SiO_2对聚氨酯杂化膜微孔结构及性能的影响

Study on effect of SiO_2 on structure and performance of hybrid PU membrane

用热致相分离法制备了PU/SiO2杂化膜,研究了不同SiO2及其用量对PU/SiO2/溶剂体系微孔膜微孔结构的影响,并测试了膜的水通量。结果表明:具有不同结构的SiO2能够提高溶剂二氧六环的结晶温度,即冷却速率加快,使微孔膜的微孔尺寸细化,同时使微量水的结晶温度也有所不同,水的冻结温度与孔尺寸的大小直接相关。在冷却速率较快的体系中,形成的微孔尺寸较小,因此其水的冻结温度较低;而冷却速率较慢,形成的微孔尺寸较大,因此其水的冻结温度较高。SiO2的结构将影响与PU之间界面成孔的形态不同,SiO2的粒径越小,其与PU膜接触面积加大,增加了膜孔的连通性,使PU膜的水通量增大。

The hybrid membranes of PU/SiO2 were prepared via thermal induced phase separation （TIPS） methods. The effects of different kind and structure of SiO2 and its concentration on the microporous structure of PU/SiO2/ Solvent composites were respectively investigated via Differential Scanning Calorimeter （DSC）. Meanwhile, the pure water flux property of membranes was tested individually. The results showed that the SiO2 could induce to elevated the crystal temperature and accelerated the cooling rate of solvent dioxane, meanwhile, a more fine microporous of membrane was achieved. Because the frozen temperature of water directly affected the microstructure and pore size of membrane, the SiO2 also had influence the frozen temperature of water, even if its quantity was small. By controlling the cooling rate, the micropore size of membrane could achieve ideally. It means that applying the faster cooling rate, getting smaller micropore size of membrane, and vice versa. The morphology of interface of SiO2 and PU was affected by SiO2 morphology. With the smaller particle size of SiO2,it would have more contacting area with PU matrix. As a resuit, the performance of membrane changed to increased the pure water flux property. It indicated that there was improved connectivity between micro pores.