Abstract A nanofibrous membrane with a hierarchical structure that was prepared from p-aramid nanofibers via a solvent-induced phase inversion process is reported herein. First, the p-aramid threads were dispersed into and mechanically stirred in a solution of potassium tert-butoxide and methanol for 36 h to yield p-aramid nanofibers. The average length and diameter of the p-aramid nanofibers were >1.0 μm and 14.6 ± 0.7 nm, respectively. Second, nanofibrous membranes were prepared via a ‘casting-and-immersion’ method in a DMSO/water mixture coagulation bath through a phase inversion mechanism. The pure water flux and bovine serum albumin (BSA) retention ratio of the membranes as well as the membrane-forming mechanism with different preparation parameters, such as the PEG additive dosage, molecular weight of the PEG additive, pre-evaporation time of the liquid film, coagulation bath composition, as well as the concentration of the casting solution, were systematically investigated. The resultant membrane had a highly desirable hierarchical structure, which contains a dense and finely porous barrier layer, as well as a highly porous support layer. This membrane exhibited a high pure water flux and a BSA retention ratio of ∼852.5 L/m2·h and 98.7% at an operating pressure of 0.2 MPa, respectively, as well as a high decomposition temperature and tensile strength of 318 °C and 17.1 MPa, respectively. The membrane showed good organic solvent resistance even after it had been soaked in a common polar organic solvent for 15 days. Furthermore, the membrane's performances were also extremely stable even with 10 h of heating at 90 °C. The membranes prepared in this work may have uses in filters for separations.

中文翻译：

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来自基于纳米纤维的溶剂诱导相转化过程的分层芳纶纳米纤维膜

摘要 本文报道了一种由对芳纶纳米纤维通过溶剂诱导相转化过程制备的具有分级结构的纳米纤维膜。首先，将对位芳纶线分散在叔丁醇钾和甲醇的溶液中并机械搅拌 36 小时，以得到对位芳纶纳米纤维。对位芳纶纳米纤维的平均长度和直径分别为 >1.0 μm 和 14.6 ± 0.7 nm。其次，通过相转化机制在 DMSO/水混合物凝固浴中通过“浇铸和浸渍”方法制备纳米纤维膜。膜的纯水通量和牛血清白蛋白 (BSA) 保留率以及不同制备参数的成膜机制，如 PEG 添加剂用量、PEG 添加剂的分子量、系统地研究了液膜的预蒸发时间、凝固浴组成以及浇铸溶液的浓度。所得膜具有非常理想的分级结构，其中包含致密且微孔的阻挡层以及高度多孔的支撑层。该膜在 0.2 MPa 的操作压力下表现出高纯水通量和约 852.5 L/m2·h 和 98.7% 的 BSA 截留率，以及 318°C 和 17.1 的高分解温度和拉伸强度兆帕，分别。即使在普通极性有机溶剂中浸泡 15 天后，该膜仍显示出良好的耐有机溶剂性。此外，即使在 90°C 下加热 10 小时，膜的性能也非常稳定。