How to improve the performance of carbon fiber composite materials? Matching strategy between carbon fiber fabric and matrix material

Improving the performance of carbon fiber composite materials involves careful selection and matching of the carbon fiber fabric and the matrix material. Here are some key strategies:

Selecting the Right Carbon Fiber Fabric

Fiber Type and Grade: Different types of carbon fibers, such as PAN - based, pitch - based, and rayon - based carbon fibers, have distinct properties. PAN - based carbon fibers are commonly used for their high strength and modulus. Within each type, there are various grades with different levels of strength, stiffness, and surface characteristics. For high - strength applications like aerospace components, high - modulus carbon fiber fabrics are preferred.

Fabric Weave Pattern: The weave pattern of the carbon fiber fabric affects the mechanical properties of the composite. Common weave patterns include plain weave, twill weave, and satin weave. Plain weave fabrics offer good in - plane strength and stability, while satin weave fabrics have a smoother surface and better drapability, which is beneficial for complex - shaped components. Selecting the appropriate weave pattern depends on the specific requirements of the final product.

Choosing the Appropriate Matrix Material

Thermosetting Resins: Epoxy resins are widely used as the matrix material for carbon fiber composites due to their good mechanical properties, high adhesion to carbon fibers, and excellent chemical resistance. For applications requiring high - temperature resistance, phenolic resins or polyimide resins can be considered. These resins can maintain their mechanical properties at elevated temperatures but may have higher processing costs.

Thermoplastic Resins: Thermoplastic resins, such as polypropylene (PP), polyethylene (PE), and polyetheretherketone (PEEK), offer advantages like high toughness, rapid processing, and recyclability. PEEK, in particular, has excellent mechanical properties and high - temperature resistance, making it suitable for demanding applications in the aerospace and automotive industries. However, the high cost of some thermoplastic resins can be a limiting factor.

Surface Treatment of Carbon Fiber

Oxidation Treatment: Oxidation treatment is often carried out on the surface of carbon fibers to increase the hydrophilicity of the fiber surface and improve the wettability of the matrix resin. This can be achieved through methods such as air oxidation, electrochemical oxidation, or plasma treatment. These treatments introduce polar functional groups on the fiber surface, enhancing the chemical bonding between the carbon fiber and the matrix.

Sizing Treatment: Sizing is a coating applied to the carbon fiber surface to protect the fibers during processing and improve their adhesion to the matrix. The sizing agent can be tailored to match the specific matrix material. For example, an epoxy - based sizing agent is suitable for epoxy - matrix composites. It helps to distribute the resin evenly on the fiber surface and forms a strong interface between the fiber and the matrix.

Optimization of Manufacturing Process

Resin Impregnation: The resin impregnation process should be carefully controlled to ensure uniform distribution of the matrix resin within the carbon fiber fabric. Techniques such as vacuum - assisted resin transfer molding (VARTM) and resin film infusion (RFI) can be used to achieve good impregnation results. In VARTM, a vacuum is applied to draw the resin into the fiber preform, while in RFI, a resin film is placed between layers of the fiber fabric and heated to melt and impregnate the fibers.

Curing Process: The curing process of the matrix resin has a significant impact on the final properties of the composite. The curing temperature, time, and pressure should be optimized according to the type of resin and the requirements of the application. For example, epoxy resins usually require a specific curing temperature and time to achieve maximum cross - linking and mechanical strength. Over - curing or under - curing can lead to reduced performance of the composite material.