拉伸和萃取工艺对PVDF中空纤维膜的力学性能和收缩率的影响

Effect of stretching process and extraction method on mechanical strength and shrinkage of PVDF hollow fiber membrane

为处理TIPS制备的PVDF中空纤维膜在干燥过程中出现的收缩现象,采用独特的酒精萃取方式和甘油水溶液热定型等工艺,研究中空纤维膜后处理工艺对膜内残余应力的影响,探究不同的干燥工艺对膜收缩率的影响.实验结果表明:水萃-酒精萃-水萃工艺可以减弱微孔膜的收缩情况,微孔膜的长度收缩率为13.69%,径向收缩率为10%左右;干燥后的微孔膜外观形貌由弯曲状变成竖直状,且经热定型后微孔膜的残余应力得以消除,增强了微孔膜的力学性能,经甘油热定型后中空纤维膜的单根断裂强度提高了4 MPa.

In order to deal with the phenomenon of shrinkage of PVDF hollow fiber membranes prepared by TIPS during the drying process,the influence of the hollow fiber membrane post-treatment process on the residual stress in the membrane was studied.With the unique alcohol extraction method and the heat-setting of the glycerol aqueous solution,the membrane shrinkage of different microporous membrane under drying processes were explored.The experimental results show that water extraction-alcohol extraction-water extraction process could reduce the shrinkage of the microporous membrane.The microporous membrane had a length shrinkage of 13.69%and a radial shrinkage of about 10%.The appearance of the dried microporous membrane changed from curved to vertical.And after heat-setting,the residual stress of the microporous membrane was eliminated,which enhances the mechanical properties of the microporous membrane,after heat-setting with glycerol,the single-root breaking strength of the hollow fiber membrane increased by 4 MPa.