Selective measurement of heteronuclear 1H-13C dipolar couplings in motionally heterogeneous semicrystalline polymer systems
Jazyk angličtina Země Spojené státy americké Médium print
Typ dokumentu časopisecké články, práce podpořená grantem
PubMed
16833857
DOI
10.1021/jp0503821
Knihovny.cz E-zdroje
- MeSH
- alanin chemie MeSH
- bentonit chemie MeSH
- izotopy uhlíku chemie MeSH
- kaprolaktam analogy a deriváty chemie MeSH
- magnetická rezonanční spektroskopie MeSH
- nanokompozity MeSH
- polyethyleny chemie MeSH
- polymery chemie MeSH
- vodík chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- alanin MeSH
- bentonit MeSH
- izotopy uhlíku MeSH
- kaprolaktam MeSH
- nylon 6 MeSH Prohlížeč
- polyethyleny MeSH
- polymery MeSH
- vodík MeSH
A pulse sequence for the selective recoupling of heteronuclear dipolar interactions in mobile amorphous phase of powdered semicrystalline polymers is described. 1H-13C dipolar interactions are selectively measured by PISEMA-type sequence. Selection of 13C magnetization originating from amorphous phase is achieved by a train of saturation pulses followed by a short delay and a direct excitation pulse on 13C spins. The development of undesired net 13C magnetization during the recoupling sequence is prevented by the efficient "reverse" 13C --> 1H cross-polarization. The efficacy of the 2D method to measure 1H-13C dipolar couplings selectively for mobile components is demonstrated on powdered crystalline L-alanine, semicrystalline polyethylene, and nanocomposite polyamide-6/montmorillonite.
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