甘油添加剂对浸没沉淀法制备PVDF微孔膜结构与性能的影响

Effect of Glycerol Additive on the Morphology and Crystallization of Prepared PVDF Membranes

不同甘油质量分数的添加剂对浸没沉淀相转化法制备聚偏氟乙烯(PVDF)微孔膜的结构及性能具有显著影响。实验结果表明,铸膜液中甘油质量分数越高,在相同的制膜条件下,铸膜液越容易发生凝胶分相,所成膜表面越发致密,孔密度降低,断面指状大孔的长度和胞腔状结构的相互贯通性增加。另外膜的空隙率均随着铸膜液中甘油质量分数的增加而增加,膜的平均孔径则当甘油质量分数为5%时达到最大,从所制得膜的膜蒸馏性能来看,在添加剂质量分数为8%的范围内,膜蒸馏通量和截留率的基本趋势是随着铸膜液中甘油质量分数的增加而上升。

Different contents of glycerol as additives have great influence on morphology and performance of polyvinylidene fluoride（PVDF） membranes prepared via immersion precipitation phase inversion technique.The results show that,the more glycerol contents added,the easier of gel phase demixing occurs in the dopes.Moreover,with the increase of the glycerol contents,the morphology of the top surface becomes densed.On the cross section of the prepared membrane,the length of the finger-like pores becomes larger and the connectivity of the globule-like pores becomes better.Within glycerol mass fraction 8%,the general performances of the prepared membrane,for example,the porosity,the flux and rejection of membrane distillation,are all increase with the increase of glycerol contents in dopes,while the mean pore size of the prepared membrane reaches the maximum when glycerol mass fraction is 5%.