不同相对湿度下亲疏水纳米纤维膜空气过滤性能实验研究

利用静电纺丝法制备了表面静态接触角为23.6°的具有亲水功能的PAN/PVP复合纳米纤维膜、接触角为81.2°的PAN纳米纤维膜、接触角为131.9°的具有疏水功能的PAN/PVDF复合纳米纤维膜。利用自行搭建的空气过滤实验台，在40%、55%、70%三种相对湿度下对三种纳米纤维膜进行空气过滤实验，对纳米纤维膜的过滤效率、阻力损失及品质因子进行分析。结果表明：三种纳米纤维膜的过滤效率随着相对湿度的增大而升高，PAN/PVP膜和PAN膜的阻力损失随着相对湿度的增大而增加，PAN/PVDF的阻力损失随着相对湿度的增大而减小；PAN/PVP膜和PAN膜的品质因子随着相对湿度的增大而减小，PAN/PVDF膜的品质因子随着相对湿度的增大而增大，湿度越大，PAN/PVDF纳米纤维膜的过滤性能越显著。     

静电纺PLA微/纳米纤维膜的浸润性能研究

采用静电纺丝技术制备聚乳酸(PLA)微/纳米纤维膜,研究了其可纺性、浸润性能及结构。结果表明:以二氯甲烷为溶剂的PLA电纺丝溶液,当PLA质量分数为7%时,可纺出纤维直径为280～690 nm的PLA微/纳米纤维膜。PLA微/纳米纤维膜与水的接触角为127.6°,高于PLA流延膜与水的接触角107.7°;红外光谱分析表明,PLA微/纳米纤维膜的分子组成没有发生变化;X光电子能谱测试表明PLA微/纳米纤维膜的表面碳氧含量比高于PLA流延膜,PLA微/纳米纤维膜的疏水性得到提高。     

铜表面复合超疏水薄膜的制备及表征

该文利用自组装技术,在HNO3(质量分数6.5%)刻蚀的铜表面制备了(3-巯基丙基)三甲氧基硅烷(MPTS)与正辛基三乙氧基硅烷(OS)的复合纳米薄膜,并通过红外光谱对膜结构进行了分析。通过扫描电子显微镜确定了该复合膜具有纳米-微米级粗糙结构;静态接触角达158.6°,滚动角为3°,表明该膜具有超疏水性能;盐水实验证明该复合膜有效地提高了铜的耐腐蚀能力。     

静电纺/熔喷醋酸丁酸纤维素复合膜的制备及性能研究

采用熔喷法及热轧处理制备醋酸丁酸纤维素(CAB)非织造布;然后以体积比6:4的丙酮与乙酸为溶剂,通过静电纺丝制备CAB纳米纤维并沉积在熔喷CAB非织造布表面,制得静电纺/熔喷CAB复合膜;对复合膜的孔径、过滤效率和透气性进行测试。结果表明:当纺丝溶液CAB质量分数为30%,纺丝电压为18 kV,喂液速率为0.2 mL/h,接收距离为21 cm时,静电纺CAB纳米纤维平均直径及直径变异系数最小,分别为359 nm和16.06%;熔喷CAB非织造布的孔径主要分布在10μm左右,对1μm气溶胶粒子的过滤效率为51.393%,在使用?8喷嘴时透气率为1 856 mm/s;静电纺/熔喷CAB复合膜的孔径分布在1.7～2.2μm,对1μm气溶胶粒子的过滤效率达96.433%,在使用?8喷嘴时透气率为735 mm/s;相比熔喷CAB非织造布,静电纺/熔喷CAB复合膜的最大孔径、最小孔径、平均孔径均减小,孔径分布区间相对较窄,过滤效率提高,透气率下降。     

