本文综述了聚合物膜制备过程中的相关基础问题和取得的研究进展.通过铸膜液邻近比和凝胶邻近比描述制膜体系的热力学状态和凝胶特性,借助于延迟相分离时间与凝胶时间来描述膜的形成过程.通过“粘性指进”来解释大孔腔的形成,从铸膜液邻近比和厚度梯度膜的概念上调控膜结构在指状孔与海绵状孔之间的转变.对于中空纤维和平板膜的制备来说,铸膜液的流变特性强烈影响着膜的结构与分离性能.通过Extreme 模型把孔径分布函数与截留分子量关联在一起,对表征膜的分离特性起到指导作用.

Some basic research progress for the formation of polymeric membranes by immersion precipitation method is reviewed. The approaching ratio and the approaching coagulant ratio are used to describe the thermodynamic state of the casting solution and the precipitation property of the coagulant. The membrane formation process is described with two macroscopic time scales, delay time and gelation time, and “viscous fingering” is used to explain the formation of macrovoids. The transition of membrane morphology between sponge-like and sponge-like structure is reviewed by changing the approaching ratio and membrane thickness. For the preparation of flat sheet and hollow fiber membranes, the rheological characteristics of the dope solution strongly influence the membrane morphology and its performance. According to Extreme model, the pore size distribution parameters and molecular weight cut-off is coupled together, which is useful for the characterizing the membrane performance.

[1] Loeb S, Sourirajan S, Sea water demineralization by means of an osmotic membranes[J].Adv Chem Ser,1962,38(1): 117-119.
[2] Strathmann H, Scheible P, Baker R W, A rational for the preparation of Lob-Sourirajan type cellulose acetate[J]. J Appl Poly Sci,1971,15(4):811-828.
[3] Li S G, van den Boomgaard T, Smolders C A,et al. Physical gelation of amorphous polymers in a mixture of solvent and nonsolvent[J]. Macromolecules,1996,29:2053-2059.
[4] Arnauts J, Berghmans H, Amorphous thermoreversible gels of atactic polystyrene[J]. Polym Commun,1987,28:66-68.
[5]王连军,李恕广,江成璋,制膜体系凝胶时间的研究[J].膜科学与技术,2001,21(3):16-20.
[6]何涛,江成璋,聚醚砜微孔膜制备中非溶剂添加剂作用的研究[J].膜科学与技术,1998,18(3):43-48.
[7] Ren J, Li Z, Wong F S, Membrane structure control of asymmetric BTDA-TDI/MDI (P84) co-polyimide membranes by phase inversion process[J]. J Membr Sci, 2004, 241:305-314.
[8] Reuvers A J,Smolders C A, Formation of membranes by means of immersion precipitation: Part II. the mechanism of formation of membranes prepared from the system cellulose acetate-acetone-water[J]. J Membr Sci, 1987, 34(1): 67-86.
[9] Strathmann H, Kock K, Amar P, et al. The formation mechanism of asymmetric membranes[J]. Desalination, 1975,16(1):179-203.
[10] McKelvey S A, Koros W J, Phase separation, vitrification, and the manifestation of macrovoids in polymeric asymmetric membranes[J], J Membr Sci, 1996,112(1): 29-39.
[11] Shojaie S S, Krantz W B, Greenberg A R, Dense polymer film and membrane formation via the dry-cast process. II. Model validation and morphological study[J].J Membr Sci, 1994,94(1):281-298.
[12]Ren J, Zhou J, Deng M, Morphology transition of asymmetric polyetherimide flat sheet membranes with different thickness by wet phase-inversion process[J], Sep Pur Technol, 2010,74:119-129.
[13]Vogrin N, Stropnik C, Musil V, et al. The wet phase separation: the effect of cast solution thickness on the appearance of macrovoids in the membrane forming ternary cellulose acetate/acetone/water system [J]. J Membr Sci, 2002, 207:139-141.
[14] Li D, Chung T S, Ren J, et al. Thickness dependence of macrovoid evolution in wet phase-inversion asymmetric membranes [J]. Ind Eng Chem Res, 2004,43:1553-1556.
[15]Zhou J, Ren J, Deng M, Morphology evolution of thickness-gradient membranes prepared by wet phase-inversion process[J], Sep Pur Technol, 2008,63: 484-486.
[16]Ren J, Zhou J, Deng M, Morphology transition of asymmetric flat sheet and thickness-gradient membranes by wet phase-inversion process[J], Desalination, 2010,253:1-8.
[17]周敬倩,任吉中,林立等,?-丁内酯对聚醚酰亚胺膜结构形态影响[J],膜科学与技术,2009,29:34-28.
[18] Chung T S, Lin W H, Vora R H, The effect of shear rates on gas separation performance of 6FDA-Durene polyimide hollow fibers[J].J Membr Sci, 2000,167(1): 55-66.
[19] Ismail A F, Shilton S J, Dunkin I R, et al. Direct measurement of rheologically induced molecular orientation in gas separation hollow fiber membranes and effects on selectivity[J], J Membr Sci, 1997,126:133-137.
[20] Ren J, Chung T S, Li D, et al. Development of asymmetric 6FDA-2,6DAT hollow fiber membranes for CO2/CH4 separation 1. The influence of dope composition and rheology on membrane morphology and separation performance[J]. J Membr Sci, 2002,207:227-240.
[21]Ren J, Li Z, Wang R, Effects of the thermodynamics and rheology of BTDA-TDI/MDI co-polyimide (P84) dope solutions on the performance and morphology of hollow fiber UF membranes[J]. J Membr Sci, 2008,309:196-208.
[22] Ekiner O M, Vassilatos G, Polyaramide hollow fibers for H2/CH4 separation II. Spinning and properties[J], J Membr Sci, 2001,186(1):71-84.
[23] Ren J, Wang R, The preparation of polymeric membranes, in: L.K. Wang, J.P. Chen, Y.T. Hung, N.H. Shammas (Eds.), Membrane and desalination technologies, Chapter 2[M].  Humana Press Inc.( in press).
[24]Qin J J, Wang R, Chung T S, Investigation of shear stress effect within a spinneret on flux, separation and thermomechanical properties of hollow fiber ultrafiltration membranes[J], J Membr Sci, 2001,175:197-213.
[25]Ismail A F, Lai P Y, Effects of phase inversion and rheological factors on the defect-free and ultrathin-skinned asymmetric polysulfone membranes for gas separation[J], Sep Purf Technol, 2003,33:127-143.
[26] Ren J, Li Z, Wong F S, A new method for the prediction of pore size distribution and MWCO for ultrafiltration membranes[J], J Membr Sci, 2006,279:558-569.