中空纤维超滤膜干燥过程中膜孔演变规律研究

摘要

Drying of polysulfone ultrafiltration hollow fiber membrane was conducted using a constant temperature and humidity box. The effect of temperature, relative humidity and drying time on the pore size, pore size distribution and molecular weight cut off (MWCO) of membranes were studied. The results indicated that with the increasing temperature, decreasing humidity and extending drying time, the pore size declined, pore size distribution was firstly narrowed and then broadened, the MWCO and permeability decreased, while morphological structures and mechanical properties did not change significantly. The pore size evolution regularity in drying process was proposed further. The larger pores and smaller pores shrank simultaneously. Smaller pores were more likely to shrink, the number of pores decreased obviously, while the bigger pores shrink limited. By controlling the dry conditions, a membrane with specific pore shrinkage of the hollow fiber membrane was obtained.%使用恒温恒湿箱对聚砜（PSf）中空纤维超滤膜进行干燥处理，研究干燥温度、相对湿度和干燥时间对膜孔径大小、孔径分布及截留分子质量（MWCO）的影响。结果表明：随着干燥温度升高、相对湿度减小、干燥时间延长，膜孔径变小，孔径分布先变窄后变宽，截留分子质量变小，膜的渗透性能呈明显降低趋势，膜整体结构和力学性能均没有明显变化；提出了膜干燥过程中的膜孔演变规律，膜内较大孔和小孔的收缩同步进行，小孔容易收缩甚至消失，膜孔数目明显减少，较大孔有限收缩。通过干燥条件的控制能够实现对膜孔一定程度的预收缩。