Nonlinear rheology and structural changes of (BS)n multiblock copolymers under shear flow
Nonlinear rheology and structural changes of (BS)n multiblock copolymers under shear flow
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DOI：
10.1021/ma070306r
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发表时间：
2007-04
期刊：
影响因子：
5.5
通讯作者：
Yumi Matsumiya;Manabu Matsumoto;H. Watanabe;T. Kanaya;Yoshiaki Takahashi
中科院分区：
文献类型：
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作者：
Yumi Matsumiya;Manabu Matsumoto;H. Watanabe;T. Kanaya;Yoshiaki Takahashi
对于一系列具有相同嵌段分子量和B/S组成的1，4-丁二烯（B）-苯乙烯（S）对称多嵌段共聚物、BSB三嵌段共聚物、BSBSB五嵌段共聚物和BSBSBSB七嵌段共聚物，在25 °C下在邻苯二甲酸二丁酯（DBP）中检查流变行为和结构。DBP是S-选择性溶剂，即，S嵌段的良溶剂和B嵌段的不良溶剂。共聚物浓度C（= 22 - 25重量%）选择为刚好高于（1重量%）相应的微相分离浓度。在平衡良好的状态下，共聚物/DBP溶液形成由S嵌段桥接的未溶解的B嵌段的球形域的bcc晶格（晶格型网络），从而在小应变下表现出弹性行为。这种晶格型网络在稳定剪切下被破坏而失去弹性，并且最重的破坏发生在接近B/S浓度波动频率的中等剪切速率下。结论：该方法简便、易行、安全。
For a series of 1,4-butadiene (B)−styrene (S) symmetrical multiblock copolymers, BSB triblock, BSBSB pentablock, and BSBSBSB heptablock copolymers having the same block molecular weights and B/S composition, the rheological behavior and structure were examined in dibutyl phthalate (DBP) at 25 °C. DBP is an S-selective solvent, i.e., a good solvent for the S blocks and a poor solvent for the B blocks. The copolymer concentrations C (= 22−25 wt %) were chosen to be just above (by 1 wt %) respective microphase separation concentrations. In a well-equilibrated state, the copolymer/DBP solutions formed a bcc lattice of the spherical domains of unsolved B blocks bridged by the S blocks (lattice-type network), thereby exhibiting elastic behavior under small strains. This lattice-type network was disrupted under steady shear to lose its elasticity, and the heaviest disruption occurred at an intermediate shear rate close to the B/S concentration fluctuation frequency. The elasticity was recovered after cessation o...