Effects of solvent and nonsolvent diffusion velocities on the morphology of cellular polyetherimide membranes prepared using supercritical CO₂ phase inversion

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• 作者：Wenhua Shi ; Gaohong He ; Wei Zhao ; Lingling Zhang ; Lin Du ; Yongdong Wang ; Xiaochen Qin
• 关键词：Supercritical CO2 ; Membrane morphology ; Diffusion velocity ; Cellular pore ; Pore size ; Porosity
• 刊名：The Journal of Supercritical Fluids
• 出版年：November, 2013
• 年：2013
• 卷：83
• 期：Complete
• 页码：6-14
• 全文大小：4682 K

文摘

Mass transfer kinetics plays a dominant role in membrane morphology. In this study, the effects of polymer concentration, supercritical CO₂ (ScCO₂) pressure and temperature on the morphology of polyetherimide (PEI) membranes prepared using ScCO₂ phase inversion were investigated from the view of the instantaneous velocity of ScCO₂ in-diffusion and the difference between average solvent out-diffusion velocity and average ScCO₂ in-diffusion velocity through the interface between the casting solution and ScCO₂, . The high instantaneous velocity of ScCO₂ in-diffusion at the moment of onset of phase separation led to a cellular pore structure in the membrane. In addition, the dramatic decrease in the resulted in the increased trends of pore size and porosity of the membrane with the increases in polymer concentration, ScCO₂ pressure and temperature.