Dynamics of shear-induced orientation transitions in block copolymers
Dynamics of shear-induced orientation transitions in block copolymers
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DOI：
10.1039/c000975j
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发表时间：
2010-04
期刊：
影响因子：
3.4
通讯作者：
J. Stasiak;M. Mackley;A. Squires;V. Castelletto;I. Hamley;G. Moggridge
中科院分区：
文献类型：
--
作者：
J. Stasiak;M. Mackley;A. Squires;V. Castelletto;I. Hamley;G. Moggridge
This research investigates the dynamics of mechanical and structural transformations of styrene–butadiene–styrene block copolymer, known as RCM1, which has cylindrical mesophase morphology. The polymer was processed using a Multipass Rheometer (MPR) with simultaneous X-ray observation. The method allowed investigation of the dynamics with 1 second time resolution. Samples were processed at 160 °C and an apparent wall shear rate in the range ∼1.4 to 1125 s−1. Microstructural alignment was quantified using a second order X-ray orientation function. The polymer showed self-organization in the melt, aligning along the capillary walls. Shear flow disrupted the organization, which then rebuilt during the post-shearing pause, as the residual pressure relaxed across the capillary. The dynamics of structure ordering and disordering was a function of shear rate. The transition was faster for high shear rate cycles.
