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Long Periods in Drawn Polyethylene
Author(s) -
Fischer E. W.,
Schmidt G. F.
Publication year - 1962
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.196204881
Subject(s) - crystallite , polyethylene , materials science , diffraction , zonal and meridional , period (music) , crystallography , single crystal , crystal (programming language) , condensed matter physics , mineralogy , composite material , optics , chemistry , geology , physics , programming language , atmospheric sciences , computer science , acoustics
Meridional reflections appearing in small‐angle X‐ray diffraction diagrams of drawn polyethylene are caused by a nearly periodic arrangement of crystalline and disordered regions. The long period, which is determined by the average distance between two consecutive crystallites, depends on the method of preparing the sample. The time and temperature dependences of the positions of the small‐angle reflections have been investigated. The growth of the long period of unoriented bulk polyethlene and polyethylene single crystal follows the same time dependence as that of stretched films. However, characteristic differences were obseved in the relationship between density and long period; they are attributed to the fact that in single crystals and in material crystallized from the melt, the chains are folded at the boundaries of the crystallites, whereas this in not the case in stretched polyethylene.