利用静电纺丝技术制备多孔聚苯乙烯纤维

利用静电纺丝技术制备聚苯乙烯（PS）聚乙烯吡咯烷酮（PVP）复合纤维,通过除去复合纤维中的PVP成分,成功地制备了PS多孔纤维,并对其进行了SEM谱图分析测试。结果表明,纺丝电压、PS与PVP配比直接影响着复合纤维的微观形态;PS／PVP复合纤维的浸泡时间、浸泡后的干燥方式、PS与PVP配比都会影响PS多孔纤维的表面形态以及纤维的内部结构。     

Processing and Properties of a Porous Oxide Matrix Composite Reinforced with Continuous Oxide Fibers

A process to manufacture porous oxide matrix/polycrystalline oxide fiber composites was developed and evaluated. The method uses infiltration of fiber cloths with an aqueous slurry of mullite/alumina powders to make prepregs. By careful manipulation of the interparticle pair potential in the slurry, a consolidated slurry with a high particle density is produced with a sufficiently low viscosity to allow efficient infiltration of the fiber tows. Vibration-assisted infiltration of stacked, cloth prepregs in combination with a simple vacuum bag technique produced composites with homogeneous microstructures. The method has the additional advantage of allowing complex shapes to be made. Subsequent infiltration of the powder mixture with an alumina precursor was made to strengthen the matrix. The porous matrix, without fibers, possessed good thermal stability and showed linear shrinkage of 0.9% on heat treatment at 1200°C. Mechanical properties were evaluated in flexural testing in a manner that precluded interlaminar shear failure before failure via the tensile stresses. It was shown that the composite produced by this method was comparable to porous oxide matrix composites manufactured by other processes using the same fibers (N610 and N720). The ratio of notch strength to unnotch strength for a crack to width ratio of 0.5 was 0.7–0.9, indicating moderate notch sensitivity. Interlaminar shear strength, which is dominated by matrix strength, changed from 7 to 12 MPa for matrix porosity ranging from 38% to 43%, respectively. The porous microstructure did not change after aging at 1200°C for 100 h. Heat treatment at 1300°C for 100 h reduced the strength for the N610 and N720 composites by 35% and 20%, respectively, and increased their brittle nature.     

Comparatively Thermal and Crystalline Study of Poly(methyl‐methacrylate)/Polyacrylonitrile Hybrids: Core–Shell Hollow Fibers,Porous Fibers,and Thin Films

The polyacrylonitrile/polymethyl‐methacrylate (PMMA/PAN) porous fibers, core–shell hollow fibers, and porous thin films are prepared by coaxial electrospinning, single electrospinning, and spin‐coating technologies, respectively. The different morphologies arising from different processes display great influences on their thermal and crystalline properties. The adding of PMMA causes porous structure due to the microphase‐separation structure of immiscible PMMA and PAN phases. The lower weight loss, higher degradation temperature, and glass‐transition temperatures of porous thin films than those of porous fibers and core–shell hollow fibers are obtained, evidencing that the polymer morphologies produced from the different process can efficiently influence their physical properties. The orthorhombic structure of PAN crystals are found in the PMMA/PAN porous thin films, but the rotational disorder PAN crystals due to intermolecular packing are observed in the PMMA/PAN porous fibers and core–shell hollow fibers, indicating that different processes cause different types of PAN crystals.

     

N,N‐Dimethylformamide Additions to the Solution for the Electrospinning of Poly(ε‐caprolactone) Nanofibers

Summary: Additives that exhibit polyelectrolyte behavior such as N,N‐dimethylformamide (DMF) may improve the electrospinning characteristics of viscoelastic polymer solutions. DMF additions to the solution lead to extensive jet splaying, thereby reducing the fiber diameter significantly. Nanofibrous structures with diameters of the order of 150 nm can be produced by the addition of about 10 vol.‐% DMF to the solvent (chloroform). DMF additions also yield a narrow, unimodal distribution of fibers, compared to the bimodal distribution typically detected in electrospun polymers.

