Superfine Fibers Research Articles

Temperature Distribution of the Air Flow Field in Melt Blowing Process: Simulation and Measurement

The melt blown nonwoven fabrics are characterized by superfine fiber structures. The key technology of achieving superfine fibers is the polymer drawing by the high velocity hot air jets. The temperature distribution of the air flow field has great influence on the polymer drawing. In this paper, the air temperature distribution of the dual slot die on an HDF-6D melt blowing nonwoven equipment is simulated and measured. The air flow field model of the dual slot die is established and solved numerically using the finite volume method and SIMPLE algorithm. The air temperature is measured with a temperature measuring system built for this research. Experimental results show that the simulation results of the air temperature coincide with the measured data which indicates the air flow flied model is effective. As this research is performed on an industrial melt blowing equipment, the results have great application values for actual production of melt blowing.

Optimum Design for the Dual Slot Die Parameters of Melt Blowing Process

Melt blowing process can produce superfine fibers. In this process, the polymer is drawn by the high velocity hot air jets from the dual slot die. The die parameters have great effects on the fiber diameter. In this paper, the die parameters of the dual slot die in an industrial melt blowing equipment are studied using the orthogonal experimental design method. Three parameters namely the inset distance, slot width and slot angle are considered. Each parameter has three levels. Nine sizes of dual slot dies with different design parameters are numerically simulated using the established air flow field model of melt blowing process. Distributions of air velocity and air temperature of nine air jet flow fields are obtained. Effects of the three parameters are studied with range analysis and variance analysis. The results show that the inset distance and slot width have significant effects on the air flow field while effect of the slot angle is unremarkable. Finally the optimal die parameters are obtained. The results lay the theoretical foundation for further studies on the computer assisted design for the dual slot die in the melt blowing process.

Study on the Preparation of PSA NanoFibers Using Electro-Spinning Technology and its Characterizations

Polysulfonamide (PSA) superfine fibers were prepared by the self-developed device using the electrospinning technology. The micro surface morphology of the manufactured PSA fibers was characterized by the Scanning Electron Microscope (SEM). It was found that the diameter of PSA fibers and its variance can be influenced by the electrospinning parameters. The experimental results indicate that the morphology of PSA fibers ranged from irregular (beaded) to uniform structure with an increase of solution concentration; the thickness and its variance of the PSA fibers were decreased with the increasing of applied voltage; the morphology and thickness of the PSA fibers were also affected by the tip-to-collector distance. Our investigation shows that the diameter of the PSA fibers can reach around 100nm when spun at the conditions of 28kv applied voltage, 10wt% solution concentration and 15 cm tip-target distance, with a related homogeneous network distribution.

Effect of Plasticizer and Load on Melt Electrospinning of PLA

Melt electrospinning was used to produce PLA superfine fibers. The high spun temperature will lead to serious degradation of PLA. To alleviate the thermal decomposition and obtain superfine fibers at low temperature, sucrrose fatty acid esters (SE) was added to decrease the viscosity of PLA melt. The diameter of PLA including SE was 1.5μm while those of pure PLA was 6.4μm. At the same time, pure PLA melt cost a long time to flow out of cylinder. So SE increased the flowability of PLA melt, which ensured PLA fibers of small diameters were get at low temperature. Spinning load or melt velocity has a direct effect on the relative molecular mass of PLA fibers.

Blown bubble-spinning for fabrication of superfine fibers

A novel method called the blown bubble-spinning is designed to produce super-fine fibers. In this method, a blowing air is used as an acting force. A silk fibroin solution is used to fabricate superfine fibers.

A Lagrange Type Polymer Drawing Model of the Melt Blowing Nonwoven Process

Melt blowing process can produce superfine fibers. In this processs, the polymer is drawn by high velocity hot air. Lagrange method is empolyed to establish and solve the polymer drawing model. The fiber diameter and vibration are predicted with the model. The predicted fiber diameter concides with the experimental data. The fiber vibration becomes larger and larger with the increase of the die-to-collector distance. Computer simulations show that higher initial air velocity and higher initial polymer temperature can producefiner fibers while initial airtemperature contribute little to the polymer drawing.

