PVA/DTC纳米纤维的制备及对铅离子的吸附行为

通过高压静电纺丝技术制备了聚乙烯醇/聚乙烯亚胺(PVA/PEI)纳米纤维膜, 对纤维膜进行功能化使其转化为对重金属离子具有高络合能力的聚乙烯醇/二硫代氨基甲酸盐功能化聚乙烯亚胺(PVA/DTC)纳米纤维膜. 研究了PVA/PEI纳米纤维膜的交联和功能化以及PVA/DTC纤维膜对铅离子的吸附行为. 结果表明, 高压静电纺丝法可制备出纤维直径分布均匀、 形貌良好的纳米纤维膜, 且交联、 功能化后仍能保持蓬松纳米纤维状的网状结构. PVA/DTC纳米纤维膜对铅离子吸附速率快, 吸附量容量高, 且具有良好的再生吸附能力, 是一种潜在的重金属离子高效吸附材料.     

PVA/GA/β-CD纳米纤维的制备及染料吸附性能

利用静电纺丝技术,以六氟异丙醇(HFIP)和水为溶剂,制备了环糊精(β-CD)含量为70%(质量分数)的聚乙烯醇(PVA)/β-CD纳米纤维,并经戊二醛(GA)交联处理得到了可用于染料吸附的PVA/GA/β-CD纳米纤维.通过红外光谱和扫描电子显微镜研究了交联反应前后纳米纤维组成和形貌的变化;考察了PVA/GA/β-CD纳米纤维对7种水溶性染料的吸附性能.结果表明,PVA/GA/β-CD纳米纤维对孔雀石绿、甲基紫和刚果红的吸附效果较好,最大吸附量分别为124.71,121.14和127.39 mg/g,4次吸附-解吸附循环后,染料去除率仍保持80%左右,在染料废水处理中具有良好的应用前景.     

AgNPs-AC复合纤维的制备及其吸附与抗菌性能

制备具有较好吸附抗菌性能的纳米过滤材料是过滤领域的一个关键问题。在多种纤维与薄膜材料的制备方法中,静电纺丝法具有比表面积大、孔隙率高的特点,为制备具有吸附抗菌性能的纳米过滤材料提供了一种有效思路。本文通过静电纺丝法制备了纳米银颗粒-活性炭(AgNPs-AC)复合纳米纤维膜,将纳米银颗粒沉积在活性炭载体上,目的是制备一种具有良好吸附抗菌功能的高性能过滤电纺复合纤维膜。通过SEM、XRD等设备对复合纳米纤维的形貌与结构进行表征,并考察该复合纤维膜的吸附性能和抗菌性能。结果表明,所制备的AgNPs-AC复合纳米纤维膜随活性炭、银浓度的增大,纤维直径分布逐步趋于均匀。并且在EVOH质量分数为10%,硝酸银/活性炭浓度比为0.05/0.085时,该复合纤维膜的吸附性能最好。此外,AgNPs-AC复合纳米纤维膜对金黄色葡萄球菌表现出良好的抗菌性能。     

双酚A分子印迹聚醚砜纳米纤维膜的制备和识别性能的研究

采用静电纺丝技术制备双酚A分子印迹聚醚砜纳米纤维膜.利用聚醚砜功能基与模板分子的相互作用形成结合位,其结构在纺丝过程中被固定下来,模板分子去除后聚醚砜纳米纤维膜上就留下能选择性结合目标分子的结合位.研究了模板分子加入量、静电纺丝电压和溶剂等纺丝条件对纳米纤维膜印迹效果的影响.识别实验表明,10％双酚A的聚醚砜印迹纳米纤...     

