Controlling Polymer Fiber Swelling via Coagulation Bath pH
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of carbon fibers faces uncertainties in the degree of swelling of polymer fibers during the coagulation process, affecting the tensile properties and density of the final product, as existing methods rely on unpredictable parameters like polymer dope pH, concentration, and viscosity.
Innovation Solution
Controlling the pH of the coagulation bath during the spinning process of polymer fibers to maintain a degree of swelling of less than or equal to 150%, typically less than 135%, thereby ensuring a denser fiber structure and reducing macrovoid formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polymer dope pH, concentration, and viscosity are used to predict coagulation bath concentration, then the coagulation process can be controlled, but the measured degree of swelling may not match predictions, leading to uncertainties in fiber properties
Solution Approach 1:
The patent changes the controlling parameter from polymer dope properties (pH, concentration, viscosity) to coagulation bath pH. By adjusting and controlling the pH of the coagulation bath, the degree of swelling can be precisely controlled and predicted, resolving the uncertainty between predicted and measured swelling degrees.
2Ease of manufacture
If the degree of swelling is too high, then the coagulation process is easier to control, but the final tensile performance decreases
Solution Approach 1:
By changing the controlling parameter to coagulation bath pH, the patent enables precise control of the degree of swelling within an optimal range. This allows the coagulation process to be controlled while maintaining tensile performance, as the pH can be adjusted to achieve the desired balance between ease of manufacture and strength.
3Ease of manufacture
If traditional parameters are used to control coagulation, then the process is straightforward, but macrovoid formation cannot be effectively prevented
Solution Approach 1:
The patent changes the control parameter to coagulation bath pH, which provides better control over fiber density and macrovoid formation. While this requires an additional parameter to control, it significantly improves the precision of fiber structure control, preventing macrovoids while maintaining processability.
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 allows for precise control of the degree of swelling, enhancing the tensile properties and reducing macrovoids in the final carbon fibers, resulting in improved mechanical performance and processing efficiency.
Implementation Method 1
Typically, a diffusional interchange occurs between the two phases in which solvent leaves the forming filament as water enters, causing the polymer to phase separate from the solvent and precipitate.
Implementation Method 2
causing the polymer to phase separate from the solvent and precipitate
Implementation Method 3
The degree of swelling represents the amount of liquid within the fiber. A low water content corresponds to a denser fiber structure while a high water content corresponds to a less dense fiber structure.
Data Source
AI summary
The present disclosure relates to the control of the degree of swelling of polymer fiber, such as polymer fiber used in the manufacturing of composite materials, by control of the pH of the coagulation bath during spinning.