Sundell Benjamin J, Lawrence John A, Harrigan Daniel J, Lin Sibo, Headrick Tatiana P, O'Brien Jeremy T, Penniman William F, Sandler Nathan
Aramco Research Center - Boston, Aramco Services Company, Boston, Massachusetts 02139, United States.
ACS Macro Lett. 2020 Sep 15;9(9):1363-1368. doi: 10.1021/acsmacrolett.0c00555. Epub 2020 Aug 31.
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 monomeric mixtures that restrict polymerization sites. In this work, a synthetic approach employing the reductive Mizoroki-Heck reaction resulted in -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 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.
下一代膜使用具有增强链刚性的高度工程化聚合物结构，但聚合过程中的困难常常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景的材料，但由于限制聚合位点的单体混合物而存在这些局限性。在这项工作中，一种采用还原型 Mizoroki-Heck 反应的合成方法得到了具有选择性的产物，对于开环易位聚合（ROMP）和加成型聚合物，其聚合产率高达>99%，实现的分子量比来自混合物的加成型聚合物高一个数量级，并且具有令人印象深刻的侧基立构规整性。由于这种对大分子控制的增强，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使用的聚二甲基硅氧烷（PDMS）。除了热学和结构表征外，X 射线衍射（XRD）和计算研究证实了纯气体和混合气体传输测试的结果，这些结果表明具有高度刚性的膜，其链堆积受到有利的破坏。
