Dynamical Heterogeneity in the Thermodynamically Miscible Polymer Blend of Poly(vinyl ethyl ether) and Styrene-co-p-hydroxystyrene Copolymer
Dynamical Heterogeneity in the Thermodynamically Miscible Polymer Blend of Poly(vinyl ethyl ether) and Styrene-co-p-hydroxystyrene Copolymer
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聚（乙烯基乙基醚）和苯乙烯-对羟基苯乙烯共聚物的热力学混溶聚合物共混物中的动力学非均质性
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发表时间：
2003
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影响因子：
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通讯作者：
J. Runt
中科院分区：
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作者：
S. H. Zhang;X. Jin;P. Painter;J. Runt
采用宽带介电谱（DRS）等实验手段研究了聚乙烯基乙基醚/苯乙烯-对羟基苯乙烯共混体系（PVEE/SHS）的动态非均匀性。在PVEE/聚对羟基苯乙烯共混物的研究中，我们发现如果存在足够的分子间氢键，则组分聚合物的链段松弛可以耦合。然而，对于SHS/PVEE共混物，即使对于分子间氢键比例与PVPh/PVEE共混物一样大的共混物，在DRS光谱中也观察到两个链段弛豫，其中由于耦合作用，发现了单个链段弛豫来自氢键的影响。这一现象可以用PVEE与苯乙烯单元之间存在的不利相互作用来解释，而PS与PVEE之间的不相容性也支持这一观点。排斥力赋予非氢键PVEE链段更大的松弛自由度，从而使它们能够更好地进行交联。
The dynamic heterogeneity of the thermodynamically miscible blend of poly(vinyl ethyl ether) and styrene-co-p-hydroxystyrene (PVEE/SHS) has been investigated using broadband dielectric spectroscopy (DRS) and other experimental probes. In our previous study of PVEE/poly(p-hydroxystyrene) blends, we found that the segmental relaxations of the component polymers can be coupled if there is sufficient intermolecular hydrogen bonding. For SHS/PVEE blends, however, two segmental relaxations are observed in the DRS spectra, even for blends with a fraction of intermolecular hydrogen bonds as large as that in the PVPh/PVEE blend, in which a single segmental relaxation was found as a result of the coupling effect from the hydrogen bonds. This behavior is explained by the existence of unfavorable interactions between PVEE and the styrene units in SHS, which is supported by the immiscibility between PS and PVEE. The repulsive force endows the non-hydrogen-bonded PVEE segments with more freedom to relax, so that they c...