超疏水超亲油玻璃纤维过滤膜的制备及其乳化水分离效率

通过溶胶-凝胶法,以MTES(甲基三乙氧基硅烷)为前驱体,在玻璃纤维(玻纤)过滤膜表面直接进行水解缩合反应,制备具有高效油水分离功能的玻纤过滤膜材料。通过扫描电子显微镜和红外光谱分析MTES处理前后玻纤过滤膜的微观形貌与表面组成的变化,并通过接触角仪测试玻纤过滤膜的接触角,采用Karl Fischer水分仪测试玻纤过滤膜的油水分离效率。结果表明:经过MTES处理后,玻纤过滤膜的微观孔隙结构不变,而纤维表面布满疏水亲油的–CH3基团和纳米凸起结构,处理后的玻纤过滤膜有超疏水超亲油性能,玻纤过滤膜对乳化水的油水分离效率可以达到96.09%。     

粉煤灰超疏水不锈钢网的制备及油水分离

采用树脂粘接法，将硬脂酸修饰后的粉煤灰用环氧树脂粘接在不锈钢网骨架表面，制备了超疏水不锈钢网，并对其进行了TEM、SEM、FTIR和接触角等表征。结果显示：在高倍显微镜下改性后的超疏水不锈钢网表面呈一定粗糙度的微纳米分级结构，静态水接触角高达153°。此外，该超疏水不锈钢网具有良好的机械稳定性和超疏水耐久性，其表面经机械磨损试验100次后水静态接触角仍高达141°。该材料用于多种油/有机溶剂与水的混合液的分离中，分离效率均高于94%。     

溶液喷射纺丝制备PES-C/PES-CB复合纳米纤维膜

通过在酚酞聚醚砜(PES-C)纺丝液中添加不同含量的两性离子改性的酚酞聚醚砜(PES-CB),然后利用溶液喷射纺丝法制备PES-CB/PES-C复合纳米纤维膜,并通过扫描电子显微镜、红外、差示扫描量热仪、热重分析、接触角等对复合纳米纤维膜进行了测试表征,最后将复合纳米纤维膜进行淀粉溶液过滤测试。结果表明,随着PES-CB含量的增加,纳米纤维的直径不断减小,当PES-CB添加量达到30%时,复合纳米纤维膜的平均直径减小到300nm左右。同时由于两性离子支链的存在,纤维膜的亲水性也得到提高,但其耐热性降低。过滤测试结果表明,随着PES-CB含量的增加,膜的抗污染能力得到明显提高,当PES-CB添加量达到30%时,过滤淀粉溶液的水通量恢复率(FRR%)达到83%左右。结合纺丝过程及过滤性能测试来看,PES-CB添加量在30%左右制备的复合纳米纤维膜综合性能最佳。     

壳聚糖/聚乙烯醇/壳寡糖抑菌纳米纤维膜的制备和性能研究

以壳聚糖（CS）为基材，使用静电纺丝的方法制备了搭载壳寡糖（CHOS）的CS/聚乙烯醇（PVA）/CHOS纳米纤维膜，并对纳米纤维膜的微观形貌、结构、抑菌性、亲水性以及溶解性能进行了研究。研究发现：CS/PVA/CHOS纳米纤维膜具备均匀密致的微观形貌；FT-IR测试表明，CHOS以物理混合的形式分散在CS/PVA/CHOS纳米纤维膜中；XRD测试表明，CHOS的加入改变了纳米纤维膜的结晶性，促进了各组分之间的相容性；水接触角测试表明纳米纤维膜具备良好的亲水性，在m（CS）：m（PVA）：m（CHOS）=20：80：10时，CS/PVA/CHOS纳米纤维膜的接触角相比于m（CS）：m（PVA）=20：80的CS/PVA纳米纤维膜由59.8°下降到37.5°；抑菌性能和溶解性能测试表明，m（CS）：m（PVA）：m（CHOS）=20：80：10时的CS/PVA/CHOS纳米纤维膜相比于未搭载CHOS的CS/PVA纳米纤维膜，抑菌性提升了38.9%，溶解率提升了38.6%。     

