PSF-g-P(PEGMA)的合成及其共混超滤膜的制备与性能研究

以氯甲基化双酚A型聚砜(PSF-CH2Cl)为大分子引发剂,通过原子转移自由基聚合(ATRP)法合成了以聚砜(PSF)为疏水主链、聚(聚乙二醇单甲醚甲基丙烯酸酯)[P(PEGMA)]为亲水侧链的梳状两亲性共聚物PSF-g-P(PEGMA).FT-IR和1H-NMR的表征结果证实了两亲性共聚物的生成.将PSF-g-P(PEGMA)与PSF进行共混,通过浸没沉淀法制备了共混超滤膜.研究发现,引入5 wt%的PSF-g-P(PEGMA),共混膜的孔隙率和平均孔径分别从65.9%和0.08μm提高到81.9%和0.18μm;将共混膜于90℃热水中浸泡24 h后,膜表面O/S从14.63提高到17.16;共混膜的亲水性和抗牛血清蛋白(BSA)吸附性能显著提升.     

基于多巴胺自聚合与表面接枝PHGH制备抗菌纳滤膜

在水溶液中将聚六亚甲基单胍盐酸盐(PHGH)共价接枝在经多巴胺自聚合改性的聚砜膜表面, 制备具有抗菌性能的纳滤膜. 采用全反射红外光谱(ATR-FTIR)、 扫描电子显微镜(SEM)和接触角测试考察膜表面的结构、 形貌和亲水性变化. 探讨PHGH含量对膜的接枝度及分离性能的影响, 并对膜的抗菌性能进行了评价. 结果表明, 经过多巴胺的自聚合和表面接枝PHGH后, 聚砜膜表面形成了具有纳滤分离性能的活性层, 并且膜表面亲水性得到改善. 随着PHGH含量的增大, 膜的纯水通量降低, 而对无机盐和染料的截留性能提高. 接枝后的复合膜具有较高的抗菌性能, 当PHGH含量为3%(质量分数)时, 抗菌率可达98.5%.     

聚砜与丙烯酸的紫外光辐射接枝共聚及其表征

在均相溶液体系下,运用紫外光辐射引发合成了聚砜与丙烯酸的接枝共聚物。用化学滴定、漫反射傅立叶变换红外光谱和热分析等技术对接枝聚合物进行了表征。结果表明:丙烯酸被接枝在聚砜链上;光照时间、单体浓度和光引发剂浓度对接枝率均有较大影响。膜表面接触角的研究表明,接枝共聚物膜的亲水性比改性前有所提高。     

UV辐照接枝制备酚酞基聚芳醚酮纳滤膜——链转移剂的作用

酚酞基聚芳醚酮(PEK-C)超滤膜的表面通过紫外辐照接枝丙烯酸(AA)可以制备对II价盐有很好截留率的亲水性纳滤膜. FTIR-ATR、表面接触角、SEM和AFM的研究结果表明, 在接枝单体溶液中加入异丙醇(i-PrOH)作为链转移剂并不影响AA在PEK-C超滤膜表面的接枝反应. 得到的改性膜同样具有优良的纳滤性能. 与不加i-PrOH的AA改性膜相比, 新合成的膜有较高的滤出液通量, 该膜对盐离子的截留率虽有所降低, 但可以通过增加接枝反应时间和辐照光源的强度来提高. i-PrOH的浓度对膜的分离性能的影响很大, 在低浓度时, 改性膜对离子的截留率会有所下降, 继续提高i-PrOH的浓度, 膜的截留率不再变化而滤出液通量会有成倍的增加, 表明链转移剂的存在可能会提高膜的接枝密度, 增加膜的表面电荷, 使膜对离子的截留率保持不变.     

