The radical polymerisation of acrylamide and its derivatives in the presence of complexing salts

The results of studies of the radical polymerisation of acrylamide and of its derivatives in the presence of inorganic salts (Lewis acids) in various solvents are correlated. It is shown that the effect of inorganic salts on the polymerisation of acrylamide depends to a large extent on the nature of the solvent. During polymerisation in water the addition of Lewis acids has no effect on the rate of the process. The effect of Lewis acids is most marked when the reaction is carried out in organic solvents of relatively low polarity. It is shown that the change in the overall rate of the process in the presence of Lewis acids is due to a change in the rate constants of the chain growth and chain breaking reactions, induced by the formation of a complex between the amide group of the propagating radicals and/or monomers and the inorganic salt. The introduction of substituents into the acrylamide suppresses the formation of a complex with the salt, and therefore the effect of the salt on the polymerisation of substituted acrylamides is less marked than in the polymerisation of acrylamide itself. The bibliography includes 52 references.