English Abstract

Structural Characterization of Vulcanized Natural Rubber by Latex State C�\NMR Spectroscopy Jinta UKAWA Junichiro SAKAI Seiichi KAWAHARA Yoshinobu ISONO Department of Chemistry, Faculty of Engineering, Nagaoka University of Technology, Nagaoka, Niigata, Japan Riichiro OHARA Toyo Tire & Rubber, Co., Ltd, Ibaraki, Osaka, Japan Nippon Gomu Kyokaishi,(2005),78(9),331-335 Original Paper in Japanese Abstract Vulcanized natural rubber was characterized by high-resolution latex-state C-NMR spectroscopy. Signals characteristic of natural rubber were shown in the spectrum without background, suggesting little effect of chemical shift anisotropy and/or dipole-dipole interaction. Half widths of signals were independent of vulcanization time, whereas spin-lattice relaxation time was dependent slightly on the time. Small signals at 44 ppm and 58 ppm in the aliphatic carbon region were assigned by Distortionless Enhancement by Polarization Transfer (DEPT) and Attached Proton Test (APT) to secondary, tertiary and quaternary carbons of cross-linking points. (Received on February 9, 2005) (Accepted on August 5, 2005) Keywords: Natural rubber, Latex, Structural characterization, NMR, Vulcanizate

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