SYNTHESIS OF POLY(1-AMINONAPHTHALENE) AND POLY(1-AMINOANTHRACENE) BY CHEMICAL OXIDATIVE POLYMERIZATION AND CHARACTERIZATION OF THE POLYMERS

Poly(1-aminonaphthalene) and poly(1-aminoanthracene) have been synthesized in high yields (90-96%) by chemical oxidative polymerization of 1-aminonaphthalene and 1-aminoanthracene using H2O2 in the presence of Fe catalyst. The oxidative polymerization of 1-aminonaphthalene and 1-aminoanthracene proceeds via successive coupling that gives the polymer structure similar to polyaniline. The polymers are brown powders and soluble in dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), H2SO4, and HCOOH. The obtained poly(1-aminonaphthalene) and poly(1-aminoanthracene) show electrical conductivities of 1.7 X 10(-6) and 1.6 x 10(-4) S cm-1, respectively, which increase to 3.8 X 10(-4) 1.5 X 10(-3) S cm-1 on doping with HCl or I2. Light scattering measurement of the polymers in NMP shows a large degree of depolarization (rho(v) = 0.33), indicating that the polymers have a linear and stiff structure. The number-average molecular weights (M(n)) of poly(1-aminonaphthalene) and poly(1-aminoanthracene) obtained are determined as 4300 and 4500, respectively, with narrow molecular weight distribution by gel permeation chromatography (vs polystyrene). The weight-average molecular weight (M(w)) of poly(1-aminoanthracene) determined by the light scattering method is 7000. H-1 NMR spectra of PNA and PAA in DMSO-d6 give rise to the absorption of the NH hydrogen in the region of delta 5-6 ppm, and the NH hydrogen of PNA is exchangeable with the water hydrogen contained in DMSO-d6 on the NMR time scale with an activation energy of 27 kJ mol-1. PNA and PAA do not show a distinct absorption peak in the visible region.