制膜条件对PVDF疏水微孔膜的结构和性能的影响

Effects of preparation conditions of hydrophobic microporous membranes of PVDF on the membrane structure and performance

探讨了浸没沉淀相转化法制备真空膜蒸馏(VMD)用聚偏氟乙烯(Polyvinylidene fluoride,PVDF)疏水微孔膜的制膜条件对膜结构和性能的影响.结果表明:不同溶解温度下制备的铸膜液所成的膜,孔径大小随铸膜液溶解温度的升高而增大,膜的水通量也随之增大;随着预蒸发时间的延长,膜表面孔径变小,膜的水通量也随之减小;凝固浴温度对膜的结构和性能也有很大影响,温度升高膜孔变大,水通量也变大;混合溶剂对膜的水通量的影响主要是由铸膜液的粘度决定.

Hydrophobic microporous membranes for vacuum membrane distillation were prepared by immersion-precipitation process with polyvinylidene fluoride （PVDF） dissolved in solvent. The effects of the dissolve temperature and pre-evaporation time of casting solution, mixed solvent, and the temperature of coagulation bath on the structure and the water flux of the membrane were investigated systematically. The experimental results indicated that with the temperature of Whether the casting solution or the coagulation bath increasing, both the pore size and the water flux increased respectively. With the pre-evaporation time increasing, both the pore size and the water flux decreased. The viscosity of cast solution determines the water flux of the membrane prepared by mixed solvent.