scholarly journals An Investigation into Hydraulic Permeability of Fibrous Membranes with Nonwoven Random and Quasi-Parallel Structures

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 54
Author(s):  
Zeman Liu ◽  
Yiqi Wang ◽  
Fei Guo
Keyword(s):  
Flow Rate ◽  
Fiber Diameter ◽  
Hydraulic Permeability ◽  
Random Structure ◽  
Electrospinning Technique ◽  
Hydraulic Flow ◽  
Parallel Structures ◽  
Fiber Arrangement ◽  
State Models ◽  
Fibrous Membranes

Fibrous membranes with a nonwoven random structure and a quasi-parallel fibrous structure can be fabricated by the electrospinning technique. The membranes with different structures exhibited different behaviors to a hydraulic flow passing through the membranes. This work presents the effects of the fiber arrangement, fiber diameter, and deformations of the fibers on the hydraulic permeability. The results showed that the hydraulic flow can generate an extrusion pressure which affects the porosity and pore structure of the fibrous membranes. The quasi-parallel fibrous membranes and nonwoven membranes exhibited similar variation tendencies to the change of the experimental variables. However, the quasi-parallel fibrous membranes exhibited a higher sensibility to the change of the hydraulic flow rate. The hydraulic permeability of the quasi-parallel fibrous membranes was further analyzed with packing state models in this work.

TiO2 nanofibers fabricated by electrospinning technique and degradation of MO dye under UV light

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Naveen Thakur ◽  
Nikesh Thakur ◽  
Viplove Bhullar ◽  
Saurabh Sharma ◽  
Aman Mahajan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fiber Diameter ◽  
Uv Light ◽  
Rutile Phase ◽  
Powder Form ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Tio2 Nanofibers ◽  
X Ray ◽  
Uv Visible

Abstract Titanium dioxide (TiO2) nanofibers were synthesized by electrospinning to optimize the photocatalytic action efficiency. The synthesis of the fibers was carried out at four different wt% concentrations: 8, 9, 10 & 11% of polymer polyvinylpyrrolidone (PVP). The TiO2 fibers were further calcined at 700 °C to get powder form. The uncalcinated and calcined TiO2 nanofibers were characterized by using X-Ray diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM) and UV-Visible spectroscopy. Raman spectroscopy confirmed the rutile phase of the calcined TiO2nanofibers in powder form with a crystallite size of 34–38 nm. The surface morphology of the uncalcinated and calcined TiO2 nanofibers was examined by SEM and the fiber diameter found to be 360–540 nm. The optical bandgap of the calcined TiO2 nanofibers was found in the range of 3.29–3.24 eV. The photocatalytic activity of the TiO2 nanofibers as examined for uncalcinated and calcined nanofibers, methyl orange (MO) dye degraded up to 98 and 78%, respectively in 180 min under the exposure of UV light. Uncalcinated TiO2 nanofibers were found more suitable for degradation of MO dye as compared to calcined nanofibers.

scholarly journals Electrospun flexible self-standing Cu–Al2O3 fibrous membranes as Fenton catalysts for bisphenol A degradation

2017 ◽  
Vol 5 (36) ◽  
pp. 19151-19158 ◽  
Author(s):  
Yan Wang ◽  
Jiang Li ◽  
Jianyang Sun ◽  
Yanbin Wang ◽  
Xu Zhao
Keyword(s):  
Bisphenol A ◽  
Catalytic Performance ◽  
Electrospinning Technique ◽  
Fibrous Membranes

Flexible Cu–Al2O3 membranes with high Fenton catalytic performance have been fabricated via electrospinning technique.

scholarly journals Electrospun Nylon-6 Nanofibers and Their Characteristics

2020 ◽  
Vol 9 (1) ◽  
pp. 9-19
Author(s):  
Ida Sriyanti ◽  
Meily P Agustini ◽  
Jaidan Jauhari ◽  
Sukemi Sukemi ◽  
Zainuddin Nawawi
Keyword(s):  
Fiber Diameter ◽  
Peak Shift ◽  
Nylon 6 ◽  
Electrospinning Process ◽  
Electrospinning Technique ◽  
Fiber Concentration ◽  
Air Filters ◽  
Xrd Pattern ◽  
Electrospinning Method ◽  
Small Wave

