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Effects of rigid segments on structure and properties of unoriented and oriented poly( p ‐phenylene terephthalamide‐ co ‐ethylene terephthalates)
Author(s) -
Yamada Kenji,
Hashimoto Kazuto,
Takayanagi Motowo,
Murata Yoshifumi
Publication year - 1987
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.1987.070330519
Subject(s) - crystallinity , materials science , copolymer , amorphous solid , crystallization , glass transition , phenylene , polymer chemistry , poly(p phenylene) , synthetic fiber , composite material , ethylene , phase (matter) , polymer , chemical engineering , crystallography , fiber , chemistry , organic chemistry , catalysis , engineering
In poly( p ‐phenylene terephthalamide‐ co ‐ethylene terephthalate) the rigid segments of p ‐phenylene terephthalamide are aggregated as crystalline domains above the weight fraction of the rigid segments, 6 wt%. The rigid segments disturb the crystallization of the flexible segments of poly(ethylene terephthalate) (PET) and are preferentially contained in the amorphous phase of the PET segments. The crystallinity of the PET segments decreased with increasing the content of the rigid segments in the copolymers and the glass transition temperature is decreased by the decrease of the crystallinity below the weight fraction of the rigid segments, 6 wt%, in spite of the depression of micro‐Brownian motion of the PET segments due to the rigid segments. The values of Young's modulus E , yield stress σ y and breaking stress σ b for the zone‐drawn copolymer were conspicuously increased by the rigid segments contained in it, in comparison with those of the zone‐drawn PET homopolymer. Such higher values of E , σ y , and σ b of the copolymer are originated by greater increases in the orientation of amorphous chains in the copolymer. The rigid segments in the amorphous phase effectively depressed the thermal shrinkage of the zone‐drawn and the zone‐annealed copolymers.