Wei Min Kang

Research on Electrospinning Process of Pullulan Nanofibers

A kind of pullulan biopolymer nanofibers with diameter of 100～700nm were obtained using redistilled water as solvent through electrospinning technology in this paper. The effects of the spinning solution concentration, applied voltage, flow rate and capillary–screen distance on morphology and diameter distribution of pullulan nanofiber were studied by SEM. The results show that, different parameters had great influence on nanofibers’ morphology and diameter. The optimal parameters of pullulan nanofibers electrospinning were: 22wt.% spinning solution concentration, 31 kV voltage, 20 cm capillary–screen distance and 0.5ml/h flow rate.

Electrospun Antibacterial Chitosan/Poly (Vinyl Alcohol) Nanofibers Containing Silver Nanoparticles

New chitosan/poly (vinyl alcohol) (PVA) nanofibers functionalized with silver nanoparticles were electrospun using solutions of PVA blended with silver nanoparticles-chitosan composites. The structure of the electrospun fibers were studied with the aid of scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results indicated that the electrospun fibers smoothly with 220 to 650 nm diameter, and the silver nanoparticles were successfully embed into the fibers which show high antibacterial activity against E.coli.

Preparation and Characterization of the Amidoxime-Modified Polyacrylonitrile (PAN-Amidoxime) Nanofibre Composite

In this research, a kind of nonwoven composite used for the absorption of heavy mental ions has been made. The composite was made of two layers of ES thermal bonded nonwovens as the protective layers and the PAN-amidoxime nanofibers which are prepared through the modification of electrospun PAN nanofibers as the interlayer. The composition was achieved by the ultrasonic bonding method. After the composition the PAN nanofibers were modified by grafting the amidoxime group to PAN. The results of FT-IR spectra and FE-SEM indicated that nitrile groups in PAN were partly converted into amidoxime groups and there were no serious cracks on the surface of PAN-amidoxime nanofibers. The results show that the amidoxime groups have been proved to be grafted to the PAN nanofibers with the percent grafting of 81.6%.

Study on Characteristics of Gas Flow Pressure in Catalytic Converter with Porous

This paper studies the different porosity of porous medium how to affect the flow pressure field under the conditions of same inlet velocity and fiber diameter by CFDmethod. Geometric model of the catalytic converter has been established and meshed by the pre-processing tool of FLUENT. The flow pressure simulation filled contours and the curve of center line static pressure distribution of the fiber porous material show that in the case of other conditions remain unchanged, the less the porosity of the fiber porous material, the higher the inlet pressure and the more the pressure loss of the porous material. The more porosity of fiber is beneficial to exhaust catalytic reaction.

Preparation and Characterization of Electrospun CPVC Nanofiber Nonwovens

In this paper, the chlorinated poly (vinyl-chloride) (CPVC) nanofiber were successfully prepared via electrospinning of the proper spinning solution, which was obtained by dissolving CPVC granules in N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) mixture. The results indicates that the morphology of the fibers is influenced by solution concentration and applied voltage. The finer and uniform nanofiber is electrospun from total solid content of the spinning solutions at 16wt.% and the spinning voltage at 26kV. The surface potential of CPVC nanofiber nonwovens increases with the spinning voltage and the filtration efficiency increases firstly and then decreases. In spinning voltage of 26 kV, filtration efficiency reaches a maximum of 99.925%.

Novel Antibacterial Nanofibers of Chitosan and Polyurethane Prepared by Electrospinning

The chitosan(CS)/polyurethane(PU) blend nanofibers have been prepared for the first time by electrospinning. Formic acid (FA) and Hexafluoroisopropanol (HFIP) were found to be the co-solvent for electrospinning. The CS/PU blend solutions in various ratios were studied for electrospinning into nanofibers. The diameter and morphology of the fibers were shown by scanning electron microscope (SEM). It was found that the average diameter of the chitosan/PU blend fibers became larger, and the morphology of the fibers became finer with the content of PU increasing. To show the molecular interactions, CS/PU fibers were characterized by Fourier transform infrared spectroscopy (FT-IR). Moreover, the antibaterial activity of blend nanofibers against Escherichia coil (E.coil) was measured via optical density method. The blend nanofibers exhibited satisfying antibacterial activity against E.coil, even the chitosan concentration was only 5wt%. Therefore, the spun nanofibers are expected to be used in the native extracellular matrix for tissue engineering.

Effect of Electrospinning Process on Electrospun Chlorinated Polyvinyl Chloride (CPVC) Nanofibers

This work focuses on preparations of CPVC nanofibers by the electrospinning. The effects of the applied voltage, the capillary and collector distance and the extrusion rate on the fiber morphology were analyzed. The morphology of the fiber was examined by scanning electron microscopy. The results indicates that when the applied voltage is 26 KV, the extrusion rate of CPVC is 0.2 ml/h and the the Capillary and Collector Distance is 15 cm, the CPVC nanofiber membrane is optimal.

Study on Characteristics of Gas Flow in Catalytic Converter with Different Outlet Diameters

. This paper studies the different diameters of tube outlet how to affect the gas flow pressure and velocity distribution in nanofiber catalytic converter by CFD (Computational Fluid Dynamics) method. Geometric model of the catalytic converter has been established and meshed by the pre-processing tool of FLUENT. The distribution of velocity and pressure in the converter which outlet diameter is 70 mm is more evenly than the converter which outlet diameter is 50 mm. It is conducive to reducing airflow static pressure in the catalytic converter that expanding the outlet diameter in the case of other conditions remains unchanged. Therefore, the larger outlet diameter is beneficial to exhaust catalytic reaction.

Preparation of Fe (III) – Amidoximated PAN Nanofibers Complexes for Degradation of Azo Dye under Visible Light Irradiation

Polyacrylonitrile (PAN) nanofibers were fabricated via electrospinning technique, and the modified Fe-polyacrylonitrile nanofibers photocatalysts(Fe-AO-n-PAN) were prepared by a reaction between PAN nanofibers (AO-n-PAN) containing amidoxime group and ferric chloride. Then Fe-AO-n-PAN were used as heterogeneous catalysts in the oxidative degradation reaction of C.I. Reactive Red 195(RR195) in water. This paper investigated the influences on the degree of the conversion from nitrile group to amidoxime group (CP%); analyzed the impacts on the Fe (III) ions content (QFe-PAN) in Fe-AO-n-PAN; and studied the effects of QFe-PAN on the decoloration rate of the dye. The results indicated that the CP% value were greatly enhanced not only with concentration of NH2OH•HCl increasing, but also gradually with the prolongation of reaction time. In addition, the QFe-PAN of Fe-AO-n-PAN increases with the rise of CFe and the CP% value. Finally, Fe-AO-n-PAN have remarkable catalytic activity on the degradation of RR 195, and higher QFe-PAN could promote the catalytic performance of Fe-AO-n-PAN.

Preparation and Characterization on PU/CS Nanofiber Membrane

PU/CS nanofiber membrane was prepared by means of electrostatic spinning. The morphology of nanofiber membrane was examined by a scanning electron microscope (SEM), and the mechanical property, water absorption, moisture permeability and antibacterial performance were also investigated. The results show that the diameter and mechanical property of PU/CS nanofiber decreased with the increase of the content of CS. However, the water absorption, moisture permeability and antibacterial performance were improved significantly with the addition of CS.