High-Temperature Sizing for Carbon Fiber Reinforced Fluorinated Addition Polyimides

The objective of this proposal is to develop a sizing system for carbon fiber that has the thermal stability to match or exceed that of the matrix resin and be chemically compatible with the fluorinated addition polyimides. More specifically, the sizing will have the same or similar composition to the matrix resin to promote miscibility and interdiffusion and endcapped with phenylethynyl functional group to allow the sizing and matrix to form covalent bonds. The sizing will be designed to be thermally stable during the full processing cycle, prevent fuzzing, and improve the processability of the fiber tow in the weaving and preform processing steps. In addition, the new sizing must meet all the criteria specified by the carbon fiber industry to be a commercially viable product. The sizing must be solvent free, nonflammable, contain no Hazardous Air Pollutants, and safe for worker exposure. The new sizing must be compatible with the manufacturing equipment and techniques employed at the plants. Major changes in processing and capital expenditure is unacceptable. To provide an advantage for our customers the sizing must ease fiber handling during manufacture and aid in secondary processes such as weaving.