Reactive polyamide-carbon fiber composites promise lower cost
BASF (Ludwigshafen, Germany) and the SGL Group (Wiesbaden, Germany) plan to jointly develop a composite material based on a reactive polyamide system and suitable carbon fibers, thereby enabling the cost-effective production of thermoplastic carbon fiber-reinforced composites.
The material system is intended for use in the T-RTM (Thermoplastic Resin Transfer Molding) process as well as the reactive injection molding (RIM) process, and reportedly permits considerably shorter processing cycles than conventional thermosetting RTM. The switch of the material system to these faster processing techniques will play a major role for the entry of light and high-strength structural components made of carbon fiber composites into automotive mass production.
As a leading producer of polyamide and caprolactam, a precursor of polyamide, BASF is contributing its competence in the development of new polymer matrix systems. The SGL Group is utilizing its material expertise along the carbon fiber value-added chain and in high-temperature processes. “To achieve good wetting of the fiber and short cycle times in T-RTM or reactive injection molding, we start from low-viscosity highly reactive caprolactam formulations”, explains Dr. Martin Jung, Head of Structural Materials Research and spokesman for BASF Research toward the automotive industry.
In order to attain an optimal bonding of the polyamide to the fiber, the new matrix systems require that a suitable carbon fiber surface treatment, the so-called finish, will be developed. Says Dr. Hubert Jäger, Head of Technology & Innovation, SGL Group: “It is only with a custom-formulated finish that this optimal bonding can form and the carbon fibers transmit their unique stiffness and strength properties fully to the part. On the basis of our many years of industrial experience, we are able to optimize processes and materials along the entire value-added chain of carbon fiber technology for new applications.”
Thermoplastic carbon fiber-reinforced composites combine the properties of carbon fibers such as high stiffness at low weight with the typical processing advantages of thermoplastics. They can be formed, recycled and welded. In this way they encourage further development of carbon fiber technology toward the goal of suitability for mass production.