Influence of shear on a lamellar triblock copolymer near the order–disorder transition
作者:
T. Tepe,
D. A. Hajduk,
M. A. Hillmyer,
P. A. Weimann,
M. Tirrell,
F. S. Bates,
K. Almdal,
K. Mortensen,
期刊:
Journal of Rheology
(AIP Available online 1997)
卷期:
Volume 41,
issue 5
页码: 1147-1171
ISSN:0148-6055
年代: 1997
DOI:10.1122/1.550819
出版商: The Society of Rheology
关键词: Copolymer, lamellar triblock;Block copolymer;Triblock copolymer;Neutron scattering;SANS
数据来源: AIP
摘要:
The effects of a large strain (600%) reciprocating steady shear on the lamellar orientation and the order–disorder transition of a nearly symmetric poly(ethylene propylene)–poly(ethylethylene)–poly(ethylene propylene) (PEP–PEE–PEP) triblock copolymer have been studied using small-angle neutron scattering and rheological measurements. Shearing in the ordered state produced parallel lamellae under all steady-state conditions investigated, and the lamellar-to-disorder transition temperature decreased dramatically with increasing shear rate. Both phenomena are qualitatively different from the documented behavior of PEP–PEE diblock copolymers. However, cooling the disordered material while shearing at a relatively low deformation rate initially induces perpendicular lamellae, analogous to the diblock response. These observations are considered in the context of theory and other experimental studies.
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