疏水SiO2/PTFPMS杂化复合膜的制备及其气体分离性能

摘要

To improve the solvent resistance property of gas separation membrane, a hydrophobic SiO2/polytrifluoropropylsiloxane (PTFPMS) hybrid composite membrane was fabricated on a porous polyetherimide (PEI) support with solution blending method. The effects of mass ratio of hydrophobic SiO2 to PTFPMS on the membrane morphology, solvent resistance, and gas separation performance of the hydrophobic SiO2/PTFPMS hybrid composite membrane were investigated. The optical microscope images show good miscibility between SiO2 and PTFPMS with the increase of blend ratio till 0.018. At blend ratios higher than 0.018, SiO2 particles exhibit obvious aggregation in the hybrid membrane. SEM images show that no obvious defect is on the surface of the SiO2/PTFPMS selective layer that is closely stuck on the PEI support. The swelling degree of the hydrophobic SiO2/PTFPMS hybrid homogeneous film is 0 in nonpolar solvent octane and is declined by 11.9%in polar solvent ethyl acetate compared with PTFPMS homogeneous film, indicating the improved solvent resistance of the SiO2/PTFPMS hybrid homogeneous film. The CO2 gas permeation rate can reach as high as 156.1 GPU and the selectivity of CO2/N2 is 15.86 when the blend ratio of SiO2 is 0.012 under the transmembrane pressure difference up to 1.0 MPa.%为了提高气体分离膜的耐溶胀特性，以多孔聚醚酰亚胺（PEI）为支撑层，采用溶液共混法制备了疏水SiO2/PTFPMS杂化复合膜，研究了疏水SiO2质量共混比对膜形态、耐溶胀性以及不同操作压差下的纯气渗透分离性能的影响。光学显微照片显示，当共混比不超过0.018时，杂化膜的透明度较高，表明疏水SiO2与PTFPMS具有较好的相容性；当SiO2与PTFPMS的共混比超过0.018时，SiO2团聚明显。SEM表征结果显示，杂化膜表面光洁，断面杂化涂层紧密贴合支撑层。疏水SiO2/PTFPMS杂化膜在异辛烷中的溶胀度为0，在乙酸乙酯中的溶胀度比PTFPMS均质膜的下降了11.9%，显示了其优异的耐溶胀性能。在操作压力为1.0 MPa，操作温度为25℃下， SiO2共混比为0.012时，疏水SiO2/PTFPMS杂化复合膜的CO2渗透通量达到最高156.1GPU，CO2/N2选择性为15.86。