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Rheological studies on the phase dissolution in a block copolymer

✍ Scribed by Rui Xie; Bingxin Yang; Bingzheng Jiang; Qizhong Zhang; Yuanze Xu

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
253 KB
Volume
63
Category
Article
ISSN
0021-8995

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✦ Synopsis

The microphase transition in a styrene-butadiene-styrene triblock copolymer was studied by rheometric mechanical spectroscopy. A high-temperature-melt rheological transition from the highly elastic, nonlinear viscous behavior typical of a multiphase structure to linear viscous behavior with insignificant elasticity typical of a single-phase structure was observed. The transition temperature is determined according to the discontinuity of the rheological properties across the transition region, which agrees well with the results obtained from the small angle X-ray scattering data and the expectation of the random phase approximation theory. Maybe for the first time, microphase dissolution was investigated rheologically. The storage modulus (G) and the loss modulus ( GЉ) increase with time during the process. An entanglement fluctuation model based on the segmental density fluctuations is presented to explain the rheological behavior in this dissolution process.

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