添加剂对PVDF凝胶速率和膜性能的影响

以聚偏氟乙烯(PVDF)为膜材料,利用自制改进的光透射仪,考察了聚乙二醇(PEG)、聚乙烯吡咯烷酮(PVP)、氯化锂、丙醇、PVP/丙醇等作为添加剂对PVDF成膜时分相延时时间、分相速率的影响.结果表明,上述添加剂都能促进PVDF铸膜液在凝胶初始阶段皮层的生成,表现为延时时间的缩短.但是所生成皮层的致密程度不同,使得它们对随后分相速率的影响也不尽相同.最终膜呈现延时分相形态还是瞬时分相形态,不但和延时时间有关,而且和分相速率有很大关系.并将含有这些添加剂的铸膜液纺制成中空纤维膜,考察了添加剂对膜形态和分离性能的影响.

Effect of additives on the demixing rate and membrane performance of PVDF membrane

Using improved self-made transmission device,the effect of PEG,PVP,LiCl,1-propanol and PVP/1-propanol etc.as additives on the demixing delay time and demixing rate of PVDF membranes were systematically investigated.It was found that all these additives can accelerate the formation of thin surface which can be seen from the shortened delay time.And the difference of the surfaces' density makes their influence on the later demixing rate different.The final morphology(delay demixing type or instantaneous demixing type) of the membrane depended on not only demixng delay time but also demixing rate.Further more,hollow fiber membranes were made using previous mentioned additives and the effect of different additives on the morphology and separation performance of membranes were also investigated.