复合无机纳米颗粒改性有机超滤膜的制备及其性能研究

为提高聚偏氟乙烯超滤膜的亲水性,增强其在水处理中的抗污染能力,采用无机纳米颗粒二氧化钛、氧化铝与聚偏氟乙烯共混,使用相转化法流延工艺制得无机改性有机高分子板式共混超滤膜;用杯式超滤装置考察了无机纳米颗粒的含量对改性膜性能的影响,用扫描电子显微镜观察纳米氧化铝颗粒、氧化钛颗粒在膜中的分布,对膜表面、断面孔结构及孔径进行观察;采用X射线光电子能谱测定改性超滤膜的元素组成及其比例.结果表明,纳米颗粒加入的总质量分数为3％,二氧化钛与氧化铝的加入质量比为1:1时,改性膜的水通量最大;纳米颗粒的加入并没有改变有机膜的微观结构和形态;改性超滤膜不仅保持了PVDF膜优良性能,而且增加了其强度、亲水性和抗污染性能.     

氧化石墨烯含量对聚偏氟乙烯超滤膜结构和性能的影响

采用浸没沉淀相转化法制备不同氧化石墨烯添加量改性聚偏氟乙烯复合超滤膜,并使用扫描电镜和接触角测量仪表征膜片断面结构及亲水性;借助超滤杯测定不同膜片的纯水通量,模拟污染后的水通量恢复率及水通量衰减率;对复合膜对大肠杆菌的抑制性也进行了表征。结果表明:当氧化石墨烯添加量为1%时,改性膜的指状孔结构明显而且较粗,水通量达到最大值为240.7L/(m~2·h);此时改性膜的亲水性、抗污染性较好,水通量衰减率较低,复合膜的抗菌性能较好。     

聚偏氟乙烯超滤膜亲水改性研究进展

膜污染会缩短超滤膜的使用寿命,增加由于水力清洗、化学清洗以及膜组件更换而产生的费用。为减少运行成本,有必要对膜污染加以控制。膜污染与原水中污染物的性质和膜本身的性质密切相关。亲水性膜具有水通量高、抗污染性能好的特点,因而提高超滤膜的亲水性是提高膜的水通量和控制膜污染的重要方法之一。简要介绍了具有良好化学稳定性、耐辐射性、耐热性的聚偏氟乙烯膜的表面亲水改性和共混亲水改性的研究进展,指出通过不同的改性方式,聚偏氟乙烯膜都能够实现亲水性的增强。     

聚偏氟乙烯紫外光接枝改性及其膜的耐污染性能研究

膜污染是影响膜分离性能的重要因素,今采用非均相表面光接枝术在聚偏氟乙烯粉料表面引入亲水性物质丙烯酸甲酯,然后采用相转移的方法制备超滤膜。运用傅里叶转换红外光谱、X光电子能谱、接触角仪等对改性前后制备的聚偏氟乙烯膜表面性能和结构进行表征;结果表明丙烯酸甲酯成功接枝到聚偏氟乙烯粉料表面上,接枝改性后膜表面亲水性和抗污染性能均有明显改善。     

葡萄糖对聚偏氟乙烯膜性能的影响

用相转化法制备了聚偏氟乙烯/葡萄糖共混膜。当聚偏氟乙烯质量分数为10%,葡萄糖质量分数为4%时,膜的水通量和孔隙率最高,为33.1 mL/(cm2.h)和92.6%;接触角也由92°减小为72°,显示出很好的亲水性。并对共混膜的微观结构、XRD、红外光谱和热稳定性进行了详细的研究,讨论了聚偏氟乙烯和葡萄糖的共混机理。     

双改性Al_2O_3/PVDF杂化膜的制备和性能

分别利用乙烯基三甲氧基硅烷对Al_2O_3粒子进行了改性、KOH对聚偏氟乙烯(PVDF)进行了改性,并以改性后的产物为制膜材料,以过氧化苯甲酰(BPO)为引发剂,将改性纳米Al_2O_3粒子引入到改性PVDF中,通过热致相变法制备了双改性Al_2O_3/PVDF杂化膜。分别考察了硅烷偶联剂对Al_2O_3粒子粒径的影响,及不同碱浓度和碱处理时间对PVDF结构的影响,并对制备的双改性膜进行了性能测试。结果表明:当硅烷偶联剂的质量分数为33%(以体系总质量计,下同)时,Al_2O_3粒子的粒径从593.45 nm降为43.47 nm,在此基础上,当改性Al_2O_3粒子的质量分数为5%时,杂化膜的截留率为83.1%,水通量为621.5 L/(m2·h),膜的拉伸强度达到5.01MPa。改性纳米Al_2O_3粒子的引入,是杂化膜通量和力学强度提高的主要原因。     

