scholarly journals Study of Air Pressure and Velocity for Solution Blow Spinning of Polyvinylidene Fluoride Nanofibres

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1014
Author(s):  
Rasheed Atif ◽  
Madeleine Combrinck ◽  
Jibran Khaliq ◽  
James Martin ◽  
Ahmed H. Hassanin ◽  
...  
Keyword(s):  
Polymer Solution ◽  
Polyvinylidene Fluoride ◽  
Fibre Diameter ◽  
Flow Characteristics ◽  
Air Pressure ◽  
Compressed Air ◽  
Input Pressure ◽  
Solution Blow Spinning ◽  
Fibre Morphology ◽  
Operational Simplicity

Solution blow spinning (SBS) is gaining popularity for producing fibres for smart textiles and energy harvesting due to its operational simplicity and high throughput. The whole SBS process is significantly dependent on the characteristics of the attenuation force, i.e., compressed air. Although variation in the fibre morphology with varying air input pressure has been widely investigated, there is no available literature on the experimentally determined flow characteristics. Here, we have experimentally measured and calculated airflow parameters, namely, output air pressure and velocity in the nozzle wake at 12 different pressure values between 1 and 6 bar and 11 different positions (retracted 5 mm to 30 mm) along the centreline. The results obtained in this work will answer many critical questions about optimum protrusion length for the polymer solution syringe and approximate mean fibre diameter for polyvinylidene fluoride (PVDF) at given output air pressure and velocity. The highest output air pressure and velocity were achieved at a distance of 3–5 mm away from the nozzle wake and should be an ideal location for the apex of the polymer solution syringe. We achieved 250 nm PVDF fibres when output air pressure and velocity were 123 kPa and 387 m/s, respectively.

scholarly journals Solution Blow Spinning of Polyvinylidene Fluoride Based Fibers for Energy Harvesting Applications: A Review

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1304 ◽  
Author(s):  
Rasheed Atif ◽  
Jibran Khaliq ◽  
Madeleine Combrinck ◽  
Ahmed H. Hassanin ◽  
Nader Shehata ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Polyvinylidene Fluoride ◽  
High Efficiency ◽  
Piezoelectric Materials ◽  
Critical Parameters ◽  
High Yield ◽  
Solution Blow Spinning ◽  
Service Conditions ◽  
Key Aspects ◽  
Operational Simplicity

Polyvinylidene fluoride (PVDF)-based piezoelectric materials (PEMs) have found extensive applications in energy harvesting which are being extended consistently to diverse fields requiring strenuous service conditions. Hence, there is a pressing need to mass produce PVDF-based PEMs with the highest possible energy harvesting ability under a given set of conditions. To achieve high yield and efficiency, solution blow spinning (SBS) technique is attracting a lot of interest due to its operational simplicity and high throughput. SBS is arguably still in its infancy when the objective is to mass produce high efficiency PVDF-based PEMs. Therefore, a deeper understanding of the critical parameters regarding design and processing of SBS is essential. The key objective of this review is to critically analyze the key aspects of SBS to produce high efficiency PVDF-based PEMs. As piezoelectric properties of neat PVDF are not intrinsically much significant, various additives are commonly incorporated to enhance its piezoelectricity. Therefore, PVDF-based copolymers and nanocomposites are also included in this review. We discuss both theoretical and experimental results regarding SBS process parameters such as solvents, dissolution methods, feed rate, viscosity, air pressure and velocity, and nozzle design. Morphological features and mechanical properties of PVDF-based nanofibers were also discussed and important applications have been presented. For completeness, key findings from electrospinning were also included. At the end, some insights are given to better direct the efforts in the field of PVDF-based PEMs using SBS technique.

scholarly journals Solution Blow Spinning of High-Performance Submicron Polyvinylidene Fluoride Fibres: Computational Fluid Mechanics Modelling and Experimental Results

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1140 ◽  
Author(s):  
Rasheed Atif ◽  
Madeleine Combrinck ◽  
Jibran Khaliq ◽  
Ahmed H. Hassanin ◽  
Nader Shehata ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
High Speed ◽  
High Performance ◽  
Fibre Diameter ◽  
Fibre Production ◽  
Computational Fluid Mechanics ◽  
Convergent Nozzle ◽  
Air Inlet ◽  
Air Chamber ◽  
Solution Blow Spinning

Computational fluid dynamics (CFD) was used to investigate characteristics of high-speed air as it is expelled from a solution blow spinning (SBS) nozzle using a k-ε turbulence model. Air velocity, pressure, temperature, turbulent kinetic energy and density contours were generated and analysed in order to achieve an optimal attenuation force for fibre production. A bespoke convergent nozzle was used to produce polyvinylidene fluoride (PVDF) fibres at air pressures between 1 and 5 bar. The nozzle comprised of four parts: a polymer solution syringe holder, an air inlet, an air chamber, and a cap that covers the air chamber. A custom-built SBS setup was used to produce PVDF submicron fibres which were consequently analysed using scanning electron microscope (SEM) for their morphological features. Both theoretical and experimental observations showed that a higher air pressure (4 bar) is more suitable to achieve thin fibres of PVDF. However, fibre diameter increased at 5 bar and intertwined ropes of fibres were also observed.

