The effects of branching and deuterium labeling on blend miscibility
The effects of branching and deuterium labeling on blend miscibility
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DOI：
10.1016/j.polymer.2017.02.089
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发表时间：
2017-04
期刊：
影响因子：
4.6
通讯作者：
J. Defelice;J. Higgins;J. Lipson
中科院分区：
文献类型：
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作者：
J. Defelice;J. Higgins;J. Lipson
聚苯乙烯（PS）在高临界溶液温度（UCST）和低临界溶液温度（LCST）混合物中的相容性受到四臂星形支化和氘标记的单独和联合作用的影响。在本文中，我们使用我们的局部相关晶格（LCL）模型来表征一组PS样品的纯态，以预测PS与聚乙烯基甲基醚（PVME） （lcst型混合物）和PS的同位素变体（ucst型混合物）的混相趋势。我们发现，四臂星形分支和/或氘标记可以改变PS的纯组分性质，如其自由体积百分比或内聚能密度，从而影响PS的性质如何与其他混合物组分“匹配”。在本文的另一部分中，我们将对混合物本身进行建模，并通过计算混合自由能的相对焓和熵贡献，提供关于PS/PVME混合物的基本热力学见解。我们观察到PS/PVME共混物的混合熵和混合焓值的变化趋势与我们对纯PS样品的纯组分性质分析在质量上相匹配。
The individual and combined effects of 4-arm star branching and deuterium labeling on polystyrene (PS) influence its compatibility in upper critical solution temperature (UCST) and lower critical solution temperature (LCST) mixtures. In this article, we use our Locally Correlated Lattice (LCL) model to characterize a set of PS samples in their pure states in order to predict miscibility trends for blends of PS with poly(vinyl methyl ether) (PVME) (LCST-type mixtures) and isotopic variants of PS (UCST-type mixtures). We find that 4-arm star branching and/or deuterium labeling can shift the pure component properties of PS, such as its percent free volume or cohesive energy density, which affects how the properties of PS ‘match’ those of the other mixture component. In another section of this article, we turn to modeling the blends, themselves, and provide fundamental thermodynamic insight about the PS/PVME mixtures by calculating the relative enthalpic and entropic contributions to the free energies of mixing. We observe trends in the values of the entropies and enthalpies of mixing for the PS/PVME blends that qualitatively match our pure component properties analysis of the pure PS samples.