Factors Influencing Diameter of Polypropylene Fiber in Melt Electrospinning

Melt electrospinning is a safer, more environmentally friendly and cheaper alternative to solution electrospinning in producing superfine fibers. In this paper, a novel melt electrospinning device was used, which has higher efficiency than conventional equipment. Polypropylene is widely used in many fields and it is difficult to find a suitable solvent for its solution electrospinning at room temperature, so it was chosen in this study. The influences of the electrospinning parameters such as temperature and voltage on the diameter of the spinning fibers have been studied. Temperatures higher than normal processing temperatures were used in present electrospinning system in order to reduce the viscosity of the polymer melt sufficiently. Good quality fibers with smooth surfaces and with diameters mostly smaller than 10 microns were spun successfully. It was found that there was an optimum point for the spinning voltage (70-80KV) and the temperature (230-260°C) to get fine fibers.

Optimal design of superfine polyamide fabric by electrostatic flocking technology

The use of superfine fibers as piles to produce flocked fabrics is underreported despite their excellent properties. Therefore, a superfine polyamide fiber was used for piles to produce flocked fabric in this study, and a full factorial design was employed with three design factors at three levels to optimize the process parameters in terms of flocking density. The flock density is found, experimentally, to increase with the decrease of flocking distance and the increase of field strength and flocking time. A ternary linear equation is also established in this study based upon the regression analysis on experimental results and verified by F-test showing that it has remarkable significance. Comparison with experimental values shows that the regression equation possesses high accuracy. The optimum parameters are empirically and experimentally determined as: flocking distance of 7 cm, field strength of 60 kV, and flocking time of 10 s.

Production of superfine fibers by the electrospinning method

Weakly conducting fluid flows in an electric field in the presence of phase interfaces are investigated theoretically and experimentally. The object of the investigation is an axisymmetric jet. The analysis is carried out within the framework of electrohydrodynamics (EHD) with allowance for surface charge transfer on mobile interfaces. The jet shape is calculated at large distances from the outflow point. The theoretical and experimental data are compared for Newtonian and polymeric fluids.

Trends in electrospinning of natural nanofibers

AbstractNanotechnology has become in recent years a topic of great interest to scientists and engineers, and is now established as prioritized research area in many countries. The reduction of the size to the nanometer range brings an array of new possibilities in terms of material properties, in particular with respect to achievable surface to volume ratios. Electrospinning of natural fibers is a novel process for producing superfine fibers by forcing a solution through a spinneret with an electric field. An experimental study on this technique has been made in this paper and the effect of systematic parameters on electrospun nanofibers were critically analyzed. Based on this study, the key process parameters have been identified according to our experimental observations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Structure and Properties of Nanocrystalline Oxide Powders

The crystalline and porous structure of superfine powders and fibers made of alumina and zirconia doped with yttria is investigated. The particle sizes were determined by the methods of coherent dispersion and scanning transmission electron microscopy. Based on data on the sizes of crystallites of the metal oxides, which were obtained by different methods, it is found that crystalline transformations of the oxides lead to dispersion of the materials. The structural transformations of the superfine oxides are accompanied by changes in crystallite sizes and in the character and size of pores. The laws established allow one to purposefully control the process of producing nanostructured oxide powders and fibers, which can be utilized as active fillers for composite materials based on various matrices.

Blends of polypropylene and modified polystyrene for dyeable fibers

AbstractBlends of polypropylene (PP) and modified atactic polystyrene (PS) with good processability were studied for dyeable fine and superfine fibers. Acrylic acid and butyl acrylate monomers were added to PS by radical suspension copolymerization. The dispersion of the additives in the PP crystal was investigated. The rheology curves of the blends were similar to that of PP under the testing conditions. Fine and superfine PP filaments were processed from these blends, and they had practical mechanical properties. The dyeability of the fabrics from the fibers was studied. The increased amorphous content and the interface between PP and modified PS allowed the dyes to penetrate the fibers. These two effects helped to improve the color intensity. The color fastness was also improved by the presence of polar groups introduced by the modified PS components. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2360–2366, 2005

Preparation, morphology, and thermoelectric property studies of BaTiO3 superfine fiber/castor oil polyurethane-based IPN nanocomposites

