Structural characterization of vulcanized natural rubber by latex state 13C NMR spectroscopy |
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| Authors: | Jinta Ukawa Seiichi Kawahara Junichiro Sakai |
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| Institution: | 1. Faculty of Engineering, Department of Chemistry, Nagaoka University of Technology, Nagaoka, Niigata 940‐2188, Japan;2. Toyo Tire and Rubber Co., Ltd, Ibaraki, Osaka 567‐0887, Japan;3. Faculty of Engineering, Department of Chemistry, Nagaoka University of Technology, Nagaoka, Niigata 940‐2188, JapanFaculty of Engineering, Department of Chemistry, Nagaoka University of Technology, Nagaoka, Niigata 940‐2188, Japan |
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| Abstract: | Structural characterization of vulcanized natural rubber was performed by high‐resolution latex‐state 13C NMR spectroscopy. The vulcanized natural rubber latex was prepared by vulcanization of high ammonia natural rubber latex with sulfur and sodium di‐n‐butyldithiocarbamate as vulcanizing agents. High resolution was attained for latex‐state 13C NMR spectroscopy even after vulcanization of the rubber latex, as is evident from no background in spectrum and narrow half width of signals, which were independent of vulcanization time. Small signals at 44 and 58 ppm in the carbon region were assigned by measurements of both distortionless enhancement by polarization transfer (DEPT) and attached proton test (APT) to secondary, tertiary, and quaternary carbons of crosslinking points. The assignment was proved by high‐resolution solution‐state NMR spectroscopy of vulcanized liquid cis‐1,4‐polyisoprene as a model, in which DEPT, APT, 2‐dimensional 1H‐13C correlation (HETCOR), and 2‐dimensional heteronuclear multiple bond correlation (HMBC) measurements were applied. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1003–1009, 2007 |
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| Keywords: | lattices NMR rubber |
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