Abstract:

Selective swelling of melt-spun block copolymers has been demonstrated to be a clean process in the manufacture of hollow-fiber membranes (HFMs). However, the performances of as-prepared HFMs remain to be improved. In this work, the multi-bore configuration in HFMs to improve their performances was constructed. The spin 3-bore and 7-bore hollow-fibers using polysulfone-block-poly(ethylene glycol) (PSF-b-PEG) were melted, followed by the axial stretching and selective swelling. The influence of the bore numbers, swelling conditions and the stretching percentage on the morphology, permeance, rejection and pressure resistance of as-prepared MHFMs was investigated. Thanks to the mutual support of the wall thickness, the permeability and pressure resistance of the MHFMs were better than those of the single-bore HFMs. Besides, the membrane properties could be effectively controlled in a wide range by adjusting the stretching percentage and swelling conditions. It was found that the permeance of 3HFMs prepared in stretching conditions could reach 20 times higher than that of stretched single-bore HFMs with similar rejection performance. This work was expected to greatly improve the clean preparation of high-performance block copolymer hollow-fiber membranes.

Key words: ultrafiltration, hollow-fiber membrane, block copolymer, multi-bore, selective swelling

摘要：

嵌段共聚物的熔纺-选择性溶胀是一种制备中空纤维膜的清洁生产工艺。本文提出构建多通道构型来提升嵌段共聚物中空纤维膜的性能，通过熔纺-拉伸-选择性溶胀，制备了具有3通道和7通道的聚砜/聚乙二醇嵌段共聚物中空纤维膜，研究了通道数、溶胀条件和拉伸行为对中空纤维膜微观结构、渗透性、截留率和耐压性的影响。由于壁厚的相互支撑作用，多通道中空纤维膜的渗透性和耐压性能都比单通道中空纤维膜有所提高，且可通过拉伸和溶胀条件实现膜性能在较大范围内的高效调控。在适当的通道数和拉伸比下，拉伸后的三通道中空纤维膜的通量比单通道中空纤维膜高20倍。此工作对使用清洁方法制备高性能的中空纤维膜具有重要意义。

关键词: 超滤, 中空纤维膜, 嵌段共聚物, 多通道, 选择性溶胀