Abstract
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 contest of theory and other experimental studies.
Original language | English (US) |
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Pages (from-to) | 1147-1171 |
Number of pages | 25 |
Journal | Journal of Rheology |
Volume | 41 |
Issue number | 5 |
DOIs | |
State | Published - Jan 1 1997 |