Polyacrylonitrile Filament Extrusion Head with Vibrating Chamber
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Solution Overview
Problem
Current methods for producing polyacrylonitrile (PAN) filaments, the precursor for carbon fiber, face challenges in reducing extrusion pressures, eliminating microbubbles, and achieving optimal molecular orientation, often requiring multiple drawing phases that are complex and costly.
Innovation Solution
A method and extrusion head that applies vibration to the polymer solution during extrusion, using a laminar flow system with a vibrating chamber to separate air bubbles and align molecules, reducing pressure requirements and the need for multiple drawing phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vibration is applied to the polymer solution during extrusion, then molecular orientation and filament homogeneity are improved, but device complexity increases due to the vibrating chamber and laminar flow system
Solution Approach 1:
The patent applies mechanical vibration to the polymer solution within the extrusion head to achieve molecular orientation and eliminate microbubbles. The vibrating chamber generates controlled vibrations that align polymer chains in the flow direction, improving filament homogeneity and reducing defects without requiring multiple subsequent drawing phases.
Solution Approach 2:
The patent introduces a laminar flow system as an intermediary mechanism between the polymer solution and the extrusion process. The laminar flow chamber creates controlled flow conditions that enhance molecular alignment and facilitate bubble removal, acting as a mediator that improves filament quality before extrusion.
2Strength
If multiple drawing phases are used to achieve molecular orientation, then filament strength is improved, but production time and process complexity increase
Solution Approach 1:
The patent performs molecular orientation as a preliminary action during the extrusion process itself, rather than requiring separate subsequent drawing phases. The vibration applied during extrusion pre-aligns the polymer molecules, achieving the orientation effect that would otherwise require multiple time-consuming drawing operations.
Solution Approach 2:
The patent merges the molecular orientation function with the extrusion process by incorporating the vibrating chamber directly into the extrusion head. This combines what were previously separate operations (extrusion and drawing/orientation) into a single integrated process step, reducing production time and simplifying the overall process.
3Productivity
If high extrusion pressure is applied to force polymer through small holes, then extrusion speed is improved, but microbubbles are trapped and filament quality deteriorates
Solution Approach 1:
The patent uses mechanical vibration within the extrusion head to prevent microbubble entrapment during extrusion. The vibrations create disturbances in the polymer flow that facilitate bubble release and prevent bubble formation, allowing high extrusion rates to be maintained without compromising filament quality.
Solution Approach 2:
The patent converts the potentially harmful effect of high extrusion pressure (which can trap bubbles) into a beneficial process by combining it with vibration. The vibration transforms the high-pressure extrusion from a bubble-trapping process into a bubble-eliminating process, allowing high productivity without quality deterioration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in filaments with reduced defects, improved homogeneity, and enhanced molecular orientation, leading to more efficient production with lower costs and improved mechanical properties.
Implementation Method 1
a chamber defined between said extruder plate and a floating plate held by means of elastic membranes and connected to a vibrating device
Implementation Method 2
the vibration that is applied to the polymer solution in the chamber before the extruder plate determines, on one hand, that the heavier particles of the material move in the direction opposite the source of the vibration, whereas the lighter particles, such as air bubbles, move towards the source of the vibration
Implementation Method 3
The PAN polymer is formed, starting from the acrylonitrile (AN) monomer, by polymerizing free radicals in aqueous suspension
Implementation Method 4
wherein said polymer is introduced into the extrusion phase under laminar flow conditions through an acceleration step
Data Source
AI summary
A method for producing filaments of polyacrylonitrile and an extrusion head for carrying out said method are provided, wherein the method comprises preparing a polyacrylonitrile polymer solution and passing said solution through an extruder plate that determines the formation of filaments, a central chamber being defined between the extruder plate and a floating plate connected to a vibrating system, said chamber being surrounded by a peripheral chamber into which the polymer solution is introduced under pressure. The polymer solution then passes through to the central chamber via small radial conduits that accelerate the material, and is subjected to vibration in the central chamber before passing through the extruder plate.