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Hydrogenation of unsaturated rubbers using diimide as a reducing agent
Author(s) -
Samran J.,
Phinyocheep P.,
Daniel P.,
Kittipoom S.
Publication year - 2004
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.20811
Subject(s) - diimide , materials science , glass transition , epoxide , isomerization , differential scanning calorimetry , polymer chemistry , thermal decomposition , natural rubber , raman spectroscopy , chemistry , organic chemistry , polymer , molecule , composite material , catalysis , perylene , physics , thermodynamics , optics
The hydrogenation of natural rubber (NR) and various epoxidized natural rubbers (ENR) was investigated by using diimide generated in situ from the thermal decomposition of p ‐toluenesulfonylhydrazide (TSH) in o ‐xylene solution at 135°C. 1 H‐NMR analysis indicated that approximately 85–95% of hydrogenation was performed with a twofold excess of TSH. FT‐IR and Raman spectroscopy were employed to confirm the microstructure characteristics of the hydrogenated rubbers. The cis – trans isomerization was also observed by 1 H‐ and 13 C‐NMR. The signal in 1 H‐NMR of the epoxide group of the ENR disappears after hydrogenation while the signal of the opened epoxide ring product was detected. This may be due to the epoxide ring opening reaction caused by the p ‐toluenesulfinic acid by‐product. The high temperature of the reaction condition leads to chain degradation in both NR and ENR. Thermal behaviors of the hydrogenated rubbers characterized by differential scanning calorimetry showed that the glass transition temperatures of the hydrogenated rubbers were increased about 10–20°C compared with the starting rubbers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 16–27, 2005