热处理对PVDF-PFSA中空纤维共混超滤膜结构及性能的影响  

Effect of Heat-Treatment on Morphology and Performance of PVDF-PFSA Hollow Fiber UF Blend Membranes

作　　者：袁国林[1] 许振良[1] 魏永明[1] 

机构地区：[1]华东理工大学化学工程研究所,上海200237

出　　处：《华东理工大学学报（自然科学版）》2009年第4期501-505,共5页Journal of East China University of Science and Technology

基　　金：国家"973"计划(2003CB615705);国家"十一五"科技支撑计划重大项目(2006BAE02A01)

摘　　要：以聚偏氟乙烯(PVDF)与全氟磺酸(PFSA)为共混膜材料,采用湿法纺丝制备了中空纤维共混超滤膜,考察了热处理温度与热处理时间对共混膜的渗透性能、膜结构、受热收缩率及机械性能的影响。结果表明:随热处理温度的升高,截留率先增加后降低,纯水通量先降低后升高,分别在80℃时达到最大值与最小值,80℃时PEG4000的截留率为95.0%,纯水通量为231 L/(m2.h.MPa);膜的渗透性能随热处理时间变化而变化,在15 min时出现极值;热处理使膜的支撑层结构发生转变,膜径向壁厚收缩率较大,轴向膜长度收缩率较小;热处理后中空纤维膜的断裂伸长率降低,而杨氏模量与断裂强度跟热处理后的膜支撑层结构密切相关;湿法纺制的PVDF-PFSA膜,经70℃热处理15 min后,制得截留分子量为4 000的中空纤维共混超滤膜,其纯水通量为261L/(m2.h.MPa)。Poly（vinylidene branes were prepared by wet-s the morphology, permeation p fluoride） （PVDF）-perfluorosulfonic acid （PFSA） hollow fiber blend mempinning method. The effects of the heat-treatment temperature and time on erformance and mechanical properties of the membranes were investigated.The results show that upon increasing the heat-treatment temperature the retention rate reaches a maximum of 95.0% for PEG4000 at 80 ℃ while the flux shows a minimum of 231 L/（m^2· h · MPa） for pure water at the same heat-treatment temperature. The appropriate heat-treatment time was 15 min for heattreatment at 70 ℃. The morphology of the membranes was changed by heat-treatment as examined by scanning electronic microscopy （SEM）. The hollow fiber membranes are shrank after the heat-treatment, and the axial shrinkage ratio of the membrane is smaller than the radial one. The elongation at break declines after heat-treatment. The Young＇s modulus and the break strength of the hollow fiber membranes closely correlate to the membrane structure after heat-treatment. The PVDF-PFSA hollow fiber blend membranes heat-treated for 15 min at 70 ℃ have a cut-off molecular weight of 4 000 and flux of 261 L/（m^2 ·h ·MPa） for pure water.

关 键 词：聚偏氟乙烯 全氟磺酸 共混 热处理 

分 类 号：TQ028.8[化学工程]