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Deep Quenching: A Special Method to Study Stress‐Induced Crystallization and Control the Lamellar Growth Direction
Author(s) -
Xu Jun,
Guo BaoHua,
Zhang ZengMin,
Wu Qiong,
Chen GuoQiang
Publication year - 2004
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.200400239
Subject(s) - lamellar structure , crystallization , quenching (fluorescence) , nucleation , materials science , stress (linguistics) , chemical engineering , crystallography , composite material , polymer chemistry , optics , chemistry , organic chemistry , fluorescence , linguistics , physics , philosophy , engineering
Summary: Liquid‐nitrogen quenching was applied to study the enthalpy effect on the stress‐induced crystallization of microbial polyesters. Crystallization bands of poly(3‐hydroxybutyrate) exhibited the potential to reveal the stress distribution in the melt; while crystallization of poly[(3‐hydroxybutyrate)‐ co ‐(3‐hydroxyhexanoate)] gave shish‐kebab structures. Polarized‐light micrographs confirmed that the enhanced nucleation was attributed to the tensile stress. Furthermore, control of the quenching direction provides a method to direct the lamellar growth.Polarized‐light micrographs of PHB film crystallized at 90 °C after quenching in liquid nitrogen from the melt. The normal of the bands, namely the lamellar growth direction, runs predominantly parallel to the stress direction.