Abstract Based on the aromatic diamine monomer containing di-tert-butylbenzene and methyl groups, this work proposes its polymerization with four different dicarboxylic acids. The prepared polyamides (PA 3a–3d) were characterized by GPC, FTIR, 1H NMR, mechanical, thermal, optical and gas separated techniques. They exhibited high solubility and good optical transparency. Their optical transmittance at 450 nm wavelength was in the range of 81.4%–86.8%, and the cutoff wavelength was in the range of 327–352 nm. The membranes also had good mechanical properties with tensile strength of 79.7–91.4 MPa, elongations at breaks of 9.0–10.9% and initial modulus of 1.5–1.9 GPa. Meanwhile, these membranes possessed good thermal properties with glass transition temperature (T g) values of 226–246 °C. The permeability of CH4, N2, and CO2 for these membranes was tested by constant pressure-variable volume method. The PA 3d containing tert-butyl moiety in the diacid units exhibited highest permeability (PCO2 = 31.4 and PN2 = 1.9) whereas PA 3c containing hexafluoroisopropylidene moiety exhibited highest selectivity (CO2/CH4 = 22.2). Graphical Abstract

中文翻译：

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具有高透明度和改进的气体分离性能的新型可溶性聚酰胺

摘要 基于含二叔丁基苯和甲基的芳香族二胺单体，提出了其与四种不同的二元羧酸的聚合反应。制备的聚酰胺（PA 3a-3d）通过 GPC、FTIR、1H NMR、机械、热、光学和气体分离技术进行表征。它们表现出高溶解度和良好的光学透明度。它们在 450 nm 波长下的透光率在 81.4%–86.8% 范围内，截止波长在 327–352 nm 范围内。该膜还具有良好的机械性能，拉伸强度为 79.7-91.4 MPa，断裂伸长率为 9.0-10.9%，初始模量为 1.5-1.9 GPa。同时，这些膜具有良好的热性能，玻璃化转变温度 (T g) 值为 226–246 °C。CH4、N2、这些膜的 CO2 是通过恒压变体积法测试的。在二酸单元中含有叔丁基部分的 PA 3d 表现出最高的渗透性（PCO2 = 31.4 和 PN2 = 1.9），而含有六氟异亚丙基部分的 PA 3c 表现出最高的选择性（CO2/CH4 = 22.2）。图形概要