Carbon Fiber Sizing With Water-Miscible Solvent Processing
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Solution Overview
Problem
The existing methods for applying sizing to carbon fibers, such as emulsification and solvent-based methods, face challenges including the use of surfactants that can negatively affect composite properties, difficulty in emulsifying high molecular weight materials, and the hazardous nature of solvent vapors, making them impractical and environmentally unsafe.
Innovation Solution
A method using a water-miscible solvent to dissolve the sizing material, followed by an aqueous coagulation and washing process to remove the solvent, minimizing solvent vapor formation and allowing the use of a broader range of sizing materials, including high molecular weight polymers and corrosive solvents, while ensuring safety and environmental sustainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If emulsification method is used to apply sizing to carbon fibers, then sizing can be applied to fibers, but surfactants remain on the final fiber product and negatively affect composite properties
Solution Approach 1:
The patent extracts and removes surfactants from the sizing application process by using alternative emulsifying agents that do not leave harmful residues on the fiber product, thereby eliminating the harmful effect on composite properties while maintaining the sizing application capability
Solution Approach 2:
The patent introduces alternative emulsifying agents as intermediaries to replace traditional surfactants, enabling the sizing material to be properly emulsified and applied to fibers without the adverse effects of conventional surfactants on final composite performance
2Ease of manufacture
If traditional emulsification method is used, then sizing can be applied to fibers, but high molecular weight materials cannot be readily emulsified
Solution Approach 1:
The patent changes the parameters of the emulsification process by using alternative emulsifying agents with different molecular structures and properties that are capable of emulsifying high molecular weight sizing materials, thereby expanding the range of usable sizing materials
Solution Approach 2:
The patent employs composite emulsifying systems that combine multiple agents or use specially formulated emulsifiers designed to handle high molecular weight materials, enabling the emulsification of a broader range of sizing materials including those with high molecular weights
3Ease of manufacture
If solvent-based method is used to apply sizing to carbon fibers, then sizing material can be dissolved and applied, but solvent vapor is produced which is hazardous to environment and workers
Solution Approach 1:
The patent changes the physical parameters of the sizing application process by using aqueous emulsions instead of organic solvents, which fundamentally alters the vaporization characteristics and eliminates hazardous solvent vapor production while maintaining effective sizing application
Solution Approach 2:
The patent converts the potentially harmful organic solvent system into a beneficial aqueous system where water serves as the carrier, eliminating the harmful vapor generation while maintaining or improving the sizing application effectiveness and adding environmental sustainability
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 effectively applies sizing to carbon fibers with minimal solvent vapor production, enabling the use of a wider variety of materials and reducing health and environmental risks, while maintaining or improving composite properties and manufacturing efficiency.
Implementation Method 1
A method of applying sizing onto carbon fiber by use of a water-miscible solvent. The method comprises dissolving the sizing material in the water-miscible solvent
Implementation Method 2
followed by an aqueous coagulation and washing process to remove the solvent
Implementation Method 3
The fibers coated with the sizing/solvent solution are dried to remove the solvent, leaving only the sizing material on the fibers
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Various embodiments directed towards methods of applying sizing to fibers are disclosed herein. In some embodiments, solvent can be used to dissolve a sizing material into a solution, which can then be used to coat the fibers. In some embodiments, a water bath is used to coagulate a sizing on the fiber surface and to remove the remove solvent after coating the fibers, so that water vapor can be created during a subsequent drying step as opposed to solvent vapors. In some embodiments, strong acids or strong bases can be used as the solvent.