Abstract:

Crosslinked polyethylene oxide (PEO) is one of the hot membrane materials currently used for CO₂ capture. However, a large number of hydroxyl groups are generated in the process of forming cross-linked PEO based on epoxy ring-opening polymerization, resulting in abundant hydrogen bonding between molecular chains, thereby reducing chain mobility, increasing the permeation resistance of gas molecules, and making the permeability of membrane materials unsatisfactory. In order to improve the CO₂ separation performance of crosslinked PEO membranes, 18-crown-6 (C6) small molecules are introduced into the PEO crosslinking network, forming a homogeneous mixture. Utilizing the cavity structure of C6 molecules and their interference with the hydrogen bonds between PEO molecular chains, both CO₂ adsorption and diffusion processes are facilitated. The CO₂ permeability is increased to 4.2 times that of the PEO membrane (636 Barrer), while maintaining a high separation selectivity (about 50), and the membrane performance remains stable during 300 h of continuous testing.

Key words: poly (ethylene oxide) (PEO), crown ether, membrane, carbon dioxide, separation

摘要：

交联聚氧化乙烯（PEO）是目前用于CO₂捕集的热点膜材料之一。然而，基于环氧开环聚合反应形成交联PEO过程中会产生大量羟基，导致分子链间形成丰富的氢键作用，从而降低链的运动性，增大气体分子的渗透阻力，使膜材料渗透性不理想。为了提升交联PEO膜的CO₂分离性能，将18-冠-6（C6）小分子引入PEO交联网络中，形成均相混合物，利用C6分子的空腔结构及其对PEO分子链间氢键作用的干扰，促进CO₂的溶解和扩散过程。CO₂渗透系数提升至PEO膜的4.2倍［636 Barrer（1 Barrer=3.35×10^-16 mol·m·m^-2·s·Pa）］，同时保持了较高的分离选择性（约50），且膜性能在300 h的连续测试中保持稳定。

关键词: 聚氧化乙烯, 冠醚, 膜, 二氧化碳, 分离