Jet breakdown without (left) and with DMF addition to the solution.     

Fabrication and Characterization of Electrospun Dopants/PS Composite Fibers with Porous and Hollow‐Porous Structures

Three different dopants are used to fabricate electrospun dopants/polystyrene (dopants/PS) composite fibers from PS solution and PS sol. The relative humidity and the influence of the dopants on the morphologies, diameter, porous structures, and dopant distribution of electrospun PS fibers are investigated. Compared to those obtained from PS solution, electrospun dopants/PS composite fibers from PS sol with hollow‐porous and multichannel hollow‐porous structures present significant advantages due to the multi‐stage degree of interfacial structure and diversity of the internal environment. In comparison to coaxial electrospun PS fibers, the electrospun dopants/PS composite fibers from PS sol obtained in one step have an improved yield and a simplified technological process simultaneously, leading to significant competitiveness in fields such as catalysis, fluidics gas storage, and sensing.

     

Generation of nanofibers via electrostatic‐Induction‐assisted solution blow spinning

Increasing attention has been given to nanofiber fabrication techniques. Solution blow spinning (SBS) is an innovative, simple, and effective method for producing nanofibers, and it only uses the drawing force of high‐velocity airflow. However, solution‐blown nanofibers easily form bundles; this results in an uneven distribution of nanofibers and an inhomogeneity of nanofiber mats. In this study, electrostatic‐induction‐assisted solution blow spinning (EISBS) was established by the introduction of an additional electrostatic field with an induction circle electrode into the SBS system. The effects of the electrostatic force on the fiber configuration and structure were examined. The results indicate that the electrostatic field effectively separated the fibers. Response surface methodology, based on the four‐factor, three‐level Box–Behnken design, was used to facilitate a more systematic understanding of the processing parameters of EISBS. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42326.     

酸性气硫回收WSA湿法制酸工艺及应用前景

丹麦托普索WSA湿法制酸工艺可以有效地利用各种生产过程中产生的含硫酸性气体直接制酸,得到商品级浓硫酸,具有适用范围广、工艺流程简单、硫回收率高、操作成本低、经济效益好等特点,是石油、石化、冶金、化肥、发电、焦化、煤化工等行业可供选择的、有竞争力的硫回收工艺路线之一。简要介绍了WSA湿法制酸方法的原理及其工艺流程、技术特点和应用前景。     

聚乙交酯纤维的结构及其降解性能

纺制了聚乙交酯(PGA)纤维,并对其进行了不同温度和时间的热处理。对处理后PGA纤维的结构进行了测试,并将其放置于恒温箱的磷酸盐缓冲液中进行两周降解处理,研究了不同热处理工艺下PGA纤维的结构及降解性能。试验结果表明:随着热处理温度的提高,PGA纤维材料的晶区取向度变化不大,结晶度逐渐增大,晶粒尺寸也相应发生变化;在试验条件下,经过恒温缓冲液两周时间的降解处理,纤维的强度保持率随热处理温度提高呈现先增大后降低的趋势,纤维的强度保持率在110℃出现最大值;同时,在热处理温度110℃时,随着热处理时间的延长,PGA纤维的强度保持率增加。     

Porous Electrospun PES/PEG Ultrafine Fibers for the Removal of Endocrine Disruptors

In this work, porous polyethersulfone (PES)/polyethylene glycol (PEG) ultrafine fibers were prepared via electrospinning technique, and then were used to removing endocrine disrupters from their aqueous solutions. The surface and the internal structures of PES/PEG ultrafine fibers were characterized by scanning electron microscopy (SEM) and the result showed that they were both porous. The porous electrospun PES/PEG ultrafine fibers can remove endocrine disrupters such as biphenyl A (BPA) and biphenyl (BP) effectively. Compared with pure PES ultrafine fibers, PES/PEG ultrafine fibers showed larger adsorption capacity and faster kinetics of uptaking target species. The hydrophilic properties and the porosity of porous PES/PEG ultrafine fibers can be controlled by adding hydrophilic materials such as polyethylene glycol (PEG), which can improve the adsorption properties of porous PES/PEG ultrafine fibers significantly. The results showed that porous electrospun PES/PEG ultrafine fibers had the potential to be used in environmental application and water treatment.     

