Journal article
Early oriented isothermal crystallization of polyethylene studied by high-time-resolution SAXS/WAXS



Publication Details
Authors:
Stribeck, N.; Camarillo, A.; Nochel, U.; Bosecke, P.; Bayer, R.
Publication year:
2007
Journal:
Analytical and Bioanalytical Chemistry
Pages range:
649-661
Volume number:
387
Start page:
649
End page:
661
ISSN:
1618-2642

Abstract
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 128 degrees C and 124 degrees C). 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.

Last updated on 2019-25-07 at 09:51