After decades of development, high-performance advanced composite material carbon fiber has become one of the preferred material solutions for upgrading aerospace, rail transportation, intelligent machinery, high-end medical equipment, and various civilian products. Carbon fiber composite materials have performance advantages such as light weight, high strength, low creep, corrosion resistance, and fatigue resistance. However, when meeting special needs, there are still certain problems or defects. How to effectively improve these problems and enhance the application value of carbon fiber composite materials is the issue that needs to be explored in this article.
1. Toughening
Carbon fiber reinforced composite materials have high strength and good performance, but the special molding process of composite materials can have a negative impact on their impact resistance, fracture toughness, and delamination strength. Carbon fiber composite materials will form different failure mechanisms under mechanical loads. Once the released strain energy exceeds the energy required to create a new surface area or generate plastic deformation near the crack tip, serious consequences may arise during these stages of crack propagation.
Adding toughening agents to resins is a conventional method to solve the brittleness and easy occurrence of small cracks in carbon fiber materials. However, toughness enhancing particles generally have poor dispersion and often form regions of high and low particle density, which can reduce the overall performance of composite materials. At present, developed countries such as Europe and America are beginning to lay nanofiber membranes between the prepreg layers. These membranes do not increase the thickness and weight of the prepreg, but can act as nanoscale reinforcing materials for brittle resin matrix in the interlayer area, ultimately forming a tougher resin (which can be used together with other toughening systems). This solution is beneficial for improving the anti delamination, damage tolerance, and anti fatigue properties of carbon fiber composite materials, reducing the occurrence of small cracks under pressure or impact.
2. Thermoplastic
At present, the most widely used carbon fiber composite materials in China are still mainly based on epoxy resin. This thermosetting carbon fiber composite material can meet general industrial or civilian needs, but for some components with extremely high performance requirements, there is still a certain gap in high temperature resistance and wear resistance of epoxy based carbon fiber composite materials. For this reason, many companies in the carbon fiber industry are actively seeking solutions.
For carbon fiber composite material systems, it is not only difficult to achieve both high strength and high temperature resistance, but also performance advantages such as wear resistance will be mutually constrained. The main reason why carbon fiber composite materials are not resistant to high temperatures is due to the matrix material. In the past, the heat resistance of composite materials was usually improved by adding bismaleimide and other methods, but the final performance results were still not very ideal. At present, the localization of unidirectional prepreg such as continuous carbon fiber reinforced PPS/PES/PA6/PEEK can replace thermosetting carbon fiber materials in special or high-end components, which can improve the comprehensive advantages of carbon fiber materials such as high strength, high temperature resistance, good wear resistance, corrosion resistance, and high safety factor. It has become one of the preferred solutions for carbon fiber composite materials that are not resistant to high temperature and wear.