聚偏氟乙烯/纳米纤维素复合超滤膜的研究

以聚偏氟乙烯为原材料,聚乙烯吡咯烷酮( PVP K30)为添加剂,并向聚偏氟乙烯铸膜液中混入纳米纤维素,采用相转化工艺制备了复合超滤膜.通过正交试验分析了各因素对产品性能的影响,并得出了制备复合超滤膜的最优条件:聚偏氟乙烯质量分数为14％,添加剂PVP K30质量分数为0.5％,纳米纤维素加入量为0.7％,空气中溶剂蒸发时间为10s,凝胶浴为水.测定复合超滤膜的水通量、截留率、平均孔径、孔隙率、力学强度等一系列性能,膜的水通量为40.7 L/(m2·h),对牛血清蛋白的截留率为91.8％,孔隙率为52.3％,平均孔径为15.3 nm.     

γ-Al2O3/TiO2混合纳米粒子改性PVDF超滤膜

为提高聚偏氟乙烯（PVDF）膜的亲水性和强度,将纳米二氧化钛（TiO2）溶胶和纳米氧化铝（γ-Al2O3）按不同比例与聚偏氟乙烯共混,采用相转化法制得共混超滤膜。考察了不同比例的混合纳米粒子对PVDF超滤膜的纯水通量、截留率、力学性能等的影响。并利用扫描电子显微镜（SEM）观察了膜的表面和内部微观结构,红外光谱分析（FTIR）和X射线衍射仪（XRD）考察纳米粒子在PVDF基体中的存在状态,通过对复合膜进行拉力测试研究混合纳米粒子对膜力学性能的影响,并使用接触角测量仪测定膜表面和水之间的接触角来定量分析比较膜表面的亲水性。结果表明,γ-Al2O3/TiO2混合比为1∶2时,膜的性能达到最优,孔隙率为74%,水通量为120 L/（m2.h）,截留率为93%,拉力最大负荷为35 N,拉伸应变为22%。     

PMMA-b-PEG-b-PMMA对相转化法制备PVDF多孔膜的改性研究

聚偏氟乙烯(PVDF)作为常用的微滤/超滤膜材料,因疏水、易受污染的特点导致其应用受到限制。采用PMMA-b-PEG-b-PMMA两亲聚合物为改性剂,以浸没-沉淀相转化法制备PVDF多孔膜,通过扫描电镜、力学拉伸、表面接触角、水通量测试等方法,表征了两亲聚合物的共混改性对膜结构与性能的影响。结果表明随着两亲嵌段聚合物含量的增加,膜主体结构都能保持海绵状结构,表面接触角从95°下降到65°,清水通量与BSA溶液通量都明显提高,PVDF膜的亲水性得到明显改善。     

等离子体改性聚偏氟乙烯超滤膜的研究

为了改善聚偏氟乙烯(PVDF)超滤膜的亲水性,采用等离子体技术对PVDF粉料进行功能化改性,使其表面带有功能化基团,以达到提高其水通量,进而改善抗污染能力的目的。实验结果表明:采用等离子体改性PVDF粉料,可以在PVDF粉料表面接上亲水性基团羟基和羰基,从而改善PVDF的亲水性。     

Polyvinylidene fluoride ultrafiltration membrane blended with nano-ZnO particle for photo-catalysis self-cleaning

A novel photo-catalysis polyvinylidene fluoride ultrafiltration membrane was successfully fabricated via phase inversion method. The membrane matrix was supplemented with nano-ZnO of different content for membrane modification. Filtration experiments, contact angle measurements, scanning electron microscope/energy dispersive X-ray spectrometer analysis, and mechanical tests were conducted to characterize the modified membranes. The photo-catalysis tests clearly showed that the modified PVDF membranes had significant photo-catalysis self-cleaning capability. PVDF-1 (adding 1.0% nano-ZnO with PVDF) membranes achieved 94.8% water flux recovery after exposure to low-pressure 10 W UV-C mercury lamp irradiation for 30 min, whereas the raw membrane only reached 63.3% recovery. The implantation of nano-ZnO on the inner surface of the membrane (i.e., the pore wall) may have been responsible for the enhancement of the photo-catalysis self-cleaning property. The pure water flux of the PVDF-1.5 (adding 1.5% nano-ZnO with PVDF) membrane was nearly five times as great as that of pure PVDF. Supplementation of nano-ZnO could improve the mechanical properties of the membrane, but excessive supplementation of nano-ZnO could cause a decline in the membrane mechanical properties.     

