丙烯酸接枝改性聚偏氟乙烯及其微孔膜制备的研究

Study on Acrylic Acid Grafting Polyvinylidene Fluoride and Preparation of Micro-Pore Membrane

用丙烯酸对聚偏氟乙烯(PVDF)进行接枝改性,采用pH致相转化法制备了改性的聚偏氟乙烯(PVDF-g-AAC)微孔膜;通过ATR-FTIR和XPS分析,表明丙烯酸单体已接枝在PVDF链上;利用SEM和AFM表征了PVDF膜和PVDF-g-AAC改性膜的表面及断面的形貌;通过纯水通量、污染通量、静态和动态接触角验证了纯PVDF膜和PVDF-g-AAC改性膜的抗污染性能和亲水性。结果表明,丙烯酸的存在使得膜的各项性能都得到显著的提高。具体表现在亲水性提高,水通量上升,抗污染性能提高。并且随着凝胶浴pH的增加,改性的PVDF膜的性能也逐渐得到提高。从对接触角的测量,证明膜的亲水性随着pH的增大而得到了提高。膜的纯水通量从670L/(m^2·h)增加至1 140L/(m^2·h);膜的蛋白吸附量从80.1μg/cm^2下降到46.7μg/cm^2,膜的抗污染性大大提高。

Polyvinylidene fluoride（PVDF） was modified by grafting acrylic acid. Modified PVDF（polyvinylidene fluoride-g-acrylic acid,PVDF-g-AAC）membrane was fabricated via pH value-induced phase-inversion method（pH-NIPS）.ATR-FTIR and XPS analyses confirmed that AAC monomer was grafted on the PVDF chain.The surface and cross-sectional morphologies of pure and modified PVDF membranes were characterized by scanning electron microscope（SEM）and atomic force microscope（AFM）.The anti-fouling property and hydrophilicity were evaluated via pure water flux,polluted flux,static and dynamic contact angle experiments.The results showed that the properties of the membrane were significantly improved by the presence of acrylic acid,with a concrete manifestation of the improvement in hydrophilicity,water flux,anti-pollution performance.And as the pH of the coagulation bath increased,the performance of the modified PVDF membrane was gradually improved.From the measurement of the contact angle,it was demonstrated that the hydrophilicity of the membrane was improved with the increase of pH.The pure water flux of the membrane increased from 670 L/（m2·h）to1 140 L/（m2·h）;the protein adsorption capacity of the membrane decreased from 80.1μg/cm2 to46.7μg/cm2.The fouling resistance of the membrane was greatly increased.