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The 1 H and 13 C NMR spectra of alternating isobutene/maleic anhydride copolymer and the corresponding acid and sodium salt — a stereochemical analysis
Author(s) -
Komber Hartmut
Publication year - 1996
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1996.021970126
Subject(s) - triad (sociology) , copolymer , maleic anhydride , chemistry , tacticity , polymer chemistry , steric effects , nmr spectra database , carbon 13 nmr , diad , proton nmr , sodium salt , nuclear overhauser effect , salt (chemistry) , monomer , nuclear magnetic resonance spectroscopy , spectral line , stereochemistry , organic chemistry , polymer , polymerization , inorganic chemistry , psychology , physics , astronomy , psychoanalysis
Abstract The 1 H and 13 C NMR spectra of an alternating isobutene/maleic anhydride copolymer and the corresponding acid and sodium salt forms were reexamined by 1D and 2D NMR methods. This copolymer contains only threo ‐succinyl units. The tacticity is characterized by a 53/47 ratio of threo‐diisotactic and threo‐disyndiotactic triads. The preference of the diisotactic triad was concluded from NMR data. A model was proposed to explain the stereoselectivity of the copolymerization reaction. This model also leads to the conclusion that the diisotactic triad should be preferred for steric reasons. 13 C‐ T 1 values and nuclear Overhauser effect (NOE) values for these three copolymers were determined and discussed in terms of segmental motion.