To develop membrane materials for gas separation, a series of semi-alicyclic polyimides was synthesized using one-step thermal solution imidization from an alicyclic dianhydride with non-planar twisted structure, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA). All synthesized polyimides exhibited amorphous structures and superior thermal stability, with high glass transition temperatures (242–288 °C) withstanding high operation temperature and pressure. They also showed excellent solubility in many polar organic solvents commonly used in the fabrication of gas separation membranes. The gas permeation properties of the polyimide membranes were measured for six representative gases (H₂, CO₂, O₂, CO, N₂, and CH₄). The gas permeabilities and selectivities of polyimide membranes were significantly influenced by the chemical structure of the diamines, which could be explained reasonably by the kinetic diameter of gases, the fractional free volumes, and d-spacing values of the polyimides. Two DOCDA-based polyimides showed very high selectivities for H₂/CH₄ and CO₂/CH₄ and slightly low permeabilities for H₂ and CO₂, which performances were comparable to the commercial polyimide materials such as P84^® and Matrimid^® used in gas separation field.

为了开发用于气体分离的膜材料，使用一步加热的溶液酰亚胺化方法从具有非平面扭曲结构的脂环族二酐5-（2,5-二氧四氢呋喃基）-3-甲基-3合成了一系列半脂环族聚酰亚胺-环己烯-1，2-二羧酸酐（DOCDA）。所有合成的聚酰亚胺均表现出无定形结构和出色的热稳定性，具有高的玻璃化转变温度（242–288°C），可承受较高的工作温度和压力。它们还显示出在许多通常用于制造气体分离膜的极性有机溶剂中的优异溶解性。对六种代表性气体（H ₂，CO ₂，O ₂，CO，N ₂和CH ₄）。聚酰亚胺膜的气体渗透性和选择性受二胺的化学结构的影响很大，这可以合理地用气体的动力学直径，自由体积分数和d-间距值来解释。基于DOCDA-两个聚酰亚胺表现出非常高的选择性用于h ₂ / CH ₄和CO ₂ / CH ₄和稍微低渗透率用于h ₂和CO ₂，其表现是与市售的聚酰亚胺材料，如P84 ^®和的Matrimid ^®中使用气体分离场。