油基纳米氧化锌分散浆的制备及其流变特性

选用硬脂酸钠对ZnO进行表面湿法改性，以环十五硅氧烷硅油为溶剂，PEG-10聚二甲基硅氧烷为分散剂，通过机械球磨法制备了纳米ZnO分散浆。利用水接触角、热重、TEM和FTIR对纳米ZnO粉体进行表征。结果表明，硬脂酸钠改性后，粉体具有疏水性，且硬脂酸钠最佳包覆量为6%（以ZnO的质量计，下同）。硬脂酸钠包覆量为6%的疏水性纳米ZnO粉体，包覆层厚度约为2 nm，此时水接触角最大为145.4°。模拟防晒乳液的防晒性能测试中，纳米氧化锌分散浆的紫外屏蔽性能显著优于粉体。流变特性测试表明，分散浆为假塑性流体，流动曲线符合Ostwald-de Wale幂律方程，具有剪切稀化特性；分散浆的黏度低，触变性小，储存稳定性高；温度升高，黏度降低，配方生产中对温度的敏感程度较小 。     

技术创新

中科院化学所纳米领域 又取得突破性进展 中国科学院化学研究所江雷研究员与徐坚研究员合作,继”超疏水性聚丙烯腈纳米纤维”之后,最近又在超疏水性纳米界而材料的研究上取得突破性进展。他们以一种亲水性的高分子聚乙烯醇为原料,制备了具有超疏水性表面的纳米纤维,纤维表面与水的接触角大于170°。这种特殊的现象是由于聚乙烯醇分子形成了具有纳米结构的表面,分子在纳米     

PAN/FPU Composite Nanofiber Membrane with Superhydrophobic and Superoleophobic Surface as a Filter Element for High-Efficiency Protective Masks

Recently, because of the outbreak of COVID-19, the demand for various types of filter elements in protective materials has increased globally. Furthermore, new requirements for the filtration performance of PM2.5 liquid (oil) particles have been put forward. In this work, Superhydrophobic and superoleophobic composite nanofibers with excellent filtration capacity for oil and salt particles are developed through the modification of polyacrylonitrile (PAN) by fluoro-polyurethane (FPU) doping. The results show that the PAN/FPU composite nanofibers doped with 9 wt% FPU has a uniform fiber morphology with a diameter of 240 ± 30 nm. Compared to the pure PAN nanofibers, the water-based contact angle of PAN/FPU increases from 90 ± 5° to 151 ± 5°, and the oil-based contact angle increases from 58 ± 2° to 152 ± 3°. Importantly, at a high flow rate of 95 L min⁻¹, the filtration efficiency of the PAN/FPU nanofiber membrane for 0.3 µm oil particles increases from 92 ± 1% to 99.2 ± 0.1%. After cyclic loading, the filtration efficiency of 0.3 µm oil particles remains above 98%. Meanwhile, the filtration efficiency for 0.3 µm salt particles remains at 98.23 ± 0.1%. The PAN/FPU nanofiber membrane developed in this work is effective in applications and has good market prospects as a protective filtration material.     

Structure and performance of electroblown PVDF-based nanofibrous electret filters

Poly(vinylidene fluoride) (PVDF)-based nanofibrous mats were produced via electrically assisted solution blowing (electroblowing). Morphology and filtration properties of the nanofibrous mats were investigated as a function of polymer concentration and applied voltage. The average fiber diameter was reduced from 727 ± 366 nm to 408 ± 143 nm and from 424 ± 233 nm to 328 ± 105 nm, using 16 wt% and 12 wt% concentrations, respectively, with an increase of electric voltage from 0 to 30 kV. In addition, the pore size of the mats produced from 12 wt% concentration decreases with the increase of electric voltage. Results showed that electroblown mats possess high filtration properties and performance. Enhancement of mechanical capturing efficiency is attributed to the reduction in fiber diameter and pore size. The enhancement of electrostatic capturing efficiency is thought to be from the improved electret property of the mats, which eliminates the need for a second step to polarize nanofibrous mats. As a result, both mechanical and electrostatic capture efficiency of the mats is enhanced compared to solution blown PVDF mats. The emerging electret property might be due to the accumulation of the electrostatic charges at high voltage and the enhanced polarized β phase, which is the result of the high drawing ratio applied to the polymer jet during the spinning process.     

