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Evaluation of the microstructure and melting behavior of drawn polypropylene fibers with a microthermal analyzer
Author(s) -
Ye Jiping,
Hasegawa T.,
Suzuki A.
Publication year - 2006
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.23412
Subject(s) - melting point , microstructure , materials science , tacticity , fiber , differential scanning calorimetry , composite material , polymer , monoclinic crystal system , crystal (programming language) , polypropylene , crystallography , crystal structure , chemistry , thermodynamics , polymerization , physics , computer science , programming language
The strong correlation of melting behavior with the microstructure of original and zone‐drawn isotactic polypropylene fibers was evaluated by microthermal analysis (micro‐TA) combined with wide‐angle X‐ray diffraction analysis. The crystal structure of both the original and zone‐drawn fibers was a monoclinic α‐form with a ∼ 0.64 nm, b ∼ 2.03 nm, and c ∼ 0.65 nm. In contrast to the absence of any oriented polymer molecules in the original fiber, the polymer molecules in the zone‐drawn fiber were extended and highly oriented in at least two different states; one arranged along the drawn axis and the other at 40° to the drawn axis. The micro‐TA‐derived melting points corresponded to these microstructural changes caused by the zone‐drawing process and differed from the melting points obtained by differential scanning calorimetery. The micro‐TA melting point of 140°C corresponded to the z‐e‐p melting point of the original fiber, being much lower than the conventional differential scanning calorimetery melting point of 163°C. As for the zone‐drawn fiber, an increase of 19°C in the melting temperature revealed its high orientation level, and the appearance of three elevated melting peaks (161, 167, and 178°C) at the highest heating rate (1500°C/min) coincided with its several oriented states. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1306–1311, 2006