The purposes of this research were to investigate the synthesized Nylon-6 nanofibers using electrospinning technique and their characteristics. The method used in this study was an experimental method with a quantitative approach. Nylon-6 nanofibers have been produced using the electrospinning method. This fiber was made with different concentrations, i.e. 20% w/w (FN1), 25% w/w (FN2), and 30% w/w (FN3). The SEM results show that the morphology of all nylon-6 nanofibers) forms perfect fibers without bead fiber. Increasing fiber concentration from 20% w/w to 30% w/w results in bigger morphology and fiber diameter. The dimensions of the FN1, FN2, and FN3 fibers are 1890 nm, 2350 nm, and 2420 nm, respectively. The results of FTIR analysis showed that the increase in the concentration of nylon-6 (b) and the electrospinning process caused a peak shift in the amide II group (CH2 bond), the carbonyl group and the CH2 stretching of the amide III group from small wave numbers to larger ones. The results of XRD characterization showed that the electrospinning process affected the changes in the XRD pattern of nylon-6 nanofiber (FN1, FN2, and FN3) in the state of semi crystal. Nylon-6 nanofibers can be used for applications in medicine, air filters, and electrode for capacitors

Swelling Behaviors and Water States of Fibrous Membranes Electrospun from PHBV-g-PVP

2012 ◽  
Vol 482-484 ◽  
pp. 1478-1482
Author(s):  
Wei Wang ◽  
Jian Da Cao ◽  
Ping Lan
Keyword(s):  
Water Absorption ◽  
Fiber Diameter ◽  
Bound Water ◽  
Free Water ◽  
Great Capacity ◽  
Electrospun Membranes ◽  
Dsc Characterization ◽  
Fibrous Membranes ◽  
Water Swelling ◽  
Swelling Behaviors

Fibrous membranes with a fiber diameter between 320 and 460 nm were electrospun from poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-graft-poly(N-vinylpyrrolidone) (PHBV-g-PVP) and their specific water absorption behaviors were investigated for biomaterial purposes. Water swelling experiments indicate that all samples have a great capacity for water uptake, while a remarkable overshoot occurs for the membranes electrospun from PHBV-g-PVP other than those from PHBV. DSC characterization indicates that only non-freezable bound water and free water can be distinguished in all electrospun membranes.

Fabrications of small diameter compliance bypass conduit using electrospinning of clinical grade polyurethane

Vascular ◽  
2019 ◽  
Vol 27 (6) ◽  
pp. 636-647 ◽  
Author(s):  
Rahim Faturechi ◽  
Ata Hashemi ◽  
Nabiollah Abolfathi ◽  
Atefeh Solouk ◽  
Alexander Seifalian
Keyword(s):  
Carotid Artery ◽  
Young’S Modulus ◽  
Common Carotid Artery ◽  
Carotid Arteries ◽  
Fiber Diameter ◽  
Young's Modulus ◽  
Small Diameter ◽  
Electrospinning Technique ◽  
Expanded Polytetrafluoroethylene ◽  
Common Carotid Arteries