分子印迹固相萃取-高效液相色谱法测定猪肉中红霉素残留

采用沉淀聚合法,以红霉素（erythromycin,ERY）为模板,甲基丙烯酸（methacrylic acid,MAA）为功能单体,乙二醇二甲基丙烯酸酯（ethyleneglycoldimethacrylate,EGDMA）为交联剂,甲醇/乙腈（1:4,v/v）为致孔剂制备了ERY分子印迹聚合物（molecularly imprinted polymers,MIPs）。通过扫描电镜、平衡吸附实验等对制备的印迹和非印迹聚合物进行表征和测定,结果表明所制备的MIPs对ERY具有特异性吸附作用。Scatchard分析证明MIPs对ERY的吸附存在两类不同结合位点,最大表观结合量（Q_max）和平衡解离常数（K_d）分别为Q_max1=45.24 mg/g,K_d1=0.028 g/L; Q_max2=87.53 mg/g,K_d2=0.20 g/L。以制备的MIPs为吸附剂的分子印迹固相萃取柱,结合高效液相色谱法能够快速检测猪肉样品中的ERY残留,线性范围为0.5~50 mg/L（r²=0.9994）,检出限（S/N=3）为0.2 mg/kg。猪肉样品中不同添加水平下ERY的加标回收率为95.2%~104.2%,相对标准偏差（RSD）小于5%。该方法选择性好,灵敏、可靠,可用于猪肉等复杂食品样本中ERY残留的检测。     

静电纺丝法制备三维聚二甲基硅氧烷纳米通道

利用静电纺丝技术构建了新型三维纳米通道系统。 在不同质量分数的聚苯乙烯（PS：Mw=1.3×105）溶液中加入一定量十二烷基磺酸钠（SDS）,于不同电压下进行静电纺丝。 所得纤维在90 ℃加热粘连后,形成三维聚苯乙烯纳米网络模板,然后于聚二甲基硅氧烷(PDMS)预聚体（含10%交联剂）灌注进入上述模板并交联形成网络复合材料,再用二硫化碳超声除去聚苯乙烯纤维。 采用扫描电子显微镜、透射电子显微镜对纤维模板形貌和纳米通道进行了表征。 结果表明,质量分数为10%的PS溶液加入0.5%SDS,在20 kV电压下进行静电纺丝,得到直径为150 nm的纤维。 SDS的加入对纺丝纤维具有平滑作用,使得粘连的纤维模板更易去除,形成的三维纳米通道直径约160 nm,与纤维模板直径一致。 该类型纳米通道可以应用于医学药物载体、纳流控芯片等众多领域。     

聚合物/TiO2杂化纳米纤维微孔膜的制备及其在染料敏化太阳能电池中的应用

利用静电纺丝技术,制备了不同的聚合物/TiO2杂化纳米纤维微孔膜,吸附液体电解质后形成聚合物/TiO2杂化纳米纤维微孔膜准固态电解质,应用于制备准固态染料敏化太阳能电池(DSSCs).测试了电纺聚合物纳米纤维微孔膜电解质的吸液率、孔隙率、离子电导率等参数,研究了纳米纤维微孔膜准固态电解质DSSCs的光伏性能.结果显示,TiO2的掺入可提高聚合物/TiO2杂化纳米纤维微孔膜对液态电解质的浸润扩散性能,从而提高纳米纤维微孔膜对液态电解质的吸附能力.组装的DSSCs的光电转换效率可达液态电解质的90%以上,并具有较好的长期工作稳定性.     

茶碱分子印迹聚酰亚胺纳米纤维膜的制备与表征

以聚酰胺酸(PAA)溶液为原料,采用静电纺丝法制备了聚酰胺酸纳米纤维膜(PAAM),热处理脱水后获得聚酰亚胺纳米纤维膜(PIM)。采用PIM表面预涂覆聚甲基丙烯酸(PMAA),以茶碱(THO)为模板分子、偶氮二异丁腈(AIBN)为引发剂、乙二醇二甲基丙烯酸酯(EDMA)为交联剂、氯仿为溶剂,在PIM表面进行了热交联反应,制备了THO分子印迹聚酰亚胺纳米纤维复合膜(PIMIM)。讨论了纺膜条件,并用傅里叶红外光谱与扫描电镜分别表征了PIMIM的结构和形态,比较了THO的洗脱方式。结果表明:较佳的纺膜条件为纺丝电压15.0kV、接收距离12.0cm和纺丝液流量0.5mL/h。以PIM为支撑体,获得了聚酰亚胺纳米纤维间有分子印迹层的PIMIM。PIMIM对THO的静态吸附结合容量达144μmol/g,对THO与可可碱(TB)的选择性分离因子达1.96。对PIMIM循环再生,索氏提取法优于超声洗脱法。     

