The changes in physical, chemical, and gas permeation properties of a heat-treated hydroxyl-functionalized Tröger's base-derived intrinsically microporous polyimide, 6FDA-HTB, were systematically studied. Polyimide samples were heat-treated for 30 min at a fixed temperature to form (i) polybenzoxazole (PBO) by thermal rearrangement (TR) from ∼420 to ∼440 °C, (ii) polymer-carbon transition (PCT) from ∼460 to ∼500 °C, and (iii) early-stage carbon (ESC) membranes from >500 to 600 °C. As frequently observed in previous studies, TR-derived PBO membranes showed an increase in gas permeability with a concomitant decrease in gas-pair selectivity. The intermediate PCT region represents a transition state from a PBO to a partially carbonized polymer with superior properties by showing a simultaneous boost in gas permeability and gas-pair selectivity. The ESC membranes formed between 550 and 600 °C possessed further enhanced selectivity due to tightening of the amorphous CMS structure. A 135-day aged 6FDA-HTB-600 membrane showed very high hydrogen permeability of 3544 barrer coupled with an outstanding H₂/CH₄ selectivity of 939. The mixed-gas separation properties of selected aged samples, pristine 6FDA-HTB, PBO (6FDA-HTB-420), intermediate PCT (6FDA-HTB-480), and early stage CMS analogs (6FDA-HTB-550 and 600), were investigated using a 1:1 CO₂/CH₄ feed up to 30 bar. In this series, early-stage CMS membranes displayed the best mixed-gas CO₂/CH₄ separation properties with performance significantly surpassing the 2018 polymer mixed-gas upper bound.

热处理的羟基官能化 Tröger 碱基衍生本征微孔聚酰亚胺的物理、化学和气体渗透性能的变化, 6FDA-HTB, 进行了系统研究。聚酰亚胺样品在固定温度下热处理 30 分钟，形成 (i) 聚苯并恶唑 (PBO) 通过热重排 (TR) 从 ~ 420 到 ~ 440 °C，(ii) 聚合物-碳转变 (PCT) 从 ~ 460到~500°C，和（iii）早期碳（ESC）膜从> 500到600°C。正如在以前的研究中经常观察到的那样，TR 衍生的 PBO 膜显示出气体渗透性的增加，同时伴随着气体对选择性的降低。中间 PCT 区域代表了从 PBO 到具有优异性能的部分碳化聚合物的过渡状态，同时显示出气体渗透性和气体对选择性的提高。由于无定形的收紧，在 550 和 600 °C 之间形成的 ESC 膜具有进一步增强的选择性内容管理系统结构。老化 135 天的 6FDA-HTB-600 膜显示出 3544 barrer 的非常高的氢渗透率以及 939 的出色 H ₂ /CH ₄选择性。所选老化样品、原始 6FDA-HTB、PBO 的混合气体分离性能 ( 6FDA-HTB-420)、中间体 PCT (6FDA-HTB-480) 和早期 CMS 类似物（6FDA-HTB-550 和 600）使用 1:1 CO 2 /CH 4 进料至 30 bar_进行了_研究。在这个系列中，早期的CMS膜表现出最好的混合气体CO ₂ /CH ₄分离性能，性能显着超过2018年聚合物混合气体上限。