English Abstract

Structural Analysis of Crosslinking Junctions of Vulcanized Natural Rubber by Field Gradient-Fast Magic Angle Spinning Solid-State NMR Spectroscopy

Department of Materials Science and Technology, Faculty of Engineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan
Nippon Gomu Kyokaishi,(2012),85(11),347-353 General Review in Japanese

Field gradient-fast-magic angle spinning (FG-FMAS) probe, developed for solid-state NMR spectroscopy, was applied to investigate crosslinking junctions of vulcanized natural rubber. Resolution of 1H- and 13C-NMR spectra and correlation between 1H and 13C of the vulcanized natural rubber were investigated by one- and two-dimensional measurements. Signals, appearing between 40 and 60 ppm, were well assigned by FG-FMAS solid state NMR spectroscopy; for instance, signal at 40 ppm was assigned to C1 of trans-1,4-isoprene units, signals at 44 ppm was to secondary carbons adjacent to carbons linking to S atom and signals at 58 ppm were to tertiary and quaternary carbons linking to S atoms. Based on the assignments of the signals, origin of outstanding mechanical properties of the vulcanized natural rubber was related to the structure of crosslinking junctions.

Keywords: FG-FMAS, Solid state NMR spectroscopy, Natural rubber, Vulcanizaties, Crosslinking Junctions