EFFECT OF MICELLAR COMPLEXATION OF BISULFITE ON POLYMERIZATION OF METHYL ACRYLATE

In previous paper, the author has reported the catalytic role of a cationic detergent, cetyltrimethylammonium bromide (CTAB) on the polymerization of acrylamide catalyzed by bisulfite ion. He interpreted the significant increases in the polymerization rate and the polymer molecular weight in the presence of CTAB to be due to complex formation between bisulfite and CTAB. In this paper, some unique features of micellar catalysis are discussed in terms of micellar (or polycationic) complexation of bisulfite, monomer selectivity, and bisulfite redox mechanisms. Experimental data are presented which show that complexes are formed between bisulfite and cationics and that these complexes, in the presence of oxygen, generate species that are capable of initiating the polymerization of methyl acrylate or acrylonitrile. An analysis of oxidation and polymerization rate data indicates that the successful polymerization of methyl acrylate in a bisulfite system requires micellar solubilization of the monomer to allow initiation by the free radicals generated by bisulfite complex oxidation which is facilitated by reducing the competitive ionic addition of bisulfite to the monomer.