Plasma Polymerization Modified Polyvinylidene Fluoride (PVDF) Membrane Development and Characterization for Degumming of Soybean Oil

Unmodified and surface‐modified polyvinylidene fluoride (PVDF) membranes were tested for their ability to degum soybean crude oil and crude oil miscellas. The membrane was modified with 1,1,1,3,3,3‐hexafluoro‐2‐propanol or hexamethyldisiloxane (HMDSO) by radio‐frequency plasma polymerization at 10–100 W glow discharge power and 1–30 min contact time. The membranes were characterized by contact angle measurements, attenuated total reflectance Fourier transform infrared spectroscopy, atomic force microscopy, and scanning electron microscopy. Modification of the PVDF membrane with HMDSO at 60 W power for 5 min increased the interfacial free energy between water and solid surface from 30 ± 2 to 64 ± 2 mJ/m². This membrane was tested for permeate flux and phospholipid rejection with crude oil and different concentrations of miscella. Although formation of the polymer film on the membrane tended to decrease membrane pore size, the modified membrane had an oil flux as good as the unmodified membrane did. In addition, the modified‐membrane improved the phospholipid rejection and removed 76 % of the phospholipids from the crude oil and 81–90 % of the phospholipids from crude oil miscellas.     

相转化法制备PVDF超滤膜及其亲水化改性研究进展

综述了聚偏氟乙烯(PVDF)超滤(UF)膜在相转化制备方法和亲水化改性两方面的最新研究进展。在相转化制备方法中,介绍了聚合物用量、溶剂的选择、添加剂的种类和用量及凝固浴组成和温度对膜结构和性能的影响;在PVDF超滤膜亲水化改性方面,介绍了共混改性、共聚改性、辐照接枝改性、等子体改性等方法的机理、特点和近年来的研究进展,指出了共混改性是今后亲水改性的主要方向。     

聚乙烯阴离子交换膜掺混聚偏氟乙烯改性表征

聚偏氟乙烯（PVDF）因含氟乙烯基单体,拥有良好的化学稳定性、热学稳定性和机械性能,与其他高分子膜材料相比更容易提高离子交换膜的性能。本实验采用热压法制备PVDF聚乙烯阴离子交换膜,探讨了PVDF含量对膜性能的影响,如膜电阻、离子交换容量、耐破度、含水率和选择透过性。利用红外光谱仪及扫描电子显微镜表征手段对PVDF膜表面性质和结构进行了分析。结果表明,当PVDF含量增加时,膜面电阻、耐破度升高。离子交换容量、含水率,反离子选择透过性降低。虽然PVDF的添加导致含水率、交换容量等膜性能的下降,但耐破度的升高表明膜稳定性和机械性能得到了提升,这赋予PVDF聚乙烯膜一定的使用价值。     

Development of mesoporous titanium dioxide hybrid poly(vinylidene fluoride) ultrafiltration membranes with photocatalytic properties

A photocatalytic activity ultrafiltration membrane (UFM) was prepared by the blending of a poly(vinylidene fluoride) (PVDF) polymer with mesoporous titanium dioxide (M‐TiO₂) particles via the phase‐inversion method. The microstructure of the membrane and Ti element distribution were characterized by scanning electron microscopy and energy‐dispersive X‐ray spectroscopy. Their properties were also determined by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, tensile stress tests, contact angle tests, bovine serum albumin retention, water flux, and permeation flux. When the M‐TiO₂ concentration reached 1 wt %, the thermal stability, mechanical properties, hydrophilicity, flux, and antifouling performance of the M‐TiO₂/PVDF UFM were improved to an optimal value with the M‐TiO₂ particles successfully entrapped and evenly distributed throughout the PVDF polymer matrix. Compared with the P25‐modified PVDF UFM (1 wt %), the M‐TiO₂‐modified PVDF UFM (1 wt %) exhibited better photocatalytic activity and wonderful stability in the UV photocatalytic degradation of the organic dye Rhodamine B. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43427.     

