提出了一种新的中空纤维膜增强方法.采用非溶剂致相分离法,将聚偏氟乙烯铸膜液和作为基膜的高固含量聚偏氟乙烯铸膜液,与芯液一起,通过特殊结构的纺丝喷头同时挤出,制备复合增强的聚偏氟乙烯中空纤维膜.期望复合膜保持原有孔径和高通量,同时具有更高的断裂强力.研究了复合层配方对膜结构和性能的影响.结果表明,随着复合层聚偏氟乙烯固含量减少,靠近外皮层的指状孔结构向大空穴结构转化,外表面开孔数和孔径增加,纯水通量增大,断裂强力有所减小.
In this study,a new method to enhance the mechanical performance of polyvinylidene fluoride(PVDF)hollow fiber membranes has been proposed.Composite hollow fiber membranes were prepared by using co-extrusion of the dopes with different PVDF contents,along with the bore liquid through a triple-orifice spinneret via non-solvent induced phase separation method.It was expected that composite membranes could maintain original pore size,high water flux,and have higher breaking strength.The effects of the formulation of composite layer on membrane structure and performance were investigated.The results show that,the finger-like structure near outer skin would turn into cavitations,the number of pores and the pore size on the outer surface increase,and so is the pure water flux,whereas the breaking strength decreases gradually with the increase in PVDF content.