The natural rubber (NR) without vulcanization is easily deformed and strained during magic-angle spinning (MAS). The elongated NR during MAS forms molecular orientation. The static 13C NMR spectra of elongated NR became anisotropic, although the static 13C NMR spectra of NR before MAS show isotropic. Angle-dependent 13C NMR spectra of strips cut from the restricted elongation NR were different from those from the maximum elongated NR. The disagreement indicated that 13C chemical shift depends on not only the molecular orientation but also the magnetic susceptibility resulting from the alignment of NR chains.
- Masashi Kitamura
- Yoshiaki Hata
- Atsushi Asano
