聚全氟乙丙烯中空纤维膜的制备及性能

以聚全氟乙丙烯(FEP)为成膜聚合物,MT-Ⅱ型复合粉为致孔剂,邻苯二甲酸二辛酯(DOP)为稀释剂,采用熔融纺丝拉伸法制备了FEP中空纤维膜,研究了其耐酸碱等性能.结果表明,FEP中空纤维膜的表面具有由拉伸孔、界面孔及溶出孔组成的多重孔结构,而其横截面为均匀分布的海绵状孔结构.FEP中空纤维膜经质量分数为25%的硫酸水溶液和25%的氢氧化钠水溶液分别处理60 d后,膜的化学结构未发生变化,而且平均孔径增大,孔径分布变窄,断裂强度保持率分别在86.8%及80.8%以上,耐酸碱性明显优于商业化聚偏氟乙烯(PVDF)中空纤维膜,显示出优异的化学稳定性及良好的热稳定性.

Preparation and Properties of Poly( tetrafluoroethylene-co-hexafluoropropylene) Hollow Fiber Membranes

Poly(tetrafluoroethylene-co-hexafluoropropylene)(FEP) hollow fiber membranes(HFMs) were prepared by melt spinning method with FEP as polymer matrix, water solubility composite powder as pore-forming agent and dioctyl phthalate(DOP) as diluent. The effects of different concentrations of acid and alkali on the structure and properties of FEP HFMs were studied. The results show that the prepared FEP HFMs have a microporous structure with stretched pores, interface microporous and dissolved microporous, and the sponge-like microporous structure is evenly distributed on the cross-section. After 60 d immersed in 25％ NaOH and H2 SO4 solution, the chemical structure of the membranes has been unaffected, while the average pore size becomes larger and the pore size distribution narrows. The retention rates of break strength reach 86. 8％ and 80. 8％, respectively. The acid and alkali resistance study indicates that the FEP HFMs have excellent chemical and thermal stability compared to commercial PVDF HFMs.