Synthesis and characterization of poly(aniline-co-xylidine)s

Copolymers were synthesized by oxidative polymerization of aniline and 2,3- xylidine (XY) at five monomer ratios using ammonium persulfate as an oxidan t in HCl medium. The yield and intrinsic viscosity of the copolymers were s ignificantly dependent on monomer ratio. The copolymers were characterized by Fourier transform Infrared spectroscopy, H-1 nuclear magnetic resonance spectroscopy, wide-angle X-ray diffraction, DSC, and thermogravimetry. The results showed that the actual content of XY unit in the copolymers is much higher than feed XY unit content but 2,3-xylidine cannot homopolymerize un der the same condition. The copolymers are amorphous and exhibit thermal de composition temperature higher than 395 degrees C, char yield larger than 2 2 wt% at 900 degrees C in nitrogen. The activation energy of thermal decomp osition for the copolymers decreased monotonically from 124 kJ mol(-1) to 4 2 kJ mol(-1) with increasing XY unit content from 10 to 90%.