Objective Compliance and viscoelastic mismatches of small diameter vascular conduits and host arteries have been the cause of conduit’s failure. Methods To reduce these mismatches, the aim of this study was to develop and characterize a polyurethane conduit, which mimics the viscoelastic behaviors of human arteries. Electrospinning technique was used to fabricate tubular polyurethane conduits with similar properties of the human common carotid artery. This was achieved by manipulating the fiber diameter by altering the syringe flow rate of the solution. The mechanical and viscoelastic properties of the fabricated electrospun polyurethane conduits were, then, compared with commercially available vascular conduits, expanded polytetrafluoroethylene, polyethylene terephthalate (Dacron®) and the healthy human common carotid arteries. In addition, a comprehensive constitutive model was proposed to capture the visco-hyperelastic behavior of the synthetic electrospun polyurethanes, commercial conduits and human common carotid arteries. Results Results showed that increasing the fiber diameter of electrospun polyurethanes from 114 to 190 nm reduced Young’s modulus from 8 to 2 MPa. Also, thicker fiber diameter yielded in higher conduits’ viscosity. Furthermore, the results revealed that proposed visco-hyperelastic model is strongly able to fit the experimental data with great precision which proofs the reliability of the proposed model to address both nonlinear elasticity and viscoelasticity of the electrospun polyurethanes, commercial conduits and human common carotid arteries. Conclusions In conclusion, statistical analysis revealed that the elastic and viscous properties of 190 nm fiber diameter conduit are very similar to that of human common carotid artery in comparison to the commercial expanded polytetrafluoroethylene and Dacron® that are up to nine and seven times stiffer than natural vessels. Therefore, based on our findings, from the mechanical point of view, by considering the amount of Young’s modulus, compliance, distensibility and viscoelastic behavior, the fabricated electrospun polyurethane with fiber diameter of 189.6 ± 52.89 nm is an optimum conduit with promising potential for substituting natural human vessels.

Effect of hydraulic flow rate, injection timing, and exhaust gas recirculation on particulate and gaseous emissions in a light-duty diesel engine

2019 ◽  
Vol 234 (5) ◽  
pp. 1279-1293 ◽  
Author(s):  
Khawar Mohiuddin ◽  
Minhoo Choi ◽  
Junkyu Park ◽  
Sungwook Park
Keyword(s):  
Diesel Engine ◽  
Flow Rate ◽  
Particle Number ◽  
Exhaust Gas Recirculation ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Gaseous Emissions ◽  
Spray Tip Penetration ◽  
Hydraulic Flow ◽  
Gas Recirculation

Nozzle hydraulic flow rate is a critical parameter that affects the combustion process and plays a vital role in the production of emissions from a diesel engine. In this study, injection characteristics, such as normalized injection rate and spray tip penetration, were analyzed for different hydraulic flow rate injectors with the help of spray experiments. To further investigate the effects of hydraulic flow rate on engine-out particulate and gaseous emissions, engine experiments were performed for different values of hydraulic flow rate in multiple injectors. Various operating conditions and loading configurations were examined, and the effects of varying start of injection and exhaust gas recirculation rates for different hydraulic flow rates were analyzed. A separate Pegasor Particle Sensor (PPS-M) sensor was used to measure and collect data on the particle number, and an analysis was conducted to investigate the relation of particle number with hydraulic flow rate, injection timing, and exhaust gas recirculation rate. Results of the spray experiment exhibited a decreasing injection duration and increasing spray tip penetration with increasing hydraulic flow rate. Effect of hydraulic flow rate on combustion and emission characteristics were analyzed from engine experiment results. Least ignition delay was achieved using a smaller hole diameter, retarded injection timing, and lowest EGR%. Higher hydraulic flow rate with retarded injection timing and higher EGR% helped in reduction of NOx emissions and brake-specific fuel consumption, but particulate emissions were increased. Best particulate matter–NOx trade-off was achieved with lowest hydraulic flow rate.

scholarly journals Designing Multifunctional Protective PVC Electrospun Fibers with Tunable Properties

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2086
Author(s):  
Pedro J. Rivero ◽  
Iker Rosagaray ◽  
Juan P. Fuertes ◽  
José F. Palacio ◽  
Rafael J. Rodríguez
Keyword(s):  
Fiber Diameter ◽  
Electrospinning Process ◽  
Operating Parameters ◽  
Electrospun Fibers ◽  
Polymeric Precursor ◽  
Operational Parameters ◽  
Electrospinning Technique ◽  
Coating Morphology ◽  
Hydrophobic Nature ◽  
First Time

In this work, the electrospinning technique is used for the fabrication of electrospun functional fibers with desired properties in order to show a superhydrophobic behavior. With the aim to obtain a coating with the best properties, a design of experiments (DoE) has been performed by controlling several inputs operating parameters, such as applied voltage, flow rate, and precursor polymeric concentration. In this work, the reference substrate to be coated is the aluminum alloy (60661T6), whereas the polymeric precursor is the polyvinyl chloride (PVC) which presents an intrinsic hydrophobic nature. Finally, in order to evaluate the coating morphology for the better performance, the following parameters—such as fiber diameter, surface roughness (Ra, Rq), optical properties, corrosion behavior, and wettability—have been deeply analyzed. To sum up, this is the first time that DoE has been used for the optimization of superhydrophobic or anticorrosive surfaces by using PVC precursor for the prediction of an adequate surface morphology as a function of the input operational parameters derived from electrospinning process with the aim to validate better performance.

