聚酰亚胺／TiO_2复合膜的制备、表征和气体渗透性测定

Preparation, Characterization, and Gas Separation Properties of Polyimide/TiO_2 Composite Membranes

以硅藻土-莫来石陶瓷膜管为支撑体,以TiO2为过渡层,通过溶胶-凝胶法制备了负载型聚酰亚胺／TiO2复合膜．采用FTIR、NMR、TG／DTA、TEM、BET和气体渗透法对复合膜进行了表征和测试．结果表明:TiO2相通过与聚酰亚胺链上羧酸基支链发生键连形成有机无机组分交错分布的网状结构;复合膜具有良好的热稳定性和有机无机兼容性;相对于聚酰亚胺膜,复合膜对H2、CO2、N2和H2O具有较高的分离性; TiO2含量为15wt％的复合膜对H2／N2、CO2／N2和H2O／N2的分离因子分别为64．2、42．5和80．8．

A series of polyimide/TiO2 composite membranes supported on TiO2/kieselguhr-mullite （K-M） were prepared via a sol-gel process. Their morphologies, chemical structures, thermal performances, pore distribution and gas permeability were characterized by transmission electron microscope （TEM）, Fourier transform infrared （FTIR）, solid-state 13C CP/MAS NMR, thermogravimetric analysis （TG/DTA）, N2 adsorption and gas permeability measurement. The results show the TiO2 phase is well dispersed in the polyimide matrix. The TiO2 phase is connected with the polyimide through the pendant carboxyl along the polyimide chain. The polyimide/TiO2 composite membrane possesses finely thermal stability. The composite membranes show higher separation properties for H2, CO2, N2 and H2O when compared to pure polyimide. The separation factors of the polyimide/TiO2 composite membranes with 5wt% TiO2 contents for H2/N2, CO2/N2 and H20/N2 are 64.2, 42.5 and 80.8, respectively.