th  - 1987 - 51st ENC Conference

MF9
NMR OF XENON ABSORBED IN SOLID POLYMERS
A PROBE OF THE AMORPHOUS STATE
Thomas R. Stengle
Dept. of Chemistry, Univ. of Massachusetts, Amherst, MA 01003
Kenneth L. Williamson*
Dept. of Chemistry, Mount Holyoke College, So. Hadley, MA 01075
Gaseous xenon is readily taken up into the amorphous regions of
solid polymers. In this state the 12eXe spectrum can be easily
obtained. In earlier work we have shown that the 120Xe resonance
is exceptionally sensitive to the nature of its surroundings,
and that it can be used to probe the structure of liquids and
lipid bilayers.1 Here we report on its application to the
amorphous regions of solid polymers. When contained within low
density polyethylene, the chemical shift of xenon is ca. 200
ppm downfield from the pure gas. The NMR lines are broad, and
their shape is especially sensitive to the surrounding
structure. In particular, the glass transition of polyethyl-
methacrylate is clearly observed by its effect on both chemical
shift and lineshape of the xenon signal. The application of
xenon NMR to several polymers will be discussed.
IK. W. Miller, N.V. Reo, A. J. M. Schoot Uiterkamp, D. P.
Stengle, T. R. Stengle and K. L. Wlliamson, Proc. Natl. Acad.
Sci. USA, 78, 4946 (1981).