模板辅助浸没凝胶法PVDF疏水微孔膜的制备与性能

以不锈钢丝网嵌入聚二甲基硅氧烷(PDMS)制得微结构模板代替平滑制膜底板,分别以N-甲基-2-吡咯烷酮(NMP)、NMP与水的混合物为溶剂,水为凝胶剂,采用模板辅助浸没凝胶法制备高度疏水聚偏氟乙烯(PVDF)微孔膜,并对膜结构、膜底面的疏水程度及膜的透过性能进行表征,分析模板微结构、PVDF固含量和铸膜液中水含量对膜结构及其性能的影响.结果表明:膜底面结构是模板微结构与相分离过程协同作用的结果;模板的辅助作用能显著提高膜底面的疏水程度,并对膜的透过性能有影响;铸膜液中聚合物固含量、水的添加量是影响膜透过性能的关键因素,对膜底面的疏水性稍有影响.研究表明,模板辅助浸入凝胶法是一种简单、理想的高度疏水PVDF微孔膜制备方法.

Preparation and performances of PVDF hydrophobic microporous membrane via immersion precipitation assisted with template

Highly hydrophobic polyvinylidene fluoride(PVDF) microporous membranes are prepared via immersion precipitation assisted with template.Templates are obtained by stainless steel mesh′s inserting into PDMS.N-methyl-2-pyrrolidone(NMP),mixtures of NMP and H2O are used as solvent,H2O as non-solvent,respectively.Then,in order to analyse the effects of the template microstructure,PVDF mass fraction and water addition in the casting solution on morphology and performances of the membrane,the structures,hydrophobic degree of the bottom surface and permeability of the membrane are characterized.It is shown that the structure of the bottom surface is determined by the template microstructure and the structure formed from phase inversion altogether.The template enhances the hydrophobic degree of the bottom surface,and increases slightly permeability of the membrane as well.PVDF mass fraction and water addition in the casting solution are key factors for permeability of the membrane,and works slightly on hydrophobic degree of the membrane’s bottom surface.It is suggested that immersion precipitation assisted with template is an ideal method to prepare highly hydrophobic PVDF membrane.