Co‐electrospun nanofibers of PVA‐SbQ and Zein for wound healing

In this study, electrospun biocompatible nanofibers with random orientation were prepared by physically blending poly(vinyl alcohol)‐stilbazol quaternized (PVA‐SbQ) with zein in acetic acid solution for wound healing. PVA‐SbQ was used as the foundation polymer as well as crosslinking agent, blended with zein to achieve desirable properties such as improved tensile strength, surface wettability, and in vitro degradable properties. Moreover, vaccarin drug was incorporated in situ into electrospun nanofibrous membranes for cell viability and cell attachment. The addition of vaccarin showed great effects on the morphology of nanofiber and enhanced cell viability and proliferation in comparison with composite nanofibers without drug. The presence of PVA‐SbQ, zein, and vaccarin drug in the nanofibrous membranes exhibited good compatibility, hydrophilicity, and biocompatibility and created a moist environment to have potential application for wound healing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42565.     

Formation of Core‐Shell Mesoporous Ceramic Fibers

Ceramic Fe–Al–O nanofibers with a core‐shell architecture were obtained by electrospinning. The fibers consist of an Fe–Al–O core with novel lamellar‐like mesopores and an Fe‐rich shell. A mechanism of this unique core and shell formation is outlined and confirmed. The described mesoporous nanofibers are highly promising for new research and applications involving catalysis, sensing and absorption of mobile components on the accessible porous core surface.     

静电纺丝法制备多孔超细聚醚砜纤维及其对双酚A的吸附性能

创新性地将静电纺丝法技术和沉浸凝胶方法相结合,制备了多种不同结构的多孔超细聚醚砜(PES)纤维,将多孔超细纤维运用于水溶液中环境激素双酚A(BPA）的吸附,并考查了多孔超细PES纤维对环境激素BPA的吸附机理。结果表明,以聚乙二醇(PEG）为致孔剂得到的多孔超细纤维的孔洞小而分布均匀,以聚乙烯醇(PVA）为致孔剂产生的多孔超细纤维的孔洞大且发生了取向;接收方式对以PVA为致孔剂的多孔超细PES纤维形貌影响大,空气浴中接收到的是多孔超细纤维,水浴中接收到的是中空多孔超细PES纤维;多孔超细PES纤维对环境激素BPA的动态吸附符合伪二阶动力学模型,等温吸附符合Freundlish等温模型。     

Structure and Properties of Viscose Fibers due to Cold Drawing

Viscose fibers (regenerated cellulose), were drawn using a stress-strain device, in conjunction with a two beam interferometric system. A recent approach is applied for determining the unknown initial value for a given viscose fiber. Optical and mechanical parameters were measured. The results were used to calculate the crystallinity, amorphous, and crystalline orientations functions. Calculation of the crosslink density and the chain entanglement density with the aid of Moony-Rivlin equation constants were given. Also, some other optical and mechanical structure parameters were given. An empirical formula is suggested for the results parameter changes. The present study throws light on the changes due to cold drawing processes for viscose fibers.     

Bi2WO6在多孔Al2O3纤维上的原位生长及其光催化性能表征

以多孔Al2O3纤维为载体,应用水热方法使Bi2WO6在纤维上原位生长.利用XRD、SEM等分析测试手段对样品进行表征,研究了在水热温度为180℃条件下,不同水热保温时间和pH值对纤维上Bi2WO6形成及结晶形貌的影响.分析评价了负载有Bi2WO6的多孔Al2O3纤维在可见光辐照下对RhB溶液的光催化降解性能.结果表明,Bi2WO6微晶不仅能够在比表面较大的多孔Al2O3纤维上原位生长,且致密均匀,并具有良好的针状结晶形貌.不同的水热保温时间和pH值对应生成的Bi2WO6结晶形貌以及光催化性能也呈现一定的规律,在保温时间为9h,pH=1的条件下,Bi2WO6生长的最为致密均匀,且保持多孔结构,在60 min内可使RhB降解95％.     

