PDMS/PVDF渗透汽化膜制备过程中的孔渗问题研究

Study on pore penetration during preparation of PDMS/PVDF membrane for pervaporation

以聚偏氟乙烯(PVDF)中空纤维超滤膜为基膜,在其表面涂覆聚二甲基硅氧烷(PDMS),制成表面完整致密的复合膜用于渗透汽化分离乙醇/水溶液实验。通过改变涂覆液浓度、涂覆液预反应时间和预反应温度改变涂覆液黏度,或者在涂覆前使用不同的堵孔剂处理基膜的方法降低孔渗的发生概率。结果表明:涂覆液黏度增大到一定程度,孔渗降低,通量增加;使用甘油和聚乙二醇(PEG)对基膜进行预处理也能有效降低孔渗。

Composite membranes of polydimethylsiloxane（PDMS）/polyvinydenefluoride（PVDF）were prepared by coating a copolymer of polysiloxane on porous PVDF hollow fiber ultra filtration membranes for pervaporation separation of ethanol/water mixtures.Two methods were suggested to prevent pore penetration：changing in the casting solution viscosity and filling the support pores with blocking materials.The results suggested that when coating solution viscosity increased to a certain degree then pore penetration decreased and permeation flux increased The presence of glycerol and polyethylene glycol（PEG）as an additive in the support layer during coating could prevent the PDMS from intruding.