2.4 Author:
   Yakimov, S. A.; Kirsh, Yu. E.; Sibel'dina, L. A.
Reference:
   Journal, RJPCAR, Russ.J.Phys.Chem.(Engl.Transl.), EN, 61, 12, 1987, 1764-1766
Title:
   The Interaction of Poly-N-vinylamides with Iodide in Water
Abstract:
The interaction of poly-N-vinylamides, namely poly-N-vinylpyrrolidinone (PVP), poly-N-vinylcaprolactam (PVC), and poly-N-vinylmethylacetamide (PVMA), with iodide in water has been investigated by 127I NMR.The binding of iodide to the poly-N-vinylamides has been demonstrated.The constant Kh for the binding of iodide in solutions at an ionic strength of unity has been determined as 12.5, 5.9, and 3.0 litre mol-1 for PVC, PVMA, and PVP solutions respectively at 292 K.An increase of the local concentration of I- ions and a significant limitation of their mobility are observed in the vicinity of the poly-N-vinylamide macromolecules.Kb for the PVP solutions increases with decrease of the ionic strength of the solution.In methanol solutions, the binding of iodide to PVP was not observed.A model is proposed for the binding mechanism according to which the molecules of water hydrating PVP, serving as a bridge between the units of the polymer chain and the iodide ions, play a direct role in the binding process.