A spectroscopic study of the solvation of 1-vinyl-2-pyrrolidone and poly(1-vinyl-2-pyrrolidone) in different solvents

The solvation of 1-vinyl-2-pyrrolidone and poly(1-vinyl-2-pyrrolidone) in solvents of varying polarity, specifically water, ethylene glycol, chloroform and carbon tetrachloride, was investigated by means of Fourier transform infrared (FT-IR), FT-Raman, UV, H-1 and C-13 NMR spectroscopy. The IR and Raman measurements made it possible to establish the structures of the solvated molecules and the type of the hydrogen bonding that was obtained. From the UV results, the strength of the vinyl double bond was estimated in the different solvents. The H-1 and C-13 NMR spectra indicated that polar solvents interact with the solutes at the carbonyl group of the pyrrolidone ring, whereas nonpolar solvents interact mainly with the vinyl group in the 1-vinyl-2-pyrrolidone and with the polymer chain in poly(1-vinyl-2-pyrrolidone). (C) 2000 Elsevier Science Ltd. All rights reserved.