关键词: 聚乙烯, 隔膜, 拉伸扩孔, 亲水改性, 聚丙烯酸钠, 超滤膜

Abstract:

Conventional polyethylene （PE） membranes show promise as substrates for ultrafiltration and reverse osmosis membranes but are limited by poor hydrophilicity， low porosity， and consequently low water flux. To address these issues， this study investigates the effects of pore expansion via stretching and hydrophilic modification on the pore structure and water flux of PE membranes. Pore structure was tailored through a stretch⁃expansion process， which increased porosity and pore size while reducing pore tortuosity， thereby enhancing filtration efficiency. Additionally， hydrophilic modification was achieved by crosslinking the membrane with a sodium polyacrylate coating. The modified membranes maintained a high bovine serum albumin （BSA） retention rate while demonstrating significantly improved water flux. The results indicated that a stretch ratio of 2 yielded optimal membrane properties， with porosity increasing to 80% and pore tortuosity decreasing to 1.6. The stretched and coated PE membranes exhibited markedly enhanced hydrophilicity， water flux， and BSA retention compared to unmodified PE membranes. The modified PE porous membrane can be directly applied as an ultrafiltration membrane and also provides a smooth， suitable surface for interfacial polymerization， making it a promising substrate for reverse osmosis membranes.

Key words: polyethylene, separator, expanding holes, hydrophilic modification, sodium polyacrylate, ultrafiltration membrane