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Site Specific Proton and Deuteron NMR Relaxation Dispersion in Selectively Deuterated Polyisoprene Melts
Author(s) -
Kariyo Sobiroh,
Stapf Siegfried,
Blümich Bernhard
Publication year - 2005
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.200500020
Subject(s) - deuterium , relaxation (psychology) , chemistry , intramolecular force , proton , polybutadiene , polymer , intermolecular force , deuterium nmr , dispersion (optics) , formalism (music) , nuclear magnetic resonance , polymer chemistry , thermodynamics , physics , molecule , atomic physics , stereochemistry , nuclear physics , organic chemistry , optics , psychology , social psychology , musical , art , copolymer , visual arts
Summary: The frequency dependence of proton and deuteron NMR relaxation times was determined in selectively deuterated and undeuterated polyisoprene melts and compared to polybutadiene melts. Master curves were generated by the Williams‐Landel‐Ferry (WLF) formalism which resulted in very similar dispersions for all samples with a high and a low frequency branch following characteristic power laws. The results show a consistently weaker frequency dependence than any reported so far for other polymer melts. The reason for this finding is identified in the distribution of intramolecular motion modes, while intermolecular contributions are ruled out.Master curves for 1 H relaxation dispersions obtained from measurements between 223 K and 348 K shifted relative to a reference temperature of 296 K.