PLGA/明胶共混体系的静电纺丝研究

采用静电纺丝技术制备了聚乳酸乙醇酸(PLGA)/明胶(Gt)的复合超细纤维, 考察了溶液浓度、电压及流速对纤维形貌的影响. 研究了不同明胶比例的纤维膜的微观形貌和干湿态的力学性能. 结果表明, 在溶液浓度0.12 g/mL, 电压7.5 kV, 流速0.8 mL/h条件下, 所得PLGA/Gt复合纤维直径较小, 粗细较均匀且缺陷少. 含有明胶的复合纤维直径远小于PLGA单纺纤维直径, 明胶的加入降低了膜的拉伸强度和断裂伸长率, 提高了膜的亲水性. 经PBS浸泡后, 复合膜的弹性得到加强. 明胶质量分数为5%和10%时, 纤维直径分布较窄, 当明胶的质量分数增加至15%时, 纤维的直径分布变宽.     

采用静电纺丝/非溶剂致相分离制备聚丙烯腈多孔超细纤维的研究

以聚丙烯腈/二甲基亚砜/N,N'-二甲基甲酰胺三元体系为纺丝液、3℃水浴为接收介质,通过静电纺丝制备了具有纳米孔结构的静电纺聚丙烯腈多孔超细纤维.探讨了溶剂比例、接收介质、聚丙烯腈浓度、纺丝电压及接收距离等因素对纤维直径和表面孔隙率的影响.结果表明最佳制备条件为混合溶剂质量比1∶1、纺丝电压16 kV、聚丙烯腈浓度15 wt%、接收距离5 cm、纺丝速率0.7 mL/h、环境温度25℃、相对湿度40%～70%.在此条件下得到的聚丙烯腈多孔超细纤维直径在420～490 nm,平均直径468 nm,表面孔隙率3.4%,纤维内部形成大量孔径为8～30 nm的孔结构,且孔径分布均匀,孔形状相对一致.N2吸附脱附测试表明,聚丙烯腈多孔纤维的BET比表面积达43.86 m2/g,是相同直径无孔聚丙烯腈纤维比表面积理论值的6倍.通过研究聚丙烯腈/(二甲基亚砜+N,N'-二甲基甲酰胺)/水的三元相图,提出非溶剂致相分离是主要成孔机理.     

Optimization and characterization of electrospun chitosan/poly(vinyl alcohol) nanofibers as a phenol adsorbent via response surface methodology

Fabrication and characterization of chitosan/poly(vinyl alcohol) electrospun nanofibers for adsorption of phenol from water were investigated. The effects of voltage (15–30 kV), solution injection flow rate (0.5–1.5 ml/hr), distance of needle and collector (10–20 cm) and chitosan/poly(vinyl alcohol) ratio (25/75, 50/50, 75/25) were studied to obtain the optimum electrospinning conditions for the maximum adsorption capacity of phenol. Central composite design (CCD) was used to investigate and optimize the processing factors for production of chitosan/poly(vinyl alcohol) nanofibers from aqueous solutions. The nanofibers were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR). Uniform beadless nanofibers with the minimum diameters of 3–11 nm were obtained at chitosan/poly(vinyl alcohol) ratio of 50/50, voltage of 22.5 kV, distance of 15 cm and injection flow rate of 1.99 ml hr^?1. Fourier transform infrared spectrum of chitosan/poly(vinyl alcohol) exhibited the existence of relevant functional groups of both poly(vinyl alcohol) and chitosan in the blends. Results of CCD show that among all processing factors, rate of electrospinning will highly affect the nanofiber adsorption. The response surface quadratic order model presented correlation coefficient explaining 69.5% of the variability in the adsorption. Copyright © 2017 John Wiley & Sons, Ltd.     

