Morphological states for a ternary polymer blend demonstrating complete wetting
Morphological states for a ternary polymer blend demonstrating complete wetting
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DOI：
10.1016/j.polymer.2010.07.014
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发表时间：
2010-09
期刊：
影响因子：
4.6
通讯作者：
S. Ravati;B. Favis
中科院分区：
文献类型：
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作者：
S. Ravati;B. Favis
在大多数情况下，三元聚合物共混物表现出完全的润湿行为。从概念上讲，这是一种状态，其中一个分量总是倾向于完全分离其他两个分量，从热力学的观点来看，被描述为三个可能的二进制扩展系数中的两个为负而另一个为正的情况，正如哈金斯扩散理论所定义的那样。这项工作考察了通过熔融混合制备的整个三元组成图上这样一个系统可能存在的全部形态状态。选择由高密度聚乙烯(HDPE)、聚苯乙烯(PS)和聚甲基丙烯酸甲酯(PMMA)组成的三元聚合物共混物作为完全润湿的模型体系，可以识别出四种形态：a)基质/核-壳分散相；b)三连续相；c)基质/两个独立分散相；d)双连续/分散相形态。电子显微镜以及一种基于聚焦离子束照射和原子力显微镜相结合的技术被用来清楚地说明和识别各种相。使用溶剂萃取/重量法来检查体系的连续性程度，以便有效地识别高度连续性的区域。使用三角形组成图来区分这些不同的形态区域，并根据各种二元组合的界面张力及其随后的展开系数来解释结果。还考虑了相对分子质量和粘度比对各种结构相尺寸的影响。
For the most part, ternary polymer blends demonstrate complete wetting behavior. Conceptually, this is the state where one of the components will always tend to completely separate the other two and from a thermodynamic viewpoint is described as the case where two of the three possible binary spreading coefficients are negative and the other is positive, as defined by Harkins spreading theory. This work examines the complete range of morphological states possible for such a system over the entire ternary composition diagram as prepared by melt mixing. A ternary polymer blend comprised of high-density polyethylene (HDPE), polystyrene (PS), and poly(methyl methacrylate) (PMMA) is selected as a model system demonstrating complete wetting and four sub-categories of morphologies can be identified including: a) matrix/core–shell dispersed phase; b) tri-continuous; c) matrix/two separate dispersed phases, and d) bi-continuous/dispersed phase morphologies. Electron microscopy as well as a technique based on the combination of focused ion beam irradiation and atomic force microscopy are used to clearly illustrate and identify the various phases. Solvent extraction/gravimetry is used to examine the extent of continuity of the systems so as to effectively identify regions of high continuity. Triangular compositional diagrams are used to distinguish these various morphological regions and the results are interpreted in light of the interfacial tension of the various binary combinations and their subsequent spreading coefficients. The effect of the molecular weight and of viscosity ratio on the phase size of the various structures is also considered.