膜科学与技术

ECTFE共混膜的结构调控及膜蒸馏性能表征

作者：周玥，刘庚，汪朝晖，汪效祖，崔朝亮

单位： 1.南京工业大学，化工学院，材料化学工程国家重点实验室，江苏南京 211816； 2. 南京工业大学，国家特种分离膜工程技术研究中心，江苏南京 211816

关键词：乙烯-三氟氯乙烯；添加剂；热致相分离；膜蒸馏

出版年,卷(期):页码： 2022,42(3):1-6

摘要：

采用热致相分离（TIPS）法，以偏苯三酸三辛酯（TOTM）为稀释剂，等规聚丙烯（iPP）、纳米二氧化硅（nano-SiO2）或微米级碳酸钙（CaCO3）为添加剂，制备乙烯-三氟氯乙烯共聚物（ECTFE）微孔膜。考察了不同种类添加剂iPP、nano-SiO2和CaCO3对ECTFE膜结构和性能的影响。结果表明：iPP的加入可以诱导液-液相分离的发生，ECTFE膜形成胞腔状结构；加入的nano-SiO2或CaCO3可调控聚合物核，改变了固-液分相过程中ECTFE膜的结晶形式，由球晶结构逐渐转变为蜂窝状结构。另外，加入nano-SiO2能有效改善ECTFE膜的机械性能，增加膜的孔径和孔隙率，ECTFE膜的拉伸率增加了44.2%，平均孔径和孔隙率分别为379.7 nm和66.1%。在真空膜蒸馏（VMD）实验中，相同的进料条件下，加入nano-SiO2的ECTFE膜渗透通量较原膜提高约24%，达到24.53 L/(m2·h)，而盐截留率高达99.97%。

A porous poly(ethylene-chlorotrifluoroethylene) (ECTFE) membrane was prepared via thermally induced phase separation (TIPS) using an environmentally friendly diluent trioctyl trimellitate (TOTM), isotatic polypropylene (iPP), nano-silica (nano-SiO2), or micron-sized calcium carbonate (CaCO3) as the additive. The effects of different types of additives iPP, nano-SiO2 and CaCO3 on the structure and properties of the membrane were investigated. The result shows that the addition of iPP could promote liquid-liquid phase separation and the membrane formed a cellular structure. The addition of nano-SiO2 and CaCO3 was used as a nucleation agent in phase separation process, making the spherulite structure transfer to honeycomb structure. In addition, the addition of nano-SiO2 could improve the mechanical properties of the ECTFE membrane and could increase the pore size and porosity of ECTFE membrane. The elongation at break of ECTFE membrane increased by 44.2%, and the average pore-size and porosity were 379.7 nm and 66.1%, respectively. In the vacuum membrane distillation (VMD) process, the permeation flux of the membrane with nano-SiO2 increased by 24.26% compared with the original membrane in the same feed conditions, reaching 24.53 L/(m2·h), and the salt rejection rate reached at 99.97%.

周玥（1991，10），女，江苏南通，硕士，助理实验师，主要研究方向为膜分离； E-mail：1406640151@qq.com

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