Characterization of poly(methyl methacrylate) nanofiber mats by electrospinning process

In this study, the aim is to describe the influence of electrospinning parameters on the morphology, the water wetting property and dye adsorption property of poly(methyl methacrylate) nanofiber mats. Specifically, the effects of solution concentration, solvent type, applied voltage, distance between the electrodes and particulate reinforcement on the diameter and shape of the nanofibers were investigated. All poly(methyl methacrylate) nanofiber mats contained beaded nanofiber structures. With increasing the polymer solution concentration, the average fiber diameter also increased. Poly(methyl methacrylate) nanofiber mat electrospun from dimethylformamide solution resulted in thicker fibers when compared with the mat electrospun from acetone solution. Increasing the electric potential difference between the collector and the syringe tip did not increase the average fiber diameter. Besides increasing the distance between the electrodes resulted in a decrease in the average fiber diameter. When compared with PMMA nanofiber mat, thicker fibers were obtained with silica nanoparticles reinforced nanofiber mat. According to the water contact angle measurements, all poly(methyl methacrylate) nanofiber mats revealed hydrophobic surface property. PMMA nanofiber mat with the highest water contact angle gave rise to the highest dye adsorption capacity.     

Preparation and characterization of high‐molecular‐weight atactic poly(vinyl alcohol)/sodium alginate/silver nanocomposite by electrospinning

High‐molecular‐weight poly(vinyl alcohol) (PVA)/sodium alginate (SA)/ silver nanocomposite was successfully prepared via electrospinning technique. Water‐based colloidal silver in a PVA/SA blend solution was directly mixing without any chemical and structural modifications into PVA/SA matrix to form an organic‐metallic nanocomposite. The effect of the addition of silver colloidal solution on the PVA/SA/silver nanocomposite was investigated through a series of experiments varying molecular weight of PVA and electrospinning processing parameters such as concentration of PVA solution, PVA/SA blend ratio, applied voltage, and tip‐to‐collector distance. In the case of PVA with number‐average degree of polymerization of 1700, by increasing the amount of SA in spinning solution, the morphology was changed from fine uniform fiber to beaded fiber or bead‐on‐string fiber structure. Increase of the amount of silver colloidal solution resulted in higher charge density on the surface of ejected jet during spinning, thus more electric charges carried by the electrospinning jet. As the charge density increased, the diameter of the nanocomposites became smaller. Transmission electron microscopy images showed that the dense silver nanoparticles were well separately dispersed in PVA/SA matrix. Energy‐disperse X‐ray analysis indicated that carbon, oxygen, natrium, and silver were the principle element of PVA/SA/silver nanocomposite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1916–1926, 2009     

Polysulfone nanofibers prepared by electrospinning and gas/jet-electrospinning

Polysulfone nanofibers were prepared by electrospinning. The electrospinning equipment was designed in a new way, wherein the spinneret was combined with a gas jet device. The intrinsic viscosity of the used polysulfone was 0.197 dL/g in dimethyl acetamide, which was also the solvent in electrospinning. The gas used in this gas jet/electrostatic spinning was nitrogen. The relationship between the process parameters and the average diameter of polysulfone nanofibers was investigated. The main process parameters studied in this work were the voltage, the flow rate of the spinning fluid, the distance between the spinneret and the nanofiber collector and the temperature in the spinning chamber. The other important factors determining the nanometer diameter were the spinning fluid properties including its viscosity, surface tension and electrical conductivity. The average diameter and the diameter distribution of electrospinning nanofibers were measured experimentally by using scanning electron microscopy. The diameter of polysulfone nanofibers prepared by the gas jet/electrostatic spinning was in the range 50–500 nm. It was found that the diameter of nanofibers mainly depended on high voltage, the gap between the spinneret and the collector and the concentration of polymer solutions. It is concluded that the gas-jet/electrospinning is a better method than the conventional electrospinning, in that it makes the nanofibers finer and more uniform and exhibits higher efficiency in the process of electrospinning. __________ Translated from Acta Polymerica Sinica, 2005, (5) (in Chinese)     