MBA接枝聚丙烯微孔膜的亲水改性研究

运用表面吸附法使聚丙烯微孔膜表面覆盖上引发剂,然后浸入氮氮亚甲基双丙烯酰胺(MBA)水溶液在一定温度下进行接枝反应。研究了引发剂用量,单体浓度,反应时间与温度对接枝率的影响,并用红外、扫描电镜对聚丙烯膜接枝前后的微孔膜进行了表征。同时对膜的亲水性和水通量进行了测试,发现其亲水性能有了极大的提高,其中接枝改性后接触角与未接枝的相比降低了90°以上,吸水率最多提高了12%,但是水通量有所下降。还对改性微孔膜的抗污染性能进行了探究。     

氨基酸修饰聚芳醚酮超滤膜的抗污染性能

膜分离技术广泛应用于水处理、医药、食品、化工等领域。但在膜使用过程中,膜容易被蛋白质和细菌所污染,降低了膜的分离性能和使用寿命,提高了膜技术的应用成本,极大的限制了膜的应用。本文以含羧基的酚酞聚芳醚酮(PEK-COOH)制备超滤膜,利用1-乙基-(3-二甲基氨基丙基)碳酰二亚胺/N-羟基琥珀酰亚胺(EDC/NHS)方法将碱性氨基酸赖氨酸(Lys)、精氨酸(Arg)、组氨酸(His)接枝至超滤膜表面。实验结果表明,接枝氨基酸后水通量增加,静态蛋白吸附量降低,同时接枝组氨酸的超滤膜过滤牛血清白蛋白(BSA)3个循环后水通量恢复率达80%,表现出良好的抗污染性能。     

超亲水聚偏氟乙烯中空纤维膜的制备及性能

采用超声辅助接枝聚合技术,将甲基丙烯酸缩水甘油酯(GMA)接枝到聚偏氟乙烯(PVDF)膜表面,制备PVDF-g-GMA膜;再利用氨基诱导环氧基团发生开环反应,将苏氨酸(Thr)接枝到PVDF-g-GMA膜表面,制备了具有两性离子结构表面的PVDF-g-GMA-Thr膜。通过衰减全反射傅里叶变换红外光谱(ATR-FTIR)、X射线光电子能谱(XPS)、接触角测试仪、场发射扫描电子显微镜(FESEM)和牛血清白蛋白(BSA)过滤实验等系统研究了改性前后PVDF膜表面的化学组成、润湿性能、表面形貌和抗污染性能。研究结果表明,随着PVDF-g-GMA接枝Thr反应时间的增加,PVDF-g-GMA-Thr膜的亲水性能明显提高,接触角从90°降为0°,呈现出超亲水性能。同时PVDF-g-GMA-Thr膜的水通量明显提高,当Thr诱导开环反应时间为12 h时,PVDF-gGMA-Thr膜的水通量高达686 L/(m²·h),与PVDF原膜相比,水通量提高了204. 5%。在BSA的过滤测试中,与PVDF膜相比,PVDF-g-GMA-Thr膜呈现出良好的截留性能和抗污染性能,BS...     

UV辐照接枝聚合制备亲水性纳滤膜

用紫外光引发自由基共聚接枝的方法对酚酞基聚芳醚酮(PEK-C)超滤膜表面进行改性制备了亲水性荷电纳滤膜. 研究了用不同单体接枝改性膜对盐溶液的截留性能, 证明了Donnan电荷效应对纳滤膜分离性能的影响. 在此基础上, 通过丙烯酸(AA)与对苯乙烯磺酸钠(SSS)的共聚接枝, 并改变它们在接枝液中的相对含量, 成功地制备出膜的表观截留率和渗透通量都较高的纳滤膜.     

改性高分子超滤膜的研究进展

随着超滤膜技术的发展,人们对膜材料的性能不断提出新的要求,其中改善膜的亲水性,提高膜的抗污染能力已成为有待解决的迫切问题.由于单一的膜材料很难同时具有良好的亲水性、成膜性、热稳定性、化学稳定性、耐酸碱性、耐微生物性侵蚀、耐氧化性和较好的机械强度等优点,因此采用膜材料改性或膜表面改性的方法来提高膜的性能,是解决这一问题的关键.本文介绍了目前国内外高分子超滤膜材料改性中常用的化学改性和物理改性方法.其中,化学改性可以通过膜材料和膜表面的化学改性来实现;而物理改性则主要是通过材料改性来实现.     

