为考察氧化还原聚合中的电化学催化效应,在双室电解池中采用铂丝为工作电极进行丙烯酰胺的电解聚合,引发剂为硫酸铈-草酸体系。Ce4+氧化草酸产生自由基,而电解可以使Ce4+再生。对电解和非电解聚合的聚丙烯酰胺产率及分子量进行了对比,结果表明,电解既能大幅提高产率,也能明显提高聚合产物的分子量,即对聚合物链的引发和增长两方面都有促进作用。保证电催化效应的关键因素除适宜的电极电势外,还要有足够大的电极面积与溶液体积之比。
Electrocatalytic effect was studied on acrylamide(AM) polymerization initiated by a Ce(IV)-oxalic acid redox initiator.The electrolytic polymerization was performed on a Pt wire working electrode in a two-compartment electrochemical cell.Electrolysis at proper potentials results in regeneration of Ce(IV) that oxidizes oxalic acid to produce radicals.The yield and molecular weight of polyacrylamide(PAM) were compared between electrolytic and nonelectrolytic polymerization.The results show that the additional electrolysis can greatly increase the yield of PAM and also can raise its molecular weight,that is,electrolysis can promote the chain initiation as well as the chain propagation.The key factor to influence the electrocatalytic effect on the polymerization is the ratio of the electrode area and the solution volume besides the electrolytic potential.