex decrease with increase in N-methylpyrrole fraction. X-ray photoelectron spectroscopy data suggest that a fixed fraction of bromine is incorporated as covalent bromide in the copolymer complex. When iodine is used, the halogen content do not show substantial differences among the copolymers but the electrical conductivity and thermal stability of the copolymers also decrease with increase in N-methylpyrrole fraction.