Optimization of electro-blown polysulfone nanofiber mats for air filtration applications

Durable, robust, and hydrophobic air filtration media was produced via electro-blow spinning (EBS) technique using polysulfone (PSU) due to its superior properties. To our knowledge, this is the first optimization study of PSU nanofiber production via EBS technique for air filtration applications. Concentration, air pressure, and voltage were determined as independent variables for the optimization based on “smaller is the better” approach of Taguchi Design of Experiment. The optimized values which supplied the smallest average fiber diameter (AFD) possible were obtained as 13 wt% PSU, 3 bar, and 7.5 kV. The AFD of the sample obtained from the confirmation experiment was calculated as 105 ± 34 nm. Surface morphologies, porosity values, and wettability behaviors of the samples were investigated by using scanning electron microscopy, gravimetric method, and water contact angle measurements, respectively. PSU nanofiber mats exhibited superhydrophobic behavior (water contact angle values up to 159.8°) which is important for various separation processes. Samples prepared at different deposition times (15, 30, 45, and 60 min) were investigated in terms of particle capture efficiency and pressure drop. The 0.3 μm particle filtration efficiency was found to be 98.09% at an expense of 202 Pa pressure drop which would be suitable for various respiratory and HVAC filter applications.     

A robust and coarse surface mesh modified by interpenetrating polymer network hydrogel for oil‐water separation

A robust and coarse surface mesh was fabricated by introducing a hydrogel coating with interpenetrating polymer network (IPN) structure on stainless steel mesh. The IPN hydrogel was prepared by crosslinking polymerization of acrylic acid (AA) followed by condensation reaction of polyvinyl alcohol (PVA) and glutaraldehyde (GA) at room temperature. As a result, the roughness of modified mesh was enhanced obviously and oil droplet underwater showed a larger contact angle. The hydrogel‐coated surface showed an underwater superoleophobicity with an oil contact angle of 153.92 ± 1.08^°. Besides, stable wettability was observed. The mesh can selectively separate oil from water with a high separation efficiency of above 99.8%. This work provides a facile method to strengthen the coating and enhance the efficiency of oil‐water separation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41949.     

Electrospun nanofibrous polyvinylidene fluoride-co-hexafluoropropylene membranes for oil–water separation

Effective separation of oil from water is of significant importance globally for various applications such as wastewater treatment, oil spill cleanup, and oil purification. Among the numerous approaches for oil removal, membrane separation is considered one of the most promising approaches due to its selectivity and ease of operation. Electrospinning is a promising technique for producing polymeric membranes with tunable structures with interconnected pores, large surface area, and high porosity. In this study, hydrophobic poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibrous membranes were electrospun and used for this purpose. The effects of various parameters (e.g., polymer concentration, applied voltage, tip to collector distance, and feed rate) were investigated to find the optimum electrospinning conditions. Further, the electrospun membranes were characterized according to average fiber diameter, morphology, average pore size, and wettability to identify the combinations most likely to succeed in oil–water filtration. The physical–chemical properties of the membranes (i.e., thickness, areal density, porosity, average pore size, water/oil contact angle, hydrostatic pressure head, and oil filtration flux) were studied based on standard test methods. The separation efficiency of eight electrospun membranes with various pore sizes and average fiber diameters were tested for diesel/water mixtures. A linear relation was found between the initial oil flux and the average pore size of the membranes. The maximum oil filtration flux of about 224 L/m²/h, achieving over 75% oil recovery in 10 min, was obtained for the electrospun membrane with the average pore size of 4.5 μm. The membranes were successfully used for eight consecutive oil–water separation cycles without noticeable loss of flux.     

