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首页> 外文期刊>Journal of Applied Polymer Science >POLARITY MEASUREMENTS IN BLOCK COPOLYMERS (POLYURETHANEIMIDES) AND CORRELATION WITH THEIR PERVAPORATION FEATURES
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POLARITY MEASUREMENTS IN BLOCK COPOLYMERS (POLYURETHANEIMIDES) AND CORRELATION WITH THEIR PERVAPORATION FEATURES

机译：嵌段共聚物（聚氨酯）的极性测量及其渗透特性的相关性

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摘要

EtOH/ETBE azeotropic mixture was separated by prevaporation through films of polyurethaneimides (PUI), i.e., alternating block copolymers varying in their structure only by their oligomeric soft blocks. Pervaporation performances strongly depend on the flexible segments: fluxes on the molecular weight and selectivity towards ethanol on the chemical structure in the decreasing order: PEG, PCL, PCD, PTMG, PPG. In order to correlate selectivity with segment polarity, a new solvatochromic polarity probe that was well soluble in PUI was synthesized. Using 13 solvents covering a wide polarity range, Vis lambda(max) of the photochromic indicator open form was linearly correlated with the E(T)(30) polarity scale. Ey illumination of the dissolved dye, PUI polarity was investigated in relation to-soft segment nature and size. The very high PUI polarity values and their splitting for highest size segments were assigned to preferential probe solvation by interblock urethane junctions combined with phase segregation. Polarity values consistent with the chemical structure of the flexible segments were provided by similar measurements on suitably end-capped precursors of these segments and were then linearly correlated with the related PUI pervaporation selectivity. (C) 1995 John Wiley and Sons, Inc. [References: 29]
机译：EtOH / ETBE共沸混合物通过聚氨酯酰亚胺（PUI）膜预蒸发而分离，即，仅由其低聚物软嵌段改变结构的交替嵌段共聚物。全蒸发性能强烈取决于柔性链段：通量取决于分子量，对化学结构的乙醇选择性按降序排列：PEG，PCL，PCD，PTMG，PPG。为了将选择性与链段极性相关联，合成了一种新的溶剂化变色极性探针，该探针可溶于PUI。使用13种覆盖宽极性范围的溶剂，光致变色指示剂开放形式的Vis lambda（max）与E（T）（30）极性标度线性相关。通过照射溶解的染料，研究了PUI极性与软链段性质和大小的关系。通过嵌段间氨基甲酸酯连接结合相分离，将非常高的PUI极性值及其对于最大尺寸段的拆分指定为优先探针溶剂化。通过对这些段的适当封端的前体进行类似的测量，可以提供与柔性段的化学结构相符的极性值，然后将其与相关的PUI渗透汽化选择性线性相关。 （C）1995 John Wiley and Sons，Inc. [参考：29]

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