In recent years aromatic polyether ketones have achieved a remarkable position among other thermoplastic polymers because of their unique combination of toughness, stiffness, thermooxidative stability, chemical and solvent resistance, electrical performance, flame retardancy, and retention of physical properties at high temperatures [1]. Perhaps the most important advantage offered by the thermoplastics over new toughened thermosets in composites and adhesive applications is the potential of lower cost manufacturing. However, many problems must be solved before thermoplastics find extensive use in aerospace structural applications.