【作者】 沈永波；

【导师】 张浩勤； 张延武；

【作者基本信息】 郑州大学 ， 化学工艺， 2010， 硕士

【摘要】 对膜进行改性,使其能满足各种分离要求,近年来已经是膜分离研究的重要内容之一。与传统的改性方法相比,原子转移自由基聚合(ATRP)具有活性/“可控”、反应条件温和、适用单体范围广等优点。本文采用原子转移自由基聚合(ATRP)法和表面引发原子转移自由基聚合(SI-ATRP)法,通过在膜内引进不同的功能单体,对常用的聚砜和聚醚砜膜进行改性研究,使膜具有不同的分离功能。具体研究内容如下：为了使疏水聚砜膜具有更强的疏水性能,从而适用于有机溶剂等分离场合,实验采用ATRP化学接枝法,首次将疏水性含氟单体2,2,2-三氟乙基甲基丙烯酸酯(TFEMA)接枝到氯甲基化聚砜(CMPSF)材料上,FT-IR红外和19F-NMR核磁共振检测分析结果表明,反应得到了结构确定的接枝聚合物PSF-g-PTFEMA,并且产物接枝量随反应时间的增加而线性增加。将PSF-g-PTFEMA与PSF共混,采用相转化法制备平板共混膜,研究发现,共混膜表面的静态水接触角从纯膜的60.17°提高到了81.07°,即改性使膜表面的疏水性能得到了提高。亲水改性是传统膜改性的主要目的,实验以氯甲基聚醚砜(CMPES)中空纤维膜为基膜,通过SI-ATRP法在膜表面接枝亲水单体聚乙醇单甲醚甲基丙烯酸酯(PEGMA),从而提高膜表面的亲水性。扫描电镜和膜的物理结构测试结果说明,反应主要发生在膜表面；ATR-FTIR分析结果表明,膜表面得到了结构确定的聚合物PES-g-P(PEGMA);GPC分析结果显示聚合物分子量随反应时间的增加而线性增加,分子量分布较窄,膜表面的接枝密度也随反应时间的增加而线性增加,说明接枝反应具有可控聚合的特征；研究还发现,在不改变膜截留性能的前提下,改性使膜的亲水性和抗污染能力都得到了明显改善。在膜的使用过程中,微生物也可以造成膜污染。为了提高膜的抑菌性能,实验再次使用SI-ATRP法,在CMPSF膜表面接枝功能单体4-乙烯基吡啶(4VP),使膜表面具有很强的络合能力,然后再在膜表面络合吸附Cu离子,通过改变溶剂用量考察单体浓度对接枝反应的影响。为了作对比研究,实验又采用共混法直接在PSF铸膜液中同时添加P4VP和Cu离子纺制中空纤维共混膜,考察了P4VP用量对共混改性的影响。通过扫描电镜观察了两种方法改性前后膜的断面和表面形貌,同时测定了膜表面Cu元素的百分含量；通过分析膜内N元素的含量变化验证膜表面聚合物的接枝量,并且考察了改性前后膜的水通量和截留率变化。实验结果说明,溶剂用量为20mL时接枝改性效果最佳,膜表面聚合物的接枝密度可以达到4.7 mg/cm2,通过络合吸附可以使膜内Cu元素的百分含量达到3.07%,膜对大肠杆菌的抑菌率达到了100%；铸膜液中P4VP的添加量为0.75%时,共混效果最佳,制得的膜内Cu元素的百分含量尽管只能达到1.68%,但是膜的抑菌率也基本达到了100%。更多还原

【Abstract】 Modifying membranes to meet the requirements of various separation has already been an important part of the study about membrane separation in recent years. Compared with the traditional modification methods, atom transfer radical polymerization(ATRP) has the advantages of activity/"controllable", mild reaction conditions, good for a wide range of monomers and so on. This article used the method of general atom transfer radical polymerization (ATRP) and the method of surface initiated atom transfer radical polymerization (SI-ATRP) to modify the commonly used polysulfone and polyethersulfone membrane by the introduction of different function monomer so that the membrane can have different separation functions. The mainly study and results of the experiments are summarized as follow:In order to make the hydrophobic membrane have a better hydrophobic property, which can be applied to organic solvent separation and other occasions, the hydrophobic fluorine-containing monomer of 2,2,2-trifluoroethyl methacrylate (TFEMA) were grafted from the chloromethylated polysulfone (CMPSF) materials via ATRP. FT-IR infrared and 19F-NMR NMR results showed that we got the grafting polymer PSF-g-PTFEMA with determined structure, Grafting yield linearly increased with reaction time. The flat blend membranes of PSF-g-PTFEMA/PSF were prepared by the wet phase inversion process. The static water contact angle of the modified membrane surface reached 81.07°from 60.17°of the pure membrane. It showed that the hydrophobicity of the membrane surface was improved by the modification.Hydrophilic modification is the mainly purpose of membrane modification. The hydrophilic monomer PEGMA was grafted from the surface of chloromethyl polyethersulfone (CMPES) hollow fiber membrane to improve the hydrophilicity of the membrane surface. FESEM and the physical structure of the membrane test results indicated the reaction mainly occured in the membrane surface. ATR-FTIR analysis showed that the PES-g-P (PEGMA) with determined structure were got on the membrane surface. GPC analysis showed the molecular weight linearly increased with the reaction and the molecular weight distribution was narrow. The grafting density on the membranes also linearly increased with the reaction time. These showed the reaction was a controlled or living process. The study also showed the hydrophilicity and anti-pollution of the membranes were significantly improved while the rejection performance was not changed.The microbes can also cause the membrane fouling. In order to improve the antibacterial properties of membranes, the functional monomers 4-vinyl pyridine (4VP) were grafted from the CMPSF membrane surface using the method of SI-ATRP to make the membrane surface have a strong complexing ability. Then the membrane surface were loaded with Cu. The effects of the monomer concentration were studied. For comparative study, the P4VP and Cu ions were directly added to the casting solution of PSF membrane using the blend method and the effects of the P4VP were studied. The section and surface morphology of the two modification membranes were scanned and the contents of Cu was measured at the same time. The contents of N were were measured to verify the content of the grafting polymer by elemental analysis. The changes of water flux and rejection of the modification membranes were investigated. The results showed that the effect of grafting was the best when the solvent amount was 20mL. The grafting density of the membrane surface reached 4.7 mg/cm2. The content of Cu can reach 3.07% through the adsorption. The E. coli inhibition rate of the membrane was 100%. The best blending membrane was got when the dosage of P4VP was 0.75% in the casting solution. Though the content of Cu can only reach 1.68%, the inhibition was almost 100%.更多还原