Electrospinning and characterization of poly(vinyl alcohol)/chitosan oligosaccharide/clay nanocomposite nanofibers in aqueous solutions

Submicron fibers of the composite of poly(vinyl alcohol) (PVA), chitosan oligosaccharide [COS, (1→4)2-amino-2-deoxy-β-d-glucose], and montmorillonite clay (MMT) were prepared using electrospinning method with aqueous solutions. Scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), thermal gravimetric analyzer, and tensile strength testing machine (Zwick) were utilized to characterize the PVA/COS/MMT nanofiber mats morphology and properties. The PVA/COS ratio and MMT concentration play important roles in nanofiber mat properties. XRD and TEM data demonstrated that exfoliated MMT layers were well-distributed within nanofiber. It was also found that the mechanical property and thermal stability were increased with COS and MMT contents.     

基于甲氧基柱[5]芳烃的聚丙烯酸酯有机膜对对硝基苯衍生物的吸附行为

柱芳烃是一类有别于冠醚、杯芳烃、葫芦脲等的柱状大环分子,具有独特的富电子空腔和口腔的可修饰性。 它们可以包结多种有机污染物,对有机污染物的吸附和脱除具有广泛的应用前景。 本文通过核磁共振和紫外滴定的方法首先研究了对硝基苯衍生物与甲氧基柱[5]芳烃(MeP5A)的包结行为,测定了包结常数。 在此基础上,将MeP5A物理混合到聚丙烯酸酯(PA)乳液中,首先制备了甲氧基柱[5]芳烃/聚丙烯酸酯(MeP5A/PA)共混乳液,然后通过静电纺丝技术,得到了MeP5A/PA纳米纤维膜。 采用红外光谱、扫描电子显微镜对MeP5A/PA纳米纤维膜的结构和形貌进行了表征。 将MeP5A/PA纳米纤维膜用于4种对硝基苯衍生物的吸附实验。 结果表明,对硝基苯乙腈显示出与MeP5A最强的包结作用,其K_a=(6.0±0.3)×10² L/mol,PA膜中引入MeP5A,增大了吸附量,但并未改变纤维状形貌。 MeP5A/PA纳米纤维膜的最佳吸附平衡时间为2 h,且MeP5A/PA纳米纤维膜中MeP5A的含量越高,吸附量越大。 但当吸附溶液中MeP5A浓度达到4 mmol/L时(对应的膜中含有的MeP5A物质的量为1.4×10^-2 mmol),其吸附基本达到平衡,继续增加MeP5A物质的量,其吸附量变化不大。     

Polypyrrole/polyamide electrospun-based sorbent for microextraction in packed syringe of organophosphorous pesticides from aquatic samples

A novel method based on microextraction in packed syringe (MEPS) as sample preparation technique coupled off-line with gas chromatography-mass spectrometry was developed using electrospun nanofibers as sorbent. For electrospinning of polypyrrole/polyamide-based nanofiber, a homogeneous solution containing nylon 6, ferric chloride and pyrrole monomer was prepared and then was drawn into a 2.5-mL syringe. By applying a voltage of 13 kV between the needle of the syringe and an aluminum-foil collector, the nanofibers could be formed on the surface of the collector. The prepared sheet was used as the sorbent for MEPS to analyze some selected organophosphorous pesticides. Important parameters influencing the extraction and desorption processes were optimized. Limits of detection were in the range of 0.04-0.1 ng/mL using time scheduled selected ion monitoring mode, and the relative standard deviation (RSD %) values with four replicates were in the range of 3.7-11.8% at a concentration level of 5 ng/mL. The linearity of the method was in the range of 0.5-500 ng/mL for diazinon and fenithrothion and 0.5-200 ng/mL for the rest of the analytes. The developed method was successfully applied to Zayandeh-roud river water samples, whereas the matrix factors were in the range of 0.87-0.98.