In the field of carbon fiber development, high-performance continuous carbon fiber thermoplastic composites - such as CF+PEEK, CF+PPS and CF+PI - have proven to be highly effective in meeting demanding requirements. These continuous reinforced thermoplastic carbon fibers offer a number of superior performance characteristics, including exceptional mechanical properties, corrosion resistance, and impact resistance. In addition, they offer secondary processing capabilities and environmental benefits that have attracted significant market attention. The current challenge lies in the difficulty of manufacturing thermoplastic carbon fiber prepregs, with the key issue being the seamless integration of continuous carbon fibers and thermoplastic resins. The following is an analysis of the advantages and disadvantages of four common thermoplastic carbon fiber PEEK prepreg processes:
1. Powder wet process
This process is widely used for thermoplastic glass fibers. Its advantages include high blend stability and excellent high temperature resistance. However, it has several disadvantages:
Uniformity issues: Achieving uniform distribution during blending is challenging, and uneven distribution can result in inconsistent product performance.
Performance limitations: Compared to long fiber composites, the mechanical properties of wet-processed powder materials are significantly inferior.
Material degradation: Removal of the carrier in the powder wet process often results in a decrease in material performance.
2. Melting method
This approach is currently used by Wuxi Zhishang New Materials and effectively addresses the limitations of the powder extrusion method, offering better performance.However, it has notable challenges:
Temperature control: Accurate melting temperature control is difficult, and a dust-free environment is required.
Impregnation inefficiency: If the temperature is not properly controlled, the prepreg may not be fully impregnated, resulting in incomplete resin penetration.
3. Film lamination method
The film lamination method preserves the original properties of carbon fibers by avoiding fiber damage during processing. However, it has some disadvantages:
Slow penetration: The polymer melt cannot quickly penetrate the fiber bundles, resulting in a longer prepreg time.
Weak interfacial bonding: The reinforcing fibers and polymer matrix may not achieve complete and tight integration, resulting in weak interfacial bonding between the resin and fibers. This prevents full utilization of the composite's properties.
Limited applicability: This method is best suited for direct prepreg of fiber fabrics with low viscosity resins.
4. Solution Impregnation Method
This method is similar to the traditional thermosetting carbon fiber prepreg process and has the advantage of ease of operation. However, it has significant disadvantages:
Solubility requirements: Many PEEK thermoplastic polymers have stringent solubility requirements that limit their application.
Increased complexity: The need to remove solvents in later stages adds extra steps, increases costs and can affect material performance.
Environmental impact: Solvents can cause environmental contamination and pose disposal challenges.
The above processes represent common methods used to produce thermoplastic carbon fiber reinforced PEEK prepregs. Regardless of the process chosen, the ultimate goal is to produce high performance, continuously reinforced thermoplastic carbon fiber PEEK prepregs. These prepregs can then be used to manufacture thermoplastic carbon fiber products through processes such as compression molding. Each process has its own strengths and limitations, and the choice depends on specific application requirements and production capabilities.