低密度聚乙烯-丙烯酸气相光接枝体系反应机理的研究

研究了以二苯甲酮(BP)为光敏剂,丙烯酸在低密度聚乙烯(LDPE)膜上两步法气相光接枝聚合;从反应的基本要素出发,利用紫外光分光光度计跟踪测定了二苯甲酮在LDPE膜中的扩散情况,发现其扩散系数随BP浓度的升高而降低,约在0.8～2.0×10-12m2.s-1之间.同样方法跟踪测定了BP在不同条件下的光还原反应,结果表明:当远紫外光被滤掉后,其半衰期大大加长,氧气的存在更是加剧了这一效应;并且通过测定不同条件下气相光接枝聚合的一些基本规律,提出单体扩散为该气相光接枝聚合的控制步骤.     

Improving hydrophilicity and protein antifouling of electrospun poly(vinylidenefluoride-hexafluoropropylene) nanofiber membranes

<正>Poly(vinylidenefluoride-hexafluoropropylene)(PVDF-HFP) nanofiber membranes with improved hydrophilicity and protein fouling resistance via surface graft copolymerization of hydrophilic monomers were prepared.The surface modification involves atmospheric pressure glow discharge plasma(APGDP) pretreatment followed by graft copolymerization of poly(ethylene glycol) methyl ether methacrylate(PEGMA).The success of the graft modification with PEGMA on the PVDF-HFP fibrous membrane is ascertained by X-ray photoelectron spectroscopy(XPS) and attenuated total reflectance Fourier transform infrared measurements(ATR-FTIR).The hydrophilic property of the nanofiber membranes is assessed by water contact angle measurements.The results show that the PEGMA grafted PVDF-HFP nanofiber membrane has a water contact angle of 0°compared with the pristine value of 132°.The protein adsorption was effectively reduced after PEGMA grafting on the PVDF-HFP nanofiber membrane surface.The PEGMA polymer grafting density on the PVDF-HFP membrane surface is measured by the gravimetric method,and the filtration performance is characterized by the measurement of water flux.The results indicate that the water flux of the grafted PVDF-HFP fibrous membrane increases significantly with the increase of the PEGMA grafting density.     

Enhancing the antifouling property of polyethersulfone ultrafiltration membranes through surface adsorption-crosslinking of poly(vinyl alcohol)

An adsorption-crosslinking process of poly(vinyl alcohol) (PVA) was introduced to modify the surface of polyethersulfone (PES) ultrafiltration membranes for enhancement of their antifouling property. XPS and water contact angle measurement confirmed the obvious enhancement of surface hydrophilicity. Ultrafiltration results showed that the spreading of PVA chains over the hydrophobic membrane surface caused substantial but acceptable decrease on membrane flux. The fouling type analysis indicated that PVA adsorption effectively improved the antifouling property of PES membranes. With a PVA concentration of 0.5 wt% and three cycles of alternative adsorption-crosslinking, the total and irreversible fouling ratio of modified membranes were 0.38 and 0.22, respectively, much lower than those of control PES membrane (0.61 and 0.47), and the flux recovery ratio was increased accordingly. The long-term ultrafiltration experiment demonstrated the improvement of recycling property and the reliability of adsorption-crosslinking process.     

