UHMWPE/EVA中空纤维膜的制备及性能研究

Preparation and properties of UHMWPE/EVA hollow fiber membrane

通过在超高相对分子质量聚乙烯(UHMWPE)纺丝液中添加不同含量的乙烯-醋酸乙烯酯共聚物(EVA),采用热致相分离法制备了UHMWPE/EVA中空纤维膜,实现对UHMWPE中空纤维膜的亲水改性,并通过扫描电子显微镜、接触角测量仪、差示扫描量热仪、万能材料试验机等对中空纤维膜的结构与性能进行了表征,采用自制UHMWPE/EVA中空纤维膜过滤装置对中空纤维膜的过滤性能及防污性能进行了评价。结果表明:随着EVA含量的增加,UHMWPE/EVA中空纤维膜的断面结构变得致密,熔点及结晶度下降,接触角减小,亲水性提高,但其拉伸强度有所下降;随着EVA含量的增加,UHMWPE/EVA中空纤维膜的孔隙率增大,但随着EVA添加质量分数(相对UHMWPE质量)进一步增大到20%,孔隙率则随之下降;当加入EVA质量分数(相对UHMWPE质量)15%时,UHMWPE/EVA中空纤维膜的纯水通量和截留率以及水通量回复率均达到最大值,即其纯水通量为435.77L/m^2·h,对牛血清蛋白及碳素墨水的截留率分别为68.5%和93.95%,水通量回复率达94.66%;UHMWPE/EVA中空纤维膜中,EVA的最佳添加量其质量分数(相对UHMWPE质量)为15%。

Ultrahigh-relative molecular mass polyethylene/ethylene-vinyl acetate(UHMWPE/EVA)hollow fiber membranes were prepared via thermally induced phase separation method by adding different amount of ethylene-vinyl acetate copolymer(EVA)into UHMWPE spinning solution in order to improve the hydrophilicity of the membranes.The structure and properties of the hollow fiber membranes were characterized with scanning electron microscope,water contact angle tester,differential scanning calorimeter and tensile strength tester,etc.The filtration and antifouling properties of the hollow fiber membranes were evaluated on a self-made UHMWPE/EVA hollow fiber membrane filtration unit.The results showed that the fracture structure of UHMWPE/EVA hollow fiber membrane became compacted,the melting point and crystallinity reduced,the contact angle decreased,the hydrophilicity increased and the tensile strength decreased in some degree with the increase of EVA content;the porosity of UHMWPE/EVA hollow fiber membrane increased with the increase of EVA content,but decreased when the mass fraction of EVA(based on UHMWPE)rose to 20%;the pure water flux,retention rate and water flux recovery rate of UHMWPE/EVA hollow fiber membrane were maximized as 435.77 L/m^2·h,68.5%and 93.95%retention for bovine serum protein and carbon ink and 94.66%,respectively,when the mass fraction of EVA(based on UHMWPE)was 15%;and the addition of EVA in UHMWPE/EVA hollow fiber membrane was optimized as 15%by mass fraction based on UHMWPE.