添加剂对聚醚砜酮超滤膜结构和性能的影响

EFFECT OF ADDITIVES ON THE STRUCTURES AND PROPERTIES OF POLY (PHTHALAZINE ETHER SULFONE KETONE)(PPESK) ULTRAFILTRATION MEMBRANE

在杂萘联苯聚醚砜酮(PPESK)铸膜液中,分别添加磺化聚醚砜酮(SPPESK)、聚乙二醇(PEG)、有机小分子和无机盐添加剂,采用相转化法制备了聚醚砜酮超滤膜,并通过扫描电镜和超滤性能测试考察了不同添加剂对超滤膜结构和性能的影响。结果表明,SPPESK的加入提高了膜的亲水性和孔隙率,使膜的渗透性显著提高。有机高分子添加剂PEG的加入,使膜亚层指状孔结构向海绵状孔结构转变。改善了孔道的连通性,提高了膜的亲水性和孔隙率,使膜的纯水通量增加而截留率略有下降。含有羟基的醇类和酸类小分子添加剂有助于纯水通量的提高。无机盐添加剂起到成孔和增溶聚合物的作用。在保持截留率相对较高的条件下,LiCl和ZnCl2可以提高膜的纯水通量。FeCl2在成膜过程中发生水解氧化,部分铁均匀分布在膜三维空间中,与聚合物相互作用,改善膜的结构和性能。

Poly （phthalazine ether sulfone ketone） （PPESK） ultrafiltration membranes were prepared using phase-inversion method with sulfonated PPESK, polyethylene glycol （PEG）, small organic molecules and inorganic salts as additives, respectively. The effect of different additives on the structures and properties of PPESK membranes were investigated by SEM and ultrafiltration test. The results show that the addition of SPPESK improves the hydrophilicity and porosity of membranes, and the membrane permeability is improved obviously. With the introduce of PEG into cast solution, the finger-like structure in membrane sublayer was gradually transformed into sponge-like structure. The connectivity between pores as well as the hydrophilicity and porosity of membrane are improved, which increase the pure water flux and decrease the retention slightly. Small organic molecules such as alcohols and acids are helpful for the increase of pure water flux because of the hydrophilic hydroxyl group. Inorganic salts additives act as pore former and polymer solubilizer. The addition of LiCI and ZnCl2 improves the pure water flux while the retention was kept relatively higher. During membrane forming process, thehydrolysisand oxidation of FeCl2 made iron uniformly exist in the three-dimensional space of membrane. The interaction between iron hydrolysate and polymer improves the membrane structure and properties.