Application Of Eelectrolysis In Polymerization Of Pam

Polyacrylamide (PAM) is widely used in oil recovery, wastewater treatment, paper industry, mine metallurgy and others.Various synthesis techniques with different redox initiation systems are ripe enough for the chemical polymerization of PAM, and the highest molecular weights of PAM is of the order of magnitude of 10 million. Electrochemical polymerization has generally been used for the preparation of conducting polymeric films on electrode surfaces for their applications in the fields such as electroanalysis and materials, but was rarely adopted for the redox initiation of homogenous polymerizations. Since electro-induced redox has advantages of decreasing the initiator species or their wastages and regulating the initiation and polymerization rates by adjusting the applied potential, it is necessary to investigate the potential application of electrolysis in the homogenous redox polymerization of polymers. In this thesis, two redox initiators, Ce(IV)-oxalic acid system and potassium persulfate system, were used for the polymerization of AM under both electrolytic and nonelectrolytic conditions. The yield and molecular weight of PAM were compared between electrolytic and nonelectrolytic polymerizations.The effects of time and potential, temperature, initator and monomer concentration, different cell designs on the yield and the molecular weight of PAM were investigated. In the presence of Ce(IV)-oxalic acid initiator, we synthesized the poylemrs whose molecular weight reached 3,000,000 by optimizing operation conditions. The products were characterized by IR spectrum. The electrolytic polymerization was performed on a Pt wire working electrode in a two-compartment electrochemical cell. Results indicated that electrolysis with a divided cell shows advantages over nonelectrolysis in increasing the yield as well as the molecular weight, that is, electrolysis can promote not only the chain initiation but also the chain propagation. The key factor to influence the electrocatalytic effects on the polymerization is the ratio of the electrode area and the solution volume besides the electrolytic potential.In the case of potassium persulfate initiator, electrolysis showed, to some extent, positive effect on the molecular weight of PAM, but no simple relationship between the molecular weight and the applied potential was observed. However, the result indicates a possible path to increase the molecular weight of PAM in potassium persulfate initiation system.