MECHANISM OF THE ELECTROCOPOLYMERIZATION OF STYRENE AND N-(3-CARBOXYPHENYL)MALEIMIDE ONTO GRAPHITE FIBERS IN AQUEOUS-SOLUTION

Electrochemical copolymerization of styrene and N- (3-carboxyphenyl) maleimide was performed in an aqueous sulfuric acid solution using AS-4 graphite fibers as the working electrode. Cyclic voltammetric analysis results suggest radical initiation of polymerization via the reduction of the N- (3 -carboxyphenyl) maleimide and sulfuric acid. Radical chain electrocopolymerization was strongly suggested by the inhibition of chain growth in the presence of hydroquinone and 2,2-diphenylpicrylhydrazyl (DPPH). Compositional analysis of copolymers and reactivity ratios r(s) approximately 0.014 and r(m) approximately 0.041 for styrene and N- (3-carboxyphenyl) maleimide [N- (3-CMI) ], respectively, confirmed a 1 : 1 alternating electrocopolymerization. Kinetic analysis shows a first- and 1/2-order dependence of the rate of chain growth on initial monomer concentration and initiator concentration, respectively. A model incorporating these data is presented.