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 CC stretching band and the CO stretching band, respectively. Furthermore, the spectra revealed that the intensity of the CC stretching band changed first, followed by that of the CO stretching band changed.