Nabais Ana R, Francisco Rute O, Alves Vítor D, Neves Luísa A, Tomé Liliana C
LAQV-REQUIMTE, Department of Chemistry, NOVA School of Science and Technology, FCT NOVA, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
LEAF-Linking Landscape, Environment, Agriculture and Food-Research Center, Associated Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisabon, Portugal.
Membranes (Basel). 2021 Dec 20;11(12):998. doi: 10.3390/membranes11120998.
Despite the fact that iongels are very attractive materials for gas separation membranes, they often show mechanical stability issues mainly due to the high ionic liquid (IL) content (≥60 wt%) needed to achieve high gas separation performances. This work investigates a strategy to improve the mechanical properties of iongel membranes, which consists in the incorporation of montmorillonite (MMT) nanoclay, from 0.2 to 7.5 wt%, into a cross-linked poly(ethylene glycol) diacrylate (PEGDA) network containing 60 wt% of the IL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Cmim][TFSI]). The iongels were prepared by a simple one-pot method using ultraviolet (UV) initiated polymerization of poly(ethylene glycol) diacrylate (PEGDA) and characterized by several techniques to assess their physico-chemical properties. The thermal stability of the iongels was influenced by the addition of higher MMT contents (>5 wt%). It was possible to improve both puncture strength and elongation at break with MMT contents up to 1 wt%. Furthermore, the highest ideal gas selectivities were achieved for iongels containing 0.5 wt% MMT, while the highest CO permeability was observed at 7.5 wt% MMT content, due to an increase in diffusivity. Remarkably, this strategy allowed for the preparation and gas permeation of self-standing iongel containing 80 wt% IL, which had not been possible up until now.
尽管离子凝胶是用于气体分离膜的极具吸引力的材料，但它们常常表现出机械稳定性问题，这主要是由于为实现高气体分离性能需要高离子液体（IL）含量（≥60 wt%）。本工作研究了一种改善离子凝胶膜机械性能的策略，该策略包括将0.2至7.5 wt%的蒙脱石（MMT）纳米粘土掺入含有60 wt%的IL 1-乙基-3-甲基咪唑双（三氟甲基磺酰）亚胺（[Cmim][TFSI]）的交联聚乙二醇二丙烯酸酯（PEGDA）网络中。离子凝胶通过聚乙二醇二丙烯酸酯（PEGDA）的紫外（UV）引发聚合的简单一锅法制备，并通过多种技术对其进行表征以评估其物理化学性质。较高MMT含量（>5 wt%）的添加影响了离子凝胶的热稳定性。MMT含量高达1 wt%时，穿刺强度和断裂伸长率均可提高。此外，含0.5 wt% MMT的离子凝胶实现了最高的理想气体选择性，而在MMT含量为7.5 wt%时观察到最高的CO渗透率，这是由于扩散率增加。值得注意的是，该策略使得制备和气体渗透含80 wt% IL的自立式离子凝胶成为可能，而这在之前是无法实现的。
