Synthesis and characterization of o-phenylenediamine and xylidine copolymers

Chemically oxidative polymerization of o-phenylenediamine and 2,3-xylidine (XY) with three molar ratios was performed by using ammonium persulfate as an oxidant in boiling glacial acetic acid. The polymerization yield decreas es significantly but the intrinsic viscosity of the polymers remains almost constant with increasing feed content of XY monomer. The resulting polymer s were characterized by H-1-nuclear magnetic resonance. UV-vis and Fourier transform infrared spectroscopies, wide-angle X-ray diffraction, and thermo gravimetry methods. The results showed that the polymers are amorphous and exhibit a thermal decomposition temperature higher than 500 degreesC. the m aximum weight-loss rate lower than 5%/min in nitrogen and air. Char yield a t 700 degreesC for the polymers is larger than 32 wt% in nitrogen but nearl y zero in air. The activation energy, order, and frequency factor of therma l decomposition for the copolymers were 43-53 kJ/mol. 0.4-1.3, and 13.5-181 .3 min(-1) in nitrogen and air. (C) 2001 Elsevier Science Ltd. All rights r eserved.