Structural analysis of vulcanized nbr using swollen state, solution state and solid state ¹H, ¹³C NMR spectroscopy

Structural analyses of vulcanized acrylonitrile butadiene rubber (NBR) were performed by using solid state ¹H and ¹³C NMR spectroscopy. Assignments of solid state ¹H and ¹³C NMR spectra of vulcanized NBR were confirmed precisely by comparing with liquid phase ¹H and ¹³C NMR spectra of swollen vulcanized NBR and solution of crude NBR. A sharp single peak at 33 ppm in ¹³C NMR was assigned as a overlap peak of methine and methylene in achlyronitoril by DEPT spectra. A broad peak at 2,09 ppm in ¹H NMR was assignable to overlap of two kinds of methylene in 1,4-butadiene peaks, which were confirmed to be the methylene adjacent to methine and methylene, respectively, by 2D NMR spectra. As a result, complete assignments of ¹H and ¹³C NMR spectra of vulcanized NBR were determined. In terms of the precise assignment of the spectra, the monomer composition of NBR could be determined.