The radical polymerization of acrylamide (AA) has been investigated in the presence of various solvents over lithium bromide (LiBr). Addition of salt has been found not to affect the total rate of the polymerization in water. The use of dimethyl sulphoxide or tetrahydrofuran caused the curves of the process rate plotted against salt concentration to show a peak of amplitude and position depending on the solvent polarity. Addition of water to the dimethyl sulphoxide (DMSO) reduces the effect of the salt on the process rate. The change of the total rate in DMSO on adding LiBr has been found to be due to a change of kp, as the k0 remains the same when various amounts of salt are present. The results are explained by a complex formation between the salt and the polymer radicals and by the conformation characteristics of the macromolecules in solution when LiBr is present.
