Exo-selective, Reductive Heck Derived Polynorbornenes with Enhanced Molecular Weights, Yields, and Hydrocarbon Gas Transport Properties,ACS Macro Letters

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Exo-selective, Reductive Heck Derived Polynorbornenes with Enhanced Molecular Weights, Yields, and Hydrocarbon Gas Transport Properties
ACS Macro Letters ( IF 5.1 ) Pub Date : 2020-08-31 , DOI: 10.1021/acsmacrolett.0c00555
Benjamin J Sundell ₁ , John A Lawrence ₁ , Daniel J Harrigan ₁ , Sibo Lin ₁ , Tatiana P Headrick ₁ , Jeremy T O'Brien ₁ , William F Penniman ₁ , Nathan Sandler ₁

Affiliation

Next-generation membranes use highly engineered polymeric structures with enhanced chain rigidity, yet difficulties in polymerization often limit molecular weights required for film formation. Addition-type polynorbornenes are promising materials for industrial gas separations, but suffer from these limitations owing to endo−exo monomeric mixtures that restrict polymerization sites. In this work, a synthetic approach employing the reductive Mizoroki–Heck reaction resulted in exo-selective products that polymerized up to >99% yields for ROMP and addition-type polymers, achieving molecular weights an order of magnitude higher than addition-type polymers from endo−exo mixtures and impressive side group stereoregularity. Due to this increased macromolecular control, these polynorbornenes demonstrate unique solubility-selective permeation with mixed gas selectivities that exceed commercially used PDMS. In addition to thermal and structural characterization, XRD and computational studies confirmed the results of pure and mixed-gas transport testing, which show highly rigid membranes with favorably disrupted chain packing.

中文翻译：

具有增强的分子量、产率和烃类气体传输特性的外选择性、还原性 Heck 衍生聚降冰片烯

下一代膜使用高度工程化的聚合物结构，具有增强的链刚性，但聚合困难通常会限制成膜所需的分子量。加成型聚降冰片烯是用于工业气体分离的有前途的材料，但由于限制聚合位点的内-外单体混合物而受到这些限制。在这项工作中，采用还原性 Mizoroki-Heck 反应的合成方法产生了外选择性产物，对于 ROMP 和加成型聚合物的聚合产率高达 > 99%，实现的分子量比来自加成型聚合物的数量级高一个数量级。内-外混合物和令人印象深刻的侧基立构规整性。由于这种增加的大分子控制，这些聚降冰片烯表现出独特的溶解度选择性渗透，其混合气体选择性超过了商业上使用的 PDMS。除了热和结构表征之外，XRD 和计算研究证实了纯气体和混合气体传输测试的结果，这些测试显示了具有良好破坏链堆积的高刚性膜。

更新日期：2020-09-15

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