聚偏氟乙烯-g-聚乙二醇共混超滤膜的制备及抗蛋白质污染性能

Preparation and Protein Anti-Fouling Properties of Polyvinylidene Fluoride Graft Polyethylene Glycol Blending Ultrafiltration Membranes

在臭氧活化下通过自由基引发的聚合反应,合成聚乙二醇(PEG)接枝聚偏氟乙烯(PVDF)共聚物(PVDF-g-PEG),并与PVDF共混制备了超滤膜,探讨了PEG链长和相对含量对超滤膜相分离进程、理化性质及抗蛋白质污染性能的影响规律。研究结果表明,PEG链长增加,接枝率明显下降。随PVDF-g-PEG在共混膜中添加量增大,相转化延迟分相趋势加大,共混膜的孔隙率和亲水性及纯水通量显著提升。当膜内PVDF-g-PEG400含量大于20%后,共混膜对牛血清蛋白(BSA)的截留率仍能保持在94%以上,但BSA的静态吸附量低于20μg/cm^2。PVDF-g-PEG能显著降低超滤膜对BSA过滤过程中的不可逆污染指数和堵孔阻力系数,延缓BSA过滤通量衰减速率,表现出优异的抗蛋白质污染性能。PEG链长对膜面粗糙度影响较大,对超滤膜抗蛋白质污染的贡献更加突出。

Polyvinylidene fluoride graft polyethylene glycol(PVDF-g-PEG) was synthesized by free radical polymerization under ozone activation. The ultrafiltration membranes were prepared by blending polyvinylidene fluoride(PVDF) with PVDF-g-PEG. The effects of the polyethylene glycol(PEG) chain length and relative contents on the phase separation process, physicochemical properties, structural parameters and anti-protein pollution of the membranes were investigated. With the increase of PVDF-g-PEG contents, the phase separation time of the phase conversion delay increases, the porosity is increased obviously, the PEG enrichment rate and hydrophilicity of the membrane surface are increased, and the pure water flux increases significantly. When the content of PVDF-g-PEG 400 is over 20%, the bovine serum protein(BSA) interception could still be maintained above 94%, and the static adsorption capacity of BSA is less than 20 μg/cm. PVDF-g-PEG can significantly reduce the irreversible pollution index and plugging resistance coefficient of the BSA filtration process, delay the flux attenuation rate of the BSA filtration, and have an excellent anti-protein pollution performance. PEG chain length has great influence on the surface roughness of membranes and has a more prominent contribution to the protein fouling resistance of ultrafiltration membranes.