Synthesis of polyacrylonitrile (PAN) catalyzed by Ni(II)/glycine chelate complex through emulsion polymerization initiated by monopersulphate

A radical polymer of acrylonitrile (AN) was prepared using a non-convention al complex initiating system Ni(II)/Glycine/KHSO5 in the absence of an adde d emulsifier. The polymerization reaction was also carried out in the prese nce of various divalent transition metal salts, certain amino acids and the ir chelate complexes in atmospheric oxygen. The metal salts and amino acids with free amino and carboxyl groups have a retarding effect on the polymer ization reaction while their chelate complexes have catalytic effect. From among the data, NiCl2/glycine chelate complex was chosen for detailed kinet ic study of acrylonitrile polymerization. The stirring of solution produces dispersion of the insoluble monomer in the continuous phase. The rate of p olymerization (R-p) was studied for varying concentration of monomer, initi ator, glycine, NiCl2 and solvents over a temperature range of 40-70 degrees C. The polymers were characterized by molecular weight determination by GP C and viscosity methods. The overall activation energy was computed to be 5 .35 kcal mol(-1). From kinetic and spectrophotometric study, the mechanism of KHSO5 decomposition by Ni(II)/glycine complex and initiation of polymeri zation was suggested.