Fabrication and Process Optimization of Thick Laminates (= 40 ply) From High-Temperature Polyimide/Carbon Fiber Composites

ABSTRACT: Composite materials are becoming more prevalent on military aircraft such as the F-22, F/A-18E/F/G, and the F-35 Lightning Joint Strike Fighter. Polyimide carbon fiber composites offer performance benefits and tremendous operational cost savings for the DoD due to their superior strength-to-weight ratio when compared to titanium. To take full advantage of the weight savings of polyimide composites, a full understanding of the reaction kinetics, volatile removal, and viscosity profile for both the polyimide condensation reaction and addition crosslinking polymerization is required. The objective of this Phase II SBIR effort will be to advance the processing science for MVK-14 FreeForm carbon fiber composites resulting in a robust manufacturing process of components for transition into DoD platforms. Maverick will focus efforts on MVK-14 FreeForm as the polyimide resin system based on its processing ease, affordability, high-performance thermal oxidative stability at temperatures between 500F to 550F, and dual use capability for turbine engine components. A thorough characterization of the material will lead to computational models for the kinetics and viscosity profiles. Dielectric sensors will be used to correlate the viscosity models with autoclave processing parameters. This will result in a robust process for the fabrication of complex MVK-14 FreeForm carbon fiber composite components. BENEFIT: A robust, thick-part cure cycle that has been validated with analytical data, testing, and process modeling will significantly increase the use of polyimide composites in military aircraft as well as in commercial markets that need to reduce fuel consumption. A successful research effort would result in a complete set of processing instructions for MVK-14 FreeForm carbon fiber prepreg that could be used by high-temperature part fabricators. The increase in manufacturing capability for this material would allow designers at aerospace companies to use more polyimide matrix composites in their applications, thus reducing weight and increasing efficiency for both DoD and commercial applications. The combination of a robust, low-cost autoclave process along with an increase in design capability will result in significant cost savings to the Military. In addition, the results of this SBIR will also be beneficial to the high-temperature polyimide composite community. The methodology for the characterization and the overall understanding of thick-laminate processing for MVK-14 FreeForm would apply to other polyimide resin systems.