Morphology and rheology of immiscible polymer blends filled with silica nanoparticles
Morphology and rheology of immiscible polymer blends filled with silica nanoparticles
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DOI：
10.1016/j.polymer.2007.07.061
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发表时间：
2007-09-21
期刊：
影响因子：
4.6
通讯作者：
Cassagnau, Ph.
中科院分区：
文献类型：
--
作者：
Elias, L.;Fenouillot, F.;Cassagnau, Ph.
研究了二氧化硅纳米粒子对不混溶聚合物共混物（聚丙烯/聚苯乙烯，PP/PS 70/30）的形态和流变性质的影响。使用两种类型的热解纳米二氧化硅：比表面积为200m(2)/g的亲水性二氧化硅和比表面积为150m(2)/g的疏水性二氧化硅。首先，观察到填充有 3 wt% 二氧化硅的共混物的 PS 液滴体积半径显着减小，从 3.25 减小到接近 1 μm。更有趣的是，显微照片的图像分析证明，亲水性二氧化硅倾向于限制在 PS 相中，而疏水性二氧化硅则位于 PP 相和 PP/PS 界面处（界面厚度约为 100-200 n）。此外，还观察到亲水性二氧化硅从PP相向PS域的迁移。流变实验数据的分析基于Palierne模型的框架，并扩展到填充的不混溶共混物。由于二氧化硅颗粒在两相中的分配及其对粘度比的影响，仅研究了有限的情况。用疏水性二氧化硅获得的流变数据更难以建模，因为模型无法考虑厚界面的存在。最后，亲水性二氧化硅均匀分散在PS液滴中和疏水性二氧化硅分散在PP基质中的假设更接近实际情况。由此可以得出结论，亲水性二氧化硅对 PP/PS 共混物的稳定机制是降低界面张力，而疏水性二氧化硅则充当刚性层，防止 PS 液滴聚结。 (c) 2007 Elsevier Ltd. 保留所有权利。
The effect of silica nanoparticles on the morphology and the theological properties of an immiscible polymer blend (polypropylene/polystyrene, PP/PS 70/30) was investigated. Two types of pyrogenic nanosilica were used: a hydrophilic silica with a specific surface area of 200 m(2)/g and a hydrophobic silica having a specific surface area of 150 m(2)/g. First, a significant reduction in the PS droplet volume radius, from 3.25 to nearly 1 mu m for filled blends with 3 wt% silica, was observed. More interestingly, image analysis of the micrographs proved that the hydrophilic silica tends to confine in the PS phase whereas hydrophobic one was located in the PP phase and at the PP/PS interface (interphase thickness approximate to 100-200 n). Furthermore, a migration of hydrophilic silica from PP phase toward PS domains was observed.An analysims of the rheological experimental data was based on the framework of the Palierne model, extended to filled immiscible blends. Due to the partition of silica particles in the two phases and its influence on the viscosity ratio, limited cases have been investigated. The rheological data obtained with the hydrophobic silica were more difficult to model since the existence of a thick interphase cannot be taken into account by the model. Finally, the hypothesis that hydrophilic silica is homogeneously dispersed in PS droplets and that hydrophobic silica is dispersed in PP matrix was much closer to the actual situation. It can be then concluded that stabilization mechanism of PP/PS blend by hydrophilic silica is the reduction in the interfacial tension whereas hydrophobic silica acts as a rigid layer preventing the coalescence of PS droplets. (c) 2007 Elsevier Ltd. All rights reserved.