【摘要】 利用流变仪对聚偏氟乙烯(PVDF)/己内酰胺(CPL)热致相分离法(TIPS)成膜体系铸膜液的流变性能进行研究.考察了剪切频率、温度、PVDF质量分数对PVDF/CPL铸膜液体系的黏度、非牛顿性指数、黏流活化能、溶液黏弹性的影响,利用TIPS法制备PVDF膜,进一步探讨了铸膜液体系的流变性能对刮膜速率、制膜温度等成膜条件的指导作用.实验结果表明:PVDF/CPL铸膜液体系为非牛顿性流体,随着PVDF质量分数的升高,PVDF/CPL铸膜液体系的黏度增加,非牛顿性指数增加,黏流活化能升高,对应膜的结构越致密,水通量降低,截留率升高,膜的拉伸强度增强.PVDF质量分数低的铸膜液体系,制膜时对温度的灵敏度低,刮膜速率对膜的制备影响大,制膜过程需要对刮膜速率精确地控制;PVDF质量分数高的铸膜液体系,对温度的灵敏度高,可以在较宽的刮膜速度范围下制膜.更多还原

【Abstract】 The rheology of caprolactam(CPL)solutions blended with poly(vinylidene fluoride)(PVDF)was studied by using rheometer.The influence of different PVDF mass fraction and temperature on the viscosity,the non-newtonian index,the viscous flow activation energy,modulus of solution of the PVDF/CPL casting solution system were inspected.The PVDF microporous membranes were prepared by the method of composite thermal induced phase separation.The guiding role of the rheological properties of casting solution system for filming conditions was discussed.The results show that PVDF/CPL casting solution system shows the characteristic of typical non-Newtonian fluid. While increasing polymer concentration,the viscosity,non-Newtonian index and viscous flow activation energy of polymer increased,the membrane density and BSA retention increased,the water flux of the membrane decreased,tensile strength of the membrane increased.The casting membrane system with low PVDF mass fraction had low sensitivity to temperature and the casting speed had a great effect on the preparation of the membrane.So the preparation of the membrane with low PVDF mass fraction needed precise control of the casting speed.The casting membrane system with high PVDF mass fraction had high sensitivity to temperature.The membrane with high PVDF mass fraction could be prepared over a wide range of casting speed at high temperature.更多还原