Hydrophilic Modification of Microporous Polysulfone Membrane via Surface‐Initiated Atom Transfer Radical Polymerization and Hydrolysis of Poly(glycidylmethacrylate)

Poly(glycidylmethacrylate) (PGMA) brushes were grafted from chloromethylated polysulfone (CMPSF) membrane surface by surface‐initiated atom transfer radical polymerization (SI‐ATRP), and the grafting was followed by hydrolysis of epoxy groups in the grafting chains to improve the membrane's hydrophilic property. Fourier transform infrared spectroscopy (FT‐IR) and X‐ray photoelectron spectroscopy (XPS) measurements confirmed the successful grafting and hydrolysis of PGMA. The grafting degree of the monomer, measured by periodic acid titration and gravimetric analysis, increased linearly with the polymerization time, while the static water contact angle of the membrane grafted with PGMA or hydrolyzed PGMA linearly decreased. In comparison with the PGMA‐grafted membranes, the hydrolyzed PGMA‐grafted membranes possess stronger hydrophilicity as indicated by their contact angle and hydration capacity, and as a result they have an improved antifouling property. Therefore, the control of the hydrophilicity of PSF membrane could be realized through adjusting the polymerization time and transforming the functional groups in the grafting chain.     

Biofouling-resistance expanded poly(tetrafluoroethylene) membrane with a hydrogel-like layer of surface-immobilized poly(ethylene glycol) methacrylate for human plasma protein repulsions

In general, it is a challenge to control the highly polar material grafting from the chemically inert Teflon-based membrane surface. This work describes the surface modification and characterization of expanded poly(tetrafluoroethylene) (ePTFE) membranes grafted with poly(ethylene glycol) methacrylate (PEGMA) macromonomer via surface-activated plasma treatment and thermally induced graft copolymerization. The chemical composition and microstructure of the surface-modified ePTFE membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), contact angle, and bio-atomic force microscopy (bio-AFM) measurements. Biofouling property of the modified membranes was evaluated by the measurements of the plasma protein (γ-globulin, fibrinogen, or albumin) adsorption determined using an enzyme-linked immunosorbent assay (ELISA). In general, the hydrophilicity of the surface of ePTFE membranes increases with increasing the grafting degree of the copolymerized PEGMA. The highly hydrated PEGMA chain on the resulting ePTFE membranes was found to form a surface hydrogel-like layer with regulated coverage in aqueous state, which can be controlled by the content of PEGMA macromonomer in the reaction solution. The relative protein adsorption was effectively reduced with increasing capacity of the hydration for the PEGMA chain grafted on the ePTFE membrane surface. From both results of protein adsorption and platelet adhesion test in vitro, it is concluded that the PEGMA-grafted hydrophilic ePTFE membranes could provide good biofouling resistance to substantially reduce plasma protein and blood platelet fouling on the membrane surface in human body temperature.     

光接枝法制备新型pH开关核孔膜

用表面光接枝方法制备了具有pH开关特性的丙烯酸接枝PET核孔膜 .XPS、SEM和AFM的表征结果证明 ,接枝膜具有非对称结构 ,丙烯酸接枝层主要在膜的向光侧表面 ,膜背侧和膜孔内没有变化 .膜孔周围的接枝链在湿态下沉入膜孔 ,接枝层对膜孔顶部产生封盖 .接枝链的体积随环境pH值的不同而变化 ,从而控制接枝膜的滤过特性 .在低接枝程度时 ,接枝链体积变化对膜孔径的影响小 ,不具有pH开关特性 ,但是接枝提高了膜的亲水性 ,通量得到提高 ;接枝程度达到一定程度时 (如 0 5 %) ,膜孔径受接枝链体积变化的影响显著 ,接枝膜表现出pH开关效应 .在pH大于 5时 ,接枝膜通量恒定 ,基本不受溶液pH值影响 .当pH值小于 4时 ,膜通量随溶液酸性的增加迅速升高 .接枝膜的开关幅度JpH =2 JpH =6 8,随接枝程度的增加而增加 .膜的通量和开关幅度可以通过接枝程度来调节     

UV-induced Self-initiated Graft Polymerization of Acrylamide onto Poly(ether ether ketone)

