AQUEOUS POLYMERIZATION OF ACRYLAMIDE INITIATED BY CERIUM(IV)-ETHYLENEDIAMINE TETRAACETIC ACID REDOX SYSTEM

Ethylenediamine tetraacetic acid (EDTA) terminated polyacrylamide was obtained by using the EDTA-cerium(IV) ammonium nitrate [Ce(IV)] redox initiator in the aqueous polymerization of acrylamide. The polymerization behaviors as a function of the concentration of Ce(IV), EDTA, and acrylamide as well as temperature were studied. The consumption rate of cerium(IV) depends a first-order reaction on the ceric ion concentration ([Ce(IV)]). The complex formation constant (K) and disproportionation constant (k(d)) of Ce(IV)-EDTA chelated complex are 1.67 X 10(4) and 3.77 X 10(-3), respectively. The rate dependences of polymerization on monomer concentration and EDTA concentration both follow a second-order reaction in the run of initial monomer concentration ([M]i) equal to 0.2 mol dm-3. The number average molecular weight increases linearly with the ratio of [M]i/[Ce(IV)]i. The mechanism and kinetics for the polymerization was proposed. The kinetic parameters involved were determined.