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Phase Development Mechanism during Drawing from Highly Entangled Polyethylene Melts
Author(s) -
Uehara Hiroki,
Kakiage Masaki,
Yamanobe Takeshi,
Komoto Tadashi,
Murakami Syozo
Publication year - 2006
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200600199
Subject(s) - materials science , diffraction , orthorhombic crystal system , metastability , plateau (mathematics) , crystallography , stress (linguistics) , phase (matter) , optics , reflection (computer programming) , strain hardening exponent , deformation (meteorology) , composite material , chemistry , physics , mathematical analysis , linguistics , philosophy , mathematics , organic chemistry , computer science , programming language
Summary: The phase development mechanism during drawing from a highly entangled melt of ultra‐high‐molecular‐weight polyethylene is analyzed by simultaneous measurements of in situ X‐ray diffraction using synchrotron radiation and stress/strain behavior. The stress/strain curve exhibits a plateau region at the initial stage of the draw, and no crystalline reflections appear on a series of in situ X‐ray diffraction patterns. However, as the sample draw proceeds above a critical strain, a metastable hexagonal reflection appears and becomes predominant, where the stress/strain curve still shows a plateau deformation. With a further increase of the strain, the intensity of the hexagonal reflection peak begins to decrease and subsequently that of the usual orthorhombic ones increase. Correspondingly, a rapid increase of draw stress, because of the strain‐hardening behavior, is recorded.Stacked line profiles extracted from in situ WAXD patterns along the equatorial direction. The red profile was obtained at the critical time of 162.5 s.