Morphology of Electrospun Natural Rubber with Acrylonitrile-Butadiene-Styrene

2009 ◽  
Vol 79-82 ◽  
pp. 1583-1586 ◽  
Author(s):  
Sarawuth Sithornkul ◽  
Poonsub Threepopnatkul
Keyword(s):  
Natural Rubber ◽  
Fiber Diameter ◽  
Electrospun Fiber ◽  
Acrylonitrile Butadiene Styrene ◽  
Solution Concentration ◽  
Electrospun Membrane ◽  
Sem Images ◽  
Electrospinning Technique ◽  
Tetramethylthiuram Disulfide ◽  
Butadiene Styrene

This research was aimed to study the electrospinning of natural rubber (NR)-acrylonitrile butadiene styrene (ABS) blend. The NR used in this research was compounded in a torque rheometor, with stearic acid, wingstay-L, dibenzothiazoledisulfide (MBTS), tetramethylthiuram disulfide (TMTD) and sulfur, respectively. The compounded NR was blended with ABS by dissolving them in tetrahydrofuran (THF), concentration of solution included 5, 10, and 15 w/w%. The ratio of NR/ABS was varied by varying the content of ABS of 20, 30, 40 and 50 wt%. Then NR/ABS electrospun membrane was built up by electrospinning technique with high voltage 15 kV, flow rate 30 ml/h, collector distance 15, 20 and 25 cm and collected the electrospun fiber on rotating circular at 1000 rpm. The morphology of electrospun fibers were characterized by scanning electron microscope (SEM). SEM images showed that NR/ABS membranes had higher porosity with decreasing ABS contents. Decreasing ABS contents, decreasing solution concentration and increasing collector distance decreased fiber diameter of electrospun NR/ABS.

scholarly journals Fabrication and Characterization of Magnetoresponsive Electrospun Nanocomposite Membranes Based on Methacrylic Random Copolymers and Magnetite Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Ioanna Savva ◽  
George Krekos ◽  
Alina Taculescu ◽  
Oana Marinica ◽  
Ladislau Vekas ◽  
...  
Keyword(s):  
Random Copolymers ◽  
Magnetic Characteristics ◽  
Stimuli Responsive ◽  
Nanocomposite Membranes ◽  
Electrospinning Technique ◽  
Responsive Materials ◽  
Fibrous Matrix ◽  
Fabrication And Characterization ◽  
Fibrous Membranes

Magnetoresponsive polymer-based fibrous nanocomposites belonging to the broad category of stimuli-responsive materials, is a relatively new class of “soft” composite materials, consisting of magnetic nanoparticles embedded within a polymeric fibrous matrix. The presence of an externally applied magnetic field influences the properties of these materials rendering them useful in numerous technological and biomedical applications including sensing, magnetic separation, catalysis and magnetic drug delivery. This study deals with the fabrication and characterization of magnetoresponsive nanocomposite fibrous membranes consisting of methacrylic random copolymers based on methyl methacrylate (MMA) and 2-(acetoacetoxy)ethyl methacrylate (AEMA) (MMA-co-AEMA) and oleic acid-coated magnetite (OA·Fe3O4) nanoparticles. The AEMA moieties containingβ-ketoester side-chain functionalities were introduced for the first time in this type of materials, because of their inherent ability to bind effectively onto inorganic surfaces providing an improved stabilization. For membrane fabrication the electrospinning technique was employed and a series of nanocomposite membranes was prepared in which the polymer content was kept constant and only the inorganic (OA·Fe3O4) content varied. Further to the characterization of these materials in regards to their morphology, composition and thermal properties, assessment of their magnetic characteristics disclosed tunable superparamagnetic behaviour at ambient temperature.

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