Rheological properties of diblock copolymer/layered‐silicate nanocomposites
Rheological properties of diblock copolymer/layered‐silicate nanocomposites
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DOI：
10.1002/polb.10209
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发表时间：
2002-07
期刊：
影响因子：
--
通讯作者：
C. Mitchell;R. Krishnamoorti
中科院分区：
文献类型：
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作者：
C. Mitchell;R. Krishnamoorti
研究了对称聚苯乙烯-聚异戊二烯嵌段共聚物和有机改性层状硅酸盐制备的纳米复合材料的熔融态粘弹性性能。采用小振幅振荡剪切法研究了三种热等效有机改性层状硅酸盐的纳米复合材料。通过对嵌段共聚物有序和无序状态下纳米复合材料的数据比较，研究了有序嵌段共聚物的畴结构和层状硅酸盐的中尺度分散对流变性能的影响。用5 wt %有机改性氟石（d ~ 10 μm）和蒙脱土（d ~ 1 μm）制备的杂化体在低频时模量的频率依赖性显著降低，在无序状态下低频时复合粘度显著增强。这种行为是根据渗透层状硅酸盐网络结构的发展来理解的。然而，在含5 wt %有机改性拉脱土（d ~ 30 nm）的无序状态和嵌段共聚物的有序状态下，所有层状硅酸盐的粘弹性性能与未填充聚合物相比只有微小的变化。©2002 Wiley期刊公司[J] .高分子材料科学与工程学报，2004,31 (4):444 - 444
The melt-state viscoelastic properties of nanocomposites prepared with a symmetrical polystyrene–polyisoprene block copolymer and organically modified layered silicates are examined. Nanocomposites based on three thermodynamically equivalent organically modified layered silicates, primarily differing in lateral disk diameter (d), are studied with small-amplitude oscillatory shear. The effects of the domain structure of the ordered block copolymer and the mesoscale dispersion of the layered silicates on the rheological properties are examined via a comparison of data for the nanocomposites in the ordered and disordered states of the block copolymer. Hybrids prepared with 5 wt % organically modified fluorohectorite (d ∼ 10 μm) and montmorillonite (d ∼ 1 μm) demonstrate a notable decrease in the frequency dependence of the moduli at low frequencies and a significant enhancement in the complex viscosity at low frequencies in the disordered state. This behavior is understood in terms of the development of a percolated layered-silicate network structure. However, the viscoelastic properties in the disordered state with 5 wt % organically modified laponite (d ∼ 30 nm) and in the ordered state of the block copolymer for all layered silicates demonstrate only minor changes from those observed for the unfilled polymer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1434–1443, 2002