热致相分离法iPP/nano-SiO_2杂化中空纤维膜的结构与透过性能

Morphology and permeability of iPP/nano-SiO_2 mixed hollow fiber membrane via thermally induced phase separation

通过熔融共混等规聚丙烯(iPP)/邻苯二甲酸二丁酯(DBP)/邻苯二甲酸二辛酯(DOP)/纳米二氧化硅(nano-SiO2)体系,采用热致相分离法(TIPS)制备了iPP中空纤维膜。对膜结构与透过性能进行了表征。用示差扫描量热仪(DSC)测定了体系的iPP动态结晶温度,融化峰值温度数值表明结晶只存在α晶型。X光电子能谱(XPS)表明nano-SiO2向膜表面发生了迁移,使得膜的亲水性有所提高,膜的接触角由120.05°降低到101.05°,降低了19.7%。随着nano-SiO2添加量的增加,膜的孔隙率和纯水通量均呈现先增大后减小的趋势。膜的孔隙率增加了20.2%,纯水通量增大了21.7%。经过拉伸后的杂化膜,孔隙率增大了27.4%,纯水通量增加了211%。研究表明:通过向铸膜液中添加nano-SiO2,可以优化膜结构,并改善膜的亲/疏水性以及透过性能。

By melting and blending isotactic polypropylene （iPP）/di-n-butyl phthalate （DBP）/dioctyl phthalate （DOP）/nano-SiO2 system, iPP hollow fiber membrane is prepared via thermally induced phase separation （TIPS） method. The membrane structure and properties are characterized. Dynamic crystallization temperatures of iPP are investigated with DSC. The melting peak temperature values show that there is only α type in the crystal. Due to migrating of nano-SiO2 from inside to surface of the membrane, which is tested by X-ray photoelectron spectroscopy, hydrophilicity of the membrane surface is enhanced. Contact angle of membrane surface reduce from 120. 05%to 101.05%. The porosity and the pure water flux of the membrane increase firstly and then decrease, with increasing the amount of nano-SiO2. The porosity is increased by 20. 2% and the pure water flux of the membrane is increased by 18%. After stretching, the porosity of the hybrid membrane is increased by 27.4% and the pure water flux of the membrane is increased by 211%. It is suggested that by adding proper amount of nano-SiO2, membrane structure can be improved. The hydrophilicity/ hydrophobicity and the permeability of the membrane can be raised as well.