The study covers the fundamental relationships between the nature of aprotic polar solvents [ N -methyl-2-pyrrolidone (NMP), N , N -dimethylacetamide (DMA), N , N -dimethylformamide (DMF) and dimethylsulfoxide (DMSO)] used for casting solution preparation and the structure and performance of poly(amide-imide) (PAI) ultrafiltration membranes. It was found that the distinctive feature of the ternary systems PAI-poly(ethylene glycol) (PEG-400, M n = 400 g mol −1 ) solvent is gel formation upon the increase in PEG-400 concentration in the solution. The PEG-400 addition to the casting solution was shown to increase pure water flux of the PAI membranes prepared from the casting solutions in different solvents. However, different patterns of the change of pure water flux when gel point is exceeded in PAI-PEG-400-solvent system were revealed. The PAI membranes obtained from the ternary systems PAI-PEG-400-solvent were found to combine high pure water flux at P = 0.1 MPa (130 L m −2 h −1 for DMSO, 120 L m −2 h −1 for DMA and 70 L m −2 h −1 for NMP) and high poly(vinylpyrrolidone) (PVP) rejection coefficients: 98–99% for PVP with M n = 40000 g mol −1 and 86–95% for PVP with M n = 10000 g mol −1 . SEM studies reveal the significant difference in the PAI membrane structure when different solvents are used for casting solution preparation. The structure of the membranes obtained from 20 wt% PAI solutions in NMP and DMA consists of the thin selective layer supported by substructure pierced by elongated macrovoids. Meanwhile, when DMSO and DMF are used as solvents the addition of PEG-400 yields the suppression of macrovoid formation and anisotropic sponge-like membrane structure is obtained.

中文翻译：

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溶剂性质对聚（酰胺-酰亚胺）超滤膜结构和性能的影响

该研究涵盖了非质子极性溶剂 [N-甲基-2-吡咯烷酮 (NMP)、N, N-二甲基乙酰胺 (DMA)、N, N-二甲基甲酰胺 (DMF) 和二甲亚砜 (DMSO)] 的性质之间的基本关系浇铸溶液的制备以及聚（酰胺-酰亚胺）（PAI）超滤膜的结构和性能。发现三元系统PAI-聚（乙二醇）（PEG-400，M n = 400 g mol -1 ）溶剂的显着特征是在溶液中PEG-400浓度增加时凝胶形成。添加到浇铸溶液中的 PEG-400 显示增加了由不同溶剂中的浇铸溶液制备的 PAI 膜的纯水通量。然而，在 PAI-PEG-400-溶剂体系中，当超过凝胶点时，纯水通量的变化呈现出不同的模式。发现从三元系统 PAI-PEG-400-溶剂获得的 PAI 膜在 P = 0.1 MPa 时结合了高纯水通量（DMSO 为 130 L m -2 h -1，DMA 为 120 L m -2 h -1 NMP 为 70 L m -2 h -1) 和高聚乙烯吡咯烷酮 (PVP) 截留系数：PVP 为 98–99%，Mn = 40000 g mol -1，PVP 为 86–95%，Mn = 10000 克摩尔 -1 。SEM 研究揭示了当使用不同溶剂制备浇铸溶液时 PAI 膜结构的显着差异。从 NMP 和 DMA 中的 20 wt% PAI 溶液获得的膜结构由由细长大孔刺穿的亚结构支撑的薄选择性层组成。同时，当使用 DMSO 和 DMF 作为溶剂时，加入 PEG-400 会抑制大孔的形成，并获得各向异性的海绵状膜结构。