负载型聚酰亚胺/SnO2杂化膜的结构和性能

通过溶胶凝胶法， 以硅藻土-莫来石陶瓷膜管为支撑体，TiO2为过渡层， 利用具有大量支链的聚酰亚胺和SnO2溶胶制备了系列不同SnO2含量的负载型聚酰亚胺/SnO2杂化膜．采用TEM、FTIR、XPS、TG/DTA、DSC、BET和气体渗透测定对系列膜的微观型态、化学结构、热稳定性、孔结构和气体渗透性能进行了表征和测试． 结果表明，SnO2相与聚酰亚胺支链羧酸基发生化学键连； 杂化膜具有较好的有机无机兼容性， 当SnO2达到15%时，SnO2相在杂化膜中以颗粒状存在， 其粒径约为5 nm；SnO2相与聚酰亚胺间的化学键连有效的提高了杂化膜的玻璃化温度； 随着SnO2含量的增加， 杂化膜的热分解温度逐渐下降； 系列膜具有均匀的孔道结构， 其孔径分别为3.8、3.1、2.8和2.4 nm． 相对于聚酰亚胺膜， 杂化膜对H2、CO2、CO和H2O具有较高的分离性，SnO2为15%的杂化膜对H2/N2、CO2/N2、CO/N2和H2O/N2的分离因子分别达到54.1、30.2、35.9和40.1．

Structures and Properties of Supported Polyimide/SnO2 Hybrid Membranes

A series of polyimide/SnO2 hybrid membranes supported on TiO2/kieselguhr-mullite were prepared from polyimide with a large amount of carboxyl and SnO2 sol via a sol-gel process. The SnO2 phase chemically linked with the polyimide through the pendant carboxyl along the polyimide. The hybrid membranes were highly homogeneous, and when the SnO2 contents reached 15wt% the SnO2 phase was observed as particles with a diameter of 5 nm dispersed in the hybrid membranes . The cross-linking between the SnO2 phase and polyimide effectively enhanced the glass temperature of the hybrid films. With the increasing of the SnO2 contents, the pore sizes of the membranes decreased, and their pore sizes were mainly focused on 3.8, 3.1, 2.8 and 2.4 nm. The hybrid membranes showed higher permeability for H2, CO2, CO and H2O when compared to the pure polyimide. The separation factors of the polyimide/SnO2 hybrid membranes with 15wt% SnO2 content for H2/N2, CO2/N2, CO/N2 and H2O/N2 were 54.1, 30.2, 35.9 and 40.1, respectively.