TIT# Early Oriented Isothermal Crystallization of Polyethylene Studied by
     High Time-Resolution SAXS/WAXS
AUT# Stribeck, N.; Almendarez Camarillo, A.; N”chel, U.; B”secke, P.;
     Bayer, R. K.;
SOU# Anal. Bioanal. Chem. (2007), 387(2), 649-661
LOC# xv102
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MAT#
ABS# During cooling from the quiescent melt of a highly oriented polyethylene
     rod, highly oriented proto-lamellae are formed first, which are not
     crystalline. This is shown in scattering data which are recorded on
     two-dimensional detectors with a cycle time of 1 s and an exposure of
     0.1 s. In the experiments small-angle X-ray scattering (SAXS) and
     wide-angle X-ray scattering (WAXS) are registered simultaneously during
     the first 3 min after quenching to a crystallization temperature. A
     non-uniform thickness between 20 and 100 nm is characteristic for the
     ensemble of proto-lamellae. During the first minute of isothermal
     treatment the number of proto-lamellae slowly increases without a change
     of the thickness distribution. As crystallization starts, the crystallites
     are not oriented in contrast to the proto-lamellae. During crystallization
     the layer thickness distribution narrows. The number of lamellae rapidly
     increases during the following 2 min of isothermal treatment (at 128øC
     and 124øC). The results are obtained by interpretation of the WAXS and of
     the multidimensional chord distribution function (CDF), a model-free
     real-space visualization of the nanostructure information contained in
     the SAXS data.