This paper reports the assignments of the 13C NMR resonances of the Sbb and Sag methylenes observed in the spectra of copolymers of propylene with trace amounts of enriched ethylene-1-13C. The assignment is achieved by comparing the chemical shifts calculated by an empirical method (at the CH2 stereochemical pseudoexad level), with the experimental spectra of regioregular copolymers with different stereochemical structure. The implications of the observed Sbb and Sag resonances on the stereochemical polymerization mechanism are also discussed.
Stereochemical Pseudohexad 13C-NMR Resonances and Regioregular Propylene/Ethylene-1-13C Copolymers
2002
Abstract
This paper reports the assignments of the 13C NMR resonances of the Sbb and Sag methylenes observed in the spectra of copolymers of propylene with trace amounts of enriched ethylene-1-13C. The assignment is achieved by comparing the chemical shifts calculated by an empirical method (at the CH2 stereochemical pseudoexad level), with the experimental spectra of regioregular copolymers with different stereochemical structure. The implications of the observed Sbb and Sag resonances on the stereochemical polymerization mechanism are also discussed.File in questo prodotto:
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