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Orientation in extruded polyethylene films
Author(s) -
Aggarwal Sundar L.,
Tilley George P.,
Sweeting Orville J.
Publication year - 1959
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.1959.070010115
Subject(s) - polyethylene , crystallite , materials science , amorphous solid , extrusion , composite material , perpendicular , film plane , diffraction , orientation (vector space) , dichroism , pole figure , absorption (acoustics) , crystallography , optics , microstructure , geometry , chemistry , magnetic anisotropy , magnetization , physics , metallurgy , mathematics , quantum mechanics , magnetic field
A discussion of the methods for studying orientation of crystalline and amorphous regions in polyethylene films is given. Extruded polyethylene films and films after having been stretched approximately 200% were studied by the methods of x‐ray diffraction and absorption of polarized infrared radiation. It is shown that in extruded polyethylene films the a ‐axes of the crystallites are oriented parallel to the extrusion direction. The amorphous regions in these are either not oriented or show only to a slight degree the orientation of chains perpendicular to the extrusion direction. When the polyethylene films are stretched, both the crystallites and the amorphous regions become oriented. In stretched films, the orientation of the crystallites is with c ‐axis parallel to the stretching direction, and the chains in the amorphous regions are also oriented parallel to the stretching direction. Two mechanisms by which a ‐axis orientation may arise during extrusion of polyethylene films, and a convenient method for determining the relative degree of a ‐axis orientation in polyethylene films are given. The relative degrees of a ‐axis orientation as determined by x‐ray diffraction and dichroism of absorption at 13.70 μ are compared for a number of film samples.