Influence of the efficacy of interfacial modification on the coarsening of cocontinuous PS/HDPE blends during quiescent annealing
Influence of the efficacy of interfacial modification on the coarsening of cocontinuous PS/HDPE blends during quiescent annealing
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DOI：
10.1002/polb.20733
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发表时间：
2006-02
期刊：
影响因子：
--
通讯作者：
Zhenhua Yuan;B. Favis
中科院分区：
文献类型：
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作者：
Zhenhua Yuan;B. Favis
本文研究了三种不同的共连续聚苯乙烯/高密度聚乙烯共混物用两种不同的界面剂改性后的静态退火。采用汞孔法对相生长进行了定量分析。在之前的研究中，研究人员发现，其中一种改性剂，即对称双嵌段共聚物，对界面具有很高的亲和力，并且在共混界面饱和之前几乎没有形成胶束。另一种改性剂是70/30的氢化SEBS，在改性剂浓度升高时形成胶束。本研究表明，在没有改性剂的情况下，共连续相尺寸线性增长，而两种界面改性剂的加入都显著抑制了PE/PS相的粗化，导致了相的非线性生长行为。然而，二嵌段共聚物抑制粗化的效果要比三嵌段共聚物有效得多，这清楚地支持了后一种改性剂形成胶束的趋势。在未改性PE/PS的情况下，毛细压力效应的驱动力非常大，毛细不稳定现象主导了粗化过程，从而导致孔径随退火时间的线性增长。当加入界面改性剂时，界面张力的降低和孔隙多分散性的降低显著降低了毛细管压力效应和毛细管不稳定现象。在这种情况下，毛管压力成为主要的速率决定步骤，导致孔径随退火时间的非线性依赖。结果表明，在界面改性剂含量较低时，相的粘度和退火温度对粗化行为有较大影响。然而，在所有这些条件下，部分相容体系的相生长仍然是非线性的。这些结果清楚地表明，使用汞孔隙率法进行的细致的定量粗化实验可以作为分析界面改性剂在高度连续或共连续体系中的有效性的工具。©2006 Wiley期刊公司[J] .化学工程学报，2001,19 (4):557 - 557
This article studies the quiescent annealing of three different cocontinuous polystyrene/high-density polyethylene blends modified with two types of interfacial agents of widely different efficacies. Quantitative analysis of phase growth was obtained using mercury porosimetry. In a previous work, it was shown that one of these modifiers, a symmetrical diblock copolymer, has a high affinity for the interface and demonstrates virtually no micelle formation prior to saturation of the blend interface. The other modifier, a hydrogenated SEBS of 70/30 composition, forms micelles at elevated concentrations of modifier. In this study, it is shown that the cocontinuous phase size grows linearly without modifier, whereas the addition of both interfacial modifiers significantly suppresses the PE/PS phase coarsening and results in nonlinear phase growth behavior. The effect of the diblock copolymer on suppressing coarsening, however, is much more effective than that for the triblock case clearly supporting the tendency toward micelle formation for that latter modifier. In the case of unmodified PE/PS, the driving force for capillary pressure effects is so high that it is the capillary instability phenomena that dominate the coarsening and hence result in a linear growth of pore size with annealing time. When interfacial modifiers are added, the influence of reduced interfacial tension and lower pore size polydispersity significantly diminishes both capillary pressure effects and capillary instability phenomena. In that case, capillary pressure becomes the main rate determining step resulting in a nonlinear dependence of pore size with annealing time. It is shown that both the viscosity of the phases and the temperature of annealing can strongly influence coarsening behavior at low levels of interfacial modifier. Under all those conditions, however, nonlinear phase growth for the partially compatibilized system was maintained. These results clearly show that careful quantitative coarsening experiments using mercury porosimetry can be used as a tool to analyze the efficacy of interfacial modifiers for highly continuous or cocontinuous systems. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 711–721, 2006