AQUEOUS POLYMERIZATION OF METHYL-METHACRYLATE AND CHARACTERIZATION OFTHE OBTAINED POLYMERS IN THE PRESENCE OF N,N-DIOXALYL P-AMINO BENZOYLN,N-DIOXALYL UREA AND ITS FE(II) AND FE(III) COMPLEXES

The emulsifier-free emulsion polymerization of methyl methacrylate (MM A) was studied using sodium bisulfite as initiator in the absence and presence of a new organic chelating agent, N,N-dioxalyl p-amino benzoy l N,N-dioxalyl urea, and its iron (II) and (III) complexes. The organi c ligand with free carboxyl groups has a retarding effect on the polym erization reaction while its iron complexes have a catalytic effect. T he mechanisms of the catalytic effect of iron complexes or the inhibit ion mechanism of the organic ligand are discussed. The effect of pH va lues on the polymerization processes was also investigated. The appare nt energy of activation was found to be 4.99 x 10(4) J/mol, 6.38 x 10( 4) J/mol, 4.46 x 10(4) J/mol, and 3.72 x 10(4) J/mol in the absence an d in the presence of 0.5 g of ligand and 0.1 g of its Fe (II) and (III ) complexes, respectively. (C) 1994 John Wiley & Sons, Inc.