High Temperature Finishes/Sizings for Polyimide Matrix Composites

New high temperature sizings are needed that are compatible with resin infusion processes to improve the properties and durability of carbon/polyimide composites. Compatibility with resin infusion processes includes compatibility with weaving and braiding operations and improved wetting with the infusing polyimide resin. Achieving these characteristics will result in reducing life cycle costs. The proposed Phase I program will explore two routes for improving handling and interfacial properties enhancement. A thermoplastic high temperature sizing, polyetherimide, known to improve the interface, will be optimized for use with AFR-PE-4 polyimide resin. In addition, an aqueous based reactive finish will be developed that is compatible with carbon fiber manufacturing. Similar solvent based finishes have been shown to greatly improve carbon/polyimide interfacial strength and thermo-oxidative stability. Development of an aqueous finish will greatly reduce costs while also improving health and safety. These sizings/finishes are expected to be compatible with weaving and braiding operations, will improve wetting during resin infusion processes, and improve the strength and durability of the resulting composites.