Carbon fiber has been widely used in many fields due to its high strength, low density and good chemical resistance. However, when carbon fiber is exposed to high temperature environments, its performance may change. The following is a detailed discussion on the changes in the performance of carbon fiber at high temperatures.
High temperature resistance
Carbon fiber itself has excellent high temperature resistance. According to theory, carbon fiber can withstand high temperatures up to 2600°C. However, carbon fiber is usually not used alone, but is composited with materials such as resin to make finished products. The high temperature resistance of such composite materials is affected by the type of resin used.
Epoxy resin composites
Epoxy resin is one of the most commonly used resins in carbon fiber composites. However, epoxy resin has relatively poor high temperature resistance and usually oxidizes and decomposes at 180~200°C. Therefore, the high temperature resistance of epoxy resin-based carbon fiber composites is usually between 100~150°C.
Thermoplastic resin composites
Compared with epoxy resin, thermoplastic resins (such as polyphenylene sulfide and polyetheretherketone) have better high temperature resistance. Carbon fiber composites made from these resins can withstand temperatures of 200-250°C.
Ceramic-based composites
Of all types of carbon fiber composites, ceramic-based composites have the strongest high-temperature resistance. These materials can remain stable at temperatures up to 1500°C and are suitable for applications in extreme environments, such as aircraft or rocket engine components.
Performance changes
When carbon fiber composites are exposed to high temperatures, their properties may change as follows:
- Strength reduction: High temperatures can cause the resin matrix to soften or decompose, which can reduce the overall strength of the composite.
- Modulus reduction: Modulus refers to the rigidity of a material, and high temperatures can reduce the rigidity of a composite.
- Brittleness: As the temperature rises, the composite may become more brittle and more prone to breakage.
Application areas
Although carbon fiber composites have a reduced performance at high temperatures, they are still widely used in many fields:
- Sports equipment: Such as carbon fiber fishing rods, tennis rackets and golf clubs, etc., use their lightweight properties to reduce the burden on athletes.
- Aerospace: Used in the manufacture of rockets, satellites and space telescopes, etc., to reduce weight and improve performance.
- Rail transit: used to manufacture train bodies, reduce weight and improve high-speed running performance.
- Medical devices: such as medical bed boards, radioactive medical boards and head supports, etc., use their lightweight and high-strength characteristics to improve load-bearing capacity and reduce X-ray doses.
- Automobile manufacturing: used to manufacture parts such as body, drive shaft, battery box and interior, reduce vehicle weight and improve durability and energy efficiency.
Conclusion
The performance changes of carbon fiber at high temperatures mainly depend on the type of resin used. Although carbon fiber itself has excellent high-temperature resistance, the high-temperature resistance of composite materials is limited by the resin. Understanding these performance changes is crucial to selecting suitable carbon fiber composite materials for specific applications.
