PMDA-ODA型聚酰亚胺炭/碳纳米管杂化膜的制备及气体分离性能研究

针对现有气体分离炭膜存在的渗透速率低等问题, 提出并设计在PMDA-ODA型聚酰亚胺前驱体中掺杂碳纳米管, 经高温热解后制备炭/碳纳米管杂化膜. 分别采用透射电镜(TEM)、X射线衍射分析(XRD)和气体渗透实验对炭/碳纳米管杂化膜的微观结构和分离性能进行表征. 实验结果表明, 在PMDA-ODA型聚酰亚胺前驱体中掺杂碳纳米管后, 碳纳米管与炭基体之间形成明显的“界面间隙”, 打破了原有炭膜中由乱层炭构成的无序微孔结构, 重新构建了杂化炭膜的孔隙结构. 与纯炭膜相比, 杂化炭膜的气体渗透速率大幅增加, 其中O₂的渗透速率增大接近4倍(达到1576 Barrer), 而O₂/N₂的分离选择性仅降低17%.

Preparation and Gas Separation Properties of Carbon/Carbon Nanotubes Hybrid Membranes Derived from PMDA-ODA Polyimide

A convenient and effective strategy was used to develop a novel carbon/carbon nanotubes(C/CNT) hybrid membrane by incorporating multi-walled carbon nanotubes(MWNT) into PMDA-ODA polyimide precursor through controlled pyrolysis process at 600℃.Transmission electron microscope,X-ray diffraction and gas permeation experiments were employed to investigate the microstructural characteristics and gas separation performance of hybrid carbon membrane.Results show that the as-prepared C/CNT hybrid membrane has excellent gas(H2,CO2,O2,N2and CH4) separation properties as compared with pure carbon membrane,and the O2 permeability of hybrid carbon membrane increases by nearly 4 times reaching 1576 Barrer,while the O2/N2 permselectivity decreasing by only 17%.It is believed that carbon membrane doped by MWNT can make effective use of the interfacial gaps formed between MWNT and carbon matrix to reconstruct the pore structure of hybrid carbon membrane,which helps to increase the gas diffusion ability and further improve the gas permeability of hybrid carbon membrane.