Thermoplastic Coated Carbon Fibers for Textile Preforms

A continuous process for producing prepreg from carbon fiber and thermo plastic matrix is described. After the tow has been spread using a pneumatic device, the process utilizes a fluidized bed to apply thermoplastic powder to the bundle. Finally, direct electrical heating of the coated fiber tow melts the polymer on the individual fibers, creating a uniform and extremely flexible prepreg. The efficiency of the process was evalu ated during initial trials in which a thermoplastic polyimide, LaRC-TPI, was applied to T-300, 3K (3000 filament) carbon fiber tow. The physical properties of unidirectional com posite specimens fabricated from this prepreg were measured, and the matrix uniformity and void content of the samples was determined. The results of these evaluations are detailed and discussed.