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Carbon‐13 NMR studies of local dynamics in polymer solutions and melts
Author(s) -
Laupretre Françoise
Publication year - 1990
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19900340108
Subject(s) - glass transition , polymer , relaxation (psychology) , anisotropy , materials science , amorphous solid , autocorrelation , chemical physics , thermodynamics , nuclear magnetic resonance , condensed matter physics , chemistry , crystallography , physics , optics , composite material , mathematics , psychology , social psychology , statistics
Carbon‐13 spin‐lattice relaxation time measurements have been performed at two experimental frequencies on a series of amorphous polymers in the bulk state at temperatures well above the glass‐transition temperatures and in solution. The high experimental values of the T 1 minimum as a function of temperature cannot be accounted for only by the specific orientation autocorrelation functions developed for polymers. They indicate the existence of an additional fast anisotropic motion, which we have assigned to librations of limited but significant extent of the internuclear CH vectors about their rest position. Moreover, in most cases, the temperature dependence of the segmental motions proves that they are involved in the glass‐rubber transition phenomena.