Wetting behavior of thermally bonded polyester nonwoven fabrics: The importance of porosity

The wetting properties of thermally bonded polyester nonwoven fabrics with different basis weights were studied. These nonwovens had the same composition: 85% poly(ethylene terephthalate) and 15% poly(butylene terephthalate) fibers. Two techniques, the 3S wicking test and sessile drop method, yielded similar water contact angles for all the nonwovens, but these results differed from the values obtained with the single fibers. In the nonwoven fabrics, the pore structure played a dominant role in the wetting properties: the existence of large pores in the thinner nonwovens reduced the dimensions of the liquid–solid interfacial perimeter. Compared with the water contact angle of the constituent single fibers, the contact angle of the fabrics was increased. A crenellated surface model was created to quantify the influence of pores on the wettability of nonwovens. It was possible to deduce the surface porosity of the fabric with this model, but only in the case of contact with nonwetting liquids such as water: this surface porosity corresponded only to the outermost layers of the fabric structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 387–394, 2006     

三次采油用耐温耐盐表面活性剂BHJ-2的研究

针对碳酸盐岩油藏具有高温、高矿化度的特点，研制出适合该类型油藏三次采油用耐温耐盐型表面活性剂BHJ-2。考察了其耐温耐盐性、界面活性、润湿性能、吸附性能、洗油效率、驱油效率等；结果表明，BHJ-2耐温达140℃，耐盐达23.3×104mg/L，吸附损失为0.574mg/g油砂，可将油-地层水-岩石接触角由亲油性109.6°转变为亲水性61.4°。在140℃高温条件下老化30d后，界面活性和洗油效率基本不变，油水界面张力为0.576mN/m，静态洗油效率达到83.7%，可提高驱替效率36.7%，研究表明BHJ-2可适用于高温高矿化度条件的亲油性碳酸盐岩油藏。     

三次采油用耐温耐盐表面活性剂BHJ-2的研究

针对碳酸盐岩油藏具有高温、高矿化度的特点,研制出适合该类型油藏三次采油用耐温耐盐型表面活性剂BHJ-2。考察了其耐温耐盐性、界面活性、润湿性能、吸附性能、洗油效率、驱油效率等;结果表明,BHJ-2耐温达140℃,耐盐达2.33×10~5mg/L,吸附损失为0.574 mg/g油砂,可将油-地层水-岩石接触角由亲油性109.6°转变为亲水性61.4°。在140℃高温条件下老化30 d后,界面活性和洗油效率基本不变,油水界面张力为0.576 m N/m,静态洗油效率达到83.7%,可提高驱替效率36.7%,研究表明,BHJ-2可适用于高温高矿化度条件的亲油性碳酸盐岩油藏。     

Wettability alterations due to crude oil composition and an anionic surfactant in petroleum reservoirs

In this study, dual-drop dual-crystal (DDDC) contact-angle measurements have been made using dolomite rock and fluid samples from the Yates reservoir (West Texas) and in the presence of an anionic (ethoxy sulfate) surfactant. The experiments have been conducted at Yates reservoir conditions (4.8 MPa and 27.8°C) and using live synthetic oil to provide realistic measurements of in situ reservoir wettability. Stocktank crude oil has also been used at reservoir conditions to study the oil compositional effects on wettability. An advancing contact angle of 152° measured for Yates dolomite rock, stocktank oil and synthetic reservoir brine showed a strong oil-wet nature. However, experiments with Yates live synthetic oil resulted in an advancing contact angle of 55°, indicating a weakly water-wet behavior. In the rock-fluids system consisting of Yates stocktank oil, the surfactant altered the wettability to less oil-wet by decreasing the advancing contact angle to 135°. For rock-fluids system with Yates live synthetic oil, the surfactant altered the wettability from weakly water-wet to strongly oil-wet by increasing the advancing contact angle from 55° to 165°. The oil-wet behavior observed with Yates live synthetic oil due to the surfactant indicates a significant wettability altering capability of the surfactant.