Catalogo Articoli (Spogli Riviste)
OPAC HELP
Titolo: Studies on different types of hydrogen bonds in poly(vinyl alcohol) films by H-1 CRAMPS and solid-state two-dimensional H-1-C-13 heteronuclear correlation analyses
Autore: Masuda, K; Kaji, H; Horii, F;
- Indirizzi:
- Kyoto Univ, Inst Chem Res, Uji, Kyoto 6110011, Japan Kyoto Univ Uji KyotoJapan 6110011 st Chem Res, Uji, Kyoto 6110011, Japan
- Titolo Testata:
- POLYMER JOURNAL
fascicolo: 2,
volume: 33,
anno: 2001,
pagine: 190 - 198
- SICI:
- 0032-3896(2001)33:2<190:SODTOH>2.0.ZU;2-H
- Fonte:
- ISI
- Lingua:
- ENG
- Soggetto:
- C-13 NMR ANALYSES; CORRELATION SPECTROSCOPY; CHAIN CONFORMATION; CHEMICAL-SHIFTS; TACTICITIES;
- Keywords:
- hydrogen bonding; chain conformation; poly(vinyl alcohol); crystal structure; cross polarization-magic angle spinning C-13 NMR; H-1 combined rotation and multiple pulse; spectroscopy; H-1-C-13 heteronuclear correlation spectroscopy;
- Tipo documento:
- Article
- Natura:
- Periodico
- Settore Disciplinare:
- Physical, Chemical & Earth Sciences
- Citazioni:
- 33
- Recensione:
- Indirizzi per estratti:
- Indirizzo: Horii, F Kyoto Univ, Inst Chem Res, Uji, Kyoto 6110011, Japan Kyoto Univ Uji Kyoto Japan 6110011 es, Uji, Kyoto 6110011, Japan
-
-
-
- Citazione:
- K. Masuda et al., "Studies on different types of hydrogen bonds in poly(vinyl alcohol) films by H-1 CRAMPS and solid-state two-dimensional H-1-C-13 heteronuclear correlation analyses", POLYM J, 33(2), 2001, pp. 190-198
Abstract
Different hydrogen-bonded states of OH groups in poly(vinyl alcohol) (PVA)films with different tacticities have been characterized by H-1 combined rotation and multiple pulse spectroscopy (CRAMPS), solid-state C-13 NMR and two-dimensional (2D) H-1-C-13 heteronuclear correlation (HETCOR) analyses. The newly developed line shape analysis for the H-1 CRAMPS spectra reveals the existence of three types of OH groups in different hydrogen-bonded states below T-g intramolecular and intermolecular hydrogen bonded OH (OHintra,OHinter) groups and OH (OHf) groups free from hydrogen banding. Above T-g another resonance line which can be assigned Co highly mobile OH (OHr) groups in the noncrystalline region appears as a result of the reduction in mole fractions of the OHintra and OHinter groups, in good accord with the confirmation of the rubbery component by the solid-state C-13 NMR line shape analysis. In contrast, the mole fraction of the OHf groups stays constant at -60-160 degreesC, indicating that these OH groups are preferentially distributed in the crystalline region. In order to examine the correlations of the results obtained by H-1 CRAMPS and solid-state C-13 NMR analyses, 2D H-1-C-13 HETCOR spectra have been also measured at room temperature for atacticand main-chain deuterated atactic PVA films. As a result, evident correlations between H-1 OH and C-13 CH constituent lines are observed at a cross polarization (CP) contact time of 120 mus, indicating the validity of the assignments for the H-1 OH and C-13 CH resonance lines made previously as well as in this work.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/21 alle ore 06:28:59