Photo-grafting of hydrophilic monomer was used to enhance the hydrophilicity of poly(ether ether ketone) (PEEK) with the aim of extending its applications to biological fields. PEEK sheets were surface modified by grafting of acrylamide(AAm) with ultraviolet(UV) irradiation in the presence or absence of benzophenone(BP). The effects of BP, irradiation time and monomer concentration on the surface wettability of PEEK were investigated. Characterization of modified PEEK using scanning electron microscopy(SEM), energy-disperse spectrometer(EDS) and water contact angle measurements shows that AAm was successfully grafted on PEEK surface both in presence and absence of BP. With the increase in irradiation time and monomer concentration, contact angles decrease to as low as 30°, demonstrating a significant improvement of surface hydrophilicity. In agreement with the decrease in contact angle, under identical conditions, the nitrogen concentration increases, suggesting the increase in grafting degree of the grafting polymerization. This investigation demonstrates a self-initiation of PEEK due to its BP-like structure in the backbone of the polymer. Though the graft polymerization proceeds more readily in the presence of BP, the self-initiated graft polymerization is clearly observed.     

紫外辐照接枝制备亲水性荷正电纳滤膜

通过在酚酞基聚芳醚酮超滤膜表面紫外辐照接枝亲水性单体二烯丙基二甲基氯化铵(DADMAC)制备了一种表面荷正电的纳滤膜. ATR-FTIR和表面水接触角的研究结果表明膜表面的接枝率和亲水性随着辐照时间和单体在接枝溶液中的浓度的增加而增加. 荷正电纳滤膜对盐溶液有很好的截留, 对盐溶液中的高价阳离子和低价阳离子的截留率分别为95%和65%. 但当溶液中存在高价负离子时, 膜的截留性能会明显下降. 表明静电效应在荷电纳滤膜的分离过程中起了重要的作用.     

紫外辐照接枝制备亲水性两性纳滤膜

通过紫外辐照在酚酞基聚芳醚酮(PEK-C)超滤膜表面引发自由基共聚反应, 依次接枝二甲基二烯丙基氯化铵(DADMAC)和对苯乙烯磺酸钠(SSS), 制成亲水性、表面载有两种不同电荷的纳滤膜. 通过测定膜的纯水通量和对不同盐溶液表观截留率的变化, 系统研究了单体浓度和接枝时间对膜的分离性能的影响. 结果表明, 用这种方法制成的亲水性两性纳滤膜对盐溶液的截留作用与两种单体在接枝液中的浓度和接枝时间有关. 膜对由高价同离子和高价反离子组成的盐表现出优良的截留作用.     

Enhancing the hydrophilic and antifouling properties of polypropylene nonwoven fabric membranes by the grafting of poly(N-vinyl-2-pyrrolidone) via the ATRP method

In this work, the surface characteristics of poly(N-vinyl-2-pyrrolidone) (PNVP)-modified nonwoven fabric (NWF) membranes and the effects of the surface characteristics on the membranes antifouling properties were investigated. Effects of grafting time, grafting temperature, and monomer concentration on the grafting degree of PNVP were systematically investigated. The effect of grafting degree on the surface characteristics was also investigated. Scanning electron microscopy (SEM) was used to characterize the structural and morphological changes on the membrane surface. The water contact angles decreased from 113±1.2° to 52±3°, which means that the hydrophilicity of the modified NWF was enhanced with increasing PNVP grafting degree. The surface free energy was calculated, which showed an increase after modification. Static bovine serum albumin (BSA) adsorption experiments were carried out, which showed a decrease of 82.5%. Permeation experiments of water and supernatant solution of active sludge were carried out to determine the antifouling characteristics against the extracellular polymeric substance. Results demonstrated that the modified NWF had higher permeation fluxes and lower flux loss in comparison with the original NWF. Bacterial adhesion on the membrane surface was largely suppressed after the introduction of PNVP.