铬酸处理液对UHMWPE纤维性能的影响

利用自行研制的铬酸处理液对超高相对分子质量聚乙烯(UHMWPE)纤维进行表面改性,并利用扫描电镜(SEM)、红外光谱(FITR)和接触角、单丝强力试验对纤维的表面性能和强度的变化进行表征。结果表明,表面处理时间和表面处理温度是影响纤维处理后性能的重要因素,UHMWPE纤维的最佳表面处理时间为3mim,最佳表面处理温度为80～85℃。     

Process Optimization and Empirical Modeling for Electrospun Poly(D,L‐lactide) Fibers using Response Surface Methodology

Summary: Ultrafine fibers were spun from poly(D ,L ‐lactide) (PDLA) solution using a homemade electrospinning set‐up. Fibers with diameter ranging from 350 to 1 900 nm were obtained. Morphologies of fibers and distribution of fiber diameters were investigated varying concentration and applied voltage by scanning electron microscopy (SEM). Average fiber diameter and distribution were determined from about 100 measurements of the random fibers with an image analyzer (SemAfore 5.0, JEOL). A more systematic understanding of process parameters of the electrospinning was obtained and a quantitative relationship between electrospinning parameters and average fiber diameter was established by response surface methodology (RSM). It was concluded that the concentration of polymer solution played an important role in the diameter of fibers and standard deviation of fiber diameter. Lower concentration tended to facilitate the formation of bead‐on‐string structures. Fiber diameter tended to increase with polymer concentration and decrease with applied voltage. Fibers with lower variation in diameter can be obtained at lower concentration regardless of applied voltage. Fibers with uniform diameter and lower variation in diameter can be obtained at higher concentration and higher applied voltage. Process conditions for electrospinning of PDLA could be chosen according to the model in this study.

Contour plots of average fiber diameter as a function of concentration and applied voltage.     

A method for scale‐up of co‐electrospun nanofibers via flat core‐shell structure spinneret

An approach to the scale‐up of co‐electrospinning via a flat core‐shell structure spinneret has been developed in this study. The spinneret with a flat surface involves shell‐holes and core‐needles. Electric field simulation reveals that the flat core‐shell spinneret configuration creates a more uniform electric field gradient. Experimental study shows that in comparison with the conventional needle co‐electrospinning, core‐shell nanofibers produced by this new designed setup are finer and of better morphology. Composite nanofibers with special morphologies can be fabricated by modifying the structure of this spinneret. The production rate of the core‐shell nanofibers can be enhanced by increasing the hole and needle number of the spinneret. This novel design is expected to provide a promising method towards the massive production of core‐shell nanofibers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41027.     

Electrospinning of plant oil‐based,non‐isocyanate polyurethanes for biomedical applications

Non‐isocyanate polyurethanes (NIPU) have rapidly emerged as a sustainable, less toxic, and environmentally friendly alternative to traditional isocyanate‐based thermoplastic polyurethane (TPU) synthesis. TPU is widely used in the medical industry due to its excellent mechanical properties and elasticity. However, little work has been done to synthesize and electrospin NIPU into fibrous mats for biomedical applications. In this work, melt polymerization of a plant oil‐based cyclic carbonate monomer with polyether soft segments and various diamines yielded isocyanate‐free, segmented poly(amide hydroxyurethane)s (PAHUs). Electrospinning of segmented PAHUs afforded ductile, free‐standing fibrous mats with Young's modulus values between 7 and 8 MPa, suitable for tissue scaffold applications. PAHU fiber mats exhibited 3–4 times greater water uptake than the electrospun TPU control, demonstrating potential utility in drug delivery. Fibroblasts adhered to electrospun PAHU fibrous mats with viability values over 90% after 72‐h, validating its biocompatibility. The results highlight the high performance and potential of electrospun isocyanate‐free polyurethanes mats for biomedical application. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46464.