聚氧化乙烯/冠醚共混膜及其二氧化碳分离性能

doi:10.11949/0438-1157.20250122

摘要/Abstract

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

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

中图分类号:

TQ 028.8

张建民, 何美贵, 贾万鑫, 赵静, 金万勤. 聚氧化乙烯/冠醚共混膜及其二氧化碳分离性能[J]. 化工学报, 2025, 76(9): 4862-4871.

Jianmin ZHANG, Meigui HE, Wanxin JIA, Jing ZHAO, Wanqin JIN. Poly(ethylene oxide)/crown ether blend membrane and performance for CO₂ separation[J]. CIESC Journal, 2025, 76(9): 4862-4871.

图/表 11

图1 PEO/C6膜的制备过程示意图

Fig.1 Schematic diagram of the preparation process of the PEO/C6 membranes

图2 (a)PEO膜和PEO/C6共混膜的照片；(b)PEO膜和PEO/C6共混膜的傅里叶变换红外光谱

Fig.2 (a) Digital photos of PEO and PEO/C6 membranes； (b) FTIR spectra of PEO and PEO/C6 membranes

图3 不同冠醚含量的PEO/C6共混膜的DSC谱图

Fig.3 DSC spectra of PEO/C6 membranes with different C6 contents

表1 PEO膜和PEO/C6膜的Tg、Tc、Tm、ΔHm和Xc

Table 1 Tg， Tc， Tm， ΔHm and Xc of PEO and PEO/C6 membranes

膜	w	T_g/℃	T_c/℃	T_m1/℃	T_m2/℃	ΔH_m/(J/g)	X_c/%
PEO	0	-47.57	—	—	—	—	—
PEO/C6(20)	0.167	-51.79	—	—	—	—	—
PEO/C6(40)	0.286	-54.05	—	—	—	—	—
PEO/C6(60)	0.375	-55.62	-5.7	6.58	20.64	6.89	4.22
PEO/C6(80)	0.444	-57.03	-6.02	7.35	16.73	18.03	11.03
PEO/C6(100)	0.500	-58.67	-9.17	—	15.38	34.11	20.88

图4 C6、PEO膜和PEO/C6共混膜的XRD谱

Fig.4 XRD pattern of C6, PEO membrane and PEO/C6 membranes

图5 (a)PEO膜和PEO/C6共混膜的密度及加性模型的拟合曲线；(b)PEO膜和PEO/C6共混膜的自由体积分数

Fig.5 (a) The linear fitting of 1/ρ with w2 according to additive model; (b) Free volume fraction of PEO and PEO/C6 membranes

图6 PEO膜和PEO/C6共混膜的TGA曲线(a)和DTG曲线(b)

Fig.6 TGA (a) and DTG (b) curves of PEO and PEO/C6 membranes

图7 PEO和PEO/C6共混膜的气体分离性能

Fig.7 Gas separation performance of PEO and PEO/C6 membranes

图8 PEO和PEO/C6共混膜的溶解系数和溶解选择性(a)及扩散系数和扩散选择性(b)

Fig.8 Solubility and solubility selectivity (a), diffusivity and diffusivity selectivity (b) of PEO and PEO/C6 membranes

图9 操作条件对 PEO/C6(100)共混膜分离性能的影响（混合气体，CO2∶N2 = 15∶85，体积比）

Fig.9 Effect of operating conditions on the separation performance of PEO/C6(100) membranes (mixed gas, CO2∶N2 = 15∶85, volume ratio)

图10 (a)PEO/C6(100)共混膜的长期稳定性测试（混合气体，CO2∶N2 = 15∶85，体积比）；(b)PEO/C6(100)共混膜与目前报道的PEO基聚合物膜的CO2/N2分离性能对比

Fig.10 (a) Long-term stability test of PEO/C6(100) membranes (mixed gas, CO2∶N2 = 15∶85, volume ratio); (b) Comparison of CO2/N2 separation performance of PEO/C6(100) membranes with reported PEO-based polymer membranes

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