TIPS法制备聚偏氟乙烯平板微孔膜及其表征

以邻苯二甲酸二甲酯（DMP）为稀释剂，采用热致相分离法（TIPS）制备了聚偏氟乙烯（PVDF）平板微孔膜。利用差示扫描量热仪分析了不同PVDF/DMP体系的结晶性能；通过测试纯水通量、孔隙率、泡点、平均孔径、拉伸强度等对膜进行了表征。结果表明：DMP含量增大，结晶温度向低温方向移动，膜拉伸强度降低，当DMP的质量分数为0.70时膜拉伸强度有明显拐点；PVDF/DMP体系冷却发生固液相分离；PVDF含量增大，膜水通量、孔隙率、最大孔径和平均孔径均减小。

Preparation and Characterization of PVDF Flat Sheet Microporous Membrane via Thermally Induced Phase Separation

The polyvinylidene fluoride (PVDF) flat microporous membrane was prepared via thermally induced phase separation (TIPS) method using dimethyl phthalate (DMP) as the diluent. The crystallization of different PVDF/DMP systems were analyzed by the differential scanning calorimetry (DSC). The membrane was characterized by pure water permeability, porosity, bubble point, mean pore radius and tensile strength. Results show that the crystallization temperature decreases with the increasing of diluent content. The PVDF/DMP system exhibits solid-liquid phase separation. With the increasing of polymer concentration, pure water permeability, porosity, maximum pore size and mean pore radius decrease. The tensile strength of the membrane reduces with the diluent content increasing, and an obvious inflexion appeares when the mass fraction of diluent is 0.70.