Determination of the chain inclination angle of isothermally crystallized bulk polyethylene
作者:
W.D. Varnell,
E. Ryba,
I.R. Harrison,
期刊:
Journal of Macromolecular Science, Part B
(Taylor Available online 1987)
卷期:
Volume 26,
issue 2
页码: 135-143
ISSN:0022-2348
年代: 1987
DOI:10.1080/00222348708248062
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The crystal lamella is well established as a basic structural unit of most semicrystalline polymers. It is also accepted that the chain axis is generally not parallel to the normal to the large flat lamella surfaces, but inclined at some angle to it. Due to the random orientation of lamellae in bulk polymers where spherulitic growth predominates, no direct method exists for determining . However, the angle has been determined by acid etching bulk samples and then using electron microscopy techniques on fragments. An alternative approach is utilized in this work. The etched fragments, after suitable washing procedures, were sedimented to form an oriented mat. An x-ray diffraction technique was employed in which the regions of high pole density for several crystallographic planes were determined. From these results, the inclination angle was determined to be 40.4°, with a standard deviation of 1.5°. This study represents the first time that an x-ray pole figure technique has been used to determine chain inclination in isotherm-ally crystallized PE.
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