Synergistic enhancement of gas selectivity in thin film composite membranes of PIM-1
Synergistic enhancement of gas selectivity in thin film composite membranes of PIM-1
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DOI：
10.1039/c8ta10691f
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发表时间：
2019-03-21
影响因子：
11.9
通讯作者：
Volkov, Alexey
中科院分区：
文献类型：
--
作者：
Borisov, Ilya;Bakhtin, Danila;Volkov, Alexey
高自由体积玻璃状聚合物或具有固有微孔性的聚合物，如聚[1-三甲基甲硅烷基-1-丙炔]（PTMSP）和聚苯并二氧六环（PIM-1）是超高气体渗透性膜材料。它们的主要缺点之一是气体选择性低。在这项研究中，薄膜复合膜（TFC）已开发出高的CO2渗透和上级CO2/N-2的选择性，由于一个强大的协同效应。TFC膜包括在多孔背衬材料上的交联的PTMSP槽层（2.07-3.44 μ m）顶上的PIM-1薄层（0.29-0.42 μ m），通过将PIM-1溶液涂覆在交联的PTMSP载体上来制造。一个关键因素是首次成功地使用氯仿和三氯乙烯（1：1）的混合溶剂涂覆PIM-1。与PIM-1（α = 18.5）和交联的PTMSP（α = 3.7）相比，所有膜样品都表现出CO2/N-2选择性（α = 35.8-55.7）的强协同增强。SEM、TEM和激光干涉法研究表明，TFC膜中气体选择性的协同增强最有可能是由于在PIM-1和交联的PTMSP槽层之间产生了非常薄的边界层。老化的TFC膜（三个月后）在保持几乎相同的高选择性的同时显示出气体渗透性的严重下降。因此，未来的成功，在预防聚合物的物理老化，与协同效应的选择性报告的第一次在这项工作中，将提供新的机会，应用聚合物的固有微孔。
High free volume glassy polymers or polymers of intrinsic microporosity such as poly[1-trimethylsilyl-1-propyne] (PTMSP) and polybenzodioxane (PIM-1) are extra high gas permeability membrane materials. One of their major drawbacks is low gas selectivity. In this study, thin film composite (TFC) membranes have been developed with high CO2 permeance and superior CO2/N-2 selectivity due to a strong synergistic effect. The TFC membranes, comprising a thin layer (0.29-0.42 mu m) of PIM-1 atop a cross-linked PTMSP gutter layer (2.07-3.44 mu m) on a porous backing material, were fabricated by coating PIM-1 solution on the cross-linked PTMSP support. A key element is that for coating PIM-1 a mixed solvent of chloroform and trichloroethylene (1: 1) was successfully implemented for the first time. All membrane samples demonstrated a strong synergistic enhancement of CO2/N-2 selectivity (alpha = 35.8-55.7) compared to PIM-1 (alpha = 18.5) and cross-linked PTMSP (alpha = 3.7). SEM, TEM and laser interferometry studies revealed that the synergistic enhancement of gas selectivity in the TFC membranes is most likely due to the creation of a very thin boundary layer between PIM-1 and the cross-linked PTMSP gutter layer. The aged TFC membranes (after three months) showed a severe drop in gas permeance while keeping nearly the same high selectivity. Thus, future success in the prevention of polymer physical aging, together with the synergy effect in selectivity reported for the first time in this work, will give new opportunities for application of polymers of intrinsic microporosity.