scholarly journals Design and Validation of a Portable Handheld Device to Produce Fine Fibers Using Centrifugal Forces

Instruments ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 27
Author(s):  
Gregory Potter ◽  
Raul Barbosa ◽  
Alexa Villarreal ◽  
Alexandra Salinas ◽  
Hector Guzman ◽  
...  
Keyword(s):  
Fiber Diameter ◽  
Orifice Diameter ◽  
Centrifugal Forces ◽  
Fiber Morphology ◽  
Handheld Device ◽  
Fiber Yield ◽  
Series Of Experiments ◽  
Arduino Microcontroller ◽  
Scanning Electron ◽  
Exit Orifice

In the present research project, a novel portable battery-powered handheld device able to produce micron and submicron fibers using centrifugal forces is proposed. The design includes spinnerets with a clamshell configuration with multiple chambers or reservoirs (2, 4, and 8) and different exit orifice diameters (400, 500, 600, and 800 µm). The rotational speed is controlled via an Arduino microcontroller. To validate the design, a series of experiments were conducted and the effect of the orifice diameter, number of chambers, and velocity on the resulting fibers’ diameter and yield was studied. For the experiments, a polymeric solution of Polyvinyl Alcohol (PVA) was prepared. The fiber yield was gravimetrically quantified, and the fiber morphology and diameter were analyzed by means of scanning electron microscopy (SEM). The experimental results showed that spinnerets with an orifice diameter of 500 microns yielded the greatest amount of fibers (0.0777 g). In addition, the number of chambers also affected the amount of fibers produced, and it was determined that the fiber diameter size is dependent on the spinneret speed. Fibers 80 nm in diameter were observed at 6500 rpm.

Effects of a PFI refiner’s operational parameters on the swellability of recycled fiber

TAPPI Journal ◽  
2020 ◽  
Vol 19 (5) ◽  
pp. 239-246
Author(s):  
XIAONING SHEN ◽  
BO LI ◽  
WENXUAN MO ◽  
XIN-SHENG CHAI
Keyword(s):  
Water Retention ◽  
Fiber Quality ◽  
Operational Parameters ◽  
Fiber Morphology ◽  
Water Retention Value ◽  
Electron Microscopic ◽  
Mathematical Relation ◽  
Scanning Electron Microscopic ◽  
Recycled Fiber ◽  
Scanning Electron

This paper presents data on the effects of operational parameters (number of revolutions, linear pressure, and gap) of the PFI refiner on the swellability of recycled fiber, which was characterized by water retention value (WRV). The results showed that the increase of recycled fiber’s WRV was proportional to the number of revolutions and the linear pressure, but inversely proportional to the gap. The mathematical relation between these parameters and the fiber WRV could be described by an empirical model for gaps greater than 0.1 mm. Scanning electron microscopic images of fiber morphology showed that the basic framework of fibers could be maintained with the gap greater than 0.1 mm, but was destroyed with smaller gaps. This model provides a technical reference for quantitative control of refining treatment and an effective method for improving recycled fiber quality.

Electrostatic-assisted centrifugal spinning for continuous collection of submicron fibers

2016 ◽  
Vol 87 (19) ◽  
pp. 2349-2357 ◽  
Author(s):  
Huanhuan Chen ◽  
XiangLong Li ◽  
Nan Li ◽  
Bin Yang
Keyword(s):  
Fiber Diameter ◽  
Electrostatic Force ◽  
Fiber Formation ◽  
Mechanism Analysis ◽  
Strongly Correlated ◽  
Fiber Morphology ◽  
Jet Trajectory ◽  
Centrifugal Spinning ◽  
Nozzle Size ◽  
Key Factor

Non-uniformity of the fiber diameter and difficulty in continuous web collection have limited the development and further application of centrifugal spinning (CS). Here, we present a feasible method for fibers' continuous collection and morphology optimization by utilizing vertical electrostatic-assisted centrifugal spinning (E-CS). The effects of spinning parameters, such as applied voltage, nozzle size, and rotational speed on fiber morphology have been evaluated systematically. We find that vertical voltage is strongly correlated with the formation of bead defects, and nozzle size is the most important parameter on fiber size, and the fiber diameter generally decreased with increasing rotation speed. Through the mechanism analysis and jet trajectory observation, we think that the Rayleigh–Taylor instability is the key factor in determining fiber formation in CS. When a vertical electrostatic force is applied to CS, the above instability phenomenon can be effectively controlled resulting more uniform fibers with thinner diameters and fewer beads.

scholarly journals Electrospinning of Cellulose Nanocrystal-Filled Poly (Vinyl Alcohol) Solutions: Material Property Assessment

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 805 ◽  
Author(s):  
J. Elliott Sanders ◽  
Yousoo Han ◽  
Todd S. Rushing ◽  
Douglas J. Gardner
Keyword(s):  
Vinyl Alcohol ◽  
Fiber Diameter ◽  
Morphological Structure ◽  
Poly Vinyl Alcohol ◽  
Oh Groups ◽  
Heat Treated ◽  
Property Assessment ◽  
Vinyl Group ◽  
Random Composite ◽  
Scanning Electron

