Low Polydispersity PAN Spinning for High-Tow Carbon Fiber
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing processes for producing carbon fiber precursor fibers face challenges in processing high-tow counts due to limitations in filament strength and interference during air gap spinning, particularly for >3,000-filament spinning, which restricts the ability to prevent wetfacing and maintain filament integrity.
Innovation Solution
A process involving spinning a polyacrylonitrile-based polymer solution with a polydispersity of less than or equal to 2 in a coagulation bath with a jet stretch of about 5 to 60, followed by drawing, oxidation, and carbonization to produce carbon fibers, allowing for the production of carbon fiber precursor fibers that can withstand higher jet stretches without filament-to-filament interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air gap spinning is used for high-tow counts (>3,000 filaments), then productivity is improved, but filament strength is insufficient leading to wetfacing and filament-to-filament interference
Solution Approach 1:
The patent applies parameter changes by modifying the polymer properties (molecular weight, polydispersity index) and spinning parameters (jet stretch, coagulation bath conditions) to enable high-tow air gap spinning. Specifically, using PAN polymer with controlled molecular weight and PDI ≤ 2, combined with jet stretch of 5-60, resolves the contradiction between high productivity and sufficient filament strength.
2Productivity
If jet stretch is increased to improve spinning efficiency, then productivity is improved, but filament-to-filament interference increases
Solution Approach 1:
The patent optimizes jet stretch to a specific range (5-60) that balances spinning efficiency with filament separation. This parameter change, combined with controlled polymer viscosity and molecular weight, prevents filament-to-filament interference while maintaining high productivity.
3Ease of manufacture
If conventional PAN polymer is used for spinning, then ease of manufacture is improved, but processability of viscous dope solution is limited
Solution Approach 1:
The patent changes the molecular weight and polydispersity parameters of PAN polymer to improve dope solution processability. By controlling PDI ≤ 2 and selecting appropriate molecular weight ranges, the patent achieves both ease of manufacture (using conventional PAN) and improved processability (reduced viscosity, better spinning characteristics).
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 enables the production of carbon fibers with improved mechanical properties and reduced downstream processing issues, enabling the production of higher-tow carbon fibers with lower pressure at the spinneret head and potentially lower costs, facilitating easier manufacture and re-design of spinnerets.
Implementation Method 1
spinning a polymer solution, wherein the polymer has a polydispersity (PDI) of less than or equal to 2, in a coagulation bath
Implementation Method 2
oxidizing the drawn carbon fiber precursor fibers of step 2) to form stabilized carbon fiber precursor fibers
Implementation Method 3
carbonizing the stabilized carbon fiber precursor fiber, thereby producing carbon fibers
Data Source
AI summary
The present disclosure relates to a process for producing one or more carbon fiber precursor fibers, particularly by spinning a polymer solution, wherein the polymer has a polydispersity (PDI) of less than or equal to 2, in a coagulation bath with a jet stretch of about 5 to about 60. The one or more carbon fiber precursor fibers produced may be used for producing carbon fiber, typically carbon fiber used in manufacturing composite materials.