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The superstructure of melt‐crystallized polyethylene. I. Screwlike orientation of unit cell in polyethylene spherulites with periodic extinction rings
Author(s) -
Fujiwara Yasuna
Publication year - 1960
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1960.070041002
Subject(s) - spherulite (polymer physics) , materials science , polyethylene , extinction (optical mineralogy) , diffraction , superstructure , crystallography , optics , morphology (biology) , composite material , radius , chemistry , polymer , physics , geology , paleontology , computer security , computer science , thermodynamics
The ringed structure in polyethylene spherulites was investigated by an x‐ray microdiffraction method. A spherulite with extinction rings whose interval is about 50 μ was observed when viewed under the polarization microscope. An asymmetric x‐ray diffraction fibrous pattern about the b axis was obtained for this specimen. This indicates that in the area of spherulite (several microns in diameter) the unit cells are never randomly oriented around a common b axis but have nearly similar orientations. A series of micro‐diffraction patterns was obtained at intervals of 13 μ (about 1/4 the extinction fringe interval), and it was shown that the unit cells have screwlike orientations with their common b axis along the spherulite radius. The distance corresponding to one‐half the pitch of the screw is just in accordance with the extinction ring interval.