The kinetics and mechanism of acrylonitrile polymerization initiated by a redox pair [potassium chromate (K2CrO4) and sodium arsenite (NaAsO2)] were studied. The overall rate of polymerization was proportional to root[K2CrO4] x [NaASO(2)], and the energy of activation was approximately 10.5 kJ/mol. Polyacrylonitrile was recovered as a coagulum in the medium. The formation of polyacrylonitrile was confirmed with Fourier transform infrared and H-1-NMR analyses. Scanning electron microscopy analysis of the polymer revealed the formation of aggregates of polymer particles (3-67 nm). Thermogravimetric studies indicated 50% weight loss at 400degreesC, and dynamic thermal analysis scan studies revealed an exothermic peak at 507degreesC due to massive oxidative thermal degradation of the polyacrylonitrile backbone. (C) 2005 Wiley Periodicals, inc.