Abstract
Structural characterizations of crosslinking points of vulcanized natural rubber were carried out by latex, solution and solid state 13C NMR spectroscopy. 13C NMR signals, newly appearing after vulcanization of natural rubber, were assigned to the crosslinking points by latex state 13C NMR spectroscopy with DEPT and APT pulse sequences. The crosslinking points were suggested to be trans-units formed after isomerization by comparison with 13C NMR spectra for vulcanized natural rubber and trans-1,4-polyisoprene. The stereo structure of crosslinking points of vulcanized natural rubber was proved by DEPT, APT and 2-dimensional NMR spectroscopy for vulcanized squalene as a model.
