Three development trends of thermoplastic carbon fiber applications

With the continuous expansion of the application market, thermosetting resin-based carbon fiber composite materials gradually show their own limitations, and they cannot fully meet the needs of high-end applications in terms of wear resistance and high temperature resistance. Under this circumstance, the status of thermoplastic resin-based carbon fiber composite materials has gradually risen, becoming an emerging force in advanced composite materials. In recent years, China's carbon fiber technology has achieved rapid development, and the application technology of thermoplastic carbon fiber composite materials has also been further promoted.

 Among carbon fiber downstream companies, our company's exploration of continuous carbon fiber reinforced thermoplastic prepregs can be said to be a microcosm of the road to localization of carbon fiber thermoplastic composites. It vividly demonstrates three trends in the application of thermoplastic carbon fibers:

 One is the development from powder carbon fiber reinforcement to continuous carbon fiber reinforcement:

 Carbon fiber thermoplastic composite materials can be divided into powder carbon fiber, chopped carbon fiber, unidirectional continuous carbon fiber and fabric carbon fiber reinforcement according to the form of reinforcing fiber. When the composite material encounters bending or shear failure, there is a process of fiber pulling out of the matrix. The longer the reinforcing fiber, the more energy provided by the external load absorbed when pulling out, and the higher the overall strength of the composite material . Therefore, compared with powder or chopped carbon fiber reinforced thermoplastic composite material, continuous carbon fiber reinforced thermoplastic composite material has better performance advantages. The most widely used injection molding process in China uses powder or chopped carbon fiber reinforced form, and the performance of the product has certain limitations. When continuous carbon fiber reinforced form is used, thermoplastic carbon fiber composite materials will usher in a wider application space.

 The second is the development from low-end thermoplastic resin to mid-to-high-end thermoplastic resin matrix:

 The thermoplastic resin matrix exhibits high viscosity characteristics during the melting process. Such high viscosity resin matrix is usually difficult to fully infiltrate the carbon fiber material, and the degree of infiltration is closely related to the performance of the prepreg. In order to further improve the degree of infiltration, our company adopted composite material modification technology, and improved the original fiber spreading device and resin extrusion equipment. While extending the width of the carbon fiber precursor tow, it increased the continuous extrusion of the resin. It significantly improves the infiltration effect of the thermoplastic resin on the carbon fiber and effectively ensures the performance of the continuous carbon fiber reinforced thermoplastic prepreg. Successfully extended the resin matrix of continuous carbon fiber thermoplastic composites from low-end thermoplastic resins such as PPS and PA to mid- to high-end resins such as PI and PEEK.

 The third is the development from hand-made in the laboratory to stable mass production:

 From the successful small-scale experiment in the laboratory to the stable mass production in the workshop, the most important thing is the design and adjustment of production equipment. Whether continuous carbon fiber reinforced thermoplastic prepregs can achieve stable mass production depends not only on the average daily output, but also on whether the quality of the prepreg is stable, that is, whether the resin content in the prepreg is controllable and the proportion is appropriate , To see if the carbon fibers in the prepreg are evenly distributed and thoroughly infiltrated, and to see if the prepreg has a smooth surface and precise dimensions. In order to have both "quality" and "quantity", our company has reached the ultimate goal of stable mass production after hundreds of adjustments. The current mass-produced continuous carbon fiber reinforced thermoplastic prepreg has a width of 60 cm.