Abstract: The interaction between poly(vinyl pyrrolidone)(PVP) and lithium chloride was studied by rheological method, ¹³C NMR and FTIR spectroscopy. The results showed that the apparent viscosity, the activation energy and the critical shear thinning rate of the concentrated PVP-LiCl-DMF solution are obviously influenced by lithium chloride. The apparent viscosity increases with the increasing of the content of the lithium chloride, and the activation energy of the solution increases as well, while the critical shear thinning rate decreases with increasing the content of lithium chloride. ¹³C NMR spectra proved the interaction between Li⁺ ion and the carbonyl group from PVP and DMF molecules in PVP/LiCl/DMF solution. These results indicate that the obvious interactions between Li⁺ ion and PVP in the solution result in the variation of the aggregation state of PVP molecules. The IR spectra of the PVP/LiCl composites showed that there are interactions between Li⁺ ion and carbonyl group in the lactam of PVP unit, and the curve fitting results also indicated the existence of several coordination structure between Li⁺ ion and carbonyl groups.

Key words: Poly(vinyl pyrrolidone), Rheology, FTIR spectroscopy, NMR spectroscopy