Study on Working Characteristics of Expansion Energy Used Booster

2011 ◽  
Author(s):  
Yan Shi ◽  
Maolin Cai
Keyword(s):  
Mathematical Model ◽  
High Pressure ◽  
Flow Characteristics ◽  
Air Pressure ◽  
Compressed Air ◽  
Output Pressure ◽  
Movement Characteristics ◽  
Output Flow ◽  
Expansion Energy ◽  
Future Work

Boosters are widely used to obtain high-pressure air. In order to obtain a higher output flow of high-pressure air, a new kind of booster is proposed, namely, the Expansion Energy Used booster (EEU booster). Output flow is improved by utilizing the expansion power of the compressed air to accelerate the piston’s movement. A mathematical model of the booster is constructed and analyzed to obtain the piston’s movement characteristics, variations of air pressure in the boosting and driving chamber as well as the characteristics of the output flow. Evaluation of simulation and experimental flow characteristics shows that the derived model corresponds well to experimental results. For a source and output air pressure of 0.6Mpa and 0.8MPa respectively, the output flow of the booster rises as the Convergent Pressure in the driving chamber increases. At a certain point, the output flow stabilizes and remains at a near constant. For an output pressure of 0.8MPa at the Optimum Work State, the output flow declines with a rise in the boosting ratio. This research lays the foundation for future work on the optimization of the EEU booster.

Solidification characteristics of polymer solution during polyvinylidene fluoride membrane preparation by nonsolvent-induced phase separation

2013 ◽  
Vol 438 ◽  
pp. 77-82 ◽  
Author(s):  
Toru Ishigami ◽  
Keisuke Nakatsuka ◽  
Yoshikage Ohmukai ◽  
Eiji Kamio ◽  
Tatsuo Maruyama ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polymer Solution ◽  
Polyvinylidene Fluoride ◽  
Membrane Preparation

scholarly journals Energy Efficiency of Pneumatic Cylinder Control with Different Levels of Compressed Air Pressure and Clamping Cartridge

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3711
Author(s):  
Vladislav Blagojevic ◽  
Dragan Seslija ◽  
Slobodan Dudic ◽  
Sasa Randjelovic
Keyword(s):  
Energy Consumption ◽  
Air Pressure ◽  
Compressed Air ◽  
Pneumatic Cylinder ◽  
Final Position ◽  
Return Stroke ◽  
Cylinder Piston ◽  
Reduce Energy Consumption ◽  
The Cost ◽  
Different Levels

Since pneumatic systems are widely used in various branches of industry, the need to find ways to reduce energy consumption in these systems has become very pressing. The reduction in energy consumption in these systems is reflected in the reduction of compressed air consumption. The paper presents a cylinder control system with a piston rod on one side, in which the reduction in energy consumption is ensured by using different levels of supply pressure in the working and the return stroke, and by holding the cylinder piston rod in its final positions with a clamping cartridge. Clamping and holding the piston rod in its final position further affects the reduction in energy consumption. Experimental data show that the application of the proposed control leads to a decrease in compressed air consumption of 25.54% to 32.97%, depending on the compressed air pressure used in the return stroke. The cost-effectiveness of the proposed cylinder control with different levels of compressed air pressure and holding the final position by clamping cartridge is presented.

Manufacturing and Evaluation of Porous PLA Nano/Micro Fibres

2016 ◽  
Vol 368 ◽  
pp. 146-149
Author(s):  
Eva Macajová
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Image Analysis ◽  
Polymer Solution ◽  
Process Parameters ◽  
Fibre Diameter ◽  
Solution Composition ◽  
Structure And Morphology ◽  
Spinning Process ◽  
Scanning Electron

This study is mainly focused on the study of pore size and shape, fibre diameter and also on the optimization of polymer solution composition and electrospinning parameters with respect to the final structure and morphology of PLA nano/microfibrous layers. The nano/microfibres were produced by electrospinning from the needle. Except the spinning process parameters, the morphology of nanofibrous layers can be also affected by the composition of the polymer solution and by the used solvents. Variations in technological process allows us to design the shape and form of nanofibrous structures upon request. The morphology of nano/microfibres was observed by scanning electron microscopy (SEM). Following image analysis and calculation enables the assessment of porosity contribution to the increase in micro/nanofibre surface area.

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