Environmentally Friendly, On-Aircraft Repair of Polyetheretherketone (PEEK) Thermoplastic Components

It has been demonstrated that the Atomflo handheld plasma tool may be used to activate polyetheretherketone composites for adhesive bonding. After a 30-second oxygen plasma treatment, the lap-shear strength of PEEK laminates bonded with AF-563 adhesive ranged from 5000+/-300 psi in double notch tests (ASTM 3165) to 6300+/-100 psi in single lap tests (ASTM 1002). In both cases, failure was 100% cohesive, indicating that outstanding adhesion had been achieved to the plasma treated surfaces. The Phase II project will focus on developing a prototype commercial tool that may be deployed at U.S. Air Force facilities for the on-aircraft repair of PEEK composites. The plasma process will be optimized to make it fast, effective and reliable. Scarf repairs will be performed on representative aircraft structures. These structures will be thoroughly evaluated for their mechanical strength and durability under environments that simulate aircraft service conditions. The prototype plasma tool, standard operating procedures, and database of mechanical properties of bonded PEEK composites will be delivered to the Air Force at the end of Phase II. This project represents an exciting opportunity for the Air Force to acquire a low-cost, environmentally friendly and field deployable technology for repairing composites on advanced fighter aircraft.