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A 13 C NMR study of hydroxylated natural rubber
Author(s) -
Perera M. C. S.,
Elix J. A.,
Bradbury J. H.
Publication year - 1987
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.1987.070330807
Subject(s) - natural rubber , carbon 13 nmr , chemistry , alcohol , hydride , hydroxylation , proton nmr , materials science , hydroboration , epoxy , organic chemistry , polymer chemistry , catalysis , hydrogen , enzyme
Two methods have been used to introduce hydroxyl groups into natural rubber. In the first method, epoxidized natural rubber was reduced with lithium aluminium hydride or aluminium hydride with the production of a tertiary alcohol. The 13 C NMR spectrum of this product was assigned in terms of shift factors from model compounds and quantitative analysis of the spectra confirmed that the hydroxylation process of partially epoxidized rubber was a random process. At higher levels of epoxidation, evidence was obtained for the formation of larger rings from adjacent epoxy groups. The second method involved hydroboration of natural rubber followed by oxidation, which was expected to produce secondary alcohol groups, but gave a mixture of secondary and tertiary alcohol groups as shown by the 13 C NMR spectrum. A reaction scheme was proposed to explain this result.