Poly (vinyl alcohol) (PVA) and cellulose nanocrystals (CNC) random composite mats were prepared using the electrospinning method. PVA/CNC mats were reinforced with weight concentrations of 0, 20 and 50% CNC (w/w) relative to PVA. Scanning electron microscopy was used to measure the fiber diameter, which ranged from 377 to 416 nm. Thermogravimetric analysis (TGA) confirmed the presence of CNC fibers in the mat fibers which were not visible by scanning electron microscope (SEM). Mechanical testing was conducted using ASTM D 638 on each sample group at 10 mm min−1. Neat PVA and PVA/CNC mats were heat treated at 170 °C for 2h hours, and the morphological structure was maintained with some fiber diameter reduction. Mechanical property results after heat treatment showed a decrease in tensile strength, an increase in tensile stiffness and a decrease in strain to yield (%). This effect was attributable to enhanced diffusion bonding of the mat fiber intersections. The CNC fibers also increased mat stiffness, and reduced strain to yield in non-treated mats. The use of CNCs show potential for compounding into bulk polymer composites as a reinforcement filler, and also show promise for chemical crosslinking attributable to the –OH groups on both the PVA, in addition to esterification of the vinyl group, and CNC.

Enhancement of AOCC Pulp by Laccase Treatment

2011 ◽  
Vol 236-238 ◽  
pp. 1336-1341
Author(s):  
Bing Sun ◽  
Yu Xin Liu ◽  
Shu Lan Shi
Keyword(s):  
Molecular Weight ◽  
Ferulic Acid ◽  
Model Compound ◽  
Fiber Surface ◽  
Gel Permeation Chromatography ◽  
Fiber Morphology ◽  
Wet Strength ◽  
Gel Permeation ◽  
Heating Treatment ◽  
Scanning Electron

The Americal Old Corrugated Containers (AOCC) was treated with laccase. Fiber morphology, molecular weight and distribution of lignin were analyzed by scanning electron microscope (SEM) and gel permeation chromatography (GPC). Through the model compound of lignin (ferulic acid) was treated by laccase, the correlative mechanism for improvement of the wet-strength of pulp by laccase was discussed. The results showed that the molecular weight of lignin decreased and the lignin adhered on the fiber surface after the pulp was treated by laccase. While the laccase treated pulp with heating treatment, the condensation degree of lignin and adhesion area on fiber increased. In addition, when the ferulic acid was treated by laccase, the results were similar to AOCC pulp.

Cavitation Erosion of HVOF Coatings

1996 ◽  
Author(s):  
R. Schwetzke ◽  
H. Kreye
Keyword(s):  
Erosion Rate ◽  
Cavitation Erosion ◽  
Metallic Alloys ◽  
Erosion Mechanism ◽  
Hvof Coatings ◽  
Coating Composition ◽  
Before And After ◽  
Series Of Experiments ◽  
The Individual ◽  
Scanning Electron

Abstract The proposed paper reports a series of experiments to investigate the cavitation erosion mechanism of HVOF coatings. Vibratory cavitation erosion tests according to ASTM G 32 have been carried out with several HVOF coatings including cermets, oxides and metallic alloys. The steady state erosion rate for each coating was determined and the effect of coating composition and microstructure on the erosion rate was investigated. The morphology and microstructure of the various coatings before and after cavitation testing were analyzed by means of light optical and scanning electron microscopy in order to study the erosion mechanism. The results demonstrate that HVOF coatings of NiCrFeBSi, WC-17Co, Cr3C2-25NiCr and Cr2O3 can exhibit a rather high resistance against cavitation erosion and should be considered for application as a protective surface layer against cavitation. Furthermore, it is shown that cavitation testing can provide a useful tool to study and characterize the bond strength between individual splats as well as the brittleness of the individual phases present in the coating.

Improvement of Morphology, Structure, and Thermal Properties of Electrospun PVA/RSF Fiber Mats by SiO2

2012 ◽  
Vol 184-185 ◽  
pp. 1017-1020 ◽  
Author(s):  
Yan Hua Liu ◽  
Li Xing Dai
Keyword(s):  
Thermal Properties ◽  
Silicon Dioxide ◽  
Solution Viscosity ◽  
Electrospun Fibers ◽  
Fiber Morphology ◽  
Fiber Mats ◽  
Hydrogen Bonding Interactions ◽  
Regenerated Silk Fibroin ◽  
Solution Conductivity ◽  
Scanning Electron

Poly(viny1 alcohol) (PVA)/regenerated silk fibroin (RSF)/silicon dioxide (SiO2) fiber mats were prepared by electrospinning of composite solutions. Fiber morphology was observed under a scanning electron microscope and effects addition of SiO2 was evaluated. Results showed that the obtained fibers exhibited a smooth outer surface, and the continuity was improved because of the different solution conductivity, solution viscosity and compatibility of PVA and RSF by the addition of 1.0 wt. % SiO2. It was found that both Si-O-C linkage and hydrogen bonding interactions were existed among SiO2, PVA, and RSF by FTIR spectroscopy. The addition of SiO2 also resulted in the decrease of crystallinity and increase of thermal properties of electrospun fibers, which were suggested as a result of enhanced compatibility and physical properties of PVA and RSF composite.

