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Frequency and molecular-mass-dependent nonexponential proton NMR relaxation in polymer melts (1992)

Hiller, W. G. ; Schneider, H. ; Fedotov, V. D.

Bognor Regis [u.a.] : Wiley-Blackwell

Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 931-942

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ISSN: 0887-6266

Keywords: nuclear magnetic resonance (NMR) relaxation in polymer melts ; relaxation of proton NMR processes in melts (theory) ; chain motions and NMR relaxation in melts ; Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Notes: A theoretical treatment of the nonexponential relaxation behavior of the different proton nuclear magnetic resonance (NMR) relaxation processes in polymer melts is presented. Formulas are derived for a three-component model given by two versions and a homogeneous distribution of correlation times. The theoretical results were tested with measurements of T1, T2e, and T2 as functions of frequency and molecular mass in linear fractionated polyethylene samples. While the T1 relaxation always yields exponential magnetization decays, the T2e and T2 measurements show biexponential relaxation behavior. From the calculations it was found that the correlation time of the local motion is independent of the molecular mass, whereas the correlation time of the slowest motional process increases with M2.8w for the three-component model and with M2.2w for the distribution of correlation times, respectively. © 1992 John Wiley & Sons, Inc.

Additional Material: 4 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/polb.1992.090300901

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13C-NMR-Untersuchungen an Phenol-Formaldehyd-Harzen. 5. Zur Charakterisierung von Reaktionsprodukten aus p-Cumylphenol und Formaldehyd (1989)

Pasch, H. ; Goetzky, P. ; Hiller, W.-G.

Weinheim : Wiley-Blackwell

Acta Polymerica 40 (1989), S. 568-571

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ISSN: 0323-7648

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Description / Table of Contents: By means of empirical substituent parameters, the 13C-NMR spectra of 2,6-bis(hydroxymethyl)-4-cumylphenol and 2,6-bis(2-hydroxy-5-cumylbenzyl)-4-cumylphenol (3) were calculated and interpreted. Using 13C-NMR-spectroscopy it was shown that in the Schottem-Baumann reaction of 3 with 2-diazo-1-oxo-1,2-dihydronaphthalene-5-sulphonic acid chloride the outer hydroxyl groups of 3 are preferred in comparison to the inner ones.

Notes: Mit Hilfe empirischer Substituentenparameter wurden die 13C-NMR-Spektren des 2,6-Bis(hydroxymethyl)-4-cumylphenols und des 2,6-Bis(2-hydroxy-5-cumylbenzyl)-4-cumylphenols (3) berechnet und interpretiert. Durch 13C-NMR-Spektroskopie wurde gezeigt, daß bei der Schotten-Baumann-Reaktion von 3 und 2-Diazo-1-oxo-1,2-dihydronaphthalen-5-sulfochlorid die außenständigen Hydroxylgruppen von 3 bevorzugt reagieren.

Additional Material: 1 Ill.