A series of castor oil polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (IPNs) and gradient IPNs, cured at room temperature, were prepared by a simultaneous IPN method. The polymerization processes were traced through IR techniques; results for the morphology and miscibility among multiple phases of materials, obtained by transmission electron microscopy, indicated that the systems belonged to graft-mode IPNs, and the domains between two phases were controlled on a nanometer scale. Thermomechanical analysis detection results showed that through interpenetration between networks, the glass-transition temperatures of the systems could be linked up effectively. Furthermore, the systems were combined with selected barium titanate superfine fibers. The composite techniques were determined, and the thermoelectric and mechanical properties were examined in detail. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 709–715, 2002; DOI 10.1002/app.10024

Preparation, morphology, and thermoelectric property studies of BaTiO3 superfine fiber/castor oil polyurethane‐based IPN nanocomposites

AbstractA series of castor oil polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (IPNs) and gradient IPNs, cured at room temperature, were prepared by a simultaneous IPN method. The polymerization processes were traced through IR techniques; results for the morphology and miscibility among multiple phases of materials, obtained by transmission electron microscopy, indicated that the systems belonged to graft‐mode IPNs, and the domains between two phases were controlled on a nanometer scale. Thermomechanical analysis detection results showed that through interpenetration between networks, the glass‐transition temperatures of the systems could be linked up effectively. Furthermore, the systems were combined with selected barium titanate superfine fibers. The composite techniques were determined, and the thermoelectric and mechanical properties were examined in detail. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 709–715, 2002; DOI 10.1002/app.10024

Preparation of Carbon Composite Board with Superfine Natural Fibers and Performance as Building Interior Materials

We newly developed carbonized material board (CMB) by adhering of carbonized material powders with superfine natural fibers as binder. The superfine cellulose and collagen fibers were prepared from defiberized milk cartons and leather scraps with a grinder, respectively. The CMB adsorbed ammonia, formaldehyde and toluene gases from 2Oppm to almost Oppm within two hours. And it was confirmed that the CMB adsorbed and desorbed moisture depending on the relative humidity of the environment. When carbonized material powder was adhered with the superfine fibers, the function of carbonized material such as adsorption or humidity conditioning were maintained in the CMB.

Morphology and thermal behavior of PP/EHDPET blend fibers by alkaline hydrolysis treatment

Polypropylene superfine fibers or cell porous fibers were prepared from the Bi-component blend fibers of polypropylene/easy hydrolytic degradation polyester (PP/ EHDPET) by alkaline hydrolysis process. EHDPET is a kind of copolyester that can be rapidly hydro-degraded in the hot alkaline solution. This article discusses the kinetics of alkaline hydrolysis of EHDPET, and the effect of catalyst, bulk ratio, and the content of PP-grafted maleic anhydride on the alkaline hydrolysis process. Meanwhile, the morphological change of the outer surface of blend fibers during this process was also investigated by the technology of scanning electron microscope.

Fibrous Support Module Composed of Braided Poly(Vinyl Alcohol) Superfine Fibers

Fibrous Support Module Composed of Braided Poly(Vinyl Alcohol) Superfine Fibers

Immobilization of biocatalysts with poly(vinyl alcohol) supports

Two polymer materials, poly(vinyl alcohol) (PVA) superfine fibers and photocrosslinkable PVA bearing styrylpyridinium groups, have been developed to immobilize biocatalysts. The former has a large surface consisting of relatively large-size pores and the fibers can immobilize a large amount of biocatalyst on their surface by ionic interaction. The latter entraps many kinds of biocatalysts by cyclodimerization caused by visible light irradiation. The biocatalysts on/in these supports maintain high activity and thermal stability. These materials can easily be formed into various shapes suitable for various applications. A new bioreactor system was constructed for evaluating a variety of biocatalysts and supports.

The Properties and Usages of Melt-Blown Superfine fibers

The Properties and Usages of Melt-Blown Superfine fibers

Immobilization of microorganisms on poly (vinyl alcohol) super fine fibers.

Aminated poly (vinyl alcohol) (PVA) super fine fibers (SFF) immobilized a lot of baker's yeast, but sulfonated SFF did not immobilize it at all. It was observed by scanning electron microscope that the yeast cells immobilized on SFF proliferated enormously, after it was immersed in glucose solution. The yeast-SFF complex charged into a glass column converted glucose to ethanol continuously.