Oxidative copolymers of aniline with o-toluidine: Their structure and thermal properties

Chemically oxidative polymerization of aniline and o-toluidine (OT) with 6 molar ratios was performed using ammonium persulfate as an oxidant in a HCl medium at -18 degreesC. It was observed that the copolymers were not regul arly dependent on the monomer ratio for yield and intrinsic viscosity. The resulting copolymers were characterized by Fourier transform IR spectroscop y, H-1-NMR spectroscopy, wide-angle X-ray diffraction, differential scannin g calorimetry, and several thermogravimetry methods. The results showed tha t the actual content of the OT unit in the copolymers was much higher than the feed content of the OT unit. Given the same reaction conditions, o-tolu idine showed a larger tendency toward homopolymerization rather than toward copolymerization with aniline. The copolymers were amorphous and exhibited thermal decomposition temperatures higher than 440 degreesC and a char yie ld larger than 39 wt % at 900 degreesC in nitrogen. The activation energy o f thermal decomposition for the copolymers was 40-244 kJ/mol in nitrogen an d 32 kJ/mol in air, respectively. (C) 2001 John Wiley & Sons, Inc.