Preparation and Characterization of Polyacrylonitrile-Based Nanofibers by Electrostatic Spinning

2012 ◽  
Vol 591-593 ◽  
pp. 1042-1045 ◽  
Author(s):  
Si Yu Li ◽  
Yan Wei Wang ◽  
Tan Wen Jun
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mass Concentration ◽  
Fiber Diameter ◽  
Solution Concentration ◽  
Electrostatic Spinning ◽  
Pan Fiber ◽  
Synthetic Reaction ◽  
Scanning Electron

PAN and P(AN-co-MA) nanofibers have been successfully prepared by electrospinning. The mass concentration is 6%-12%, voltage of 15-25 kV, tip-to-collector distance is 25 cm. The morphology of the obtained samples was measured by a Scanning electron microscopy (SEM). The results showed that there were some large beads distributed on the PAN fiber skeleton when the spinning solution concentration is low. With the spinning solution concentration increased, the bead structure is gradually reduced. The fiber diameter increased with the concentration. For the synthetic reaction mixture P(AN-co-MA), it could obtain uniform nanofibers easily

Doxorubicin release from optimized electrospun polylactic acid nanofibers

2016 ◽  
Vol 47 (1) ◽  
pp. 71-88 ◽  
Author(s):  
Amir Doustgani
Keyword(s):  
Differential Scanning Calorimetry ◽  
Drug Release ◽  
Polylactic Acid ◽  
Fiber Diameter ◽  
Experimental Result ◽  
Coefficient Of Determination ◽  
Release Mechanism ◽  
Burst Release ◽  
Fiber Morphology ◽  
Scanning Calorimetry

Electrospinning has been known as an efficient method for fabrication of polymer nanofibers. In this study, an electrospun nanofibrous mats based on polylactic acid with a defined release using doxorubicin was developed. The effects of process parameters, such as concentration, distance, applied voltage, temperature and flow rate on the mean diameter of electrospun doxorubicin-loaded polylactic acid nanofibers were investigated. The fiber morphology and mean fiber diameter of prepared nanofibers were investigated by scanning electron microscopy. Differential scanning calorimetry was employed to identify the presence of doxorubicin within nanofibers. Response surface methodology based on a five-level, five-variable central composite design was used to model the average diameter of electrospun polylactic acid/doxorubicin nanofibers. Mean fiber diameter was correlated to these variables by using a polynomial function at a 95% confidence level. The coefficient of determination of the model was found to be 0.93. The predicted fiber diameter was in good agreement with the experimental result. Differential scanning calorimetry results showed that the doxorubicin was loaded into the nanofibers successfully. In vitro drug release in phosphate-buffered solution and acetate buffer for the optimized and non-optimized samples demonstrated that diffusion is the dominant drug release mechanism for drug-loaded fibers. The initial burst release was observed for non-optimized nanofibers compared to optimized nanofibers. Optimized drug-loaded polylactic acid nanofibers could be good candidates for biomedical applications.

Optimization of Solvent System and Polymer Concentration for Synthesis of Polyvinyl Alcohol (PVA) Fiber Using Rotary Forcespinning Technique

2015 ◽  
Vol 1123 ◽  
pp. 20-23 ◽  
Author(s):  
Muhammad Miftahul Munir ◽  
Ahmad Fauzi ◽  
Ade Yeti Nuryantini ◽  
Nursuhud ◽  
Eri Sofiari ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Fiber Diameter ◽  
Polymer Concentration ◽  
Solvent System ◽  
Polymer Fiber ◽  
Fiber Morphology ◽  
Ethanol Content ◽  
Optimization Parameters ◽  
Pva Fiber

Rotary forcespinning is one of techniques used for fabrication of polymer fiber. In this paper optimization of several parameters for synthesis of Polyvinyl Alcohol (PVA) fiber using rotary forcespinning technique was described. In order to obtain PVA fiber with smallest diameter the optimization parameters of solvent system and polymer concentration were performed. The results show that PVA dissolved in water as a single solvent produced fiber with high wettability. A mixture of water and ethanol as a solvent system was developed with variation in ethanol content. The effects of ethanol content on fiber diameter were investigated. Rotary forcespinning using solvent with ethanol content below 30% resulted in PVA fiber with high wettability, while solvent ethanol content of more than 70% was unable to dissolve PVA completely. The effect of PVA concentration on the fiber morphology was investigated by adjusting PVA concentration in the range of 9 to 13 weight %. The diameter of the PVA fiber was uniform and could be controlled by adjusting the PVA concentration.

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