Characterization of chain transfer reaction during radical polymerization of silver nanocomposite polyvinylpyrrolidone by using 2D hetero-spectral IR/NMR correlation spectroscopy

We determined the mechanism of the chain transfer reaction for the radical polymerization of N-vinylpyrrolidone (NVP) by using 2D FTIR correlation spectroscopy and 2D hetero-spectral NMR/FTIR correlation spectroscopy. NVP was successfully polymerized using a radical polymerization process with AgNO3 as the chain transfer agent. 2D FTIR correlation spectra showed that there were two bands at 1660 and 1676 cm(-1). These two bands at 1660 and 1676 cm(-1), which were not readily noticeable in the 1D spectra, were clearly observed in the synchronous 2D correlation spectrum. The intensity of the band at 1660 cm(-1) decreased before that at 1676 cm(-1) increased during the polymerization reaction. The synchronous hetero-spectral 2D NMR/FTIR correlation spectra clearly showed that the bands at 1660 and 1676 cm(-1) FTIR spectra can be assigned to the C=C stretching band and the C=O stretching band, respectively. Furthermore, the spectra revealed that the intensity of the C=C stretching band changed first, followed by that of the C=O stretching band changed. (C) 2011 Elsevier B.V. All rights reserved.