O-chloranil initiated polymerization of pyrrole in presence of N-vinylcarbazole and some properties of the polymer

Abstract

The polymerization of a mixture of N-vinylcarbazole (NVC) and pyrrole (PY) by O-chloranil in toluene yields an insoluble black polymer P(PY-NVC) which exhibits properties distinct from PPY or PNVC. The inclusion of either monomer moieties in P(PY-NVC) has been endorsed by IR spectroscopy. Kinetics of PPY-OCA homopolymerization and of PY-NVC-OCA copolymerization have been elucidated. TGA reveals the stability order as PNVC > P(PY-NVC) > PPY. DSC analyses reveal a single inflection for P(PY-NVC) around (198–202 °C) and for PPY and PNVC around 180 and 228 °C respectively. PPY exhibits a high dielectric constant (~ 350) at 10 Hz while P(PY-NVC) or PNVC exhibit values (~ 11) and (~5) respectively—the dielectric constant falling consistently with increasing frequency as does the dielectric loss parameter also—suggesting interfacial polarization. P(PY-NVC) shows maximum d.c. conductivity of 3.5 x 10 −6ohm −1cm −1depending on [PY]/[NVC] mole ratio. For PPY, the conductivity is in the range (10 −3–10 −5)ohm −1cm −1 and the conductivity in all these polymers is dependent on the concentrations of the monomers, O-CA and runs parallel to the trend in conversion.