聚偏氟乙烯微孔膜的制备与透过性能研究

采用相转化法制备聚偏氟乙烯（PVDF）微孔膜,研究了铸膜液中聚偏氟乙烯含量、溶剂的种类、添加剂的种类和含量、膜厚度以及操作压力等因素对聚偏氟乙烯膜水通量的影响,采用扫描电子显微镜观测了制备膜的表面结构。结果表明,制膜条件对聚偏氟乙烯微孔膜通量有重要影响,通量随添加剂含量和压力的增大而增大,随PVDF含量和膜厚度的增大而减小;当压力上升到0．16MPa时,通量将不随压力变化,达到极限通量。     

聚偏氟乙烯/聚醋酸乙烯酯共混小截留分子量超滤膜

引　言随着膜分离技术越来越广泛的应用 ,对膜材料的品种和性能提出了新的要求 ,尤其是小截留分子量超滤膜在国内的需求越来越大 .聚偏氟乙烯(ＰＶＤＦ)具有极好的化学稳定性 ,制出的超滤膜强度高、韧性好、耐温、耐腐蚀 ,尤其适用于有机溶剂体系的过滤、提纯和浓缩[1] .但ＰＶＤＦ膜疏水性较强 ,水通量不够大 ,影响了应用范围的扩大 .用共混来改善膜的性能 ,是膜改性方法之一 .与ＰＶＤＦ共混制备超滤膜的第 2组分已被研究的有尼龙 - 6 [2 ] 、聚砜[3] 、聚丙烯腈[4 ] 、聚乙二醇[5] 、聚甲基丙烯酸甲酯[5] 等 .本工作采用亲水性很强的聚醋…     

水中汞离子净化用共混改性超滤膜的研制

采用相转化法,以聚偏氟乙烯（PVDF）、二硫化二苯并噻唑、聚乙二醇（PECA00）、吐温80和N,N-二甲基乙酰胺（DMAe）为原料制备具有汞离子吸附能力的二硫化二苯并噻唑共混改性聚偏氟乙烯超滤膜,并对影响超滤膜结构和性能的各个因素进行了研究。结果表明,在二硫化二苯并噻唑质量分数为0．4％、共混温度为70℃、共混时间为6h条件下所制备的超滤膜性能最佳。在25℃、0．1MPa下,膜的纯水通量为312L／m^2·h,卵清蛋白截留率为83．46％,接触角为72．35°;在25℃、pH值为7左右的条件下,膜吸附汞离子在6h达到吸附平衡。汞离子最大吸附量为0．331mg／cm^2。     

Preparation and performance of the novel PVDF ultrafiltration membranes blending with PVA modified SiO2 hydrophilic nanoparticles

In this study, PVA‐SiO₂ was synthesized by modifying silica (SiO₂) with polyvinyl alcohol (PVA), then a novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was prepared by incorporating the prepared PVA‐SiO₂ into membrane matrix using the non‐solvent induced phase separation (NIPS) method. The effects of PVA‐SiO₂ particle on the properties of the PVDF membrane were systematically studied by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT‐IR), surface pore size, porosity, and water contact angle. The results indicated that with the addition of PVA‐SiO₂ particles in the PVDF UF membranes, membrane mean pore size increased from 80.06 to 126.00 nm, porosity improved from 77.4% to 89.1%, and water contact angle decreased from 75.61° to 63.10°. Furthermore, ultrafiltration experiments were conducted in terms of pure water flux, bovine serum albumin (BSA) rejection, and anti‐fouling performance. It indicated that with the addition of PVA‐SiO₂ particles, pure water flux increased from 70 to 126 L/m² h, BSA rejection increased from 67% to 86%, flux recovery ratio increased from 60% to 96%, total fouling ratio decreased from 50% to 18.7%, and irreversible fouling ratio decreased from 40% to 4%. Membrane anti‐fouling property was improved, and it can be expected that this work may provide some references to the improvement of the anti‐fouling performance of the PVDF ultrafiltration membrane. POLYM. ENG. SCI., 59:E412–E421, 2019. © 2018 Society of Plastics Engineers     

Effect of different forms of nano-ZnO on the properties of PVDF/ZnO hybrid membranes

In this article, polyvinylidene fluoride (PVDF)/ZnO hybrid membranes with different forms of nano-ZnO as additives were prepared by thermally induced phase separation. The effects of the morphology of ZnO particles on the microstructure and properties of hybrid membranes were systematically investigated. Three different forms of nano-ZnO were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Then a series of tests were made through XRD, Fourier transform infrared, differential scanning calorimeter, SEM, energy-dispersive X-ray spectroscopy, atomic force microscopy, mechanical strength testing, porosity measurement, water contact angle measurement, pure water flux measurement, rejection measurement, flux recovery rate (FRR) measurement, and photocatalytic degradation testing to characterize the hybrid membrane. The results show that the hybrid membranes which were doped with different forms of ZnO have different structures and properties. Porous ZnO has the best modification effect on PVDF membranes. The PVDF/porous ZnO hybrid membranes' water flux and OVA rejection can reach 1.6 and 1.3 times of pure PVDF membrane, respectively, and its FRR can reach about 95%. The hybrid membrane doped with porous ZnO has excellent self-cleaning performance, and its degradation rate of MB can reach about 51%.